* [RFC 1/8] locking: Move mutex into kernel/locking/
2013-11-05 12:10 [RFC 0/8] Move locking primitives into kernel/locking/ Peter Zijlstra
@ 2013-11-05 12:10 ` Peter Zijlstra
2013-11-05 20:26 ` Michel Lespinasse
2013-11-05 12:10 ` [RFC 2/8] locking: Move lockdep " Peter Zijlstra
` (9 subsequent siblings)
10 siblings, 1 reply; 23+ messages in thread
From: Peter Zijlstra @ 2013-11-05 12:10 UTC (permalink / raw)
To: torvalds, akpm
Cc: paulmck, oleg, dhowells, willy, tglx, rostedt, airlied,
maarten.lankhorst, walken, linux-kernel, Ingo Molnar,
Peter Zijlstra
[-- Attachment #1: peterz-move-locking-mutex.patch --]
[-- Type: text/plain, Size: 68395 bytes --]
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
---
kernel/Makefile | 6
kernel/locking/Makefile | 9
kernel/locking/mutex-debug.c | 110 ++++
kernel/locking/mutex-debug.h | 55 ++
kernel/locking/mutex.c | 960 +++++++++++++++++++++++++++++++++++++++++++
kernel/locking/mutex.h | 48 ++
kernel/mutex-debug.c | 110 ----
kernel/mutex-debug.h | 55 --
kernel/mutex.c | 960 -------------------------------------------
kernel/mutex.h | 48 --
10 files changed, 1184 insertions(+), 1177 deletions(-)
Index: linux-2.6/kernel/Makefile
===================================================================
--- linux-2.6.orig/kernel/Makefile
+++ linux-2.6/kernel/Makefile
@@ -7,7 +7,7 @@ obj-y = fork.o exec_domain.o panic.o
sysctl.o sysctl_binary.o capability.o ptrace.o timer.o user.o \
signal.o sys.o kmod.o workqueue.o pid.o task_work.o \
extable.o params.o posix-timers.o \
- kthread.o sys_ni.o posix-cpu-timers.o mutex.o \
+ kthread.o sys_ni.o posix-cpu-timers.o \
hrtimer.o rwsem.o nsproxy.o semaphore.o \
notifier.o ksysfs.o cred.o reboot.o \
async.o range.o groups.o lglock.o smpboot.o
@@ -16,13 +16,12 @@ ifdef CONFIG_FUNCTION_TRACER
# Do not trace debug files and internal ftrace files
CFLAGS_REMOVE_lockdep.o = -pg
CFLAGS_REMOVE_lockdep_proc.o = -pg
-CFLAGS_REMOVE_mutex-debug.o = -pg
-CFLAGS_REMOVE_rtmutex-debug.o = -pg
CFLAGS_REMOVE_cgroup-debug.o = -pg
CFLAGS_REMOVE_irq_work.o = -pg
endif
obj-y += sched/
+obj-y += locking/
obj-y += power/
obj-y += printk/
obj-y += cpu/
@@ -34,7 +33,6 @@ obj-$(CONFIG_FREEZER) += freezer.o
obj-$(CONFIG_PROFILING) += profile.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
obj-y += time/
-obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
obj-$(CONFIG_LOCKDEP) += lockdep.o
ifeq ($(CONFIG_PROC_FS),y)
obj-$(CONFIG_LOCKDEP) += lockdep_proc.o
Index: linux-2.6/kernel/locking/Makefile
===================================================================
--- /dev/null
+++ linux-2.6/kernel/locking/Makefile
@@ -0,0 +1,9 @@
+
+obj-y += mutex.o
+
+ifdef CONFIG_FUNCTION_TRACER
+CFLAGS_REMOVE_mutex-debug.o = -pg
+CFLAGS_REMOVE_rtmutex-debug.o = -pg
+endif
+
+obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
Index: linux-2.6/kernel/locking/mutex-debug.c
===================================================================
--- /dev/null
+++ linux-2.6/kernel/locking/mutex-debug.c
@@ -0,0 +1,110 @@
+/*
+ * kernel/mutex-debug.c
+ *
+ * Debugging code for mutexes
+ *
+ * Started by Ingo Molnar:
+ *
+ * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *
+ * lock debugging, locking tree, deadlock detection started by:
+ *
+ * Copyright (C) 2004, LynuxWorks, Inc., Igor Manyilov, Bill Huey
+ * Released under the General Public License (GPL).
+ */
+#include <linux/mutex.h>
+#include <linux/delay.h>
+#include <linux/export.h>
+#include <linux/poison.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/kallsyms.h>
+#include <linux/interrupt.h>
+#include <linux/debug_locks.h>
+
+#include "mutex-debug.h"
+
+/*
+ * Must be called with lock->wait_lock held.
+ */
+void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
+{
+ memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter));
+ waiter->magic = waiter;
+ INIT_LIST_HEAD(&waiter->list);
+}
+
+void debug_mutex_wake_waiter(struct mutex *lock, struct mutex_waiter *waiter)
+{
+ SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock));
+ DEBUG_LOCKS_WARN_ON(list_empty(&lock->wait_list));
+ DEBUG_LOCKS_WARN_ON(waiter->magic != waiter);
+ DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
+}
+
+void debug_mutex_free_waiter(struct mutex_waiter *waiter)
+{
+ DEBUG_LOCKS_WARN_ON(!list_empty(&waiter->list));
+ memset(waiter, MUTEX_DEBUG_FREE, sizeof(*waiter));
+}
+
+void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
+ struct thread_info *ti)
+{
+ SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock));
+
+ /* Mark the current thread as blocked on the lock: */
+ ti->task->blocked_on = waiter;
+}
+
+void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
+ struct thread_info *ti)
+{
+ DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
+ DEBUG_LOCKS_WARN_ON(waiter->task != ti->task);
+ DEBUG_LOCKS_WARN_ON(ti->task->blocked_on != waiter);
+ ti->task->blocked_on = NULL;
+
+ list_del_init(&waiter->list);
+ waiter->task = NULL;
+}
+
+void debug_mutex_unlock(struct mutex *lock)
+{
+ if (unlikely(!debug_locks))
+ return;
+
+ DEBUG_LOCKS_WARN_ON(lock->magic != lock);
+ DEBUG_LOCKS_WARN_ON(lock->owner != current);
+ DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
+ mutex_clear_owner(lock);
+}
+
+void debug_mutex_init(struct mutex *lock, const char *name,
+ struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ /*
+ * Make sure we are not reinitializing a held lock:
+ */
+ debug_check_no_locks_freed((void *)lock, sizeof(*lock));
+ lockdep_init_map(&lock->dep_map, name, key, 0);
+#endif
+ lock->magic = lock;
+}
+
+/***
+ * mutex_destroy - mark a mutex unusable
+ * @lock: the mutex to be destroyed
+ *
+ * This function marks the mutex uninitialized, and any subsequent
+ * use of the mutex is forbidden. The mutex must not be locked when
+ * this function is called.
+ */
+void mutex_destroy(struct mutex *lock)
+{
+ DEBUG_LOCKS_WARN_ON(mutex_is_locked(lock));
+ lock->magic = NULL;
+}
+
+EXPORT_SYMBOL_GPL(mutex_destroy);
Index: linux-2.6/kernel/locking/mutex-debug.h
===================================================================
--- /dev/null
+++ linux-2.6/kernel/locking/mutex-debug.h
@@ -0,0 +1,55 @@
+/*
+ * Mutexes: blocking mutual exclusion locks
+ *
+ * started by Ingo Molnar:
+ *
+ * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *
+ * This file contains mutex debugging related internal declarations,
+ * prototypes and inline functions, for the CONFIG_DEBUG_MUTEXES case.
+ * More details are in kernel/mutex-debug.c.
+ */
+
+/*
+ * This must be called with lock->wait_lock held.
+ */
+extern void debug_mutex_lock_common(struct mutex *lock,
+ struct mutex_waiter *waiter);
+extern void debug_mutex_wake_waiter(struct mutex *lock,
+ struct mutex_waiter *waiter);
+extern void debug_mutex_free_waiter(struct mutex_waiter *waiter);
+extern void debug_mutex_add_waiter(struct mutex *lock,
+ struct mutex_waiter *waiter,
+ struct thread_info *ti);
+extern void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
+ struct thread_info *ti);
+extern void debug_mutex_unlock(struct mutex *lock);
+extern void debug_mutex_init(struct mutex *lock, const char *name,
+ struct lock_class_key *key);
+
+static inline void mutex_set_owner(struct mutex *lock)
+{
+ lock->owner = current;
+}
+
+static inline void mutex_clear_owner(struct mutex *lock)
+{
+ lock->owner = NULL;
+}
+
+#define spin_lock_mutex(lock, flags) \
+ do { \
+ struct mutex *l = container_of(lock, struct mutex, wait_lock); \
+ \
+ DEBUG_LOCKS_WARN_ON(in_interrupt()); \
+ local_irq_save(flags); \
+ arch_spin_lock(&(lock)->rlock.raw_lock);\
+ DEBUG_LOCKS_WARN_ON(l->magic != l); \
+ } while (0)
+
+#define spin_unlock_mutex(lock, flags) \
+ do { \
+ arch_spin_unlock(&(lock)->rlock.raw_lock); \
+ local_irq_restore(flags); \
+ preempt_check_resched(); \
+ } while (0)
Index: linux-2.6/kernel/locking/mutex.c
===================================================================
--- /dev/null
+++ linux-2.6/kernel/locking/mutex.c
@@ -0,0 +1,960 @@
+/*
+ * kernel/mutex.c
+ *
+ * Mutexes: blocking mutual exclusion locks
+ *
+ * Started by Ingo Molnar:
+ *
+ * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *
+ * Many thanks to Arjan van de Ven, Thomas Gleixner, Steven Rostedt and
+ * David Howells for suggestions and improvements.
+ *
+ * - Adaptive spinning for mutexes by Peter Zijlstra. (Ported to mainline
+ * from the -rt tree, where it was originally implemented for rtmutexes
+ * by Steven Rostedt, based on work by Gregory Haskins, Peter Morreale
+ * and Sven Dietrich.
+ *
+ * Also see Documentation/mutex-design.txt.
+ */
+#include <linux/mutex.h>
+#include <linux/ww_mutex.h>
+#include <linux/sched.h>
+#include <linux/sched/rt.h>
+#include <linux/export.h>
+#include <linux/spinlock.h>
+#include <linux/interrupt.h>
+#include <linux/debug_locks.h>
+
+/*
+ * In the DEBUG case we are using the "NULL fastpath" for mutexes,
+ * which forces all calls into the slowpath:
+ */
+#ifdef CONFIG_DEBUG_MUTEXES
+# include "mutex-debug.h"
+# include <asm-generic/mutex-null.h>
+#else
+# include "mutex.h"
+# include <asm/mutex.h>
+#endif
+
+/*
+ * A negative mutex count indicates that waiters are sleeping waiting for the
+ * mutex.
+ */
+#define MUTEX_SHOW_NO_WAITER(mutex) (atomic_read(&(mutex)->count) >= 0)
+
+void
+__mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key)
+{
+ atomic_set(&lock->count, 1);
+ spin_lock_init(&lock->wait_lock);
+ INIT_LIST_HEAD(&lock->wait_list);
+ mutex_clear_owner(lock);
+#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
+ lock->spin_mlock = NULL;
+#endif
+
+ debug_mutex_init(lock, name, key);
+}
+
+EXPORT_SYMBOL(__mutex_init);
+
+#ifndef CONFIG_DEBUG_LOCK_ALLOC
+/*
+ * We split the mutex lock/unlock logic into separate fastpath and
+ * slowpath functions, to reduce the register pressure on the fastpath.
+ * We also put the fastpath first in the kernel image, to make sure the
+ * branch is predicted by the CPU as default-untaken.
+ */
+static __used noinline void __sched
+__mutex_lock_slowpath(atomic_t *lock_count);
+
+/**
+ * mutex_lock - acquire the mutex
+ * @lock: the mutex to be acquired
+ *
+ * Lock the mutex exclusively for this task. If the mutex is not
+ * available right now, it will sleep until it can get it.
+ *
+ * The mutex must later on be released by the same task that
+ * acquired it. Recursive locking is not allowed. The task
+ * may not exit without first unlocking the mutex. Also, kernel
+ * memory where the mutex resides mutex must not be freed with
+ * the mutex still locked. The mutex must first be initialized
+ * (or statically defined) before it can be locked. memset()-ing
+ * the mutex to 0 is not allowed.
+ *
+ * ( The CONFIG_DEBUG_MUTEXES .config option turns on debugging
+ * checks that will enforce the restrictions and will also do
+ * deadlock debugging. )
+ *
+ * This function is similar to (but not equivalent to) down().
+ */
+void __sched mutex_lock(struct mutex *lock)
+{
+ might_sleep();
+ /*
+ * The locking fastpath is the 1->0 transition from
+ * 'unlocked' into 'locked' state.
+ */
+ __mutex_fastpath_lock(&lock->count, __mutex_lock_slowpath);
+ mutex_set_owner(lock);
+}
+
+EXPORT_SYMBOL(mutex_lock);
+#endif
+
+#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
+/*
+ * In order to avoid a stampede of mutex spinners from acquiring the mutex
+ * more or less simultaneously, the spinners need to acquire a MCS lock
+ * first before spinning on the owner field.
+ *
+ * We don't inline mspin_lock() so that perf can correctly account for the
+ * time spent in this lock function.
+ */
+struct mspin_node {
+ struct mspin_node *next ;
+ int locked; /* 1 if lock acquired */
+};
+#define MLOCK(mutex) ((struct mspin_node **)&((mutex)->spin_mlock))
+
+static noinline
+void mspin_lock(struct mspin_node **lock, struct mspin_node *node)
+{
+ struct mspin_node *prev;
+
+ /* Init node */
+ node->locked = 0;
+ node->next = NULL;
+
+ prev = xchg(lock, node);
+ if (likely(prev == NULL)) {
+ /* Lock acquired */
+ node->locked = 1;
+ return;
+ }
+ ACCESS_ONCE(prev->next) = node;
+ smp_wmb();
+ /* Wait until the lock holder passes the lock down */
+ while (!ACCESS_ONCE(node->locked))
+ arch_mutex_cpu_relax();
+}
+
+static void mspin_unlock(struct mspin_node **lock, struct mspin_node *node)
+{
+ struct mspin_node *next = ACCESS_ONCE(node->next);
+
+ if (likely(!next)) {
+ /*
+ * Release the lock by setting it to NULL
+ */
+ if (cmpxchg(lock, node, NULL) == node)
+ return;
+ /* Wait until the next pointer is set */
+ while (!(next = ACCESS_ONCE(node->next)))
+ arch_mutex_cpu_relax();
+ }
+ ACCESS_ONCE(next->locked) = 1;
+ smp_wmb();
+}
+
+/*
+ * Mutex spinning code migrated from kernel/sched/core.c
+ */
+
+static inline bool owner_running(struct mutex *lock, struct task_struct *owner)
+{
+ if (lock->owner != owner)
+ return false;
+
+ /*
+ * Ensure we emit the owner->on_cpu, dereference _after_ checking
+ * lock->owner still matches owner, if that fails, owner might
+ * point to free()d memory, if it still matches, the rcu_read_lock()
+ * ensures the memory stays valid.
+ */
+ barrier();
+
+ return owner->on_cpu;
+}
+
+/*
+ * Look out! "owner" is an entirely speculative pointer
+ * access and not reliable.
+ */
+static noinline
+int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner)
+{
+ rcu_read_lock();
+ while (owner_running(lock, owner)) {
+ if (need_resched())
+ break;
+
+ arch_mutex_cpu_relax();
+ }
+ rcu_read_unlock();
+
+ /*
+ * We break out the loop above on need_resched() and when the
+ * owner changed, which is a sign for heavy contention. Return
+ * success only when lock->owner is NULL.
+ */
+ return lock->owner == NULL;
+}
+
+/*
+ * Initial check for entering the mutex spinning loop
+ */
+static inline int mutex_can_spin_on_owner(struct mutex *lock)
+{
+ struct task_struct *owner;
+ int retval = 1;
+
+ rcu_read_lock();
+ owner = ACCESS_ONCE(lock->owner);
+ if (owner)
+ retval = owner->on_cpu;
+ rcu_read_unlock();
+ /*
+ * if lock->owner is not set, the mutex owner may have just acquired
+ * it and not set the owner yet or the mutex has been released.
+ */
+ return retval;
+}
+#endif
+
+static __used noinline void __sched __mutex_unlock_slowpath(atomic_t *lock_count);
+
+/**
+ * mutex_unlock - release the mutex
+ * @lock: the mutex to be released
+ *
+ * Unlock a mutex that has been locked by this task previously.
+ *
+ * This function must not be used in interrupt context. Unlocking
+ * of a not locked mutex is not allowed.
+ *
+ * This function is similar to (but not equivalent to) up().
+ */
+void __sched mutex_unlock(struct mutex *lock)
+{
+ /*
+ * The unlocking fastpath is the 0->1 transition from 'locked'
+ * into 'unlocked' state:
+ */
+#ifndef CONFIG_DEBUG_MUTEXES
+ /*
+ * When debugging is enabled we must not clear the owner before time,
+ * the slow path will always be taken, and that clears the owner field
+ * after verifying that it was indeed current.
+ */
+ mutex_clear_owner(lock);
+#endif
+ __mutex_fastpath_unlock(&lock->count, __mutex_unlock_slowpath);
+}
+
+EXPORT_SYMBOL(mutex_unlock);
+
+/**
+ * ww_mutex_unlock - release the w/w mutex
+ * @lock: the mutex to be released
+ *
+ * Unlock a mutex that has been locked by this task previously with any of the
+ * ww_mutex_lock* functions (with or without an acquire context). It is
+ * forbidden to release the locks after releasing the acquire context.
+ *
+ * This function must not be used in interrupt context. Unlocking
+ * of a unlocked mutex is not allowed.
+ */
+void __sched ww_mutex_unlock(struct ww_mutex *lock)
+{
+ /*
+ * The unlocking fastpath is the 0->1 transition from 'locked'
+ * into 'unlocked' state:
+ */
+ if (lock->ctx) {
+#ifdef CONFIG_DEBUG_MUTEXES
+ DEBUG_LOCKS_WARN_ON(!lock->ctx->acquired);
+#endif
+ if (lock->ctx->acquired > 0)
+ lock->ctx->acquired--;
+ lock->ctx = NULL;
+ }
+
+#ifndef CONFIG_DEBUG_MUTEXES
+ /*
+ * When debugging is enabled we must not clear the owner before time,
+ * the slow path will always be taken, and that clears the owner field
+ * after verifying that it was indeed current.
+ */
+ mutex_clear_owner(&lock->base);
+#endif
+ __mutex_fastpath_unlock(&lock->base.count, __mutex_unlock_slowpath);
+}
+EXPORT_SYMBOL(ww_mutex_unlock);
+
+static inline int __sched
+__mutex_lock_check_stamp(struct mutex *lock, struct ww_acquire_ctx *ctx)
+{
+ struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
+ struct ww_acquire_ctx *hold_ctx = ACCESS_ONCE(ww->ctx);
+
+ if (!hold_ctx)
+ return 0;
+
+ if (unlikely(ctx == hold_ctx))
+ return -EALREADY;
+
+ if (ctx->stamp - hold_ctx->stamp <= LONG_MAX &&
+ (ctx->stamp != hold_ctx->stamp || ctx > hold_ctx)) {
+#ifdef CONFIG_DEBUG_MUTEXES
+ DEBUG_LOCKS_WARN_ON(ctx->contending_lock);
+ ctx->contending_lock = ww;
+#endif
+ return -EDEADLK;
+ }
+
+ return 0;
+}
+
+static __always_inline void ww_mutex_lock_acquired(struct ww_mutex *ww,
+ struct ww_acquire_ctx *ww_ctx)
+{
+#ifdef CONFIG_DEBUG_MUTEXES
+ /*
+ * If this WARN_ON triggers, you used ww_mutex_lock to acquire,
+ * but released with a normal mutex_unlock in this call.
+ *
+ * This should never happen, always use ww_mutex_unlock.
+ */
+ DEBUG_LOCKS_WARN_ON(ww->ctx);
+
+ /*
+ * Not quite done after calling ww_acquire_done() ?
+ */
+ DEBUG_LOCKS_WARN_ON(ww_ctx->done_acquire);
+
+ if (ww_ctx->contending_lock) {
+ /*
+ * After -EDEADLK you tried to
+ * acquire a different ww_mutex? Bad!
+ */
+ DEBUG_LOCKS_WARN_ON(ww_ctx->contending_lock != ww);
+
+ /*
+ * You called ww_mutex_lock after receiving -EDEADLK,
+ * but 'forgot' to unlock everything else first?
+ */
+ DEBUG_LOCKS_WARN_ON(ww_ctx->acquired > 0);
+ ww_ctx->contending_lock = NULL;
+ }
+
+ /*
+ * Naughty, using a different class will lead to undefined behavior!
+ */
+ DEBUG_LOCKS_WARN_ON(ww_ctx->ww_class != ww->ww_class);
+#endif
+ ww_ctx->acquired++;
+}
+
+/*
+ * after acquiring lock with fastpath or when we lost out in contested
+ * slowpath, set ctx and wake up any waiters so they can recheck.
+ *
+ * This function is never called when CONFIG_DEBUG_LOCK_ALLOC is set,
+ * as the fastpath and opportunistic spinning are disabled in that case.
+ */
+static __always_inline void
+ww_mutex_set_context_fastpath(struct ww_mutex *lock,
+ struct ww_acquire_ctx *ctx)
+{
+ unsigned long flags;
+ struct mutex_waiter *cur;
+
+ ww_mutex_lock_acquired(lock, ctx);
+
+ lock->ctx = ctx;
+
+ /*
+ * The lock->ctx update should be visible on all cores before
+ * the atomic read is done, otherwise contended waiters might be
+ * missed. The contended waiters will either see ww_ctx == NULL
+ * and keep spinning, or it will acquire wait_lock, add itself
+ * to waiter list and sleep.
+ */
+ smp_mb(); /* ^^^ */
+
+ /*
+ * Check if lock is contended, if not there is nobody to wake up
+ */
+ if (likely(atomic_read(&lock->base.count) == 0))
+ return;
+
+ /*
+ * Uh oh, we raced in fastpath, wake up everyone in this case,
+ * so they can see the new lock->ctx.
+ */
+ spin_lock_mutex(&lock->base.wait_lock, flags);
+ list_for_each_entry(cur, &lock->base.wait_list, list) {
+ debug_mutex_wake_waiter(&lock->base, cur);
+ wake_up_process(cur->task);
+ }
+ spin_unlock_mutex(&lock->base.wait_lock, flags);
+}
+
+/*
+ * Lock a mutex (possibly interruptible), slowpath:
+ */
+static __always_inline int __sched
+__mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
+ struct lockdep_map *nest_lock, unsigned long ip,
+ struct ww_acquire_ctx *ww_ctx, const bool use_ww_ctx)
+{
+ struct task_struct *task = current;
+ struct mutex_waiter waiter;
+ unsigned long flags;
+ int ret;
+
+ preempt_disable();
+ mutex_acquire_nest(&lock->dep_map, subclass, 0, nest_lock, ip);
+
+#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
+ /*
+ * Optimistic spinning.
+ *
+ * We try to spin for acquisition when we find that there are no
+ * pending waiters and the lock owner is currently running on a
+ * (different) CPU.
+ *
+ * The rationale is that if the lock owner is running, it is likely to
+ * release the lock soon.
+ *
+ * Since this needs the lock owner, and this mutex implementation
+ * doesn't track the owner atomically in the lock field, we need to
+ * track it non-atomically.
+ *
+ * We can't do this for DEBUG_MUTEXES because that relies on wait_lock
+ * to serialize everything.
+ *
+ * The mutex spinners are queued up using MCS lock so that only one
+ * spinner can compete for the mutex. However, if mutex spinning isn't
+ * going to happen, there is no point in going through the lock/unlock
+ * overhead.
+ */
+ if (!mutex_can_spin_on_owner(lock))
+ goto slowpath;
+
+ for (;;) {
+ struct task_struct *owner;
+ struct mspin_node node;
+
+ if (use_ww_ctx && ww_ctx->acquired > 0) {
+ struct ww_mutex *ww;
+
+ ww = container_of(lock, struct ww_mutex, base);
+ /*
+ * If ww->ctx is set the contents are undefined, only
+ * by acquiring wait_lock there is a guarantee that
+ * they are not invalid when reading.
+ *
+ * As such, when deadlock detection needs to be
+ * performed the optimistic spinning cannot be done.
+ */
+ if (ACCESS_ONCE(ww->ctx))
+ goto slowpath;
+ }
+
+ /*
+ * If there's an owner, wait for it to either
+ * release the lock or go to sleep.
+ */
+ mspin_lock(MLOCK(lock), &node);
+ owner = ACCESS_ONCE(lock->owner);
+ if (owner && !mutex_spin_on_owner(lock, owner)) {
+ mspin_unlock(MLOCK(lock), &node);
+ goto slowpath;
+ }
+
+ if ((atomic_read(&lock->count) == 1) &&
+ (atomic_cmpxchg(&lock->count, 1, 0) == 1)) {
+ lock_acquired(&lock->dep_map, ip);
+ if (use_ww_ctx) {
+ struct ww_mutex *ww;
+ ww = container_of(lock, struct ww_mutex, base);
+
+ ww_mutex_set_context_fastpath(ww, ww_ctx);
+ }
+
+ mutex_set_owner(lock);
+ mspin_unlock(MLOCK(lock), &node);
+ preempt_enable();
+ return 0;
+ }
+ mspin_unlock(MLOCK(lock), &node);
+
+ /*
+ * When there's no owner, we might have preempted between the
+ * owner acquiring the lock and setting the owner field. If
+ * we're an RT task that will live-lock because we won't let
+ * the owner complete.
+ */
+ if (!owner && (need_resched() || rt_task(task)))
+ goto slowpath;
+
+ /*
+ * The cpu_relax() call is a compiler barrier which forces
+ * everything in this loop to be re-loaded. We don't need
+ * memory barriers as we'll eventually observe the right
+ * values at the cost of a few extra spins.
+ */
+ arch_mutex_cpu_relax();
+ }
+slowpath:
+#endif
+ spin_lock_mutex(&lock->wait_lock, flags);
+
+ /* once more, can we acquire the lock? */
+ if (MUTEX_SHOW_NO_WAITER(lock) && (atomic_xchg(&lock->count, 0) == 1))
+ goto skip_wait;
+
+ debug_mutex_lock_common(lock, &waiter);
+ debug_mutex_add_waiter(lock, &waiter, task_thread_info(task));
+
+ /* add waiting tasks to the end of the waitqueue (FIFO): */
+ list_add_tail(&waiter.list, &lock->wait_list);
+ waiter.task = task;
+
+ lock_contended(&lock->dep_map, ip);
+
+ for (;;) {
+ /*
+ * Lets try to take the lock again - this is needed even if
+ * we get here for the first time (shortly after failing to
+ * acquire the lock), to make sure that we get a wakeup once
+ * it's unlocked. Later on, if we sleep, this is the
+ * operation that gives us the lock. We xchg it to -1, so
+ * that when we release the lock, we properly wake up the
+ * other waiters:
+ */
+ if (MUTEX_SHOW_NO_WAITER(lock) &&
+ (atomic_xchg(&lock->count, -1) == 1))
+ break;
+
+ /*
+ * got a signal? (This code gets eliminated in the
+ * TASK_UNINTERRUPTIBLE case.)
+ */
+ if (unlikely(signal_pending_state(state, task))) {
+ ret = -EINTR;
+ goto err;
+ }
+
+ if (use_ww_ctx && ww_ctx->acquired > 0) {
+ ret = __mutex_lock_check_stamp(lock, ww_ctx);
+ if (ret)
+ goto err;
+ }
+
+ __set_task_state(task, state);
+
+ /* didn't get the lock, go to sleep: */
+ spin_unlock_mutex(&lock->wait_lock, flags);
+ schedule_preempt_disabled();
+ spin_lock_mutex(&lock->wait_lock, flags);
+ }
+ mutex_remove_waiter(lock, &waiter, current_thread_info());
+ /* set it to 0 if there are no waiters left: */
+ if (likely(list_empty(&lock->wait_list)))
+ atomic_set(&lock->count, 0);
+ debug_mutex_free_waiter(&waiter);
+
+skip_wait:
+ /* got the lock - cleanup and rejoice! */
+ lock_acquired(&lock->dep_map, ip);
+ mutex_set_owner(lock);
+
+ if (use_ww_ctx) {
+ struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
+ struct mutex_waiter *cur;
+
+ /*
+ * This branch gets optimized out for the common case,
+ * and is only important for ww_mutex_lock.
+ */
+ ww_mutex_lock_acquired(ww, ww_ctx);
+ ww->ctx = ww_ctx;
+
+ /*
+ * Give any possible sleeping processes the chance to wake up,
+ * so they can recheck if they have to back off.
+ */
+ list_for_each_entry(cur, &lock->wait_list, list) {
+ debug_mutex_wake_waiter(lock, cur);
+ wake_up_process(cur->task);
+ }
+ }
+
+ spin_unlock_mutex(&lock->wait_lock, flags);
+ preempt_enable();
+ return 0;
+
+err:
+ mutex_remove_waiter(lock, &waiter, task_thread_info(task));
+ spin_unlock_mutex(&lock->wait_lock, flags);
+ debug_mutex_free_waiter(&waiter);
+ mutex_release(&lock->dep_map, 1, ip);
+ preempt_enable();
+ return ret;
+}
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void __sched
+mutex_lock_nested(struct mutex *lock, unsigned int subclass)
+{
+ might_sleep();
+ __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE,
+ subclass, NULL, _RET_IP_, NULL, 0);
+}
+
+EXPORT_SYMBOL_GPL(mutex_lock_nested);
+
+void __sched
+_mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest)
+{
+ might_sleep();
+ __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE,
+ 0, nest, _RET_IP_, NULL, 0);
+}
+
+EXPORT_SYMBOL_GPL(_mutex_lock_nest_lock);
+
+int __sched
+mutex_lock_killable_nested(struct mutex *lock, unsigned int subclass)
+{
+ might_sleep();
+ return __mutex_lock_common(lock, TASK_KILLABLE,
+ subclass, NULL, _RET_IP_, NULL, 0);
+}
+EXPORT_SYMBOL_GPL(mutex_lock_killable_nested);
+
+int __sched
+mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass)
+{
+ might_sleep();
+ return __mutex_lock_common(lock, TASK_INTERRUPTIBLE,
+ subclass, NULL, _RET_IP_, NULL, 0);
+}
+
+EXPORT_SYMBOL_GPL(mutex_lock_interruptible_nested);
+
+static inline int
+ww_mutex_deadlock_injection(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+#ifdef CONFIG_DEBUG_WW_MUTEX_SLOWPATH
+ unsigned tmp;
+
+ if (ctx->deadlock_inject_countdown-- == 0) {
+ tmp = ctx->deadlock_inject_interval;
+ if (tmp > UINT_MAX/4)
+ tmp = UINT_MAX;
+ else
+ tmp = tmp*2 + tmp + tmp/2;
+
+ ctx->deadlock_inject_interval = tmp;
+ ctx->deadlock_inject_countdown = tmp;
+ ctx->contending_lock = lock;
+
+ ww_mutex_unlock(lock);
+
+ return -EDEADLK;
+ }
+#endif
+
+ return 0;
+}
+
+int __sched
+__ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+ int ret;
+
+ might_sleep();
+ ret = __mutex_lock_common(&lock->base, TASK_UNINTERRUPTIBLE,
+ 0, &ctx->dep_map, _RET_IP_, ctx, 1);
+ if (!ret && ctx->acquired > 1)
+ return ww_mutex_deadlock_injection(lock, ctx);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(__ww_mutex_lock);
+
+int __sched
+__ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+ int ret;
+
+ might_sleep();
+ ret = __mutex_lock_common(&lock->base, TASK_INTERRUPTIBLE,
+ 0, &ctx->dep_map, _RET_IP_, ctx, 1);
+
+ if (!ret && ctx->acquired > 1)
+ return ww_mutex_deadlock_injection(lock, ctx);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(__ww_mutex_lock_interruptible);
+
+#endif
+
+/*
+ * Release the lock, slowpath:
+ */
+static inline void
+__mutex_unlock_common_slowpath(atomic_t *lock_count, int nested)
+{
+ struct mutex *lock = container_of(lock_count, struct mutex, count);
+ unsigned long flags;
+
+ spin_lock_mutex(&lock->wait_lock, flags);
+ mutex_release(&lock->dep_map, nested, _RET_IP_);
+ debug_mutex_unlock(lock);
+
+ /*
+ * some architectures leave the lock unlocked in the fastpath failure
+ * case, others need to leave it locked. In the later case we have to
+ * unlock it here
+ */
+ if (__mutex_slowpath_needs_to_unlock())
+ atomic_set(&lock->count, 1);
+
+ if (!list_empty(&lock->wait_list)) {
+ /* get the first entry from the wait-list: */
+ struct mutex_waiter *waiter =
+ list_entry(lock->wait_list.next,
+ struct mutex_waiter, list);
+
+ debug_mutex_wake_waiter(lock, waiter);
+
+ wake_up_process(waiter->task);
+ }
+
+ spin_unlock_mutex(&lock->wait_lock, flags);
+}
+
+/*
+ * Release the lock, slowpath:
+ */
+static __used noinline void
+__mutex_unlock_slowpath(atomic_t *lock_count)
+{
+ __mutex_unlock_common_slowpath(lock_count, 1);
+}
+
+#ifndef CONFIG_DEBUG_LOCK_ALLOC
+/*
+ * Here come the less common (and hence less performance-critical) APIs:
+ * mutex_lock_interruptible() and mutex_trylock().
+ */
+static noinline int __sched
+__mutex_lock_killable_slowpath(struct mutex *lock);
+
+static noinline int __sched
+__mutex_lock_interruptible_slowpath(struct mutex *lock);
+
+/**
+ * mutex_lock_interruptible - acquire the mutex, interruptible
+ * @lock: the mutex to be acquired
+ *
+ * Lock the mutex like mutex_lock(), and return 0 if the mutex has
+ * been acquired or sleep until the mutex becomes available. If a
+ * signal arrives while waiting for the lock then this function
+ * returns -EINTR.
+ *
+ * This function is similar to (but not equivalent to) down_interruptible().
+ */
+int __sched mutex_lock_interruptible(struct mutex *lock)
+{
+ int ret;
+
+ might_sleep();
+ ret = __mutex_fastpath_lock_retval(&lock->count);
+ if (likely(!ret)) {
+ mutex_set_owner(lock);
+ return 0;
+ } else
+ return __mutex_lock_interruptible_slowpath(lock);
+}
+
+EXPORT_SYMBOL(mutex_lock_interruptible);
+
+int __sched mutex_lock_killable(struct mutex *lock)
+{
+ int ret;
+
+ might_sleep();
+ ret = __mutex_fastpath_lock_retval(&lock->count);
+ if (likely(!ret)) {
+ mutex_set_owner(lock);
+ return 0;
+ } else
+ return __mutex_lock_killable_slowpath(lock);
+}
+EXPORT_SYMBOL(mutex_lock_killable);
+
+static __used noinline void __sched
+__mutex_lock_slowpath(atomic_t *lock_count)
+{
+ struct mutex *lock = container_of(lock_count, struct mutex, count);
+
+ __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0,
+ NULL, _RET_IP_, NULL, 0);
+}
+
+static noinline int __sched
+__mutex_lock_killable_slowpath(struct mutex *lock)
+{
+ return __mutex_lock_common(lock, TASK_KILLABLE, 0,
+ NULL, _RET_IP_, NULL, 0);
+}
+
+static noinline int __sched
+__mutex_lock_interruptible_slowpath(struct mutex *lock)
+{
+ return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, 0,
+ NULL, _RET_IP_, NULL, 0);
+}
+
+static noinline int __sched
+__ww_mutex_lock_slowpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+ return __mutex_lock_common(&lock->base, TASK_UNINTERRUPTIBLE, 0,
+ NULL, _RET_IP_, ctx, 1);
+}
+
+static noinline int __sched
+__ww_mutex_lock_interruptible_slowpath(struct ww_mutex *lock,
+ struct ww_acquire_ctx *ctx)
+{
+ return __mutex_lock_common(&lock->base, TASK_INTERRUPTIBLE, 0,
+ NULL, _RET_IP_, ctx, 1);
+}
+
+#endif
+
+/*
+ * Spinlock based trylock, we take the spinlock and check whether we
+ * can get the lock:
+ */
+static inline int __mutex_trylock_slowpath(atomic_t *lock_count)
+{
+ struct mutex *lock = container_of(lock_count, struct mutex, count);
+ unsigned long flags;
+ int prev;
+
+ spin_lock_mutex(&lock->wait_lock, flags);
+
+ prev = atomic_xchg(&lock->count, -1);
+ if (likely(prev == 1)) {
+ mutex_set_owner(lock);
+ mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+ }
+
+ /* Set it back to 0 if there are no waiters: */
+ if (likely(list_empty(&lock->wait_list)))
+ atomic_set(&lock->count, 0);
+
+ spin_unlock_mutex(&lock->wait_lock, flags);
+
+ return prev == 1;
+}
+
+/**
+ * mutex_trylock - try to acquire the mutex, without waiting
+ * @lock: the mutex to be acquired
+ *
+ * Try to acquire the mutex atomically. Returns 1 if the mutex
+ * has been acquired successfully, and 0 on contention.
+ *
+ * NOTE: this function follows the spin_trylock() convention, so
+ * it is negated from the down_trylock() return values! Be careful
+ * about this when converting semaphore users to mutexes.
+ *
+ * This function must not be used in interrupt context. The
+ * mutex must be released by the same task that acquired it.
+ */
+int __sched mutex_trylock(struct mutex *lock)
+{
+ int ret;
+
+ ret = __mutex_fastpath_trylock(&lock->count, __mutex_trylock_slowpath);
+ if (ret)
+ mutex_set_owner(lock);
+
+ return ret;
+}
+EXPORT_SYMBOL(mutex_trylock);
+
+#ifndef CONFIG_DEBUG_LOCK_ALLOC
+int __sched
+__ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+ int ret;
+
+ might_sleep();
+
+ ret = __mutex_fastpath_lock_retval(&lock->base.count);
+
+ if (likely(!ret)) {
+ ww_mutex_set_context_fastpath(lock, ctx);
+ mutex_set_owner(&lock->base);
+ } else
+ ret = __ww_mutex_lock_slowpath(lock, ctx);
+ return ret;
+}
+EXPORT_SYMBOL(__ww_mutex_lock);
+
+int __sched
+__ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+ int ret;
+
+ might_sleep();
+
+ ret = __mutex_fastpath_lock_retval(&lock->base.count);
+
+ if (likely(!ret)) {
+ ww_mutex_set_context_fastpath(lock, ctx);
+ mutex_set_owner(&lock->base);
+ } else
+ ret = __ww_mutex_lock_interruptible_slowpath(lock, ctx);
+ return ret;
+}
+EXPORT_SYMBOL(__ww_mutex_lock_interruptible);
+
+#endif
+
+/**
+ * atomic_dec_and_mutex_lock - return holding mutex if we dec to 0
+ * @cnt: the atomic which we are to dec
+ * @lock: the mutex to return holding if we dec to 0
+ *
+ * return true and hold lock if we dec to 0, return false otherwise
+ */
+int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock)
+{
+ /* dec if we can't possibly hit 0 */
+ if (atomic_add_unless(cnt, -1, 1))
+ return 0;
+ /* we might hit 0, so take the lock */
+ mutex_lock(lock);
+ if (!atomic_dec_and_test(cnt)) {
+ /* when we actually did the dec, we didn't hit 0 */
+ mutex_unlock(lock);
+ return 0;
+ }
+ /* we hit 0, and we hold the lock */
+ return 1;
+}
+EXPORT_SYMBOL(atomic_dec_and_mutex_lock);
Index: linux-2.6/kernel/locking/mutex.h
===================================================================
--- /dev/null
+++ linux-2.6/kernel/locking/mutex.h
@@ -0,0 +1,48 @@
+/*
+ * Mutexes: blocking mutual exclusion locks
+ *
+ * started by Ingo Molnar:
+ *
+ * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *
+ * This file contains mutex debugging related internal prototypes, for the
+ * !CONFIG_DEBUG_MUTEXES case. Most of them are NOPs:
+ */
+
+#define spin_lock_mutex(lock, flags) \
+ do { spin_lock(lock); (void)(flags); } while (0)
+#define spin_unlock_mutex(lock, flags) \
+ do { spin_unlock(lock); (void)(flags); } while (0)
+#define mutex_remove_waiter(lock, waiter, ti) \
+ __list_del((waiter)->list.prev, (waiter)->list.next)
+
+#ifdef CONFIG_SMP
+static inline void mutex_set_owner(struct mutex *lock)
+{
+ lock->owner = current;
+}
+
+static inline void mutex_clear_owner(struct mutex *lock)
+{
+ lock->owner = NULL;
+}
+#else
+static inline void mutex_set_owner(struct mutex *lock)
+{
+}
+
+static inline void mutex_clear_owner(struct mutex *lock)
+{
+}
+#endif
+
+#define debug_mutex_wake_waiter(lock, waiter) do { } while (0)
+#define debug_mutex_free_waiter(waiter) do { } while (0)
+#define debug_mutex_add_waiter(lock, waiter, ti) do { } while (0)
+#define debug_mutex_unlock(lock) do { } while (0)
+#define debug_mutex_init(lock, name, key) do { } while (0)
+
+static inline void
+debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
+{
+}
Index: linux-2.6/kernel/mutex-debug.c
===================================================================
--- linux-2.6.orig/kernel/mutex-debug.c
+++ /dev/null
@@ -1,110 +0,0 @@
-/*
- * kernel/mutex-debug.c
- *
- * Debugging code for mutexes
- *
- * Started by Ingo Molnar:
- *
- * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- *
- * lock debugging, locking tree, deadlock detection started by:
- *
- * Copyright (C) 2004, LynuxWorks, Inc., Igor Manyilov, Bill Huey
- * Released under the General Public License (GPL).
- */
-#include <linux/mutex.h>
-#include <linux/delay.h>
-#include <linux/export.h>
-#include <linux/poison.h>
-#include <linux/sched.h>
-#include <linux/spinlock.h>
-#include <linux/kallsyms.h>
-#include <linux/interrupt.h>
-#include <linux/debug_locks.h>
-
-#include "mutex-debug.h"
-
-/*
- * Must be called with lock->wait_lock held.
- */
-void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
-{
- memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter));
- waiter->magic = waiter;
- INIT_LIST_HEAD(&waiter->list);
-}
-
-void debug_mutex_wake_waiter(struct mutex *lock, struct mutex_waiter *waiter)
-{
- SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock));
- DEBUG_LOCKS_WARN_ON(list_empty(&lock->wait_list));
- DEBUG_LOCKS_WARN_ON(waiter->magic != waiter);
- DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
-}
-
-void debug_mutex_free_waiter(struct mutex_waiter *waiter)
-{
- DEBUG_LOCKS_WARN_ON(!list_empty(&waiter->list));
- memset(waiter, MUTEX_DEBUG_FREE, sizeof(*waiter));
-}
-
-void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
- struct thread_info *ti)
-{
- SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock));
-
- /* Mark the current thread as blocked on the lock: */
- ti->task->blocked_on = waiter;
-}
-
-void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
- struct thread_info *ti)
-{
- DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
- DEBUG_LOCKS_WARN_ON(waiter->task != ti->task);
- DEBUG_LOCKS_WARN_ON(ti->task->blocked_on != waiter);
- ti->task->blocked_on = NULL;
-
- list_del_init(&waiter->list);
- waiter->task = NULL;
-}
-
-void debug_mutex_unlock(struct mutex *lock)
-{
- if (unlikely(!debug_locks))
- return;
-
- DEBUG_LOCKS_WARN_ON(lock->magic != lock);
- DEBUG_LOCKS_WARN_ON(lock->owner != current);
- DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
- mutex_clear_owner(lock);
-}
-
-void debug_mutex_init(struct mutex *lock, const char *name,
- struct lock_class_key *key)
-{
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
- /*
- * Make sure we are not reinitializing a held lock:
- */
- debug_check_no_locks_freed((void *)lock, sizeof(*lock));
- lockdep_init_map(&lock->dep_map, name, key, 0);
-#endif
- lock->magic = lock;
-}
-
-/***
- * mutex_destroy - mark a mutex unusable
- * @lock: the mutex to be destroyed
- *
- * This function marks the mutex uninitialized, and any subsequent
- * use of the mutex is forbidden. The mutex must not be locked when
- * this function is called.
- */
-void mutex_destroy(struct mutex *lock)
-{
- DEBUG_LOCKS_WARN_ON(mutex_is_locked(lock));
- lock->magic = NULL;
-}
-
-EXPORT_SYMBOL_GPL(mutex_destroy);
Index: linux-2.6/kernel/mutex-debug.h
===================================================================
--- linux-2.6.orig/kernel/mutex-debug.h
+++ /dev/null
@@ -1,55 +0,0 @@
-/*
- * Mutexes: blocking mutual exclusion locks
- *
- * started by Ingo Molnar:
- *
- * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- *
- * This file contains mutex debugging related internal declarations,
- * prototypes and inline functions, for the CONFIG_DEBUG_MUTEXES case.
- * More details are in kernel/mutex-debug.c.
- */
-
-/*
- * This must be called with lock->wait_lock held.
- */
-extern void debug_mutex_lock_common(struct mutex *lock,
- struct mutex_waiter *waiter);
-extern void debug_mutex_wake_waiter(struct mutex *lock,
- struct mutex_waiter *waiter);
-extern void debug_mutex_free_waiter(struct mutex_waiter *waiter);
-extern void debug_mutex_add_waiter(struct mutex *lock,
- struct mutex_waiter *waiter,
- struct thread_info *ti);
-extern void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
- struct thread_info *ti);
-extern void debug_mutex_unlock(struct mutex *lock);
-extern void debug_mutex_init(struct mutex *lock, const char *name,
- struct lock_class_key *key);
-
-static inline void mutex_set_owner(struct mutex *lock)
-{
- lock->owner = current;
-}
-
-static inline void mutex_clear_owner(struct mutex *lock)
-{
- lock->owner = NULL;
-}
-
-#define spin_lock_mutex(lock, flags) \
- do { \
- struct mutex *l = container_of(lock, struct mutex, wait_lock); \
- \
- DEBUG_LOCKS_WARN_ON(in_interrupt()); \
- local_irq_save(flags); \
- arch_spin_lock(&(lock)->rlock.raw_lock);\
- DEBUG_LOCKS_WARN_ON(l->magic != l); \
- } while (0)
-
-#define spin_unlock_mutex(lock, flags) \
- do { \
- arch_spin_unlock(&(lock)->rlock.raw_lock); \
- local_irq_restore(flags); \
- preempt_check_resched(); \
- } while (0)
Index: linux-2.6/kernel/mutex.c
===================================================================
--- linux-2.6.orig/kernel/mutex.c
+++ /dev/null
@@ -1,960 +0,0 @@
-/*
- * kernel/mutex.c
- *
- * Mutexes: blocking mutual exclusion locks
- *
- * Started by Ingo Molnar:
- *
- * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- *
- * Many thanks to Arjan van de Ven, Thomas Gleixner, Steven Rostedt and
- * David Howells for suggestions and improvements.
- *
- * - Adaptive spinning for mutexes by Peter Zijlstra. (Ported to mainline
- * from the -rt tree, where it was originally implemented for rtmutexes
- * by Steven Rostedt, based on work by Gregory Haskins, Peter Morreale
- * and Sven Dietrich.
- *
- * Also see Documentation/mutex-design.txt.
- */
-#include <linux/mutex.h>
-#include <linux/ww_mutex.h>
-#include <linux/sched.h>
-#include <linux/sched/rt.h>
-#include <linux/export.h>
-#include <linux/spinlock.h>
-#include <linux/interrupt.h>
-#include <linux/debug_locks.h>
-
-/*
- * In the DEBUG case we are using the "NULL fastpath" for mutexes,
- * which forces all calls into the slowpath:
- */
-#ifdef CONFIG_DEBUG_MUTEXES
-# include "mutex-debug.h"
-# include <asm-generic/mutex-null.h>
-#else
-# include "mutex.h"
-# include <asm/mutex.h>
-#endif
-
-/*
- * A negative mutex count indicates that waiters are sleeping waiting for the
- * mutex.
- */
-#define MUTEX_SHOW_NO_WAITER(mutex) (atomic_read(&(mutex)->count) >= 0)
-
-void
-__mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key)
-{
- atomic_set(&lock->count, 1);
- spin_lock_init(&lock->wait_lock);
- INIT_LIST_HEAD(&lock->wait_list);
- mutex_clear_owner(lock);
-#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
- lock->spin_mlock = NULL;
-#endif
-
- debug_mutex_init(lock, name, key);
-}
-
-EXPORT_SYMBOL(__mutex_init);
-
-#ifndef CONFIG_DEBUG_LOCK_ALLOC
-/*
- * We split the mutex lock/unlock logic into separate fastpath and
- * slowpath functions, to reduce the register pressure on the fastpath.
- * We also put the fastpath first in the kernel image, to make sure the
- * branch is predicted by the CPU as default-untaken.
- */
-static __used noinline void __sched
-__mutex_lock_slowpath(atomic_t *lock_count);
-
-/**
- * mutex_lock - acquire the mutex
- * @lock: the mutex to be acquired
- *
- * Lock the mutex exclusively for this task. If the mutex is not
- * available right now, it will sleep until it can get it.
- *
- * The mutex must later on be released by the same task that
- * acquired it. Recursive locking is not allowed. The task
- * may not exit without first unlocking the mutex. Also, kernel
- * memory where the mutex resides mutex must not be freed with
- * the mutex still locked. The mutex must first be initialized
- * (or statically defined) before it can be locked. memset()-ing
- * the mutex to 0 is not allowed.
- *
- * ( The CONFIG_DEBUG_MUTEXES .config option turns on debugging
- * checks that will enforce the restrictions and will also do
- * deadlock debugging. )
- *
- * This function is similar to (but not equivalent to) down().
- */
-void __sched mutex_lock(struct mutex *lock)
-{
- might_sleep();
- /*
- * The locking fastpath is the 1->0 transition from
- * 'unlocked' into 'locked' state.
- */
- __mutex_fastpath_lock(&lock->count, __mutex_lock_slowpath);
- mutex_set_owner(lock);
-}
-
-EXPORT_SYMBOL(mutex_lock);
-#endif
-
-#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
-/*
- * In order to avoid a stampede of mutex spinners from acquiring the mutex
- * more or less simultaneously, the spinners need to acquire a MCS lock
- * first before spinning on the owner field.
- *
- * We don't inline mspin_lock() so that perf can correctly account for the
- * time spent in this lock function.
- */
-struct mspin_node {
- struct mspin_node *next ;
- int locked; /* 1 if lock acquired */
-};
-#define MLOCK(mutex) ((struct mspin_node **)&((mutex)->spin_mlock))
-
-static noinline
-void mspin_lock(struct mspin_node **lock, struct mspin_node *node)
-{
- struct mspin_node *prev;
-
- /* Init node */
- node->locked = 0;
- node->next = NULL;
-
- prev = xchg(lock, node);
- if (likely(prev == NULL)) {
- /* Lock acquired */
- node->locked = 1;
- return;
- }
- ACCESS_ONCE(prev->next) = node;
- smp_wmb();
- /* Wait until the lock holder passes the lock down */
- while (!ACCESS_ONCE(node->locked))
- arch_mutex_cpu_relax();
-}
-
-static void mspin_unlock(struct mspin_node **lock, struct mspin_node *node)
-{
- struct mspin_node *next = ACCESS_ONCE(node->next);
-
- if (likely(!next)) {
- /*
- * Release the lock by setting it to NULL
- */
- if (cmpxchg(lock, node, NULL) == node)
- return;
- /* Wait until the next pointer is set */
- while (!(next = ACCESS_ONCE(node->next)))
- arch_mutex_cpu_relax();
- }
- ACCESS_ONCE(next->locked) = 1;
- smp_wmb();
-}
-
-/*
- * Mutex spinning code migrated from kernel/sched/core.c
- */
-
-static inline bool owner_running(struct mutex *lock, struct task_struct *owner)
-{
- if (lock->owner != owner)
- return false;
-
- /*
- * Ensure we emit the owner->on_cpu, dereference _after_ checking
- * lock->owner still matches owner, if that fails, owner might
- * point to free()d memory, if it still matches, the rcu_read_lock()
- * ensures the memory stays valid.
- */
- barrier();
-
- return owner->on_cpu;
-}
-
-/*
- * Look out! "owner" is an entirely speculative pointer
- * access and not reliable.
- */
-static noinline
-int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner)
-{
- rcu_read_lock();
- while (owner_running(lock, owner)) {
- if (need_resched())
- break;
-
- arch_mutex_cpu_relax();
- }
- rcu_read_unlock();
-
- /*
- * We break out the loop above on need_resched() and when the
- * owner changed, which is a sign for heavy contention. Return
- * success only when lock->owner is NULL.
- */
- return lock->owner == NULL;
-}
-
-/*
- * Initial check for entering the mutex spinning loop
- */
-static inline int mutex_can_spin_on_owner(struct mutex *lock)
-{
- struct task_struct *owner;
- int retval = 1;
-
- rcu_read_lock();
- owner = ACCESS_ONCE(lock->owner);
- if (owner)
- retval = owner->on_cpu;
- rcu_read_unlock();
- /*
- * if lock->owner is not set, the mutex owner may have just acquired
- * it and not set the owner yet or the mutex has been released.
- */
- return retval;
-}
-#endif
-
-static __used noinline void __sched __mutex_unlock_slowpath(atomic_t *lock_count);
-
-/**
- * mutex_unlock - release the mutex
- * @lock: the mutex to be released
- *
- * Unlock a mutex that has been locked by this task previously.
- *
- * This function must not be used in interrupt context. Unlocking
- * of a not locked mutex is not allowed.
- *
- * This function is similar to (but not equivalent to) up().
- */
-void __sched mutex_unlock(struct mutex *lock)
-{
- /*
- * The unlocking fastpath is the 0->1 transition from 'locked'
- * into 'unlocked' state:
- */
-#ifndef CONFIG_DEBUG_MUTEXES
- /*
- * When debugging is enabled we must not clear the owner before time,
- * the slow path will always be taken, and that clears the owner field
- * after verifying that it was indeed current.
- */
- mutex_clear_owner(lock);
-#endif
- __mutex_fastpath_unlock(&lock->count, __mutex_unlock_slowpath);
-}
-
-EXPORT_SYMBOL(mutex_unlock);
-
-/**
- * ww_mutex_unlock - release the w/w mutex
- * @lock: the mutex to be released
- *
- * Unlock a mutex that has been locked by this task previously with any of the
- * ww_mutex_lock* functions (with or without an acquire context). It is
- * forbidden to release the locks after releasing the acquire context.
- *
- * This function must not be used in interrupt context. Unlocking
- * of a unlocked mutex is not allowed.
- */
-void __sched ww_mutex_unlock(struct ww_mutex *lock)
-{
- /*
- * The unlocking fastpath is the 0->1 transition from 'locked'
- * into 'unlocked' state:
- */
- if (lock->ctx) {
-#ifdef CONFIG_DEBUG_MUTEXES
- DEBUG_LOCKS_WARN_ON(!lock->ctx->acquired);
-#endif
- if (lock->ctx->acquired > 0)
- lock->ctx->acquired--;
- lock->ctx = NULL;
- }
-
-#ifndef CONFIG_DEBUG_MUTEXES
- /*
- * When debugging is enabled we must not clear the owner before time,
- * the slow path will always be taken, and that clears the owner field
- * after verifying that it was indeed current.
- */
- mutex_clear_owner(&lock->base);
-#endif
- __mutex_fastpath_unlock(&lock->base.count, __mutex_unlock_slowpath);
-}
-EXPORT_SYMBOL(ww_mutex_unlock);
-
-static inline int __sched
-__mutex_lock_check_stamp(struct mutex *lock, struct ww_acquire_ctx *ctx)
-{
- struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
- struct ww_acquire_ctx *hold_ctx = ACCESS_ONCE(ww->ctx);
-
- if (!hold_ctx)
- return 0;
-
- if (unlikely(ctx == hold_ctx))
- return -EALREADY;
-
- if (ctx->stamp - hold_ctx->stamp <= LONG_MAX &&
- (ctx->stamp != hold_ctx->stamp || ctx > hold_ctx)) {
-#ifdef CONFIG_DEBUG_MUTEXES
- DEBUG_LOCKS_WARN_ON(ctx->contending_lock);
- ctx->contending_lock = ww;
-#endif
- return -EDEADLK;
- }
-
- return 0;
-}
-
-static __always_inline void ww_mutex_lock_acquired(struct ww_mutex *ww,
- struct ww_acquire_ctx *ww_ctx)
-{
-#ifdef CONFIG_DEBUG_MUTEXES
- /*
- * If this WARN_ON triggers, you used ww_mutex_lock to acquire,
- * but released with a normal mutex_unlock in this call.
- *
- * This should never happen, always use ww_mutex_unlock.
- */
- DEBUG_LOCKS_WARN_ON(ww->ctx);
-
- /*
- * Not quite done after calling ww_acquire_done() ?
- */
- DEBUG_LOCKS_WARN_ON(ww_ctx->done_acquire);
-
- if (ww_ctx->contending_lock) {
- /*
- * After -EDEADLK you tried to
- * acquire a different ww_mutex? Bad!
- */
- DEBUG_LOCKS_WARN_ON(ww_ctx->contending_lock != ww);
-
- /*
- * You called ww_mutex_lock after receiving -EDEADLK,
- * but 'forgot' to unlock everything else first?
- */
- DEBUG_LOCKS_WARN_ON(ww_ctx->acquired > 0);
- ww_ctx->contending_lock = NULL;
- }
-
- /*
- * Naughty, using a different class will lead to undefined behavior!
- */
- DEBUG_LOCKS_WARN_ON(ww_ctx->ww_class != ww->ww_class);
-#endif
- ww_ctx->acquired++;
-}
-
-/*
- * after acquiring lock with fastpath or when we lost out in contested
- * slowpath, set ctx and wake up any waiters so they can recheck.
- *
- * This function is never called when CONFIG_DEBUG_LOCK_ALLOC is set,
- * as the fastpath and opportunistic spinning are disabled in that case.
- */
-static __always_inline void
-ww_mutex_set_context_fastpath(struct ww_mutex *lock,
- struct ww_acquire_ctx *ctx)
-{
- unsigned long flags;
- struct mutex_waiter *cur;
-
- ww_mutex_lock_acquired(lock, ctx);
-
- lock->ctx = ctx;
-
- /*
- * The lock->ctx update should be visible on all cores before
- * the atomic read is done, otherwise contended waiters might be
- * missed. The contended waiters will either see ww_ctx == NULL
- * and keep spinning, or it will acquire wait_lock, add itself
- * to waiter list and sleep.
- */
- smp_mb(); /* ^^^ */
-
- /*
- * Check if lock is contended, if not there is nobody to wake up
- */
- if (likely(atomic_read(&lock->base.count) == 0))
- return;
-
- /*
- * Uh oh, we raced in fastpath, wake up everyone in this case,
- * so they can see the new lock->ctx.
- */
- spin_lock_mutex(&lock->base.wait_lock, flags);
- list_for_each_entry(cur, &lock->base.wait_list, list) {
- debug_mutex_wake_waiter(&lock->base, cur);
- wake_up_process(cur->task);
- }
- spin_unlock_mutex(&lock->base.wait_lock, flags);
-}
-
-/*
- * Lock a mutex (possibly interruptible), slowpath:
- */
-static __always_inline int __sched
-__mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
- struct lockdep_map *nest_lock, unsigned long ip,
- struct ww_acquire_ctx *ww_ctx, const bool use_ww_ctx)
-{
- struct task_struct *task = current;
- struct mutex_waiter waiter;
- unsigned long flags;
- int ret;
-
- preempt_disable();
- mutex_acquire_nest(&lock->dep_map, subclass, 0, nest_lock, ip);
-
-#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
- /*
- * Optimistic spinning.
- *
- * We try to spin for acquisition when we find that there are no
- * pending waiters and the lock owner is currently running on a
- * (different) CPU.
- *
- * The rationale is that if the lock owner is running, it is likely to
- * release the lock soon.
- *
- * Since this needs the lock owner, and this mutex implementation
- * doesn't track the owner atomically in the lock field, we need to
- * track it non-atomically.
- *
- * We can't do this for DEBUG_MUTEXES because that relies on wait_lock
- * to serialize everything.
- *
- * The mutex spinners are queued up using MCS lock so that only one
- * spinner can compete for the mutex. However, if mutex spinning isn't
- * going to happen, there is no point in going through the lock/unlock
- * overhead.
- */
- if (!mutex_can_spin_on_owner(lock))
- goto slowpath;
-
- for (;;) {
- struct task_struct *owner;
- struct mspin_node node;
-
- if (use_ww_ctx && ww_ctx->acquired > 0) {
- struct ww_mutex *ww;
-
- ww = container_of(lock, struct ww_mutex, base);
- /*
- * If ww->ctx is set the contents are undefined, only
- * by acquiring wait_lock there is a guarantee that
- * they are not invalid when reading.
- *
- * As such, when deadlock detection needs to be
- * performed the optimistic spinning cannot be done.
- */
- if (ACCESS_ONCE(ww->ctx))
- goto slowpath;
- }
-
- /*
- * If there's an owner, wait for it to either
- * release the lock or go to sleep.
- */
- mspin_lock(MLOCK(lock), &node);
- owner = ACCESS_ONCE(lock->owner);
- if (owner && !mutex_spin_on_owner(lock, owner)) {
- mspin_unlock(MLOCK(lock), &node);
- goto slowpath;
- }
-
- if ((atomic_read(&lock->count) == 1) &&
- (atomic_cmpxchg(&lock->count, 1, 0) == 1)) {
- lock_acquired(&lock->dep_map, ip);
- if (use_ww_ctx) {
- struct ww_mutex *ww;
- ww = container_of(lock, struct ww_mutex, base);
-
- ww_mutex_set_context_fastpath(ww, ww_ctx);
- }
-
- mutex_set_owner(lock);
- mspin_unlock(MLOCK(lock), &node);
- preempt_enable();
- return 0;
- }
- mspin_unlock(MLOCK(lock), &node);
-
- /*
- * When there's no owner, we might have preempted between the
- * owner acquiring the lock and setting the owner field. If
- * we're an RT task that will live-lock because we won't let
- * the owner complete.
- */
- if (!owner && (need_resched() || rt_task(task)))
- goto slowpath;
-
- /*
- * The cpu_relax() call is a compiler barrier which forces
- * everything in this loop to be re-loaded. We don't need
- * memory barriers as we'll eventually observe the right
- * values at the cost of a few extra spins.
- */
- arch_mutex_cpu_relax();
- }
-slowpath:
-#endif
- spin_lock_mutex(&lock->wait_lock, flags);
-
- /* once more, can we acquire the lock? */
- if (MUTEX_SHOW_NO_WAITER(lock) && (atomic_xchg(&lock->count, 0) == 1))
- goto skip_wait;
-
- debug_mutex_lock_common(lock, &waiter);
- debug_mutex_add_waiter(lock, &waiter, task_thread_info(task));
-
- /* add waiting tasks to the end of the waitqueue (FIFO): */
- list_add_tail(&waiter.list, &lock->wait_list);
- waiter.task = task;
-
- lock_contended(&lock->dep_map, ip);
-
- for (;;) {
- /*
- * Lets try to take the lock again - this is needed even if
- * we get here for the first time (shortly after failing to
- * acquire the lock), to make sure that we get a wakeup once
- * it's unlocked. Later on, if we sleep, this is the
- * operation that gives us the lock. We xchg it to -1, so
- * that when we release the lock, we properly wake up the
- * other waiters:
- */
- if (MUTEX_SHOW_NO_WAITER(lock) &&
- (atomic_xchg(&lock->count, -1) == 1))
- break;
-
- /*
- * got a signal? (This code gets eliminated in the
- * TASK_UNINTERRUPTIBLE case.)
- */
- if (unlikely(signal_pending_state(state, task))) {
- ret = -EINTR;
- goto err;
- }
-
- if (use_ww_ctx && ww_ctx->acquired > 0) {
- ret = __mutex_lock_check_stamp(lock, ww_ctx);
- if (ret)
- goto err;
- }
-
- __set_task_state(task, state);
-
- /* didn't get the lock, go to sleep: */
- spin_unlock_mutex(&lock->wait_lock, flags);
- schedule_preempt_disabled();
- spin_lock_mutex(&lock->wait_lock, flags);
- }
- mutex_remove_waiter(lock, &waiter, current_thread_info());
- /* set it to 0 if there are no waiters left: */
- if (likely(list_empty(&lock->wait_list)))
- atomic_set(&lock->count, 0);
- debug_mutex_free_waiter(&waiter);
-
-skip_wait:
- /* got the lock - cleanup and rejoice! */
- lock_acquired(&lock->dep_map, ip);
- mutex_set_owner(lock);
-
- if (use_ww_ctx) {
- struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
- struct mutex_waiter *cur;
-
- /*
- * This branch gets optimized out for the common case,
- * and is only important for ww_mutex_lock.
- */
- ww_mutex_lock_acquired(ww, ww_ctx);
- ww->ctx = ww_ctx;
-
- /*
- * Give any possible sleeping processes the chance to wake up,
- * so they can recheck if they have to back off.
- */
- list_for_each_entry(cur, &lock->wait_list, list) {
- debug_mutex_wake_waiter(lock, cur);
- wake_up_process(cur->task);
- }
- }
-
- spin_unlock_mutex(&lock->wait_lock, flags);
- preempt_enable();
- return 0;
-
-err:
- mutex_remove_waiter(lock, &waiter, task_thread_info(task));
- spin_unlock_mutex(&lock->wait_lock, flags);
- debug_mutex_free_waiter(&waiter);
- mutex_release(&lock->dep_map, 1, ip);
- preempt_enable();
- return ret;
-}
-
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-void __sched
-mutex_lock_nested(struct mutex *lock, unsigned int subclass)
-{
- might_sleep();
- __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE,
- subclass, NULL, _RET_IP_, NULL, 0);
-}
-
-EXPORT_SYMBOL_GPL(mutex_lock_nested);
-
-void __sched
-_mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest)
-{
- might_sleep();
- __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE,
- 0, nest, _RET_IP_, NULL, 0);
-}
-
-EXPORT_SYMBOL_GPL(_mutex_lock_nest_lock);
-
-int __sched
-mutex_lock_killable_nested(struct mutex *lock, unsigned int subclass)
-{
- might_sleep();
- return __mutex_lock_common(lock, TASK_KILLABLE,
- subclass, NULL, _RET_IP_, NULL, 0);
-}
-EXPORT_SYMBOL_GPL(mutex_lock_killable_nested);
-
-int __sched
-mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass)
-{
- might_sleep();
- return __mutex_lock_common(lock, TASK_INTERRUPTIBLE,
- subclass, NULL, _RET_IP_, NULL, 0);
-}
-
-EXPORT_SYMBOL_GPL(mutex_lock_interruptible_nested);
-
-static inline int
-ww_mutex_deadlock_injection(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
-{
-#ifdef CONFIG_DEBUG_WW_MUTEX_SLOWPATH
- unsigned tmp;
-
- if (ctx->deadlock_inject_countdown-- == 0) {
- tmp = ctx->deadlock_inject_interval;
- if (tmp > UINT_MAX/4)
- tmp = UINT_MAX;
- else
- tmp = tmp*2 + tmp + tmp/2;
-
- ctx->deadlock_inject_interval = tmp;
- ctx->deadlock_inject_countdown = tmp;
- ctx->contending_lock = lock;
-
- ww_mutex_unlock(lock);
-
- return -EDEADLK;
- }
-#endif
-
- return 0;
-}
-
-int __sched
-__ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
-{
- int ret;
-
- might_sleep();
- ret = __mutex_lock_common(&lock->base, TASK_UNINTERRUPTIBLE,
- 0, &ctx->dep_map, _RET_IP_, ctx, 1);
- if (!ret && ctx->acquired > 1)
- return ww_mutex_deadlock_injection(lock, ctx);
-
- return ret;
-}
-EXPORT_SYMBOL_GPL(__ww_mutex_lock);
-
-int __sched
-__ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
-{
- int ret;
-
- might_sleep();
- ret = __mutex_lock_common(&lock->base, TASK_INTERRUPTIBLE,
- 0, &ctx->dep_map, _RET_IP_, ctx, 1);
-
- if (!ret && ctx->acquired > 1)
- return ww_mutex_deadlock_injection(lock, ctx);
-
- return ret;
-}
-EXPORT_SYMBOL_GPL(__ww_mutex_lock_interruptible);
-
-#endif
-
-/*
- * Release the lock, slowpath:
- */
-static inline void
-__mutex_unlock_common_slowpath(atomic_t *lock_count, int nested)
-{
- struct mutex *lock = container_of(lock_count, struct mutex, count);
- unsigned long flags;
-
- spin_lock_mutex(&lock->wait_lock, flags);
- mutex_release(&lock->dep_map, nested, _RET_IP_);
- debug_mutex_unlock(lock);
-
- /*
- * some architectures leave the lock unlocked in the fastpath failure
- * case, others need to leave it locked. In the later case we have to
- * unlock it here
- */
- if (__mutex_slowpath_needs_to_unlock())
- atomic_set(&lock->count, 1);
-
- if (!list_empty(&lock->wait_list)) {
- /* get the first entry from the wait-list: */
- struct mutex_waiter *waiter =
- list_entry(lock->wait_list.next,
- struct mutex_waiter, list);
-
- debug_mutex_wake_waiter(lock, waiter);
-
- wake_up_process(waiter->task);
- }
-
- spin_unlock_mutex(&lock->wait_lock, flags);
-}
-
-/*
- * Release the lock, slowpath:
- */
-static __used noinline void
-__mutex_unlock_slowpath(atomic_t *lock_count)
-{
- __mutex_unlock_common_slowpath(lock_count, 1);
-}
-
-#ifndef CONFIG_DEBUG_LOCK_ALLOC
-/*
- * Here come the less common (and hence less performance-critical) APIs:
- * mutex_lock_interruptible() and mutex_trylock().
- */
-static noinline int __sched
-__mutex_lock_killable_slowpath(struct mutex *lock);
-
-static noinline int __sched
-__mutex_lock_interruptible_slowpath(struct mutex *lock);
-
-/**
- * mutex_lock_interruptible - acquire the mutex, interruptible
- * @lock: the mutex to be acquired
- *
- * Lock the mutex like mutex_lock(), and return 0 if the mutex has
- * been acquired or sleep until the mutex becomes available. If a
- * signal arrives while waiting for the lock then this function
- * returns -EINTR.
- *
- * This function is similar to (but not equivalent to) down_interruptible().
- */
-int __sched mutex_lock_interruptible(struct mutex *lock)
-{
- int ret;
-
- might_sleep();
- ret = __mutex_fastpath_lock_retval(&lock->count);
- if (likely(!ret)) {
- mutex_set_owner(lock);
- return 0;
- } else
- return __mutex_lock_interruptible_slowpath(lock);
-}
-
-EXPORT_SYMBOL(mutex_lock_interruptible);
-
-int __sched mutex_lock_killable(struct mutex *lock)
-{
- int ret;
-
- might_sleep();
- ret = __mutex_fastpath_lock_retval(&lock->count);
- if (likely(!ret)) {
- mutex_set_owner(lock);
- return 0;
- } else
- return __mutex_lock_killable_slowpath(lock);
-}
-EXPORT_SYMBOL(mutex_lock_killable);
-
-static __used noinline void __sched
-__mutex_lock_slowpath(atomic_t *lock_count)
-{
- struct mutex *lock = container_of(lock_count, struct mutex, count);
-
- __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0,
- NULL, _RET_IP_, NULL, 0);
-}
-
-static noinline int __sched
-__mutex_lock_killable_slowpath(struct mutex *lock)
-{
- return __mutex_lock_common(lock, TASK_KILLABLE, 0,
- NULL, _RET_IP_, NULL, 0);
-}
-
-static noinline int __sched
-__mutex_lock_interruptible_slowpath(struct mutex *lock)
-{
- return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, 0,
- NULL, _RET_IP_, NULL, 0);
-}
-
-static noinline int __sched
-__ww_mutex_lock_slowpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
-{
- return __mutex_lock_common(&lock->base, TASK_UNINTERRUPTIBLE, 0,
- NULL, _RET_IP_, ctx, 1);
-}
-
-static noinline int __sched
-__ww_mutex_lock_interruptible_slowpath(struct ww_mutex *lock,
- struct ww_acquire_ctx *ctx)
-{
- return __mutex_lock_common(&lock->base, TASK_INTERRUPTIBLE, 0,
- NULL, _RET_IP_, ctx, 1);
-}
-
-#endif
-
-/*
- * Spinlock based trylock, we take the spinlock and check whether we
- * can get the lock:
- */
-static inline int __mutex_trylock_slowpath(atomic_t *lock_count)
-{
- struct mutex *lock = container_of(lock_count, struct mutex, count);
- unsigned long flags;
- int prev;
-
- spin_lock_mutex(&lock->wait_lock, flags);
-
- prev = atomic_xchg(&lock->count, -1);
- if (likely(prev == 1)) {
- mutex_set_owner(lock);
- mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
- }
-
- /* Set it back to 0 if there are no waiters: */
- if (likely(list_empty(&lock->wait_list)))
- atomic_set(&lock->count, 0);
-
- spin_unlock_mutex(&lock->wait_lock, flags);
-
- return prev == 1;
-}
-
-/**
- * mutex_trylock - try to acquire the mutex, without waiting
- * @lock: the mutex to be acquired
- *
- * Try to acquire the mutex atomically. Returns 1 if the mutex
- * has been acquired successfully, and 0 on contention.
- *
- * NOTE: this function follows the spin_trylock() convention, so
- * it is negated from the down_trylock() return values! Be careful
- * about this when converting semaphore users to mutexes.
- *
- * This function must not be used in interrupt context. The
- * mutex must be released by the same task that acquired it.
- */
-int __sched mutex_trylock(struct mutex *lock)
-{
- int ret;
-
- ret = __mutex_fastpath_trylock(&lock->count, __mutex_trylock_slowpath);
- if (ret)
- mutex_set_owner(lock);
-
- return ret;
-}
-EXPORT_SYMBOL(mutex_trylock);
-
-#ifndef CONFIG_DEBUG_LOCK_ALLOC
-int __sched
-__ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
-{
- int ret;
-
- might_sleep();
-
- ret = __mutex_fastpath_lock_retval(&lock->base.count);
-
- if (likely(!ret)) {
- ww_mutex_set_context_fastpath(lock, ctx);
- mutex_set_owner(&lock->base);
- } else
- ret = __ww_mutex_lock_slowpath(lock, ctx);
- return ret;
-}
-EXPORT_SYMBOL(__ww_mutex_lock);
-
-int __sched
-__ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
-{
- int ret;
-
- might_sleep();
-
- ret = __mutex_fastpath_lock_retval(&lock->base.count);
-
- if (likely(!ret)) {
- ww_mutex_set_context_fastpath(lock, ctx);
- mutex_set_owner(&lock->base);
- } else
- ret = __ww_mutex_lock_interruptible_slowpath(lock, ctx);
- return ret;
-}
-EXPORT_SYMBOL(__ww_mutex_lock_interruptible);
-
-#endif
-
-/**
- * atomic_dec_and_mutex_lock - return holding mutex if we dec to 0
- * @cnt: the atomic which we are to dec
- * @lock: the mutex to return holding if we dec to 0
- *
- * return true and hold lock if we dec to 0, return false otherwise
- */
-int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock)
-{
- /* dec if we can't possibly hit 0 */
- if (atomic_add_unless(cnt, -1, 1))
- return 0;
- /* we might hit 0, so take the lock */
- mutex_lock(lock);
- if (!atomic_dec_and_test(cnt)) {
- /* when we actually did the dec, we didn't hit 0 */
- mutex_unlock(lock);
- return 0;
- }
- /* we hit 0, and we hold the lock */
- return 1;
-}
-EXPORT_SYMBOL(atomic_dec_and_mutex_lock);
Index: linux-2.6/kernel/mutex.h
===================================================================
--- linux-2.6.orig/kernel/mutex.h
+++ /dev/null
@@ -1,48 +0,0 @@
-/*
- * Mutexes: blocking mutual exclusion locks
- *
- * started by Ingo Molnar:
- *
- * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- *
- * This file contains mutex debugging related internal prototypes, for the
- * !CONFIG_DEBUG_MUTEXES case. Most of them are NOPs:
- */
-
-#define spin_lock_mutex(lock, flags) \
- do { spin_lock(lock); (void)(flags); } while (0)
-#define spin_unlock_mutex(lock, flags) \
- do { spin_unlock(lock); (void)(flags); } while (0)
-#define mutex_remove_waiter(lock, waiter, ti) \
- __list_del((waiter)->list.prev, (waiter)->list.next)
-
-#ifdef CONFIG_SMP
-static inline void mutex_set_owner(struct mutex *lock)
-{
- lock->owner = current;
-}
-
-static inline void mutex_clear_owner(struct mutex *lock)
-{
- lock->owner = NULL;
-}
-#else
-static inline void mutex_set_owner(struct mutex *lock)
-{
-}
-
-static inline void mutex_clear_owner(struct mutex *lock)
-{
-}
-#endif
-
-#define debug_mutex_wake_waiter(lock, waiter) do { } while (0)
-#define debug_mutex_free_waiter(waiter) do { } while (0)
-#define debug_mutex_add_waiter(lock, waiter, ti) do { } while (0)
-#define debug_mutex_unlock(lock) do { } while (0)
-#define debug_mutex_init(lock, name, key) do { } while (0)
-
-static inline void
-debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
-{
-}
^ permalink raw reply [flat|nested] 23+ messages in thread* [RFC 2/8] locking: Move lockdep into kernel/locking/
2013-11-05 12:10 [RFC 0/8] Move locking primitives into kernel/locking/ Peter Zijlstra
2013-11-05 12:10 ` [RFC 1/8] locking: Move mutex " Peter Zijlstra
@ 2013-11-05 12:10 ` Peter Zijlstra
2013-11-05 12:10 ` [RFC 3/8] locking: Move spinlock " Peter Zijlstra
` (8 subsequent siblings)
10 siblings, 0 replies; 23+ messages in thread
From: Peter Zijlstra @ 2013-11-05 12:10 UTC (permalink / raw)
To: torvalds, akpm
Cc: paulmck, oleg, dhowells, willy, tglx, rostedt, airlied,
maarten.lankhorst, walken, linux-kernel, Ingo Molnar,
Peter Zijlstra
[-- Attachment #1: peterz-move-locking-lockdep.patch --]
[-- Type: text/plain, Size: 271199 bytes --]
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
---
kernel/Makefile | 6
kernel/lockdep.c | 4257 -------------------------------------
kernel/lockdep_internals.h | 170 -
kernel/lockdep_proc.c | 683 -----
kernel/lockdep_states.h | 9
kernel/locking/Makefile | 6
kernel/locking/lockdep.c | 4257 +++++++++++++++++++++++++++++++++++++
kernel/locking/lockdep_internals.h | 170 +
kernel/locking/lockdep_proc.c | 683 +++++
kernel/locking/lockdep_states.h | 9
10 files changed, 5125 insertions(+), 5125 deletions(-)
Index: linux-2.6/kernel/Makefile
===================================================================
--- linux-2.6.orig/kernel/Makefile
+++ linux-2.6/kernel/Makefile
@@ -14,8 +14,6 @@ obj-y = fork.o exec_domain.o panic.o
ifdef CONFIG_FUNCTION_TRACER
# Do not trace debug files and internal ftrace files
-CFLAGS_REMOVE_lockdep.o = -pg
-CFLAGS_REMOVE_lockdep_proc.o = -pg
CFLAGS_REMOVE_cgroup-debug.o = -pg
CFLAGS_REMOVE_irq_work.o = -pg
endif
@@ -33,10 +31,6 @@ obj-$(CONFIG_FREEZER) += freezer.o
obj-$(CONFIG_PROFILING) += profile.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
obj-y += time/
-obj-$(CONFIG_LOCKDEP) += lockdep.o
-ifeq ($(CONFIG_PROC_FS),y)
-obj-$(CONFIG_LOCKDEP) += lockdep_proc.o
-endif
obj-$(CONFIG_FUTEX) += futex.o
ifeq ($(CONFIG_COMPAT),y)
obj-$(CONFIG_FUTEX) += futex_compat.o
Index: linux-2.6/kernel/lockdep.c
===================================================================
--- linux-2.6.orig/kernel/lockdep.c
+++ /dev/null
@@ -1,4257 +0,0 @@
-/*
- * kernel/lockdep.c
- *
- * Runtime locking correctness validator
- *
- * Started by Ingo Molnar:
- *
- * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
- *
- * this code maps all the lock dependencies as they occur in a live kernel
- * and will warn about the following classes of locking bugs:
- *
- * - lock inversion scenarios
- * - circular lock dependencies
- * - hardirq/softirq safe/unsafe locking bugs
- *
- * Bugs are reported even if the current locking scenario does not cause
- * any deadlock at this point.
- *
- * I.e. if anytime in the past two locks were taken in a different order,
- * even if it happened for another task, even if those were different
- * locks (but of the same class as this lock), this code will detect it.
- *
- * Thanks to Arjan van de Ven for coming up with the initial idea of
- * mapping lock dependencies runtime.
- */
-#define DISABLE_BRANCH_PROFILING
-#include <linux/mutex.h>
-#include <linux/sched.h>
-#include <linux/delay.h>
-#include <linux/module.h>
-#include <linux/proc_fs.h>
-#include <linux/seq_file.h>
-#include <linux/spinlock.h>
-#include <linux/kallsyms.h>
-#include <linux/interrupt.h>
-#include <linux/stacktrace.h>
-#include <linux/debug_locks.h>
-#include <linux/irqflags.h>
-#include <linux/utsname.h>
-#include <linux/hash.h>
-#include <linux/ftrace.h>
-#include <linux/stringify.h>
-#include <linux/bitops.h>
-#include <linux/gfp.h>
-#include <linux/kmemcheck.h>
-
-#include <asm/sections.h>
-
-#include "lockdep_internals.h"
-
-#define CREATE_TRACE_POINTS
-#include <trace/events/lock.h>
-
-#ifdef CONFIG_PROVE_LOCKING
-int prove_locking = 1;
-module_param(prove_locking, int, 0644);
-#else
-#define prove_locking 0
-#endif
-
-#ifdef CONFIG_LOCK_STAT
-int lock_stat = 1;
-module_param(lock_stat, int, 0644);
-#else
-#define lock_stat 0
-#endif
-
-/*
- * lockdep_lock: protects the lockdep graph, the hashes and the
- * class/list/hash allocators.
- *
- * This is one of the rare exceptions where it's justified
- * to use a raw spinlock - we really dont want the spinlock
- * code to recurse back into the lockdep code...
- */
-static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
-
-static int graph_lock(void)
-{
- arch_spin_lock(&lockdep_lock);
- /*
- * Make sure that if another CPU detected a bug while
- * walking the graph we dont change it (while the other
- * CPU is busy printing out stuff with the graph lock
- * dropped already)
- */
- if (!debug_locks) {
- arch_spin_unlock(&lockdep_lock);
- return 0;
- }
- /* prevent any recursions within lockdep from causing deadlocks */
- current->lockdep_recursion++;
- return 1;
-}
-
-static inline int graph_unlock(void)
-{
- if (debug_locks && !arch_spin_is_locked(&lockdep_lock)) {
- /*
- * The lockdep graph lock isn't locked while we expect it to
- * be, we're confused now, bye!
- */
- return DEBUG_LOCKS_WARN_ON(1);
- }
-
- current->lockdep_recursion--;
- arch_spin_unlock(&lockdep_lock);
- return 0;
-}
-
-/*
- * Turn lock debugging off and return with 0 if it was off already,
- * and also release the graph lock:
- */
-static inline int debug_locks_off_graph_unlock(void)
-{
- int ret = debug_locks_off();
-
- arch_spin_unlock(&lockdep_lock);
-
- return ret;
-}
-
-static int lockdep_initialized;
-
-unsigned long nr_list_entries;
-static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
-
-/*
- * All data structures here are protected by the global debug_lock.
- *
- * Mutex key structs only get allocated, once during bootup, and never
- * get freed - this significantly simplifies the debugging code.
- */
-unsigned long nr_lock_classes;
-static struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
-
-static inline struct lock_class *hlock_class(struct held_lock *hlock)
-{
- if (!hlock->class_idx) {
- /*
- * Someone passed in garbage, we give up.
- */
- DEBUG_LOCKS_WARN_ON(1);
- return NULL;
- }
- return lock_classes + hlock->class_idx - 1;
-}
-
-#ifdef CONFIG_LOCK_STAT
-static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS],
- cpu_lock_stats);
-
-static inline u64 lockstat_clock(void)
-{
- return local_clock();
-}
-
-static int lock_point(unsigned long points[], unsigned long ip)
-{
- int i;
-
- for (i = 0; i < LOCKSTAT_POINTS; i++) {
- if (points[i] == 0) {
- points[i] = ip;
- break;
- }
- if (points[i] == ip)
- break;
- }
-
- return i;
-}
-
-static void lock_time_inc(struct lock_time *lt, u64 time)
-{
- if (time > lt->max)
- lt->max = time;
-
- if (time < lt->min || !lt->nr)
- lt->min = time;
-
- lt->total += time;
- lt->nr++;
-}
-
-static inline void lock_time_add(struct lock_time *src, struct lock_time *dst)
-{
- if (!src->nr)
- return;
-
- if (src->max > dst->max)
- dst->max = src->max;
-
- if (src->min < dst->min || !dst->nr)
- dst->min = src->min;
-
- dst->total += src->total;
- dst->nr += src->nr;
-}
-
-struct lock_class_stats lock_stats(struct lock_class *class)
-{
- struct lock_class_stats stats;
- int cpu, i;
-
- memset(&stats, 0, sizeof(struct lock_class_stats));
- for_each_possible_cpu(cpu) {
- struct lock_class_stats *pcs =
- &per_cpu(cpu_lock_stats, cpu)[class - lock_classes];
-
- for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++)
- stats.contention_point[i] += pcs->contention_point[i];
-
- for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++)
- stats.contending_point[i] += pcs->contending_point[i];
-
- lock_time_add(&pcs->read_waittime, &stats.read_waittime);
- lock_time_add(&pcs->write_waittime, &stats.write_waittime);
-
- lock_time_add(&pcs->read_holdtime, &stats.read_holdtime);
- lock_time_add(&pcs->write_holdtime, &stats.write_holdtime);
-
- for (i = 0; i < ARRAY_SIZE(stats.bounces); i++)
- stats.bounces[i] += pcs->bounces[i];
- }
-
- return stats;
-}
-
-void clear_lock_stats(struct lock_class *class)
-{
- int cpu;
-
- for_each_possible_cpu(cpu) {
- struct lock_class_stats *cpu_stats =
- &per_cpu(cpu_lock_stats, cpu)[class - lock_classes];
-
- memset(cpu_stats, 0, sizeof(struct lock_class_stats));
- }
- memset(class->contention_point, 0, sizeof(class->contention_point));
- memset(class->contending_point, 0, sizeof(class->contending_point));
-}
-
-static struct lock_class_stats *get_lock_stats(struct lock_class *class)
-{
- return &get_cpu_var(cpu_lock_stats)[class - lock_classes];
-}
-
-static void put_lock_stats(struct lock_class_stats *stats)
-{
- put_cpu_var(cpu_lock_stats);
-}
-
-static void lock_release_holdtime(struct held_lock *hlock)
-{
- struct lock_class_stats *stats;
- u64 holdtime;
-
- if (!lock_stat)
- return;
-
- holdtime = lockstat_clock() - hlock->holdtime_stamp;
-
- stats = get_lock_stats(hlock_class(hlock));
- if (hlock->read)
- lock_time_inc(&stats->read_holdtime, holdtime);
- else
- lock_time_inc(&stats->write_holdtime, holdtime);
- put_lock_stats(stats);
-}
-#else
-static inline void lock_release_holdtime(struct held_lock *hlock)
-{
-}
-#endif
-
-/*
- * We keep a global list of all lock classes. The list only grows,
- * never shrinks. The list is only accessed with the lockdep
- * spinlock lock held.
- */
-LIST_HEAD(all_lock_classes);
-
-/*
- * The lockdep classes are in a hash-table as well, for fast lookup:
- */
-#define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1)
-#define CLASSHASH_SIZE (1UL << CLASSHASH_BITS)
-#define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS)
-#define classhashentry(key) (classhash_table + __classhashfn((key)))
-
-static struct list_head classhash_table[CLASSHASH_SIZE];
-
-/*
- * We put the lock dependency chains into a hash-table as well, to cache
- * their existence:
- */
-#define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1)
-#define CHAINHASH_SIZE (1UL << CHAINHASH_BITS)
-#define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS)
-#define chainhashentry(chain) (chainhash_table + __chainhashfn((chain)))
-
-static struct list_head chainhash_table[CHAINHASH_SIZE];
-
-/*
- * The hash key of the lock dependency chains is a hash itself too:
- * it's a hash of all locks taken up to that lock, including that lock.
- * It's a 64-bit hash, because it's important for the keys to be
- * unique.
- */
-#define iterate_chain_key(key1, key2) \
- (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \
- ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \
- (key2))
-
-void lockdep_off(void)
-{
- current->lockdep_recursion++;
-}
-EXPORT_SYMBOL(lockdep_off);
-
-void lockdep_on(void)
-{
- current->lockdep_recursion--;
-}
-EXPORT_SYMBOL(lockdep_on);
-
-/*
- * Debugging switches:
- */
-
-#define VERBOSE 0
-#define VERY_VERBOSE 0
-
-#if VERBOSE
-# define HARDIRQ_VERBOSE 1
-# define SOFTIRQ_VERBOSE 1
-# define RECLAIM_VERBOSE 1
-#else
-# define HARDIRQ_VERBOSE 0
-# define SOFTIRQ_VERBOSE 0
-# define RECLAIM_VERBOSE 0
-#endif
-
-#if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE
-/*
- * Quick filtering for interesting events:
- */
-static int class_filter(struct lock_class *class)
-{
-#if 0
- /* Example */
- if (class->name_version == 1 &&
- !strcmp(class->name, "lockname"))
- return 1;
- if (class->name_version == 1 &&
- !strcmp(class->name, "&struct->lockfield"))
- return 1;
-#endif
- /* Filter everything else. 1 would be to allow everything else */
- return 0;
-}
-#endif
-
-static int verbose(struct lock_class *class)
-{
-#if VERBOSE
- return class_filter(class);
-#endif
- return 0;
-}
-
-/*
- * Stack-trace: tightly packed array of stack backtrace
- * addresses. Protected by the graph_lock.
- */
-unsigned long nr_stack_trace_entries;
-static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES];
-
-static void print_lockdep_off(const char *bug_msg)
-{
- printk(KERN_DEBUG "%s\n", bug_msg);
- printk(KERN_DEBUG "turning off the locking correctness validator.\n");
- printk(KERN_DEBUG "Please attach the output of /proc/lock_stat to the bug report\n");
-}
-
-static int save_trace(struct stack_trace *trace)
-{
- trace->nr_entries = 0;
- trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries;
- trace->entries = stack_trace + nr_stack_trace_entries;
-
- trace->skip = 3;
-
- save_stack_trace(trace);
-
- /*
- * Some daft arches put -1 at the end to indicate its a full trace.
- *
- * <rant> this is buggy anyway, since it takes a whole extra entry so a
- * complete trace that maxes out the entries provided will be reported
- * as incomplete, friggin useless </rant>
- */
- if (trace->nr_entries != 0 &&
- trace->entries[trace->nr_entries-1] == ULONG_MAX)
- trace->nr_entries--;
-
- trace->max_entries = trace->nr_entries;
-
- nr_stack_trace_entries += trace->nr_entries;
-
- if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) {
- if (!debug_locks_off_graph_unlock())
- return 0;
-
- print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!");
- dump_stack();
-
- return 0;
- }
-
- return 1;
-}
-
-unsigned int nr_hardirq_chains;
-unsigned int nr_softirq_chains;
-unsigned int nr_process_chains;
-unsigned int max_lockdep_depth;
-
-#ifdef CONFIG_DEBUG_LOCKDEP
-/*
- * We cannot printk in early bootup code. Not even early_printk()
- * might work. So we mark any initialization errors and printk
- * about it later on, in lockdep_info().
- */
-static int lockdep_init_error;
-static const char *lock_init_error;
-static unsigned long lockdep_init_trace_data[20];
-static struct stack_trace lockdep_init_trace = {
- .max_entries = ARRAY_SIZE(lockdep_init_trace_data),
- .entries = lockdep_init_trace_data,
-};
-
-/*
- * Various lockdep statistics:
- */
-DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats);
-#endif
-
-/*
- * Locking printouts:
- */
-
-#define __USAGE(__STATE) \
- [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \
- [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \
- [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\
- [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R",
-
-static const char *usage_str[] =
-{
-#define LOCKDEP_STATE(__STATE) __USAGE(__STATE)
-#include "lockdep_states.h"
-#undef LOCKDEP_STATE
- [LOCK_USED] = "INITIAL USE",
-};
-
-const char * __get_key_name(struct lockdep_subclass_key *key, char *str)
-{
- return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str);
-}
-
-static inline unsigned long lock_flag(enum lock_usage_bit bit)
-{
- return 1UL << bit;
-}
-
-static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit)
-{
- char c = '.';
-
- if (class->usage_mask & lock_flag(bit + 2))
- c = '+';
- if (class->usage_mask & lock_flag(bit)) {
- c = '-';
- if (class->usage_mask & lock_flag(bit + 2))
- c = '?';
- }
-
- return c;
-}
-
-void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS])
-{
- int i = 0;
-
-#define LOCKDEP_STATE(__STATE) \
- usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \
- usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ);
-#include "lockdep_states.h"
-#undef LOCKDEP_STATE
-
- usage[i] = '\0';
-}
-
-static void __print_lock_name(struct lock_class *class)
-{
- char str[KSYM_NAME_LEN];
- const char *name;
-
- name = class->name;
- if (!name) {
- name = __get_key_name(class->key, str);
- printk("%s", name);
- } else {
- printk("%s", name);
- if (class->name_version > 1)
- printk("#%d", class->name_version);
- if (class->subclass)
- printk("/%d", class->subclass);
- }
-}
-
-static void print_lock_name(struct lock_class *class)
-{
- char usage[LOCK_USAGE_CHARS];
-
- get_usage_chars(class, usage);
-
- printk(" (");
- __print_lock_name(class);
- printk("){%s}", usage);
-}
-
-static void print_lockdep_cache(struct lockdep_map *lock)
-{
- const char *name;
- char str[KSYM_NAME_LEN];
-
- name = lock->name;
- if (!name)
- name = __get_key_name(lock->key->subkeys, str);
-
- printk("%s", name);
-}
-
-static void print_lock(struct held_lock *hlock)
-{
- print_lock_name(hlock_class(hlock));
- printk(", at: ");
- print_ip_sym(hlock->acquire_ip);
-}
-
-static void lockdep_print_held_locks(struct task_struct *curr)
-{
- int i, depth = curr->lockdep_depth;
-
- if (!depth) {
- printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr));
- return;
- }
- printk("%d lock%s held by %s/%d:\n",
- depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr));
-
- for (i = 0; i < depth; i++) {
- printk(" #%d: ", i);
- print_lock(curr->held_locks + i);
- }
-}
-
-static void print_kernel_ident(void)
-{
- printk("%s %.*s %s\n", init_utsname()->release,
- (int)strcspn(init_utsname()->version, " "),
- init_utsname()->version,
- print_tainted());
-}
-
-static int very_verbose(struct lock_class *class)
-{
-#if VERY_VERBOSE
- return class_filter(class);
-#endif
- return 0;
-}
-
-/*
- * Is this the address of a static object:
- */
-static int static_obj(void *obj)
-{
- unsigned long start = (unsigned long) &_stext,
- end = (unsigned long) &_end,
- addr = (unsigned long) obj;
-
- /*
- * static variable?
- */
- if ((addr >= start) && (addr < end))
- return 1;
-
- if (arch_is_kernel_data(addr))
- return 1;
-
- /*
- * in-kernel percpu var?
- */
- if (is_kernel_percpu_address(addr))
- return 1;
-
- /*
- * module static or percpu var?
- */
- return is_module_address(addr) || is_module_percpu_address(addr);
-}
-
-/*
- * To make lock name printouts unique, we calculate a unique
- * class->name_version generation counter:
- */
-static int count_matching_names(struct lock_class *new_class)
-{
- struct lock_class *class;
- int count = 0;
-
- if (!new_class->name)
- return 0;
-
- list_for_each_entry(class, &all_lock_classes, lock_entry) {
- if (new_class->key - new_class->subclass == class->key)
- return class->name_version;
- if (class->name && !strcmp(class->name, new_class->name))
- count = max(count, class->name_version);
- }
-
- return count + 1;
-}
-
-/*
- * Register a lock's class in the hash-table, if the class is not present
- * yet. Otherwise we look it up. We cache the result in the lock object
- * itself, so actual lookup of the hash should be once per lock object.
- */
-static inline struct lock_class *
-look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
-{
- struct lockdep_subclass_key *key;
- struct list_head *hash_head;
- struct lock_class *class;
-
-#ifdef CONFIG_DEBUG_LOCKDEP
- /*
- * If the architecture calls into lockdep before initializing
- * the hashes then we'll warn about it later. (we cannot printk
- * right now)
- */
- if (unlikely(!lockdep_initialized)) {
- lockdep_init();
- lockdep_init_error = 1;
- lock_init_error = lock->name;
- save_stack_trace(&lockdep_init_trace);
- }
-#endif
-
- if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) {
- debug_locks_off();
- printk(KERN_ERR
- "BUG: looking up invalid subclass: %u\n", subclass);
- printk(KERN_ERR
- "turning off the locking correctness validator.\n");
- dump_stack();
- return NULL;
- }
-
- /*
- * Static locks do not have their class-keys yet - for them the key
- * is the lock object itself:
- */
- if (unlikely(!lock->key))
- lock->key = (void *)lock;
-
- /*
- * NOTE: the class-key must be unique. For dynamic locks, a static
- * lock_class_key variable is passed in through the mutex_init()
- * (or spin_lock_init()) call - which acts as the key. For static
- * locks we use the lock object itself as the key.
- */
- BUILD_BUG_ON(sizeof(struct lock_class_key) >
- sizeof(struct lockdep_map));
-
- key = lock->key->subkeys + subclass;
-
- hash_head = classhashentry(key);
-
- /*
- * We can walk the hash lockfree, because the hash only
- * grows, and we are careful when adding entries to the end:
- */
- list_for_each_entry(class, hash_head, hash_entry) {
- if (class->key == key) {
- /*
- * Huh! same key, different name? Did someone trample
- * on some memory? We're most confused.
- */
- WARN_ON_ONCE(class->name != lock->name);
- return class;
- }
- }
-
- return NULL;
-}
-
-/*
- * Register a lock's class in the hash-table, if the class is not present
- * yet. Otherwise we look it up. We cache the result in the lock object
- * itself, so actual lookup of the hash should be once per lock object.
- */
-static inline struct lock_class *
-register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
-{
- struct lockdep_subclass_key *key;
- struct list_head *hash_head;
- struct lock_class *class;
- unsigned long flags;
-
- class = look_up_lock_class(lock, subclass);
- if (likely(class))
- goto out_set_class_cache;
-
- /*
- * Debug-check: all keys must be persistent!
- */
- if (!static_obj(lock->key)) {
- debug_locks_off();
- printk("INFO: trying to register non-static key.\n");
- printk("the code is fine but needs lockdep annotation.\n");
- printk("turning off the locking correctness validator.\n");
- dump_stack();
-
- return NULL;
- }
-
- key = lock->key->subkeys + subclass;
- hash_head = classhashentry(key);
-
- raw_local_irq_save(flags);
- if (!graph_lock()) {
- raw_local_irq_restore(flags);
- return NULL;
- }
- /*
- * We have to do the hash-walk again, to avoid races
- * with another CPU:
- */
- list_for_each_entry(class, hash_head, hash_entry)
- if (class->key == key)
- goto out_unlock_set;
- /*
- * Allocate a new key from the static array, and add it to
- * the hash:
- */
- if (nr_lock_classes >= MAX_LOCKDEP_KEYS) {
- if (!debug_locks_off_graph_unlock()) {
- raw_local_irq_restore(flags);
- return NULL;
- }
- raw_local_irq_restore(flags);
-
- print_lockdep_off("BUG: MAX_LOCKDEP_KEYS too low!");
- dump_stack();
- return NULL;
- }
- class = lock_classes + nr_lock_classes++;
- debug_atomic_inc(nr_unused_locks);
- class->key = key;
- class->name = lock->name;
- class->subclass = subclass;
- INIT_LIST_HEAD(&class->lock_entry);
- INIT_LIST_HEAD(&class->locks_before);
- INIT_LIST_HEAD(&class->locks_after);
- class->name_version = count_matching_names(class);
- /*
- * We use RCU's safe list-add method to make
- * parallel walking of the hash-list safe:
- */
- list_add_tail_rcu(&class->hash_entry, hash_head);
- /*
- * Add it to the global list of classes:
- */
- list_add_tail_rcu(&class->lock_entry, &all_lock_classes);
-
- if (verbose(class)) {
- graph_unlock();
- raw_local_irq_restore(flags);
-
- printk("\nnew class %p: %s", class->key, class->name);
- if (class->name_version > 1)
- printk("#%d", class->name_version);
- printk("\n");
- dump_stack();
-
- raw_local_irq_save(flags);
- if (!graph_lock()) {
- raw_local_irq_restore(flags);
- return NULL;
- }
- }
-out_unlock_set:
- graph_unlock();
- raw_local_irq_restore(flags);
-
-out_set_class_cache:
- if (!subclass || force)
- lock->class_cache[0] = class;
- else if (subclass < NR_LOCKDEP_CACHING_CLASSES)
- lock->class_cache[subclass] = class;
-
- /*
- * Hash collision, did we smoke some? We found a class with a matching
- * hash but the subclass -- which is hashed in -- didn't match.
- */
- if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass))
- return NULL;
-
- return class;
-}
-
-#ifdef CONFIG_PROVE_LOCKING
-/*
- * Allocate a lockdep entry. (assumes the graph_lock held, returns
- * with NULL on failure)
- */
-static struct lock_list *alloc_list_entry(void)
-{
- if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) {
- if (!debug_locks_off_graph_unlock())
- return NULL;
-
- print_lockdep_off("BUG: MAX_LOCKDEP_ENTRIES too low!");
- dump_stack();
- return NULL;
- }
- return list_entries + nr_list_entries++;
-}
-
-/*
- * Add a new dependency to the head of the list:
- */
-static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
- struct list_head *head, unsigned long ip,
- int distance, struct stack_trace *trace)
-{
- struct lock_list *entry;
- /*
- * Lock not present yet - get a new dependency struct and
- * add it to the list:
- */
- entry = alloc_list_entry();
- if (!entry)
- return 0;
-
- entry->class = this;
- entry->distance = distance;
- entry->trace = *trace;
- /*
- * Since we never remove from the dependency list, the list can
- * be walked lockless by other CPUs, it's only allocation
- * that must be protected by the spinlock. But this also means
- * we must make new entries visible only once writes to the
- * entry become visible - hence the RCU op:
- */
- list_add_tail_rcu(&entry->entry, head);
-
- return 1;
-}
-
-/*
- * For good efficiency of modular, we use power of 2
- */
-#define MAX_CIRCULAR_QUEUE_SIZE 4096UL
-#define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1)
-
-/*
- * The circular_queue and helpers is used to implement the
- * breadth-first search(BFS)algorithem, by which we can build
- * the shortest path from the next lock to be acquired to the
- * previous held lock if there is a circular between them.
- */
-struct circular_queue {
- unsigned long element[MAX_CIRCULAR_QUEUE_SIZE];
- unsigned int front, rear;
-};
-
-static struct circular_queue lock_cq;
-
-unsigned int max_bfs_queue_depth;
-
-static unsigned int lockdep_dependency_gen_id;
-
-static inline void __cq_init(struct circular_queue *cq)
-{
- cq->front = cq->rear = 0;
- lockdep_dependency_gen_id++;
-}
-
-static inline int __cq_empty(struct circular_queue *cq)
-{
- return (cq->front == cq->rear);
-}
-
-static inline int __cq_full(struct circular_queue *cq)
-{
- return ((cq->rear + 1) & CQ_MASK) == cq->front;
-}
-
-static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem)
-{
- if (__cq_full(cq))
- return -1;
-
- cq->element[cq->rear] = elem;
- cq->rear = (cq->rear + 1) & CQ_MASK;
- return 0;
-}
-
-static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem)
-{
- if (__cq_empty(cq))
- return -1;
-
- *elem = cq->element[cq->front];
- cq->front = (cq->front + 1) & CQ_MASK;
- return 0;
-}
-
-static inline unsigned int __cq_get_elem_count(struct circular_queue *cq)
-{
- return (cq->rear - cq->front) & CQ_MASK;
-}
-
-static inline void mark_lock_accessed(struct lock_list *lock,
- struct lock_list *parent)
-{
- unsigned long nr;
-
- nr = lock - list_entries;
- WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */
- lock->parent = parent;
- lock->class->dep_gen_id = lockdep_dependency_gen_id;
-}
-
-static inline unsigned long lock_accessed(struct lock_list *lock)
-{
- unsigned long nr;
-
- nr = lock - list_entries;
- WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */
- return lock->class->dep_gen_id == lockdep_dependency_gen_id;
-}
-
-static inline struct lock_list *get_lock_parent(struct lock_list *child)
-{
- return child->parent;
-}
-
-static inline int get_lock_depth(struct lock_list *child)
-{
- int depth = 0;
- struct lock_list *parent;
-
- while ((parent = get_lock_parent(child))) {
- child = parent;
- depth++;
- }
- return depth;
-}
-
-static int __bfs(struct lock_list *source_entry,
- void *data,
- int (*match)(struct lock_list *entry, void *data),
- struct lock_list **target_entry,
- int forward)
-{
- struct lock_list *entry;
- struct list_head *head;
- struct circular_queue *cq = &lock_cq;
- int ret = 1;
-
- if (match(source_entry, data)) {
- *target_entry = source_entry;
- ret = 0;
- goto exit;
- }
-
- if (forward)
- head = &source_entry->class->locks_after;
- else
- head = &source_entry->class->locks_before;
-
- if (list_empty(head))
- goto exit;
-
- __cq_init(cq);
- __cq_enqueue(cq, (unsigned long)source_entry);
-
- while (!__cq_empty(cq)) {
- struct lock_list *lock;
-
- __cq_dequeue(cq, (unsigned long *)&lock);
-
- if (!lock->class) {
- ret = -2;
- goto exit;
- }
-
- if (forward)
- head = &lock->class->locks_after;
- else
- head = &lock->class->locks_before;
-
- list_for_each_entry(entry, head, entry) {
- if (!lock_accessed(entry)) {
- unsigned int cq_depth;
- mark_lock_accessed(entry, lock);
- if (match(entry, data)) {
- *target_entry = entry;
- ret = 0;
- goto exit;
- }
-
- if (__cq_enqueue(cq, (unsigned long)entry)) {
- ret = -1;
- goto exit;
- }
- cq_depth = __cq_get_elem_count(cq);
- if (max_bfs_queue_depth < cq_depth)
- max_bfs_queue_depth = cq_depth;
- }
- }
- }
-exit:
- return ret;
-}
-
-static inline int __bfs_forwards(struct lock_list *src_entry,
- void *data,
- int (*match)(struct lock_list *entry, void *data),
- struct lock_list **target_entry)
-{
- return __bfs(src_entry, data, match, target_entry, 1);
-
-}
-
-static inline int __bfs_backwards(struct lock_list *src_entry,
- void *data,
- int (*match)(struct lock_list *entry, void *data),
- struct lock_list **target_entry)
-{
- return __bfs(src_entry, data, match, target_entry, 0);
-
-}
-
-/*
- * Recursive, forwards-direction lock-dependency checking, used for
- * both noncyclic checking and for hardirq-unsafe/softirq-unsafe
- * checking.
- */
-
-/*
- * Print a dependency chain entry (this is only done when a deadlock
- * has been detected):
- */
-static noinline int
-print_circular_bug_entry(struct lock_list *target, int depth)
-{
- if (debug_locks_silent)
- return 0;
- printk("\n-> #%u", depth);
- print_lock_name(target->class);
- printk(":\n");
- print_stack_trace(&target->trace, 6);
-
- return 0;
-}
-
-static void
-print_circular_lock_scenario(struct held_lock *src,
- struct held_lock *tgt,
- struct lock_list *prt)
-{
- struct lock_class *source = hlock_class(src);
- struct lock_class *target = hlock_class(tgt);
- struct lock_class *parent = prt->class;
-
- /*
- * A direct locking problem where unsafe_class lock is taken
- * directly by safe_class lock, then all we need to show
- * is the deadlock scenario, as it is obvious that the
- * unsafe lock is taken under the safe lock.
- *
- * But if there is a chain instead, where the safe lock takes
- * an intermediate lock (middle_class) where this lock is
- * not the same as the safe lock, then the lock chain is
- * used to describe the problem. Otherwise we would need
- * to show a different CPU case for each link in the chain
- * from the safe_class lock to the unsafe_class lock.
- */
- if (parent != source) {
- printk("Chain exists of:\n ");
- __print_lock_name(source);
- printk(" --> ");
- __print_lock_name(parent);
- printk(" --> ");
- __print_lock_name(target);
- printk("\n\n");
- }
-
- printk(" Possible unsafe locking scenario:\n\n");
- printk(" CPU0 CPU1\n");
- printk(" ---- ----\n");
- printk(" lock(");
- __print_lock_name(target);
- printk(");\n");
- printk(" lock(");
- __print_lock_name(parent);
- printk(");\n");
- printk(" lock(");
- __print_lock_name(target);
- printk(");\n");
- printk(" lock(");
- __print_lock_name(source);
- printk(");\n");
- printk("\n *** DEADLOCK ***\n\n");
-}
-
-/*
- * When a circular dependency is detected, print the
- * header first:
- */
-static noinline int
-print_circular_bug_header(struct lock_list *entry, unsigned int depth,
- struct held_lock *check_src,
- struct held_lock *check_tgt)
-{
- struct task_struct *curr = current;
-
- if (debug_locks_silent)
- return 0;
-
- printk("\n");
- printk("======================================================\n");
- printk("[ INFO: possible circular locking dependency detected ]\n");
- print_kernel_ident();
- printk("-------------------------------------------------------\n");
- printk("%s/%d is trying to acquire lock:\n",
- curr->comm, task_pid_nr(curr));
- print_lock(check_src);
- printk("\nbut task is already holding lock:\n");
- print_lock(check_tgt);
- printk("\nwhich lock already depends on the new lock.\n\n");
- printk("\nthe existing dependency chain (in reverse order) is:\n");
-
- print_circular_bug_entry(entry, depth);
-
- return 0;
-}
-
-static inline int class_equal(struct lock_list *entry, void *data)
-{
- return entry->class == data;
-}
-
-static noinline int print_circular_bug(struct lock_list *this,
- struct lock_list *target,
- struct held_lock *check_src,
- struct held_lock *check_tgt)
-{
- struct task_struct *curr = current;
- struct lock_list *parent;
- struct lock_list *first_parent;
- int depth;
-
- if (!debug_locks_off_graph_unlock() || debug_locks_silent)
- return 0;
-
- if (!save_trace(&this->trace))
- return 0;
-
- depth = get_lock_depth(target);
-
- print_circular_bug_header(target, depth, check_src, check_tgt);
-
- parent = get_lock_parent(target);
- first_parent = parent;
-
- while (parent) {
- print_circular_bug_entry(parent, --depth);
- parent = get_lock_parent(parent);
- }
-
- printk("\nother info that might help us debug this:\n\n");
- print_circular_lock_scenario(check_src, check_tgt,
- first_parent);
-
- lockdep_print_held_locks(curr);
-
- printk("\nstack backtrace:\n");
- dump_stack();
-
- return 0;
-}
-
-static noinline int print_bfs_bug(int ret)
-{
- if (!debug_locks_off_graph_unlock())
- return 0;
-
- /*
- * Breadth-first-search failed, graph got corrupted?
- */
- WARN(1, "lockdep bfs error:%d\n", ret);
-
- return 0;
-}
-
-static int noop_count(struct lock_list *entry, void *data)
-{
- (*(unsigned long *)data)++;
- return 0;
-}
-
-unsigned long __lockdep_count_forward_deps(struct lock_list *this)
-{
- unsigned long count = 0;
- struct lock_list *uninitialized_var(target_entry);
-
- __bfs_forwards(this, (void *)&count, noop_count, &target_entry);
-
- return count;
-}
-unsigned long lockdep_count_forward_deps(struct lock_class *class)
-{
- unsigned long ret, flags;
- struct lock_list this;
-
- this.parent = NULL;
- this.class = class;
-
- local_irq_save(flags);
- arch_spin_lock(&lockdep_lock);
- ret = __lockdep_count_forward_deps(&this);
- arch_spin_unlock(&lockdep_lock);
- local_irq_restore(flags);
-
- return ret;
-}
-
-unsigned long __lockdep_count_backward_deps(struct lock_list *this)
-{
- unsigned long count = 0;
- struct lock_list *uninitialized_var(target_entry);
-
- __bfs_backwards(this, (void *)&count, noop_count, &target_entry);
-
- return count;
-}
-
-unsigned long lockdep_count_backward_deps(struct lock_class *class)
-{
- unsigned long ret, flags;
- struct lock_list this;
-
- this.parent = NULL;
- this.class = class;
-
- local_irq_save(flags);
- arch_spin_lock(&lockdep_lock);
- ret = __lockdep_count_backward_deps(&this);
- arch_spin_unlock(&lockdep_lock);
- local_irq_restore(flags);
-
- return ret;
-}
-
-/*
- * Prove that the dependency graph starting at <entry> can not
- * lead to <target>. Print an error and return 0 if it does.
- */
-static noinline int
-check_noncircular(struct lock_list *root, struct lock_class *target,
- struct lock_list **target_entry)
-{
- int result;
-
- debug_atomic_inc(nr_cyclic_checks);
-
- result = __bfs_forwards(root, target, class_equal, target_entry);
-
- return result;
-}
-
-#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
-/*
- * Forwards and backwards subgraph searching, for the purposes of
- * proving that two subgraphs can be connected by a new dependency
- * without creating any illegal irq-safe -> irq-unsafe lock dependency.
- */
-
-static inline int usage_match(struct lock_list *entry, void *bit)
-{
- return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit);
-}
-
-
-
-/*
- * Find a node in the forwards-direction dependency sub-graph starting
- * at @root->class that matches @bit.
- *
- * Return 0 if such a node exists in the subgraph, and put that node
- * into *@target_entry.
- *
- * Return 1 otherwise and keep *@target_entry unchanged.
- * Return <0 on error.
- */
-static int
-find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit,
- struct lock_list **target_entry)
-{
- int result;
-
- debug_atomic_inc(nr_find_usage_forwards_checks);
-
- result = __bfs_forwards(root, (void *)bit, usage_match, target_entry);
-
- return result;
-}
-
-/*
- * Find a node in the backwards-direction dependency sub-graph starting
- * at @root->class that matches @bit.
- *
- * Return 0 if such a node exists in the subgraph, and put that node
- * into *@target_entry.
- *
- * Return 1 otherwise and keep *@target_entry unchanged.
- * Return <0 on error.
- */
-static int
-find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit,
- struct lock_list **target_entry)
-{
- int result;
-
- debug_atomic_inc(nr_find_usage_backwards_checks);
-
- result = __bfs_backwards(root, (void *)bit, usage_match, target_entry);
-
- return result;
-}
-
-static void print_lock_class_header(struct lock_class *class, int depth)
-{
- int bit;
-
- printk("%*s->", depth, "");
- print_lock_name(class);
- printk(" ops: %lu", class->ops);
- printk(" {\n");
-
- for (bit = 0; bit < LOCK_USAGE_STATES; bit++) {
- if (class->usage_mask & (1 << bit)) {
- int len = depth;
-
- len += printk("%*s %s", depth, "", usage_str[bit]);
- len += printk(" at:\n");
- print_stack_trace(class->usage_traces + bit, len);
- }
- }
- printk("%*s }\n", depth, "");
-
- printk("%*s ... key at: ",depth,"");
- print_ip_sym((unsigned long)class->key);
-}
-
-/*
- * printk the shortest lock dependencies from @start to @end in reverse order:
- */
-static void __used
-print_shortest_lock_dependencies(struct lock_list *leaf,
- struct lock_list *root)
-{
- struct lock_list *entry = leaf;
- int depth;
-
- /*compute depth from generated tree by BFS*/
- depth = get_lock_depth(leaf);
-
- do {
- print_lock_class_header(entry->class, depth);
- printk("%*s ... acquired at:\n", depth, "");
- print_stack_trace(&entry->trace, 2);
- printk("\n");
-
- if (depth == 0 && (entry != root)) {
- printk("lockdep:%s bad path found in chain graph\n", __func__);
- break;
- }
-
- entry = get_lock_parent(entry);
- depth--;
- } while (entry && (depth >= 0));
-
- return;
-}
-
-static void
-print_irq_lock_scenario(struct lock_list *safe_entry,
- struct lock_list *unsafe_entry,
- struct lock_class *prev_class,
- struct lock_class *next_class)
-{
- struct lock_class *safe_class = safe_entry->class;
- struct lock_class *unsafe_class = unsafe_entry->class;
- struct lock_class *middle_class = prev_class;
-
- if (middle_class == safe_class)
- middle_class = next_class;
-
- /*
- * A direct locking problem where unsafe_class lock is taken
- * directly by safe_class lock, then all we need to show
- * is the deadlock scenario, as it is obvious that the
- * unsafe lock is taken under the safe lock.
- *
- * But if there is a chain instead, where the safe lock takes
- * an intermediate lock (middle_class) where this lock is
- * not the same as the safe lock, then the lock chain is
- * used to describe the problem. Otherwise we would need
- * to show a different CPU case for each link in the chain
- * from the safe_class lock to the unsafe_class lock.
- */
- if (middle_class != unsafe_class) {
- printk("Chain exists of:\n ");
- __print_lock_name(safe_class);
- printk(" --> ");
- __print_lock_name(middle_class);
- printk(" --> ");
- __print_lock_name(unsafe_class);
- printk("\n\n");
- }
-
- printk(" Possible interrupt unsafe locking scenario:\n\n");
- printk(" CPU0 CPU1\n");
- printk(" ---- ----\n");
- printk(" lock(");
- __print_lock_name(unsafe_class);
- printk(");\n");
- printk(" local_irq_disable();\n");
- printk(" lock(");
- __print_lock_name(safe_class);
- printk(");\n");
- printk(" lock(");
- __print_lock_name(middle_class);
- printk(");\n");
- printk(" <Interrupt>\n");
- printk(" lock(");
- __print_lock_name(safe_class);
- printk(");\n");
- printk("\n *** DEADLOCK ***\n\n");
-}
-
-static int
-print_bad_irq_dependency(struct task_struct *curr,
- struct lock_list *prev_root,
- struct lock_list *next_root,
- struct lock_list *backwards_entry,
- struct lock_list *forwards_entry,
- struct held_lock *prev,
- struct held_lock *next,
- enum lock_usage_bit bit1,
- enum lock_usage_bit bit2,
- const char *irqclass)
-{
- if (!debug_locks_off_graph_unlock() || debug_locks_silent)
- return 0;
-
- printk("\n");
- printk("======================================================\n");
- printk("[ INFO: %s-safe -> %s-unsafe lock order detected ]\n",
- irqclass, irqclass);
- print_kernel_ident();
- printk("------------------------------------------------------\n");
- printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n",
- curr->comm, task_pid_nr(curr),
- curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT,
- curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT,
- curr->hardirqs_enabled,
- curr->softirqs_enabled);
- print_lock(next);
-
- printk("\nand this task is already holding:\n");
- print_lock(prev);
- printk("which would create a new lock dependency:\n");
- print_lock_name(hlock_class(prev));
- printk(" ->");
- print_lock_name(hlock_class(next));
- printk("\n");
-
- printk("\nbut this new dependency connects a %s-irq-safe lock:\n",
- irqclass);
- print_lock_name(backwards_entry->class);
- printk("\n... which became %s-irq-safe at:\n", irqclass);
-
- print_stack_trace(backwards_entry->class->usage_traces + bit1, 1);
-
- printk("\nto a %s-irq-unsafe lock:\n", irqclass);
- print_lock_name(forwards_entry->class);
- printk("\n... which became %s-irq-unsafe at:\n", irqclass);
- printk("...");
-
- print_stack_trace(forwards_entry->class->usage_traces + bit2, 1);
-
- printk("\nother info that might help us debug this:\n\n");
- print_irq_lock_scenario(backwards_entry, forwards_entry,
- hlock_class(prev), hlock_class(next));
-
- lockdep_print_held_locks(curr);
-
- printk("\nthe dependencies between %s-irq-safe lock", irqclass);
- printk(" and the holding lock:\n");
- if (!save_trace(&prev_root->trace))
- return 0;
- print_shortest_lock_dependencies(backwards_entry, prev_root);
-
- printk("\nthe dependencies between the lock to be acquired");
- printk(" and %s-irq-unsafe lock:\n", irqclass);
- if (!save_trace(&next_root->trace))
- return 0;
- print_shortest_lock_dependencies(forwards_entry, next_root);
-
- printk("\nstack backtrace:\n");
- dump_stack();
-
- return 0;
-}
-
-static int
-check_usage(struct task_struct *curr, struct held_lock *prev,
- struct held_lock *next, enum lock_usage_bit bit_backwards,
- enum lock_usage_bit bit_forwards, const char *irqclass)
-{
- int ret;
- struct lock_list this, that;
- struct lock_list *uninitialized_var(target_entry);
- struct lock_list *uninitialized_var(target_entry1);
-
- this.parent = NULL;
-
- this.class = hlock_class(prev);
- ret = find_usage_backwards(&this, bit_backwards, &target_entry);
- if (ret < 0)
- return print_bfs_bug(ret);
- if (ret == 1)
- return ret;
-
- that.parent = NULL;
- that.class = hlock_class(next);
- ret = find_usage_forwards(&that, bit_forwards, &target_entry1);
- if (ret < 0)
- return print_bfs_bug(ret);
- if (ret == 1)
- return ret;
-
- return print_bad_irq_dependency(curr, &this, &that,
- target_entry, target_entry1,
- prev, next,
- bit_backwards, bit_forwards, irqclass);
-}
-
-static const char *state_names[] = {
-#define LOCKDEP_STATE(__STATE) \
- __stringify(__STATE),
-#include "lockdep_states.h"
-#undef LOCKDEP_STATE
-};
-
-static const char *state_rnames[] = {
-#define LOCKDEP_STATE(__STATE) \
- __stringify(__STATE)"-READ",
-#include "lockdep_states.h"
-#undef LOCKDEP_STATE
-};
-
-static inline const char *state_name(enum lock_usage_bit bit)
-{
- return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2];
-}
-
-static int exclusive_bit(int new_bit)
-{
- /*
- * USED_IN
- * USED_IN_READ
- * ENABLED
- * ENABLED_READ
- *
- * bit 0 - write/read
- * bit 1 - used_in/enabled
- * bit 2+ state
- */
-
- int state = new_bit & ~3;
- int dir = new_bit & 2;
-
- /*
- * keep state, bit flip the direction and strip read.
- */
- return state | (dir ^ 2);
-}
-
-static int check_irq_usage(struct task_struct *curr, struct held_lock *prev,
- struct held_lock *next, enum lock_usage_bit bit)
-{
- /*
- * Prove that the new dependency does not connect a hardirq-safe
- * lock with a hardirq-unsafe lock - to achieve this we search
- * the backwards-subgraph starting at <prev>, and the
- * forwards-subgraph starting at <next>:
- */
- if (!check_usage(curr, prev, next, bit,
- exclusive_bit(bit), state_name(bit)))
- return 0;
-
- bit++; /* _READ */
-
- /*
- * Prove that the new dependency does not connect a hardirq-safe-read
- * lock with a hardirq-unsafe lock - to achieve this we search
- * the backwards-subgraph starting at <prev>, and the
- * forwards-subgraph starting at <next>:
- */
- if (!check_usage(curr, prev, next, bit,
- exclusive_bit(bit), state_name(bit)))
- return 0;
-
- return 1;
-}
-
-static int
-check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
- struct held_lock *next)
-{
-#define LOCKDEP_STATE(__STATE) \
- if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \
- return 0;
-#include "lockdep_states.h"
-#undef LOCKDEP_STATE
-
- return 1;
-}
-
-static void inc_chains(void)
-{
- if (current->hardirq_context)
- nr_hardirq_chains++;
- else {
- if (current->softirq_context)
- nr_softirq_chains++;
- else
- nr_process_chains++;
- }
-}
-
-#else
-
-static inline int
-check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
- struct held_lock *next)
-{
- return 1;
-}
-
-static inline void inc_chains(void)
-{
- nr_process_chains++;
-}
-
-#endif
-
-static void
-print_deadlock_scenario(struct held_lock *nxt,
- struct held_lock *prv)
-{
- struct lock_class *next = hlock_class(nxt);
- struct lock_class *prev = hlock_class(prv);
-
- printk(" Possible unsafe locking scenario:\n\n");
- printk(" CPU0\n");
- printk(" ----\n");
- printk(" lock(");
- __print_lock_name(prev);
- printk(");\n");
- printk(" lock(");
- __print_lock_name(next);
- printk(");\n");
- printk("\n *** DEADLOCK ***\n\n");
- printk(" May be due to missing lock nesting notation\n\n");
-}
-
-static int
-print_deadlock_bug(struct task_struct *curr, struct held_lock *prev,
- struct held_lock *next)
-{
- if (!debug_locks_off_graph_unlock() || debug_locks_silent)
- return 0;
-
- printk("\n");
- printk("=============================================\n");
- printk("[ INFO: possible recursive locking detected ]\n");
- print_kernel_ident();
- printk("---------------------------------------------\n");
- printk("%s/%d is trying to acquire lock:\n",
- curr->comm, task_pid_nr(curr));
- print_lock(next);
- printk("\nbut task is already holding lock:\n");
- print_lock(prev);
-
- printk("\nother info that might help us debug this:\n");
- print_deadlock_scenario(next, prev);
- lockdep_print_held_locks(curr);
-
- printk("\nstack backtrace:\n");
- dump_stack();
-
- return 0;
-}
-
-/*
- * Check whether we are holding such a class already.
- *
- * (Note that this has to be done separately, because the graph cannot
- * detect such classes of deadlocks.)
- *
- * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read
- */
-static int
-check_deadlock(struct task_struct *curr, struct held_lock *next,
- struct lockdep_map *next_instance, int read)
-{
- struct held_lock *prev;
- struct held_lock *nest = NULL;
- int i;
-
- for (i = 0; i < curr->lockdep_depth; i++) {
- prev = curr->held_locks + i;
-
- if (prev->instance == next->nest_lock)
- nest = prev;
-
- if (hlock_class(prev) != hlock_class(next))
- continue;
-
- /*
- * Allow read-after-read recursion of the same
- * lock class (i.e. read_lock(lock)+read_lock(lock)):
- */
- if ((read == 2) && prev->read)
- return 2;
-
- /*
- * We're holding the nest_lock, which serializes this lock's
- * nesting behaviour.
- */
- if (nest)
- return 2;
-
- return print_deadlock_bug(curr, prev, next);
- }
- return 1;
-}
-
-/*
- * There was a chain-cache miss, and we are about to add a new dependency
- * to a previous lock. We recursively validate the following rules:
- *
- * - would the adding of the <prev> -> <next> dependency create a
- * circular dependency in the graph? [== circular deadlock]
- *
- * - does the new prev->next dependency connect any hardirq-safe lock
- * (in the full backwards-subgraph starting at <prev>) with any
- * hardirq-unsafe lock (in the full forwards-subgraph starting at
- * <next>)? [== illegal lock inversion with hardirq contexts]
- *
- * - does the new prev->next dependency connect any softirq-safe lock
- * (in the full backwards-subgraph starting at <prev>) with any
- * softirq-unsafe lock (in the full forwards-subgraph starting at
- * <next>)? [== illegal lock inversion with softirq contexts]
- *
- * any of these scenarios could lead to a deadlock.
- *
- * Then if all the validations pass, we add the forwards and backwards
- * dependency.
- */
-static int
-check_prev_add(struct task_struct *curr, struct held_lock *prev,
- struct held_lock *next, int distance, int trylock_loop)
-{
- struct lock_list *entry;
- int ret;
- struct lock_list this;
- struct lock_list *uninitialized_var(target_entry);
- /*
- * Static variable, serialized by the graph_lock().
- *
- * We use this static variable to save the stack trace in case
- * we call into this function multiple times due to encountering
- * trylocks in the held lock stack.
- */
- static struct stack_trace trace;
-
- /*
- * Prove that the new <prev> -> <next> dependency would not
- * create a circular dependency in the graph. (We do this by
- * forward-recursing into the graph starting at <next>, and
- * checking whether we can reach <prev>.)
- *
- * We are using global variables to control the recursion, to
- * keep the stackframe size of the recursive functions low:
- */
- this.class = hlock_class(next);
- this.parent = NULL;
- ret = check_noncircular(&this, hlock_class(prev), &target_entry);
- if (unlikely(!ret))
- return print_circular_bug(&this, target_entry, next, prev);
- else if (unlikely(ret < 0))
- return print_bfs_bug(ret);
-
- if (!check_prev_add_irq(curr, prev, next))
- return 0;
-
- /*
- * For recursive read-locks we do all the dependency checks,
- * but we dont store read-triggered dependencies (only
- * write-triggered dependencies). This ensures that only the
- * write-side dependencies matter, and that if for example a
- * write-lock never takes any other locks, then the reads are
- * equivalent to a NOP.
- */
- if (next->read == 2 || prev->read == 2)
- return 1;
- /*
- * Is the <prev> -> <next> dependency already present?
- *
- * (this may occur even though this is a new chain: consider
- * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3
- * chains - the second one will be new, but L1 already has
- * L2 added to its dependency list, due to the first chain.)
- */
- list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) {
- if (entry->class == hlock_class(next)) {
- if (distance == 1)
- entry->distance = 1;
- return 2;
- }
- }
-
- if (!trylock_loop && !save_trace(&trace))
- return 0;
-
- /*
- * Ok, all validations passed, add the new lock
- * to the previous lock's dependency list:
- */
- ret = add_lock_to_list(hlock_class(prev), hlock_class(next),
- &hlock_class(prev)->locks_after,
- next->acquire_ip, distance, &trace);
-
- if (!ret)
- return 0;
-
- ret = add_lock_to_list(hlock_class(next), hlock_class(prev),
- &hlock_class(next)->locks_before,
- next->acquire_ip, distance, &trace);
- if (!ret)
- return 0;
-
- /*
- * Debugging printouts:
- */
- if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) {
- graph_unlock();
- printk("\n new dependency: ");
- print_lock_name(hlock_class(prev));
- printk(" => ");
- print_lock_name(hlock_class(next));
- printk("\n");
- dump_stack();
- return graph_lock();
- }
- return 1;
-}
-
-/*
- * Add the dependency to all directly-previous locks that are 'relevant'.
- * The ones that are relevant are (in increasing distance from curr):
- * all consecutive trylock entries and the final non-trylock entry - or
- * the end of this context's lock-chain - whichever comes first.
- */
-static int
-check_prevs_add(struct task_struct *curr, struct held_lock *next)
-{
- int depth = curr->lockdep_depth;
- int trylock_loop = 0;
- struct held_lock *hlock;
-
- /*
- * Debugging checks.
- *
- * Depth must not be zero for a non-head lock:
- */
- if (!depth)
- goto out_bug;
- /*
- * At least two relevant locks must exist for this
- * to be a head:
- */
- if (curr->held_locks[depth].irq_context !=
- curr->held_locks[depth-1].irq_context)
- goto out_bug;
-
- for (;;) {
- int distance = curr->lockdep_depth - depth + 1;
- hlock = curr->held_locks + depth-1;
- /*
- * Only non-recursive-read entries get new dependencies
- * added:
- */
- if (hlock->read != 2) {
- if (!check_prev_add(curr, hlock, next,
- distance, trylock_loop))
- return 0;
- /*
- * Stop after the first non-trylock entry,
- * as non-trylock entries have added their
- * own direct dependencies already, so this
- * lock is connected to them indirectly:
- */
- if (!hlock->trylock)
- break;
- }
- depth--;
- /*
- * End of lock-stack?
- */
- if (!depth)
- break;
- /*
- * Stop the search if we cross into another context:
- */
- if (curr->held_locks[depth].irq_context !=
- curr->held_locks[depth-1].irq_context)
- break;
- trylock_loop = 1;
- }
- return 1;
-out_bug:
- if (!debug_locks_off_graph_unlock())
- return 0;
-
- /*
- * Clearly we all shouldn't be here, but since we made it we
- * can reliable say we messed up our state. See the above two
- * gotos for reasons why we could possibly end up here.
- */
- WARN_ON(1);
-
- return 0;
-}
-
-unsigned long nr_lock_chains;
-struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
-int nr_chain_hlocks;
-static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS];
-
-struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i)
-{
- return lock_classes + chain_hlocks[chain->base + i];
-}
-
-/*
- * Look up a dependency chain. If the key is not present yet then
- * add it and return 1 - in this case the new dependency chain is
- * validated. If the key is already hashed, return 0.
- * (On return with 1 graph_lock is held.)
- */
-static inline int lookup_chain_cache(struct task_struct *curr,
- struct held_lock *hlock,
- u64 chain_key)
-{
- struct lock_class *class = hlock_class(hlock);
- struct list_head *hash_head = chainhashentry(chain_key);
- struct lock_chain *chain;
- struct held_lock *hlock_curr;
- int i, j;
-
- /*
- * We might need to take the graph lock, ensure we've got IRQs
- * disabled to make this an IRQ-safe lock.. for recursion reasons
- * lockdep won't complain about its own locking errors.
- */
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return 0;
- /*
- * We can walk it lock-free, because entries only get added
- * to the hash:
- */
- list_for_each_entry(chain, hash_head, entry) {
- if (chain->chain_key == chain_key) {
-cache_hit:
- debug_atomic_inc(chain_lookup_hits);
- if (very_verbose(class))
- printk("\nhash chain already cached, key: "
- "%016Lx tail class: [%p] %s\n",
- (unsigned long long)chain_key,
- class->key, class->name);
- return 0;
- }
- }
- if (very_verbose(class))
- printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n",
- (unsigned long long)chain_key, class->key, class->name);
- /*
- * Allocate a new chain entry from the static array, and add
- * it to the hash:
- */
- if (!graph_lock())
- return 0;
- /*
- * We have to walk the chain again locked - to avoid duplicates:
- */
- list_for_each_entry(chain, hash_head, entry) {
- if (chain->chain_key == chain_key) {
- graph_unlock();
- goto cache_hit;
- }
- }
- if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) {
- if (!debug_locks_off_graph_unlock())
- return 0;
-
- print_lockdep_off("BUG: MAX_LOCKDEP_CHAINS too low!");
- dump_stack();
- return 0;
- }
- chain = lock_chains + nr_lock_chains++;
- chain->chain_key = chain_key;
- chain->irq_context = hlock->irq_context;
- /* Find the first held_lock of current chain */
- for (i = curr->lockdep_depth - 1; i >= 0; i--) {
- hlock_curr = curr->held_locks + i;
- if (hlock_curr->irq_context != hlock->irq_context)
- break;
- }
- i++;
- chain->depth = curr->lockdep_depth + 1 - i;
- if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) {
- chain->base = nr_chain_hlocks;
- nr_chain_hlocks += chain->depth;
- for (j = 0; j < chain->depth - 1; j++, i++) {
- int lock_id = curr->held_locks[i].class_idx - 1;
- chain_hlocks[chain->base + j] = lock_id;
- }
- chain_hlocks[chain->base + j] = class - lock_classes;
- }
- list_add_tail_rcu(&chain->entry, hash_head);
- debug_atomic_inc(chain_lookup_misses);
- inc_chains();
-
- return 1;
-}
-
-static int validate_chain(struct task_struct *curr, struct lockdep_map *lock,
- struct held_lock *hlock, int chain_head, u64 chain_key)
-{
- /*
- * Trylock needs to maintain the stack of held locks, but it
- * does not add new dependencies, because trylock can be done
- * in any order.
- *
- * We look up the chain_key and do the O(N^2) check and update of
- * the dependencies only if this is a new dependency chain.
- * (If lookup_chain_cache() returns with 1 it acquires
- * graph_lock for us)
- */
- if (!hlock->trylock && (hlock->check == 2) &&
- lookup_chain_cache(curr, hlock, chain_key)) {
- /*
- * Check whether last held lock:
- *
- * - is irq-safe, if this lock is irq-unsafe
- * - is softirq-safe, if this lock is hardirq-unsafe
- *
- * And check whether the new lock's dependency graph
- * could lead back to the previous lock.
- *
- * any of these scenarios could lead to a deadlock. If
- * All validations
- */
- int ret = check_deadlock(curr, hlock, lock, hlock->read);
-
- if (!ret)
- return 0;
- /*
- * Mark recursive read, as we jump over it when
- * building dependencies (just like we jump over
- * trylock entries):
- */
- if (ret == 2)
- hlock->read = 2;
- /*
- * Add dependency only if this lock is not the head
- * of the chain, and if it's not a secondary read-lock:
- */
- if (!chain_head && ret != 2)
- if (!check_prevs_add(curr, hlock))
- return 0;
- graph_unlock();
- } else
- /* after lookup_chain_cache(): */
- if (unlikely(!debug_locks))
- return 0;
-
- return 1;
-}
-#else
-static inline int validate_chain(struct task_struct *curr,
- struct lockdep_map *lock, struct held_lock *hlock,
- int chain_head, u64 chain_key)
-{
- return 1;
-}
-#endif
-
-/*
- * We are building curr_chain_key incrementally, so double-check
- * it from scratch, to make sure that it's done correctly:
- */
-static void check_chain_key(struct task_struct *curr)
-{
-#ifdef CONFIG_DEBUG_LOCKDEP
- struct held_lock *hlock, *prev_hlock = NULL;
- unsigned int i, id;
- u64 chain_key = 0;
-
- for (i = 0; i < curr->lockdep_depth; i++) {
- hlock = curr->held_locks + i;
- if (chain_key != hlock->prev_chain_key) {
- debug_locks_off();
- /*
- * We got mighty confused, our chain keys don't match
- * with what we expect, someone trample on our task state?
- */
- WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n",
- curr->lockdep_depth, i,
- (unsigned long long)chain_key,
- (unsigned long long)hlock->prev_chain_key);
- return;
- }
- id = hlock->class_idx - 1;
- /*
- * Whoops ran out of static storage again?
- */
- if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
- return;
-
- if (prev_hlock && (prev_hlock->irq_context !=
- hlock->irq_context))
- chain_key = 0;
- chain_key = iterate_chain_key(chain_key, id);
- prev_hlock = hlock;
- }
- if (chain_key != curr->curr_chain_key) {
- debug_locks_off();
- /*
- * More smoking hash instead of calculating it, damn see these
- * numbers float.. I bet that a pink elephant stepped on my memory.
- */
- WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n",
- curr->lockdep_depth, i,
- (unsigned long long)chain_key,
- (unsigned long long)curr->curr_chain_key);
- }
-#endif
-}
-
-static void
-print_usage_bug_scenario(struct held_lock *lock)
-{
- struct lock_class *class = hlock_class(lock);
-
- printk(" Possible unsafe locking scenario:\n\n");
- printk(" CPU0\n");
- printk(" ----\n");
- printk(" lock(");
- __print_lock_name(class);
- printk(");\n");
- printk(" <Interrupt>\n");
- printk(" lock(");
- __print_lock_name(class);
- printk(");\n");
- printk("\n *** DEADLOCK ***\n\n");
-}
-
-static int
-print_usage_bug(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit)
-{
- if (!debug_locks_off_graph_unlock() || debug_locks_silent)
- return 0;
-
- printk("\n");
- printk("=================================\n");
- printk("[ INFO: inconsistent lock state ]\n");
- print_kernel_ident();
- printk("---------------------------------\n");
-
- printk("inconsistent {%s} -> {%s} usage.\n",
- usage_str[prev_bit], usage_str[new_bit]);
-
- printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n",
- curr->comm, task_pid_nr(curr),
- trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT,
- trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT,
- trace_hardirqs_enabled(curr),
- trace_softirqs_enabled(curr));
- print_lock(this);
-
- printk("{%s} state was registered at:\n", usage_str[prev_bit]);
- print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1);
-
- print_irqtrace_events(curr);
- printk("\nother info that might help us debug this:\n");
- print_usage_bug_scenario(this);
-
- lockdep_print_held_locks(curr);
-
- printk("\nstack backtrace:\n");
- dump_stack();
-
- return 0;
-}
-
-/*
- * Print out an error if an invalid bit is set:
- */
-static inline int
-valid_state(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit)
-{
- if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit)))
- return print_usage_bug(curr, this, bad_bit, new_bit);
- return 1;
-}
-
-static int mark_lock(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit new_bit);
-
-#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
-
-/*
- * print irq inversion bug:
- */
-static int
-print_irq_inversion_bug(struct task_struct *curr,
- struct lock_list *root, struct lock_list *other,
- struct held_lock *this, int forwards,
- const char *irqclass)
-{
- struct lock_list *entry = other;
- struct lock_list *middle = NULL;
- int depth;
-
- if (!debug_locks_off_graph_unlock() || debug_locks_silent)
- return 0;
-
- printk("\n");
- printk("=========================================================\n");
- printk("[ INFO: possible irq lock inversion dependency detected ]\n");
- print_kernel_ident();
- printk("---------------------------------------------------------\n");
- printk("%s/%d just changed the state of lock:\n",
- curr->comm, task_pid_nr(curr));
- print_lock(this);
- if (forwards)
- printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass);
- else
- printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass);
- print_lock_name(other->class);
- printk("\n\nand interrupts could create inverse lock ordering between them.\n\n");
-
- printk("\nother info that might help us debug this:\n");
-
- /* Find a middle lock (if one exists) */
- depth = get_lock_depth(other);
- do {
- if (depth == 0 && (entry != root)) {
- printk("lockdep:%s bad path found in chain graph\n", __func__);
- break;
- }
- middle = entry;
- entry = get_lock_parent(entry);
- depth--;
- } while (entry && entry != root && (depth >= 0));
- if (forwards)
- print_irq_lock_scenario(root, other,
- middle ? middle->class : root->class, other->class);
- else
- print_irq_lock_scenario(other, root,
- middle ? middle->class : other->class, root->class);
-
- lockdep_print_held_locks(curr);
-
- printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n");
- if (!save_trace(&root->trace))
- return 0;
- print_shortest_lock_dependencies(other, root);
-
- printk("\nstack backtrace:\n");
- dump_stack();
-
- return 0;
-}
-
-/*
- * Prove that in the forwards-direction subgraph starting at <this>
- * there is no lock matching <mask>:
- */
-static int
-check_usage_forwards(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit bit, const char *irqclass)
-{
- int ret;
- struct lock_list root;
- struct lock_list *uninitialized_var(target_entry);
-
- root.parent = NULL;
- root.class = hlock_class(this);
- ret = find_usage_forwards(&root, bit, &target_entry);
- if (ret < 0)
- return print_bfs_bug(ret);
- if (ret == 1)
- return ret;
-
- return print_irq_inversion_bug(curr, &root, target_entry,
- this, 1, irqclass);
-}
-
-/*
- * Prove that in the backwards-direction subgraph starting at <this>
- * there is no lock matching <mask>:
- */
-static int
-check_usage_backwards(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit bit, const char *irqclass)
-{
- int ret;
- struct lock_list root;
- struct lock_list *uninitialized_var(target_entry);
-
- root.parent = NULL;
- root.class = hlock_class(this);
- ret = find_usage_backwards(&root, bit, &target_entry);
- if (ret < 0)
- return print_bfs_bug(ret);
- if (ret == 1)
- return ret;
-
- return print_irq_inversion_bug(curr, &root, target_entry,
- this, 0, irqclass);
-}
-
-void print_irqtrace_events(struct task_struct *curr)
-{
- printk("irq event stamp: %u\n", curr->irq_events);
- printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event);
- print_ip_sym(curr->hardirq_enable_ip);
- printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event);
- print_ip_sym(curr->hardirq_disable_ip);
- printk("softirqs last enabled at (%u): ", curr->softirq_enable_event);
- print_ip_sym(curr->softirq_enable_ip);
- printk("softirqs last disabled at (%u): ", curr->softirq_disable_event);
- print_ip_sym(curr->softirq_disable_ip);
-}
-
-static int HARDIRQ_verbose(struct lock_class *class)
-{
-#if HARDIRQ_VERBOSE
- return class_filter(class);
-#endif
- return 0;
-}
-
-static int SOFTIRQ_verbose(struct lock_class *class)
-{
-#if SOFTIRQ_VERBOSE
- return class_filter(class);
-#endif
- return 0;
-}
-
-static int RECLAIM_FS_verbose(struct lock_class *class)
-{
-#if RECLAIM_VERBOSE
- return class_filter(class);
-#endif
- return 0;
-}
-
-#define STRICT_READ_CHECKS 1
-
-static int (*state_verbose_f[])(struct lock_class *class) = {
-#define LOCKDEP_STATE(__STATE) \
- __STATE##_verbose,
-#include "lockdep_states.h"
-#undef LOCKDEP_STATE
-};
-
-static inline int state_verbose(enum lock_usage_bit bit,
- struct lock_class *class)
-{
- return state_verbose_f[bit >> 2](class);
-}
-
-typedef int (*check_usage_f)(struct task_struct *, struct held_lock *,
- enum lock_usage_bit bit, const char *name);
-
-static int
-mark_lock_irq(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit new_bit)
-{
- int excl_bit = exclusive_bit(new_bit);
- int read = new_bit & 1;
- int dir = new_bit & 2;
-
- /*
- * mark USED_IN has to look forwards -- to ensure no dependency
- * has ENABLED state, which would allow recursion deadlocks.
- *
- * mark ENABLED has to look backwards -- to ensure no dependee
- * has USED_IN state, which, again, would allow recursion deadlocks.
- */
- check_usage_f usage = dir ?
- check_usage_backwards : check_usage_forwards;
-
- /*
- * Validate that this particular lock does not have conflicting
- * usage states.
- */
- if (!valid_state(curr, this, new_bit, excl_bit))
- return 0;
-
- /*
- * Validate that the lock dependencies don't have conflicting usage
- * states.
- */
- if ((!read || !dir || STRICT_READ_CHECKS) &&
- !usage(curr, this, excl_bit, state_name(new_bit & ~1)))
- return 0;
-
- /*
- * Check for read in write conflicts
- */
- if (!read) {
- if (!valid_state(curr, this, new_bit, excl_bit + 1))
- return 0;
-
- if (STRICT_READ_CHECKS &&
- !usage(curr, this, excl_bit + 1,
- state_name(new_bit + 1)))
- return 0;
- }
-
- if (state_verbose(new_bit, hlock_class(this)))
- return 2;
-
- return 1;
-}
-
-enum mark_type {
-#define LOCKDEP_STATE(__STATE) __STATE,
-#include "lockdep_states.h"
-#undef LOCKDEP_STATE
-};
-
-/*
- * Mark all held locks with a usage bit:
- */
-static int
-mark_held_locks(struct task_struct *curr, enum mark_type mark)
-{
- enum lock_usage_bit usage_bit;
- struct held_lock *hlock;
- int i;
-
- for (i = 0; i < curr->lockdep_depth; i++) {
- hlock = curr->held_locks + i;
-
- usage_bit = 2 + (mark << 2); /* ENABLED */
- if (hlock->read)
- usage_bit += 1; /* READ */
-
- BUG_ON(usage_bit >= LOCK_USAGE_STATES);
-
- if (hlock_class(hlock)->key == __lockdep_no_validate__.subkeys)
- continue;
-
- if (!mark_lock(curr, hlock, usage_bit))
- return 0;
- }
-
- return 1;
-}
-
-/*
- * Hardirqs will be enabled:
- */
-static void __trace_hardirqs_on_caller(unsigned long ip)
-{
- struct task_struct *curr = current;
-
- /* we'll do an OFF -> ON transition: */
- curr->hardirqs_enabled = 1;
-
- /*
- * We are going to turn hardirqs on, so set the
- * usage bit for all held locks:
- */
- if (!mark_held_locks(curr, HARDIRQ))
- return;
- /*
- * If we have softirqs enabled, then set the usage
- * bit for all held locks. (disabled hardirqs prevented
- * this bit from being set before)
- */
- if (curr->softirqs_enabled)
- if (!mark_held_locks(curr, SOFTIRQ))
- return;
-
- curr->hardirq_enable_ip = ip;
- curr->hardirq_enable_event = ++curr->irq_events;
- debug_atomic_inc(hardirqs_on_events);
-}
-
-void trace_hardirqs_on_caller(unsigned long ip)
-{
- time_hardirqs_on(CALLER_ADDR0, ip);
-
- if (unlikely(!debug_locks || current->lockdep_recursion))
- return;
-
- if (unlikely(current->hardirqs_enabled)) {
- /*
- * Neither irq nor preemption are disabled here
- * so this is racy by nature but losing one hit
- * in a stat is not a big deal.
- */
- __debug_atomic_inc(redundant_hardirqs_on);
- return;
- }
-
- /*
- * We're enabling irqs and according to our state above irqs weren't
- * already enabled, yet we find the hardware thinks they are in fact
- * enabled.. someone messed up their IRQ state tracing.
- */
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return;
-
- /*
- * See the fine text that goes along with this variable definition.
- */
- if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled)))
- return;
-
- /*
- * Can't allow enabling interrupts while in an interrupt handler,
- * that's general bad form and such. Recursion, limited stack etc..
- */
- if (DEBUG_LOCKS_WARN_ON(current->hardirq_context))
- return;
-
- current->lockdep_recursion = 1;
- __trace_hardirqs_on_caller(ip);
- current->lockdep_recursion = 0;
-}
-EXPORT_SYMBOL(trace_hardirqs_on_caller);
-
-void trace_hardirqs_on(void)
-{
- trace_hardirqs_on_caller(CALLER_ADDR0);
-}
-EXPORT_SYMBOL(trace_hardirqs_on);
-
-/*
- * Hardirqs were disabled:
- */
-void trace_hardirqs_off_caller(unsigned long ip)
-{
- struct task_struct *curr = current;
-
- time_hardirqs_off(CALLER_ADDR0, ip);
-
- if (unlikely(!debug_locks || current->lockdep_recursion))
- return;
-
- /*
- * So we're supposed to get called after you mask local IRQs, but for
- * some reason the hardware doesn't quite think you did a proper job.
- */
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return;
-
- if (curr->hardirqs_enabled) {
- /*
- * We have done an ON -> OFF transition:
- */
- curr->hardirqs_enabled = 0;
- curr->hardirq_disable_ip = ip;
- curr->hardirq_disable_event = ++curr->irq_events;
- debug_atomic_inc(hardirqs_off_events);
- } else
- debug_atomic_inc(redundant_hardirqs_off);
-}
-EXPORT_SYMBOL(trace_hardirqs_off_caller);
-
-void trace_hardirqs_off(void)
-{
- trace_hardirqs_off_caller(CALLER_ADDR0);
-}
-EXPORT_SYMBOL(trace_hardirqs_off);
-
-/*
- * Softirqs will be enabled:
- */
-void trace_softirqs_on(unsigned long ip)
-{
- struct task_struct *curr = current;
-
- if (unlikely(!debug_locks || current->lockdep_recursion))
- return;
-
- /*
- * We fancy IRQs being disabled here, see softirq.c, avoids
- * funny state and nesting things.
- */
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return;
-
- if (curr->softirqs_enabled) {
- debug_atomic_inc(redundant_softirqs_on);
- return;
- }
-
- current->lockdep_recursion = 1;
- /*
- * We'll do an OFF -> ON transition:
- */
- curr->softirqs_enabled = 1;
- curr->softirq_enable_ip = ip;
- curr->softirq_enable_event = ++curr->irq_events;
- debug_atomic_inc(softirqs_on_events);
- /*
- * We are going to turn softirqs on, so set the
- * usage bit for all held locks, if hardirqs are
- * enabled too:
- */
- if (curr->hardirqs_enabled)
- mark_held_locks(curr, SOFTIRQ);
- current->lockdep_recursion = 0;
-}
-
-/*
- * Softirqs were disabled:
- */
-void trace_softirqs_off(unsigned long ip)
-{
- struct task_struct *curr = current;
-
- if (unlikely(!debug_locks || current->lockdep_recursion))
- return;
-
- /*
- * We fancy IRQs being disabled here, see softirq.c
- */
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return;
-
- if (curr->softirqs_enabled) {
- /*
- * We have done an ON -> OFF transition:
- */
- curr->softirqs_enabled = 0;
- curr->softirq_disable_ip = ip;
- curr->softirq_disable_event = ++curr->irq_events;
- debug_atomic_inc(softirqs_off_events);
- /*
- * Whoops, we wanted softirqs off, so why aren't they?
- */
- DEBUG_LOCKS_WARN_ON(!softirq_count());
- } else
- debug_atomic_inc(redundant_softirqs_off);
-}
-
-static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags)
-{
- struct task_struct *curr = current;
-
- if (unlikely(!debug_locks))
- return;
-
- /* no reclaim without waiting on it */
- if (!(gfp_mask & __GFP_WAIT))
- return;
-
- /* this guy won't enter reclaim */
- if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC))
- return;
-
- /* We're only interested __GFP_FS allocations for now */
- if (!(gfp_mask & __GFP_FS))
- return;
-
- /*
- * Oi! Can't be having __GFP_FS allocations with IRQs disabled.
- */
- if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags)))
- return;
-
- mark_held_locks(curr, RECLAIM_FS);
-}
-
-static void check_flags(unsigned long flags);
-
-void lockdep_trace_alloc(gfp_t gfp_mask)
-{
- unsigned long flags;
-
- if (unlikely(current->lockdep_recursion))
- return;
-
- raw_local_irq_save(flags);
- check_flags(flags);
- current->lockdep_recursion = 1;
- __lockdep_trace_alloc(gfp_mask, flags);
- current->lockdep_recursion = 0;
- raw_local_irq_restore(flags);
-}
-
-static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
-{
- /*
- * If non-trylock use in a hardirq or softirq context, then
- * mark the lock as used in these contexts:
- */
- if (!hlock->trylock) {
- if (hlock->read) {
- if (curr->hardirq_context)
- if (!mark_lock(curr, hlock,
- LOCK_USED_IN_HARDIRQ_READ))
- return 0;
- if (curr->softirq_context)
- if (!mark_lock(curr, hlock,
- LOCK_USED_IN_SOFTIRQ_READ))
- return 0;
- } else {
- if (curr->hardirq_context)
- if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ))
- return 0;
- if (curr->softirq_context)
- if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ))
- return 0;
- }
- }
- if (!hlock->hardirqs_off) {
- if (hlock->read) {
- if (!mark_lock(curr, hlock,
- LOCK_ENABLED_HARDIRQ_READ))
- return 0;
- if (curr->softirqs_enabled)
- if (!mark_lock(curr, hlock,
- LOCK_ENABLED_SOFTIRQ_READ))
- return 0;
- } else {
- if (!mark_lock(curr, hlock,
- LOCK_ENABLED_HARDIRQ))
- return 0;
- if (curr->softirqs_enabled)
- if (!mark_lock(curr, hlock,
- LOCK_ENABLED_SOFTIRQ))
- return 0;
- }
- }
-
- /*
- * We reuse the irq context infrastructure more broadly as a general
- * context checking code. This tests GFP_FS recursion (a lock taken
- * during reclaim for a GFP_FS allocation is held over a GFP_FS
- * allocation).
- */
- if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) {
- if (hlock->read) {
- if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ))
- return 0;
- } else {
- if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS))
- return 0;
- }
- }
-
- return 1;
-}
-
-static int separate_irq_context(struct task_struct *curr,
- struct held_lock *hlock)
-{
- unsigned int depth = curr->lockdep_depth;
-
- /*
- * Keep track of points where we cross into an interrupt context:
- */
- hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) +
- curr->softirq_context;
- if (depth) {
- struct held_lock *prev_hlock;
-
- prev_hlock = curr->held_locks + depth-1;
- /*
- * If we cross into another context, reset the
- * hash key (this also prevents the checking and the
- * adding of the dependency to 'prev'):
- */
- if (prev_hlock->irq_context != hlock->irq_context)
- return 1;
- }
- return 0;
-}
-
-#else /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */
-
-static inline
-int mark_lock_irq(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit new_bit)
-{
- WARN_ON(1); /* Impossible innit? when we don't have TRACE_IRQFLAG */
- return 1;
-}
-
-static inline int mark_irqflags(struct task_struct *curr,
- struct held_lock *hlock)
-{
- return 1;
-}
-
-static inline int separate_irq_context(struct task_struct *curr,
- struct held_lock *hlock)
-{
- return 0;
-}
-
-void lockdep_trace_alloc(gfp_t gfp_mask)
-{
-}
-
-#endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */
-
-/*
- * Mark a lock with a usage bit, and validate the state transition:
- */
-static int mark_lock(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit new_bit)
-{
- unsigned int new_mask = 1 << new_bit, ret = 1;
-
- /*
- * If already set then do not dirty the cacheline,
- * nor do any checks:
- */
- if (likely(hlock_class(this)->usage_mask & new_mask))
- return 1;
-
- if (!graph_lock())
- return 0;
- /*
- * Make sure we didn't race:
- */
- if (unlikely(hlock_class(this)->usage_mask & new_mask)) {
- graph_unlock();
- return 1;
- }
-
- hlock_class(this)->usage_mask |= new_mask;
-
- if (!save_trace(hlock_class(this)->usage_traces + new_bit))
- return 0;
-
- switch (new_bit) {
-#define LOCKDEP_STATE(__STATE) \
- case LOCK_USED_IN_##__STATE: \
- case LOCK_USED_IN_##__STATE##_READ: \
- case LOCK_ENABLED_##__STATE: \
- case LOCK_ENABLED_##__STATE##_READ:
-#include "lockdep_states.h"
-#undef LOCKDEP_STATE
- ret = mark_lock_irq(curr, this, new_bit);
- if (!ret)
- return 0;
- break;
- case LOCK_USED:
- debug_atomic_dec(nr_unused_locks);
- break;
- default:
- if (!debug_locks_off_graph_unlock())
- return 0;
- WARN_ON(1);
- return 0;
- }
-
- graph_unlock();
-
- /*
- * We must printk outside of the graph_lock:
- */
- if (ret == 2) {
- printk("\nmarked lock as {%s}:\n", usage_str[new_bit]);
- print_lock(this);
- print_irqtrace_events(curr);
- dump_stack();
- }
-
- return ret;
-}
-
-/*
- * Initialize a lock instance's lock-class mapping info:
- */
-void lockdep_init_map(struct lockdep_map *lock, const char *name,
- struct lock_class_key *key, int subclass)
-{
- int i;
-
- kmemcheck_mark_initialized(lock, sizeof(*lock));
-
- for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
- lock->class_cache[i] = NULL;
-
-#ifdef CONFIG_LOCK_STAT
- lock->cpu = raw_smp_processor_id();
-#endif
-
- /*
- * Can't be having no nameless bastards around this place!
- */
- if (DEBUG_LOCKS_WARN_ON(!name)) {
- lock->name = "NULL";
- return;
- }
-
- lock->name = name;
-
- /*
- * No key, no joy, we need to hash something.
- */
- if (DEBUG_LOCKS_WARN_ON(!key))
- return;
- /*
- * Sanity check, the lock-class key must be persistent:
- */
- if (!static_obj(key)) {
- printk("BUG: key %p not in .data!\n", key);
- /*
- * What it says above ^^^^^, I suggest you read it.
- */
- DEBUG_LOCKS_WARN_ON(1);
- return;
- }
- lock->key = key;
-
- if (unlikely(!debug_locks))
- return;
-
- if (subclass)
- register_lock_class(lock, subclass, 1);
-}
-EXPORT_SYMBOL_GPL(lockdep_init_map);
-
-struct lock_class_key __lockdep_no_validate__;
-EXPORT_SYMBOL_GPL(__lockdep_no_validate__);
-
-static int
-print_lock_nested_lock_not_held(struct task_struct *curr,
- struct held_lock *hlock,
- unsigned long ip)
-{
- if (!debug_locks_off())
- return 0;
- if (debug_locks_silent)
- return 0;
-
- printk("\n");
- printk("==================================\n");
- printk("[ BUG: Nested lock was not taken ]\n");
- print_kernel_ident();
- printk("----------------------------------\n");
-
- printk("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr));
- print_lock(hlock);
-
- printk("\nbut this task is not holding:\n");
- printk("%s\n", hlock->nest_lock->name);
-
- printk("\nstack backtrace:\n");
- dump_stack();
-
- printk("\nother info that might help us debug this:\n");
- lockdep_print_held_locks(curr);
-
- printk("\nstack backtrace:\n");
- dump_stack();
-
- return 0;
-}
-
-static int __lock_is_held(struct lockdep_map *lock);
-
-/*
- * This gets called for every mutex_lock*()/spin_lock*() operation.
- * We maintain the dependency maps and validate the locking attempt:
- */
-static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
- int trylock, int read, int check, int hardirqs_off,
- struct lockdep_map *nest_lock, unsigned long ip,
- int references)
-{
- struct task_struct *curr = current;
- struct lock_class *class = NULL;
- struct held_lock *hlock;
- unsigned int depth, id;
- int chain_head = 0;
- int class_idx;
- u64 chain_key;
-
- if (!prove_locking)
- check = 1;
-
- if (unlikely(!debug_locks))
- return 0;
-
- /*
- * Lockdep should run with IRQs disabled, otherwise we could
- * get an interrupt which would want to take locks, which would
- * end up in lockdep and have you got a head-ache already?
- */
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return 0;
-
- if (lock->key == &__lockdep_no_validate__)
- check = 1;
-
- if (subclass < NR_LOCKDEP_CACHING_CLASSES)
- class = lock->class_cache[subclass];
- /*
- * Not cached?
- */
- if (unlikely(!class)) {
- class = register_lock_class(lock, subclass, 0);
- if (!class)
- return 0;
- }
- atomic_inc((atomic_t *)&class->ops);
- if (very_verbose(class)) {
- printk("\nacquire class [%p] %s", class->key, class->name);
- if (class->name_version > 1)
- printk("#%d", class->name_version);
- printk("\n");
- dump_stack();
- }
-
- /*
- * Add the lock to the list of currently held locks.
- * (we dont increase the depth just yet, up until the
- * dependency checks are done)
- */
- depth = curr->lockdep_depth;
- /*
- * Ran out of static storage for our per-task lock stack again have we?
- */
- if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH))
- return 0;
-
- class_idx = class - lock_classes + 1;
-
- if (depth) {
- hlock = curr->held_locks + depth - 1;
- if (hlock->class_idx == class_idx && nest_lock) {
- if (hlock->references)
- hlock->references++;
- else
- hlock->references = 2;
-
- return 1;
- }
- }
-
- hlock = curr->held_locks + depth;
- /*
- * Plain impossible, we just registered it and checked it weren't no
- * NULL like.. I bet this mushroom I ate was good!
- */
- if (DEBUG_LOCKS_WARN_ON(!class))
- return 0;
- hlock->class_idx = class_idx;
- hlock->acquire_ip = ip;
- hlock->instance = lock;
- hlock->nest_lock = nest_lock;
- hlock->trylock = trylock;
- hlock->read = read;
- hlock->check = check;
- hlock->hardirqs_off = !!hardirqs_off;
- hlock->references = references;
-#ifdef CONFIG_LOCK_STAT
- hlock->waittime_stamp = 0;
- hlock->holdtime_stamp = lockstat_clock();
-#endif
-
- if (check == 2 && !mark_irqflags(curr, hlock))
- return 0;
-
- /* mark it as used: */
- if (!mark_lock(curr, hlock, LOCK_USED))
- return 0;
-
- /*
- * Calculate the chain hash: it's the combined hash of all the
- * lock keys along the dependency chain. We save the hash value
- * at every step so that we can get the current hash easily
- * after unlock. The chain hash is then used to cache dependency
- * results.
- *
- * The 'key ID' is what is the most compact key value to drive
- * the hash, not class->key.
- */
- id = class - lock_classes;
- /*
- * Whoops, we did it again.. ran straight out of our static allocation.
- */
- if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
- return 0;
-
- chain_key = curr->curr_chain_key;
- if (!depth) {
- /*
- * How can we have a chain hash when we ain't got no keys?!
- */
- if (DEBUG_LOCKS_WARN_ON(chain_key != 0))
- return 0;
- chain_head = 1;
- }
-
- hlock->prev_chain_key = chain_key;
- if (separate_irq_context(curr, hlock)) {
- chain_key = 0;
- chain_head = 1;
- }
- chain_key = iterate_chain_key(chain_key, id);
-
- if (nest_lock && !__lock_is_held(nest_lock))
- return print_lock_nested_lock_not_held(curr, hlock, ip);
-
- if (!validate_chain(curr, lock, hlock, chain_head, chain_key))
- return 0;
-
- curr->curr_chain_key = chain_key;
- curr->lockdep_depth++;
- check_chain_key(curr);
-#ifdef CONFIG_DEBUG_LOCKDEP
- if (unlikely(!debug_locks))
- return 0;
-#endif
- if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) {
- debug_locks_off();
- print_lockdep_off("BUG: MAX_LOCK_DEPTH too low!");
- printk(KERN_DEBUG "depth: %i max: %lu!\n",
- curr->lockdep_depth, MAX_LOCK_DEPTH);
-
- lockdep_print_held_locks(current);
- debug_show_all_locks();
- dump_stack();
-
- return 0;
- }
-
- if (unlikely(curr->lockdep_depth > max_lockdep_depth))
- max_lockdep_depth = curr->lockdep_depth;
-
- return 1;
-}
-
-static int
-print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock,
- unsigned long ip)
-{
- if (!debug_locks_off())
- return 0;
- if (debug_locks_silent)
- return 0;
-
- printk("\n");
- printk("=====================================\n");
- printk("[ BUG: bad unlock balance detected! ]\n");
- print_kernel_ident();
- printk("-------------------------------------\n");
- printk("%s/%d is trying to release lock (",
- curr->comm, task_pid_nr(curr));
- print_lockdep_cache(lock);
- printk(") at:\n");
- print_ip_sym(ip);
- printk("but there are no more locks to release!\n");
- printk("\nother info that might help us debug this:\n");
- lockdep_print_held_locks(curr);
-
- printk("\nstack backtrace:\n");
- dump_stack();
-
- return 0;
-}
-
-/*
- * Common debugging checks for both nested and non-nested unlock:
- */
-static int check_unlock(struct task_struct *curr, struct lockdep_map *lock,
- unsigned long ip)
-{
- if (unlikely(!debug_locks))
- return 0;
- /*
- * Lockdep should run with IRQs disabled, recursion, head-ache, etc..
- */
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return 0;
-
- if (curr->lockdep_depth <= 0)
- return print_unlock_imbalance_bug(curr, lock, ip);
-
- return 1;
-}
-
-static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock)
-{
- if (hlock->instance == lock)
- return 1;
-
- if (hlock->references) {
- struct lock_class *class = lock->class_cache[0];
-
- if (!class)
- class = look_up_lock_class(lock, 0);
-
- /*
- * If look_up_lock_class() failed to find a class, we're trying
- * to test if we hold a lock that has never yet been acquired.
- * Clearly if the lock hasn't been acquired _ever_, we're not
- * holding it either, so report failure.
- */
- if (!class)
- return 0;
-
- /*
- * References, but not a lock we're actually ref-counting?
- * State got messed up, follow the sites that change ->references
- * and try to make sense of it.
- */
- if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock))
- return 0;
-
- if (hlock->class_idx == class - lock_classes + 1)
- return 1;
- }
-
- return 0;
-}
-
-static int
-__lock_set_class(struct lockdep_map *lock, const char *name,
- struct lock_class_key *key, unsigned int subclass,
- unsigned long ip)
-{
- struct task_struct *curr = current;
- struct held_lock *hlock, *prev_hlock;
- struct lock_class *class;
- unsigned int depth;
- int i;
-
- depth = curr->lockdep_depth;
- /*
- * This function is about (re)setting the class of a held lock,
- * yet we're not actually holding any locks. Naughty user!
- */
- if (DEBUG_LOCKS_WARN_ON(!depth))
- return 0;
-
- prev_hlock = NULL;
- for (i = depth-1; i >= 0; i--) {
- hlock = curr->held_locks + i;
- /*
- * We must not cross into another context:
- */
- if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
- break;
- if (match_held_lock(hlock, lock))
- goto found_it;
- prev_hlock = hlock;
- }
- return print_unlock_imbalance_bug(curr, lock, ip);
-
-found_it:
- lockdep_init_map(lock, name, key, 0);
- class = register_lock_class(lock, subclass, 0);
- hlock->class_idx = class - lock_classes + 1;
-
- curr->lockdep_depth = i;
- curr->curr_chain_key = hlock->prev_chain_key;
-
- for (; i < depth; i++) {
- hlock = curr->held_locks + i;
- if (!__lock_acquire(hlock->instance,
- hlock_class(hlock)->subclass, hlock->trylock,
- hlock->read, hlock->check, hlock->hardirqs_off,
- hlock->nest_lock, hlock->acquire_ip,
- hlock->references))
- return 0;
- }
-
- /*
- * I took it apart and put it back together again, except now I have
- * these 'spare' parts.. where shall I put them.
- */
- if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth))
- return 0;
- return 1;
-}
-
-/*
- * Remove the lock to the list of currently held locks in a
- * potentially non-nested (out of order) manner. This is a
- * relatively rare operation, as all the unlock APIs default
- * to nested mode (which uses lock_release()):
- */
-static int
-lock_release_non_nested(struct task_struct *curr,
- struct lockdep_map *lock, unsigned long ip)
-{
- struct held_lock *hlock, *prev_hlock;
- unsigned int depth;
- int i;
-
- /*
- * Check whether the lock exists in the current stack
- * of held locks:
- */
- depth = curr->lockdep_depth;
- /*
- * So we're all set to release this lock.. wait what lock? We don't
- * own any locks, you've been drinking again?
- */
- if (DEBUG_LOCKS_WARN_ON(!depth))
- return 0;
-
- prev_hlock = NULL;
- for (i = depth-1; i >= 0; i--) {
- hlock = curr->held_locks + i;
- /*
- * We must not cross into another context:
- */
- if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
- break;
- if (match_held_lock(hlock, lock))
- goto found_it;
- prev_hlock = hlock;
- }
- return print_unlock_imbalance_bug(curr, lock, ip);
-
-found_it:
- if (hlock->instance == lock)
- lock_release_holdtime(hlock);
-
- if (hlock->references) {
- hlock->references--;
- if (hlock->references) {
- /*
- * We had, and after removing one, still have
- * references, the current lock stack is still
- * valid. We're done!
- */
- return 1;
- }
- }
-
- /*
- * We have the right lock to unlock, 'hlock' points to it.
- * Now we remove it from the stack, and add back the other
- * entries (if any), recalculating the hash along the way:
- */
-
- curr->lockdep_depth = i;
- curr->curr_chain_key = hlock->prev_chain_key;
-
- for (i++; i < depth; i++) {
- hlock = curr->held_locks + i;
- if (!__lock_acquire(hlock->instance,
- hlock_class(hlock)->subclass, hlock->trylock,
- hlock->read, hlock->check, hlock->hardirqs_off,
- hlock->nest_lock, hlock->acquire_ip,
- hlock->references))
- return 0;
- }
-
- /*
- * We had N bottles of beer on the wall, we drank one, but now
- * there's not N-1 bottles of beer left on the wall...
- */
- if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1))
- return 0;
- return 1;
-}
-
-/*
- * Remove the lock to the list of currently held locks - this gets
- * called on mutex_unlock()/spin_unlock*() (or on a failed
- * mutex_lock_interruptible()). This is done for unlocks that nest
- * perfectly. (i.e. the current top of the lock-stack is unlocked)
- */
-static int lock_release_nested(struct task_struct *curr,
- struct lockdep_map *lock, unsigned long ip)
-{
- struct held_lock *hlock;
- unsigned int depth;
-
- /*
- * Pop off the top of the lock stack:
- */
- depth = curr->lockdep_depth - 1;
- hlock = curr->held_locks + depth;
-
- /*
- * Is the unlock non-nested:
- */
- if (hlock->instance != lock || hlock->references)
- return lock_release_non_nested(curr, lock, ip);
- curr->lockdep_depth--;
-
- /*
- * No more locks, but somehow we've got hash left over, who left it?
- */
- if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0)))
- return 0;
-
- curr->curr_chain_key = hlock->prev_chain_key;
-
- lock_release_holdtime(hlock);
-
-#ifdef CONFIG_DEBUG_LOCKDEP
- hlock->prev_chain_key = 0;
- hlock->class_idx = 0;
- hlock->acquire_ip = 0;
- hlock->irq_context = 0;
-#endif
- return 1;
-}
-
-/*
- * Remove the lock to the list of currently held locks - this gets
- * called on mutex_unlock()/spin_unlock*() (or on a failed
- * mutex_lock_interruptible()). This is done for unlocks that nest
- * perfectly. (i.e. the current top of the lock-stack is unlocked)
- */
-static void
-__lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
-{
- struct task_struct *curr = current;
-
- if (!check_unlock(curr, lock, ip))
- return;
-
- if (nested) {
- if (!lock_release_nested(curr, lock, ip))
- return;
- } else {
- if (!lock_release_non_nested(curr, lock, ip))
- return;
- }
-
- check_chain_key(curr);
-}
-
-static int __lock_is_held(struct lockdep_map *lock)
-{
- struct task_struct *curr = current;
- int i;
-
- for (i = 0; i < curr->lockdep_depth; i++) {
- struct held_lock *hlock = curr->held_locks + i;
-
- if (match_held_lock(hlock, lock))
- return 1;
- }
-
- return 0;
-}
-
-/*
- * Check whether we follow the irq-flags state precisely:
- */
-static void check_flags(unsigned long flags)
-{
-#if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \
- defined(CONFIG_TRACE_IRQFLAGS)
- if (!debug_locks)
- return;
-
- if (irqs_disabled_flags(flags)) {
- if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) {
- printk("possible reason: unannotated irqs-off.\n");
- }
- } else {
- if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) {
- printk("possible reason: unannotated irqs-on.\n");
- }
- }
-
- /*
- * We dont accurately track softirq state in e.g.
- * hardirq contexts (such as on 4KSTACKS), so only
- * check if not in hardirq contexts:
- */
- if (!hardirq_count()) {
- if (softirq_count()) {
- /* like the above, but with softirqs */
- DEBUG_LOCKS_WARN_ON(current->softirqs_enabled);
- } else {
- /* lick the above, does it taste good? */
- DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled);
- }
- }
-
- if (!debug_locks)
- print_irqtrace_events(current);
-#endif
-}
-
-void lock_set_class(struct lockdep_map *lock, const char *name,
- struct lock_class_key *key, unsigned int subclass,
- unsigned long ip)
-{
- unsigned long flags;
-
- if (unlikely(current->lockdep_recursion))
- return;
-
- raw_local_irq_save(flags);
- current->lockdep_recursion = 1;
- check_flags(flags);
- if (__lock_set_class(lock, name, key, subclass, ip))
- check_chain_key(current);
- current->lockdep_recursion = 0;
- raw_local_irq_restore(flags);
-}
-EXPORT_SYMBOL_GPL(lock_set_class);
-
-/*
- * We are not always called with irqs disabled - do that here,
- * and also avoid lockdep recursion:
- */
-void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
- int trylock, int read, int check,
- struct lockdep_map *nest_lock, unsigned long ip)
-{
- unsigned long flags;
-
- if (unlikely(current->lockdep_recursion))
- return;
-
- raw_local_irq_save(flags);
- check_flags(flags);
-
- current->lockdep_recursion = 1;
- trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip);
- __lock_acquire(lock, subclass, trylock, read, check,
- irqs_disabled_flags(flags), nest_lock, ip, 0);
- current->lockdep_recursion = 0;
- raw_local_irq_restore(flags);
-}
-EXPORT_SYMBOL_GPL(lock_acquire);
-
-void lock_release(struct lockdep_map *lock, int nested,
- unsigned long ip)
-{
- unsigned long flags;
-
- if (unlikely(current->lockdep_recursion))
- return;
-
- raw_local_irq_save(flags);
- check_flags(flags);
- current->lockdep_recursion = 1;
- trace_lock_release(lock, ip);
- __lock_release(lock, nested, ip);
- current->lockdep_recursion = 0;
- raw_local_irq_restore(flags);
-}
-EXPORT_SYMBOL_GPL(lock_release);
-
-int lock_is_held(struct lockdep_map *lock)
-{
- unsigned long flags;
- int ret = 0;
-
- if (unlikely(current->lockdep_recursion))
- return 1; /* avoid false negative lockdep_assert_held() */
-
- raw_local_irq_save(flags);
- check_flags(flags);
-
- current->lockdep_recursion = 1;
- ret = __lock_is_held(lock);
- current->lockdep_recursion = 0;
- raw_local_irq_restore(flags);
-
- return ret;
-}
-EXPORT_SYMBOL_GPL(lock_is_held);
-
-void lockdep_set_current_reclaim_state(gfp_t gfp_mask)
-{
- current->lockdep_reclaim_gfp = gfp_mask;
-}
-
-void lockdep_clear_current_reclaim_state(void)
-{
- current->lockdep_reclaim_gfp = 0;
-}
-
-#ifdef CONFIG_LOCK_STAT
-static int
-print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock,
- unsigned long ip)
-{
- if (!debug_locks_off())
- return 0;
- if (debug_locks_silent)
- return 0;
-
- printk("\n");
- printk("=================================\n");
- printk("[ BUG: bad contention detected! ]\n");
- print_kernel_ident();
- printk("---------------------------------\n");
- printk("%s/%d is trying to contend lock (",
- curr->comm, task_pid_nr(curr));
- print_lockdep_cache(lock);
- printk(") at:\n");
- print_ip_sym(ip);
- printk("but there are no locks held!\n");
- printk("\nother info that might help us debug this:\n");
- lockdep_print_held_locks(curr);
-
- printk("\nstack backtrace:\n");
- dump_stack();
-
- return 0;
-}
-
-static void
-__lock_contended(struct lockdep_map *lock, unsigned long ip)
-{
- struct task_struct *curr = current;
- struct held_lock *hlock, *prev_hlock;
- struct lock_class_stats *stats;
- unsigned int depth;
- int i, contention_point, contending_point;
-
- depth = curr->lockdep_depth;
- /*
- * Whee, we contended on this lock, except it seems we're not
- * actually trying to acquire anything much at all..
- */
- if (DEBUG_LOCKS_WARN_ON(!depth))
- return;
-
- prev_hlock = NULL;
- for (i = depth-1; i >= 0; i--) {
- hlock = curr->held_locks + i;
- /*
- * We must not cross into another context:
- */
- if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
- break;
- if (match_held_lock(hlock, lock))
- goto found_it;
- prev_hlock = hlock;
- }
- print_lock_contention_bug(curr, lock, ip);
- return;
-
-found_it:
- if (hlock->instance != lock)
- return;
-
- hlock->waittime_stamp = lockstat_clock();
-
- contention_point = lock_point(hlock_class(hlock)->contention_point, ip);
- contending_point = lock_point(hlock_class(hlock)->contending_point,
- lock->ip);
-
- stats = get_lock_stats(hlock_class(hlock));
- if (contention_point < LOCKSTAT_POINTS)
- stats->contention_point[contention_point]++;
- if (contending_point < LOCKSTAT_POINTS)
- stats->contending_point[contending_point]++;
- if (lock->cpu != smp_processor_id())
- stats->bounces[bounce_contended + !!hlock->read]++;
- put_lock_stats(stats);
-}
-
-static void
-__lock_acquired(struct lockdep_map *lock, unsigned long ip)
-{
- struct task_struct *curr = current;
- struct held_lock *hlock, *prev_hlock;
- struct lock_class_stats *stats;
- unsigned int depth;
- u64 now, waittime = 0;
- int i, cpu;
-
- depth = curr->lockdep_depth;
- /*
- * Yay, we acquired ownership of this lock we didn't try to
- * acquire, how the heck did that happen?
- */
- if (DEBUG_LOCKS_WARN_ON(!depth))
- return;
-
- prev_hlock = NULL;
- for (i = depth-1; i >= 0; i--) {
- hlock = curr->held_locks + i;
- /*
- * We must not cross into another context:
- */
- if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
- break;
- if (match_held_lock(hlock, lock))
- goto found_it;
- prev_hlock = hlock;
- }
- print_lock_contention_bug(curr, lock, _RET_IP_);
- return;
-
-found_it:
- if (hlock->instance != lock)
- return;
-
- cpu = smp_processor_id();
- if (hlock->waittime_stamp) {
- now = lockstat_clock();
- waittime = now - hlock->waittime_stamp;
- hlock->holdtime_stamp = now;
- }
-
- trace_lock_acquired(lock, ip);
-
- stats = get_lock_stats(hlock_class(hlock));
- if (waittime) {
- if (hlock->read)
- lock_time_inc(&stats->read_waittime, waittime);
- else
- lock_time_inc(&stats->write_waittime, waittime);
- }
- if (lock->cpu != cpu)
- stats->bounces[bounce_acquired + !!hlock->read]++;
- put_lock_stats(stats);
-
- lock->cpu = cpu;
- lock->ip = ip;
-}
-
-void lock_contended(struct lockdep_map *lock, unsigned long ip)
-{
- unsigned long flags;
-
- if (unlikely(!lock_stat))
- return;
-
- if (unlikely(current->lockdep_recursion))
- return;
-
- raw_local_irq_save(flags);
- check_flags(flags);
- current->lockdep_recursion = 1;
- trace_lock_contended(lock, ip);
- __lock_contended(lock, ip);
- current->lockdep_recursion = 0;
- raw_local_irq_restore(flags);
-}
-EXPORT_SYMBOL_GPL(lock_contended);
-
-void lock_acquired(struct lockdep_map *lock, unsigned long ip)
-{
- unsigned long flags;
-
- if (unlikely(!lock_stat))
- return;
-
- if (unlikely(current->lockdep_recursion))
- return;
-
- raw_local_irq_save(flags);
- check_flags(flags);
- current->lockdep_recursion = 1;
- __lock_acquired(lock, ip);
- current->lockdep_recursion = 0;
- raw_local_irq_restore(flags);
-}
-EXPORT_SYMBOL_GPL(lock_acquired);
-#endif
-
-/*
- * Used by the testsuite, sanitize the validator state
- * after a simulated failure:
- */
-
-void lockdep_reset(void)
-{
- unsigned long flags;
- int i;
-
- raw_local_irq_save(flags);
- current->curr_chain_key = 0;
- current->lockdep_depth = 0;
- current->lockdep_recursion = 0;
- memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock));
- nr_hardirq_chains = 0;
- nr_softirq_chains = 0;
- nr_process_chains = 0;
- debug_locks = 1;
- for (i = 0; i < CHAINHASH_SIZE; i++)
- INIT_LIST_HEAD(chainhash_table + i);
- raw_local_irq_restore(flags);
-}
-
-static void zap_class(struct lock_class *class)
-{
- int i;
-
- /*
- * Remove all dependencies this lock is
- * involved in:
- */
- for (i = 0; i < nr_list_entries; i++) {
- if (list_entries[i].class == class)
- list_del_rcu(&list_entries[i].entry);
- }
- /*
- * Unhash the class and remove it from the all_lock_classes list:
- */
- list_del_rcu(&class->hash_entry);
- list_del_rcu(&class->lock_entry);
-
- class->key = NULL;
-}
-
-static inline int within(const void *addr, void *start, unsigned long size)
-{
- return addr >= start && addr < start + size;
-}
-
-void lockdep_free_key_range(void *start, unsigned long size)
-{
- struct lock_class *class, *next;
- struct list_head *head;
- unsigned long flags;
- int i;
- int locked;
-
- raw_local_irq_save(flags);
- locked = graph_lock();
-
- /*
- * Unhash all classes that were created by this module:
- */
- for (i = 0; i < CLASSHASH_SIZE; i++) {
- head = classhash_table + i;
- if (list_empty(head))
- continue;
- list_for_each_entry_safe(class, next, head, hash_entry) {
- if (within(class->key, start, size))
- zap_class(class);
- else if (within(class->name, start, size))
- zap_class(class);
- }
- }
-
- if (locked)
- graph_unlock();
- raw_local_irq_restore(flags);
-}
-
-void lockdep_reset_lock(struct lockdep_map *lock)
-{
- struct lock_class *class, *next;
- struct list_head *head;
- unsigned long flags;
- int i, j;
- int locked;
-
- raw_local_irq_save(flags);
-
- /*
- * Remove all classes this lock might have:
- */
- for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) {
- /*
- * If the class exists we look it up and zap it:
- */
- class = look_up_lock_class(lock, j);
- if (class)
- zap_class(class);
- }
- /*
- * Debug check: in the end all mapped classes should
- * be gone.
- */
- locked = graph_lock();
- for (i = 0; i < CLASSHASH_SIZE; i++) {
- head = classhash_table + i;
- if (list_empty(head))
- continue;
- list_for_each_entry_safe(class, next, head, hash_entry) {
- int match = 0;
-
- for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++)
- match |= class == lock->class_cache[j];
-
- if (unlikely(match)) {
- if (debug_locks_off_graph_unlock()) {
- /*
- * We all just reset everything, how did it match?
- */
- WARN_ON(1);
- }
- goto out_restore;
- }
- }
- }
- if (locked)
- graph_unlock();
-
-out_restore:
- raw_local_irq_restore(flags);
-}
-
-void lockdep_init(void)
-{
- int i;
-
- /*
- * Some architectures have their own start_kernel()
- * code which calls lockdep_init(), while we also
- * call lockdep_init() from the start_kernel() itself,
- * and we want to initialize the hashes only once:
- */
- if (lockdep_initialized)
- return;
-
- for (i = 0; i < CLASSHASH_SIZE; i++)
- INIT_LIST_HEAD(classhash_table + i);
-
- for (i = 0; i < CHAINHASH_SIZE; i++)
- INIT_LIST_HEAD(chainhash_table + i);
-
- lockdep_initialized = 1;
-}
-
-void __init lockdep_info(void)
-{
- printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n");
-
- printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES);
- printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH);
- printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS);
- printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE);
- printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES);
- printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS);
- printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE);
-
- printk(" memory used by lock dependency info: %lu kB\n",
- (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS +
- sizeof(struct list_head) * CLASSHASH_SIZE +
- sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES +
- sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS +
- sizeof(struct list_head) * CHAINHASH_SIZE
-#ifdef CONFIG_PROVE_LOCKING
- + sizeof(struct circular_queue)
-#endif
- ) / 1024
- );
-
- printk(" per task-struct memory footprint: %lu bytes\n",
- sizeof(struct held_lock) * MAX_LOCK_DEPTH);
-
-#ifdef CONFIG_DEBUG_LOCKDEP
- if (lockdep_init_error) {
- printk("WARNING: lockdep init error! lock-%s was acquired"
- "before lockdep_init\n", lock_init_error);
- printk("Call stack leading to lockdep invocation was:\n");
- print_stack_trace(&lockdep_init_trace, 0);
- }
-#endif
-}
-
-static void
-print_freed_lock_bug(struct task_struct *curr, const void *mem_from,
- const void *mem_to, struct held_lock *hlock)
-{
- if (!debug_locks_off())
- return;
- if (debug_locks_silent)
- return;
-
- printk("\n");
- printk("=========================\n");
- printk("[ BUG: held lock freed! ]\n");
- print_kernel_ident();
- printk("-------------------------\n");
- printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n",
- curr->comm, task_pid_nr(curr), mem_from, mem_to-1);
- print_lock(hlock);
- lockdep_print_held_locks(curr);
-
- printk("\nstack backtrace:\n");
- dump_stack();
-}
-
-static inline int not_in_range(const void* mem_from, unsigned long mem_len,
- const void* lock_from, unsigned long lock_len)
-{
- return lock_from + lock_len <= mem_from ||
- mem_from + mem_len <= lock_from;
-}
-
-/*
- * Called when kernel memory is freed (or unmapped), or if a lock
- * is destroyed or reinitialized - this code checks whether there is
- * any held lock in the memory range of <from> to <to>:
- */
-void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len)
-{
- struct task_struct *curr = current;
- struct held_lock *hlock;
- unsigned long flags;
- int i;
-
- if (unlikely(!debug_locks))
- return;
-
- local_irq_save(flags);
- for (i = 0; i < curr->lockdep_depth; i++) {
- hlock = curr->held_locks + i;
-
- if (not_in_range(mem_from, mem_len, hlock->instance,
- sizeof(*hlock->instance)))
- continue;
-
- print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock);
- break;
- }
- local_irq_restore(flags);
-}
-EXPORT_SYMBOL_GPL(debug_check_no_locks_freed);
-
-static void print_held_locks_bug(void)
-{
- if (!debug_locks_off())
- return;
- if (debug_locks_silent)
- return;
-
- printk("\n");
- printk("=====================================\n");
- printk("[ BUG: %s/%d still has locks held! ]\n",
- current->comm, task_pid_nr(current));
- print_kernel_ident();
- printk("-------------------------------------\n");
- lockdep_print_held_locks(current);
- printk("\nstack backtrace:\n");
- dump_stack();
-}
-
-void debug_check_no_locks_held(void)
-{
- if (unlikely(current->lockdep_depth > 0))
- print_held_locks_bug();
-}
-EXPORT_SYMBOL_GPL(debug_check_no_locks_held);
-
-void debug_show_all_locks(void)
-{
- struct task_struct *g, *p;
- int count = 10;
- int unlock = 1;
-
- if (unlikely(!debug_locks)) {
- printk("INFO: lockdep is turned off.\n");
- return;
- }
- printk("\nShowing all locks held in the system:\n");
-
- /*
- * Here we try to get the tasklist_lock as hard as possible,
- * if not successful after 2 seconds we ignore it (but keep
- * trying). This is to enable a debug printout even if a
- * tasklist_lock-holding task deadlocks or crashes.
- */
-retry:
- if (!read_trylock(&tasklist_lock)) {
- if (count == 10)
- printk("hm, tasklist_lock locked, retrying... ");
- if (count) {
- count--;
- printk(" #%d", 10-count);
- mdelay(200);
- goto retry;
- }
- printk(" ignoring it.\n");
- unlock = 0;
- } else {
- if (count != 10)
- printk(KERN_CONT " locked it.\n");
- }
-
- do_each_thread(g, p) {
- /*
- * It's not reliable to print a task's held locks
- * if it's not sleeping (or if it's not the current
- * task):
- */
- if (p->state == TASK_RUNNING && p != current)
- continue;
- if (p->lockdep_depth)
- lockdep_print_held_locks(p);
- if (!unlock)
- if (read_trylock(&tasklist_lock))
- unlock = 1;
- } while_each_thread(g, p);
-
- printk("\n");
- printk("=============================================\n\n");
-
- if (unlock)
- read_unlock(&tasklist_lock);
-}
-EXPORT_SYMBOL_GPL(debug_show_all_locks);
-
-/*
- * Careful: only use this function if you are sure that
- * the task cannot run in parallel!
- */
-void debug_show_held_locks(struct task_struct *task)
-{
- if (unlikely(!debug_locks)) {
- printk("INFO: lockdep is turned off.\n");
- return;
- }
- lockdep_print_held_locks(task);
-}
-EXPORT_SYMBOL_GPL(debug_show_held_locks);
-
-void lockdep_sys_exit(void)
-{
- struct task_struct *curr = current;
-
- if (unlikely(curr->lockdep_depth)) {
- if (!debug_locks_off())
- return;
- printk("\n");
- printk("================================================\n");
- printk("[ BUG: lock held when returning to user space! ]\n");
- print_kernel_ident();
- printk("------------------------------------------------\n");
- printk("%s/%d is leaving the kernel with locks still held!\n",
- curr->comm, curr->pid);
- lockdep_print_held_locks(curr);
- }
-}
-
-void lockdep_rcu_suspicious(const char *file, const int line, const char *s)
-{
- struct task_struct *curr = current;
-
-#ifndef CONFIG_PROVE_RCU_REPEATEDLY
- if (!debug_locks_off())
- return;
-#endif /* #ifdef CONFIG_PROVE_RCU_REPEATEDLY */
- /* Note: the following can be executed concurrently, so be careful. */
- printk("\n");
- printk("===============================\n");
- printk("[ INFO: suspicious RCU usage. ]\n");
- print_kernel_ident();
- printk("-------------------------------\n");
- printk("%s:%d %s!\n", file, line, s);
- printk("\nother info that might help us debug this:\n\n");
- printk("\n%srcu_scheduler_active = %d, debug_locks = %d\n",
- !rcu_lockdep_current_cpu_online()
- ? "RCU used illegally from offline CPU!\n"
- : !rcu_is_watching()
- ? "RCU used illegally from idle CPU!\n"
- : "",
- rcu_scheduler_active, debug_locks);
-
- /*
- * If a CPU is in the RCU-free window in idle (ie: in the section
- * between rcu_idle_enter() and rcu_idle_exit(), then RCU
- * considers that CPU to be in an "extended quiescent state",
- * which means that RCU will be completely ignoring that CPU.
- * Therefore, rcu_read_lock() and friends have absolutely no
- * effect on a CPU running in that state. In other words, even if
- * such an RCU-idle CPU has called rcu_read_lock(), RCU might well
- * delete data structures out from under it. RCU really has no
- * choice here: we need to keep an RCU-free window in idle where
- * the CPU may possibly enter into low power mode. This way we can
- * notice an extended quiescent state to other CPUs that started a grace
- * period. Otherwise we would delay any grace period as long as we run
- * in the idle task.
- *
- * So complain bitterly if someone does call rcu_read_lock(),
- * rcu_read_lock_bh() and so on from extended quiescent states.
- */
- if (!rcu_is_watching())
- printk("RCU used illegally from extended quiescent state!\n");
-
- lockdep_print_held_locks(curr);
- printk("\nstack backtrace:\n");
- dump_stack();
-}
-EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious);
Index: linux-2.6/kernel/lockdep_internals.h
===================================================================
--- linux-2.6.orig/kernel/lockdep_internals.h
+++ /dev/null
@@ -1,170 +0,0 @@
-/*
- * kernel/lockdep_internals.h
- *
- * Runtime locking correctness validator
- *
- * lockdep subsystem internal functions and variables.
- */
-
-/*
- * Lock-class usage-state bits:
- */
-enum lock_usage_bit {
-#define LOCKDEP_STATE(__STATE) \
- LOCK_USED_IN_##__STATE, \
- LOCK_USED_IN_##__STATE##_READ, \
- LOCK_ENABLED_##__STATE, \
- LOCK_ENABLED_##__STATE##_READ,
-#include "lockdep_states.h"
-#undef LOCKDEP_STATE
- LOCK_USED,
- LOCK_USAGE_STATES
-};
-
-/*
- * Usage-state bitmasks:
- */
-#define __LOCKF(__STATE) LOCKF_##__STATE = (1 << LOCK_##__STATE),
-
-enum {
-#define LOCKDEP_STATE(__STATE) \
- __LOCKF(USED_IN_##__STATE) \
- __LOCKF(USED_IN_##__STATE##_READ) \
- __LOCKF(ENABLED_##__STATE) \
- __LOCKF(ENABLED_##__STATE##_READ)
-#include "lockdep_states.h"
-#undef LOCKDEP_STATE
- __LOCKF(USED)
-};
-
-#define LOCKF_ENABLED_IRQ (LOCKF_ENABLED_HARDIRQ | LOCKF_ENABLED_SOFTIRQ)
-#define LOCKF_USED_IN_IRQ (LOCKF_USED_IN_HARDIRQ | LOCKF_USED_IN_SOFTIRQ)
-
-#define LOCKF_ENABLED_IRQ_READ \
- (LOCKF_ENABLED_HARDIRQ_READ | LOCKF_ENABLED_SOFTIRQ_READ)
-#define LOCKF_USED_IN_IRQ_READ \
- (LOCKF_USED_IN_HARDIRQ_READ | LOCKF_USED_IN_SOFTIRQ_READ)
-
-/*
- * MAX_LOCKDEP_ENTRIES is the maximum number of lock dependencies
- * we track.
- *
- * We use the per-lock dependency maps in two ways: we grow it by adding
- * every to-be-taken lock to all currently held lock's own dependency
- * table (if it's not there yet), and we check it for lock order
- * conflicts and deadlocks.
- */
-#define MAX_LOCKDEP_ENTRIES 16384UL
-
-#define MAX_LOCKDEP_CHAINS_BITS 15
-#define MAX_LOCKDEP_CHAINS (1UL << MAX_LOCKDEP_CHAINS_BITS)
-
-#define MAX_LOCKDEP_CHAIN_HLOCKS (MAX_LOCKDEP_CHAINS*5)
-
-/*
- * Stack-trace: tightly packed array of stack backtrace
- * addresses. Protected by the hash_lock.
- */
-#define MAX_STACK_TRACE_ENTRIES 262144UL
-
-extern struct list_head all_lock_classes;
-extern struct lock_chain lock_chains[];
-
-#define LOCK_USAGE_CHARS (1+LOCK_USAGE_STATES/2)
-
-extern void get_usage_chars(struct lock_class *class,
- char usage[LOCK_USAGE_CHARS]);
-
-extern const char * __get_key_name(struct lockdep_subclass_key *key, char *str);
-
-struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i);
-
-extern unsigned long nr_lock_classes;
-extern unsigned long nr_list_entries;
-extern unsigned long nr_lock_chains;
-extern int nr_chain_hlocks;
-extern unsigned long nr_stack_trace_entries;
-
-extern unsigned int nr_hardirq_chains;
-extern unsigned int nr_softirq_chains;
-extern unsigned int nr_process_chains;
-extern unsigned int max_lockdep_depth;
-extern unsigned int max_recursion_depth;
-
-extern unsigned int max_bfs_queue_depth;
-
-#ifdef CONFIG_PROVE_LOCKING
-extern unsigned long lockdep_count_forward_deps(struct lock_class *);
-extern unsigned long lockdep_count_backward_deps(struct lock_class *);
-#else
-static inline unsigned long
-lockdep_count_forward_deps(struct lock_class *class)
-{
- return 0;
-}
-static inline unsigned long
-lockdep_count_backward_deps(struct lock_class *class)
-{
- return 0;
-}
-#endif
-
-#ifdef CONFIG_DEBUG_LOCKDEP
-
-#include <asm/local.h>
-/*
- * Various lockdep statistics.
- * We want them per cpu as they are often accessed in fast path
- * and we want to avoid too much cache bouncing.
- */
-struct lockdep_stats {
- int chain_lookup_hits;
- int chain_lookup_misses;
- int hardirqs_on_events;
- int hardirqs_off_events;
- int redundant_hardirqs_on;
- int redundant_hardirqs_off;
- int softirqs_on_events;
- int softirqs_off_events;
- int redundant_softirqs_on;
- int redundant_softirqs_off;
- int nr_unused_locks;
- int nr_cyclic_checks;
- int nr_cyclic_check_recursions;
- int nr_find_usage_forwards_checks;
- int nr_find_usage_forwards_recursions;
- int nr_find_usage_backwards_checks;
- int nr_find_usage_backwards_recursions;
-};
-
-DECLARE_PER_CPU(struct lockdep_stats, lockdep_stats);
-
-#define __debug_atomic_inc(ptr) \
- this_cpu_inc(lockdep_stats.ptr);
-
-#define debug_atomic_inc(ptr) { \
- WARN_ON_ONCE(!irqs_disabled()); \
- __this_cpu_inc(lockdep_stats.ptr); \
-}
-
-#define debug_atomic_dec(ptr) { \
- WARN_ON_ONCE(!irqs_disabled()); \
- __this_cpu_dec(lockdep_stats.ptr); \
-}
-
-#define debug_atomic_read(ptr) ({ \
- struct lockdep_stats *__cpu_lockdep_stats; \
- unsigned long long __total = 0; \
- int __cpu; \
- for_each_possible_cpu(__cpu) { \
- __cpu_lockdep_stats = &per_cpu(lockdep_stats, __cpu); \
- __total += __cpu_lockdep_stats->ptr; \
- } \
- __total; \
-})
-#else
-# define __debug_atomic_inc(ptr) do { } while (0)
-# define debug_atomic_inc(ptr) do { } while (0)
-# define debug_atomic_dec(ptr) do { } while (0)
-# define debug_atomic_read(ptr) 0
-#endif
Index: linux-2.6/kernel/lockdep_proc.c
===================================================================
--- linux-2.6.orig/kernel/lockdep_proc.c
+++ /dev/null
@@ -1,683 +0,0 @@
-/*
- * kernel/lockdep_proc.c
- *
- * Runtime locking correctness validator
- *
- * Started by Ingo Molnar:
- *
- * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
- *
- * Code for /proc/lockdep and /proc/lockdep_stats:
- *
- */
-#include <linux/export.h>
-#include <linux/proc_fs.h>
-#include <linux/seq_file.h>
-#include <linux/kallsyms.h>
-#include <linux/debug_locks.h>
-#include <linux/vmalloc.h>
-#include <linux/sort.h>
-#include <asm/uaccess.h>
-#include <asm/div64.h>
-
-#include "lockdep_internals.h"
-
-static void *l_next(struct seq_file *m, void *v, loff_t *pos)
-{
- return seq_list_next(v, &all_lock_classes, pos);
-}
-
-static void *l_start(struct seq_file *m, loff_t *pos)
-{
- return seq_list_start_head(&all_lock_classes, *pos);
-}
-
-static void l_stop(struct seq_file *m, void *v)
-{
-}
-
-static void print_name(struct seq_file *m, struct lock_class *class)
-{
- char str[KSYM_NAME_LEN];
- const char *name = class->name;
-
- if (!name) {
- name = __get_key_name(class->key, str);
- seq_printf(m, "%s", name);
- } else{
- seq_printf(m, "%s", name);
- if (class->name_version > 1)
- seq_printf(m, "#%d", class->name_version);
- if (class->subclass)
- seq_printf(m, "/%d", class->subclass);
- }
-}
-
-static int l_show(struct seq_file *m, void *v)
-{
- struct lock_class *class = list_entry(v, struct lock_class, lock_entry);
- struct lock_list *entry;
- char usage[LOCK_USAGE_CHARS];
-
- if (v == &all_lock_classes) {
- seq_printf(m, "all lock classes:\n");
- return 0;
- }
-
- seq_printf(m, "%p", class->key);
-#ifdef CONFIG_DEBUG_LOCKDEP
- seq_printf(m, " OPS:%8ld", class->ops);
-#endif
-#ifdef CONFIG_PROVE_LOCKING
- seq_printf(m, " FD:%5ld", lockdep_count_forward_deps(class));
- seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class));
-#endif
-
- get_usage_chars(class, usage);
- seq_printf(m, " %s", usage);
-
- seq_printf(m, ": ");
- print_name(m, class);
- seq_puts(m, "\n");
-
- list_for_each_entry(entry, &class->locks_after, entry) {
- if (entry->distance == 1) {
- seq_printf(m, " -> [%p] ", entry->class->key);
- print_name(m, entry->class);
- seq_puts(m, "\n");
- }
- }
- seq_puts(m, "\n");
-
- return 0;
-}
-
-static const struct seq_operations lockdep_ops = {
- .start = l_start,
- .next = l_next,
- .stop = l_stop,
- .show = l_show,
-};
-
-static int lockdep_open(struct inode *inode, struct file *file)
-{
- return seq_open(file, &lockdep_ops);
-}
-
-static const struct file_operations proc_lockdep_operations = {
- .open = lockdep_open,
- .read = seq_read,
- .llseek = seq_lseek,
- .release = seq_release,
-};
-
-#ifdef CONFIG_PROVE_LOCKING
-static void *lc_start(struct seq_file *m, loff_t *pos)
-{
- if (*pos == 0)
- return SEQ_START_TOKEN;
-
- if (*pos - 1 < nr_lock_chains)
- return lock_chains + (*pos - 1);
-
- return NULL;
-}
-
-static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
-{
- (*pos)++;
- return lc_start(m, pos);
-}
-
-static void lc_stop(struct seq_file *m, void *v)
-{
-}
-
-static int lc_show(struct seq_file *m, void *v)
-{
- struct lock_chain *chain = v;
- struct lock_class *class;
- int i;
-
- if (v == SEQ_START_TOKEN) {
- seq_printf(m, "all lock chains:\n");
- return 0;
- }
-
- seq_printf(m, "irq_context: %d\n", chain->irq_context);
-
- for (i = 0; i < chain->depth; i++) {
- class = lock_chain_get_class(chain, i);
- if (!class->key)
- continue;
-
- seq_printf(m, "[%p] ", class->key);
- print_name(m, class);
- seq_puts(m, "\n");
- }
- seq_puts(m, "\n");
-
- return 0;
-}
-
-static const struct seq_operations lockdep_chains_ops = {
- .start = lc_start,
- .next = lc_next,
- .stop = lc_stop,
- .show = lc_show,
-};
-
-static int lockdep_chains_open(struct inode *inode, struct file *file)
-{
- return seq_open(file, &lockdep_chains_ops);
-}
-
-static const struct file_operations proc_lockdep_chains_operations = {
- .open = lockdep_chains_open,
- .read = seq_read,
- .llseek = seq_lseek,
- .release = seq_release,
-};
-#endif /* CONFIG_PROVE_LOCKING */
-
-static void lockdep_stats_debug_show(struct seq_file *m)
-{
-#ifdef CONFIG_DEBUG_LOCKDEP
- unsigned long long hi1 = debug_atomic_read(hardirqs_on_events),
- hi2 = debug_atomic_read(hardirqs_off_events),
- hr1 = debug_atomic_read(redundant_hardirqs_on),
- hr2 = debug_atomic_read(redundant_hardirqs_off),
- si1 = debug_atomic_read(softirqs_on_events),
- si2 = debug_atomic_read(softirqs_off_events),
- sr1 = debug_atomic_read(redundant_softirqs_on),
- sr2 = debug_atomic_read(redundant_softirqs_off);
-
- seq_printf(m, " chain lookup misses: %11llu\n",
- debug_atomic_read(chain_lookup_misses));
- seq_printf(m, " chain lookup hits: %11llu\n",
- debug_atomic_read(chain_lookup_hits));
- seq_printf(m, " cyclic checks: %11llu\n",
- debug_atomic_read(nr_cyclic_checks));
- seq_printf(m, " find-mask forwards checks: %11llu\n",
- debug_atomic_read(nr_find_usage_forwards_checks));
- seq_printf(m, " find-mask backwards checks: %11llu\n",
- debug_atomic_read(nr_find_usage_backwards_checks));
-
- seq_printf(m, " hardirq on events: %11llu\n", hi1);
- seq_printf(m, " hardirq off events: %11llu\n", hi2);
- seq_printf(m, " redundant hardirq ons: %11llu\n", hr1);
- seq_printf(m, " redundant hardirq offs: %11llu\n", hr2);
- seq_printf(m, " softirq on events: %11llu\n", si1);
- seq_printf(m, " softirq off events: %11llu\n", si2);
- seq_printf(m, " redundant softirq ons: %11llu\n", sr1);
- seq_printf(m, " redundant softirq offs: %11llu\n", sr2);
-#endif
-}
-
-static int lockdep_stats_show(struct seq_file *m, void *v)
-{
- struct lock_class *class;
- unsigned long nr_unused = 0, nr_uncategorized = 0,
- nr_irq_safe = 0, nr_irq_unsafe = 0,
- nr_softirq_safe = 0, nr_softirq_unsafe = 0,
- nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
- nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
- nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
- nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
- sum_forward_deps = 0;
-
- list_for_each_entry(class, &all_lock_classes, lock_entry) {
-
- if (class->usage_mask == 0)
- nr_unused++;
- if (class->usage_mask == LOCKF_USED)
- nr_uncategorized++;
- if (class->usage_mask & LOCKF_USED_IN_IRQ)
- nr_irq_safe++;
- if (class->usage_mask & LOCKF_ENABLED_IRQ)
- nr_irq_unsafe++;
- if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
- nr_softirq_safe++;
- if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ)
- nr_softirq_unsafe++;
- if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
- nr_hardirq_safe++;
- if (class->usage_mask & LOCKF_ENABLED_HARDIRQ)
- nr_hardirq_unsafe++;
- if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
- nr_irq_read_safe++;
- if (class->usage_mask & LOCKF_ENABLED_IRQ_READ)
- nr_irq_read_unsafe++;
- if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
- nr_softirq_read_safe++;
- if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ)
- nr_softirq_read_unsafe++;
- if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
- nr_hardirq_read_safe++;
- if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ)
- nr_hardirq_read_unsafe++;
-
-#ifdef CONFIG_PROVE_LOCKING
- sum_forward_deps += lockdep_count_forward_deps(class);
-#endif
- }
-#ifdef CONFIG_DEBUG_LOCKDEP
- DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused);
-#endif
- seq_printf(m, " lock-classes: %11lu [max: %lu]\n",
- nr_lock_classes, MAX_LOCKDEP_KEYS);
- seq_printf(m, " direct dependencies: %11lu [max: %lu]\n",
- nr_list_entries, MAX_LOCKDEP_ENTRIES);
- seq_printf(m, " indirect dependencies: %11lu\n",
- sum_forward_deps);
-
- /*
- * Total number of dependencies:
- *
- * All irq-safe locks may nest inside irq-unsafe locks,
- * plus all the other known dependencies:
- */
- seq_printf(m, " all direct dependencies: %11lu\n",
- nr_irq_unsafe * nr_irq_safe +
- nr_hardirq_unsafe * nr_hardirq_safe +
- nr_list_entries);
-
-#ifdef CONFIG_PROVE_LOCKING
- seq_printf(m, " dependency chains: %11lu [max: %lu]\n",
- nr_lock_chains, MAX_LOCKDEP_CHAINS);
- seq_printf(m, " dependency chain hlocks: %11d [max: %lu]\n",
- nr_chain_hlocks, MAX_LOCKDEP_CHAIN_HLOCKS);
-#endif
-
-#ifdef CONFIG_TRACE_IRQFLAGS
- seq_printf(m, " in-hardirq chains: %11u\n",
- nr_hardirq_chains);
- seq_printf(m, " in-softirq chains: %11u\n",
- nr_softirq_chains);
-#endif
- seq_printf(m, " in-process chains: %11u\n",
- nr_process_chains);
- seq_printf(m, " stack-trace entries: %11lu [max: %lu]\n",
- nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
- seq_printf(m, " combined max dependencies: %11u\n",
- (nr_hardirq_chains + 1) *
- (nr_softirq_chains + 1) *
- (nr_process_chains + 1)
- );
- seq_printf(m, " hardirq-safe locks: %11lu\n",
- nr_hardirq_safe);
- seq_printf(m, " hardirq-unsafe locks: %11lu\n",
- nr_hardirq_unsafe);
- seq_printf(m, " softirq-safe locks: %11lu\n",
- nr_softirq_safe);
- seq_printf(m, " softirq-unsafe locks: %11lu\n",
- nr_softirq_unsafe);
- seq_printf(m, " irq-safe locks: %11lu\n",
- nr_irq_safe);
- seq_printf(m, " irq-unsafe locks: %11lu\n",
- nr_irq_unsafe);
-
- seq_printf(m, " hardirq-read-safe locks: %11lu\n",
- nr_hardirq_read_safe);
- seq_printf(m, " hardirq-read-unsafe locks: %11lu\n",
- nr_hardirq_read_unsafe);
- seq_printf(m, " softirq-read-safe locks: %11lu\n",
- nr_softirq_read_safe);
- seq_printf(m, " softirq-read-unsafe locks: %11lu\n",
- nr_softirq_read_unsafe);
- seq_printf(m, " irq-read-safe locks: %11lu\n",
- nr_irq_read_safe);
- seq_printf(m, " irq-read-unsafe locks: %11lu\n",
- nr_irq_read_unsafe);
-
- seq_printf(m, " uncategorized locks: %11lu\n",
- nr_uncategorized);
- seq_printf(m, " unused locks: %11lu\n",
- nr_unused);
- seq_printf(m, " max locking depth: %11u\n",
- max_lockdep_depth);
-#ifdef CONFIG_PROVE_LOCKING
- seq_printf(m, " max bfs queue depth: %11u\n",
- max_bfs_queue_depth);
-#endif
- lockdep_stats_debug_show(m);
- seq_printf(m, " debug_locks: %11u\n",
- debug_locks);
-
- return 0;
-}
-
-static int lockdep_stats_open(struct inode *inode, struct file *file)
-{
- return single_open(file, lockdep_stats_show, NULL);
-}
-
-static const struct file_operations proc_lockdep_stats_operations = {
- .open = lockdep_stats_open,
- .read = seq_read,
- .llseek = seq_lseek,
- .release = single_release,
-};
-
-#ifdef CONFIG_LOCK_STAT
-
-struct lock_stat_data {
- struct lock_class *class;
- struct lock_class_stats stats;
-};
-
-struct lock_stat_seq {
- struct lock_stat_data *iter_end;
- struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
-};
-
-/*
- * sort on absolute number of contentions
- */
-static int lock_stat_cmp(const void *l, const void *r)
-{
- const struct lock_stat_data *dl = l, *dr = r;
- unsigned long nl, nr;
-
- nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
- nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
-
- return nr - nl;
-}
-
-static void seq_line(struct seq_file *m, char c, int offset, int length)
-{
- int i;
-
- for (i = 0; i < offset; i++)
- seq_puts(m, " ");
- for (i = 0; i < length; i++)
- seq_printf(m, "%c", c);
- seq_puts(m, "\n");
-}
-
-static void snprint_time(char *buf, size_t bufsiz, s64 nr)
-{
- s64 div;
- s32 rem;
-
- nr += 5; /* for display rounding */
- div = div_s64_rem(nr, 1000, &rem);
- snprintf(buf, bufsiz, "%lld.%02d", (long long)div, (int)rem/10);
-}
-
-static void seq_time(struct seq_file *m, s64 time)
-{
- char num[15];
-
- snprint_time(num, sizeof(num), time);
- seq_printf(m, " %14s", num);
-}
-
-static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
-{
- seq_printf(m, "%14lu", lt->nr);
- seq_time(m, lt->min);
- seq_time(m, lt->max);
- seq_time(m, lt->total);
- seq_time(m, lt->nr ? do_div(lt->total, lt->nr) : 0);
-}
-
-static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
-{
- char name[39];
- struct lock_class *class;
- struct lock_class_stats *stats;
- int i, namelen;
-
- class = data->class;
- stats = &data->stats;
-
- namelen = 38;
- if (class->name_version > 1)
- namelen -= 2; /* XXX truncates versions > 9 */
- if (class->subclass)
- namelen -= 2;
-
- if (!class->name) {
- char str[KSYM_NAME_LEN];
- const char *key_name;
-
- key_name = __get_key_name(class->key, str);
- snprintf(name, namelen, "%s", key_name);
- } else {
- snprintf(name, namelen, "%s", class->name);
- }
- namelen = strlen(name);
- if (class->name_version > 1) {
- snprintf(name+namelen, 3, "#%d", class->name_version);
- namelen += 2;
- }
- if (class->subclass) {
- snprintf(name+namelen, 3, "/%d", class->subclass);
- namelen += 2;
- }
-
- if (stats->write_holdtime.nr) {
- if (stats->read_holdtime.nr)
- seq_printf(m, "%38s-W:", name);
- else
- seq_printf(m, "%40s:", name);
-
- seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
- seq_lock_time(m, &stats->write_waittime);
- seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
- seq_lock_time(m, &stats->write_holdtime);
- seq_puts(m, "\n");
- }
-
- if (stats->read_holdtime.nr) {
- seq_printf(m, "%38s-R:", name);
- seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
- seq_lock_time(m, &stats->read_waittime);
- seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
- seq_lock_time(m, &stats->read_holdtime);
- seq_puts(m, "\n");
- }
-
- if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
- return;
-
- if (stats->read_holdtime.nr)
- namelen += 2;
-
- for (i = 0; i < LOCKSTAT_POINTS; i++) {
- char ip[32];
-
- if (class->contention_point[i] == 0)
- break;
-
- if (!i)
- seq_line(m, '-', 40-namelen, namelen);
-
- snprintf(ip, sizeof(ip), "[<%p>]",
- (void *)class->contention_point[i]);
- seq_printf(m, "%40s %14lu %29s %pS\n",
- name, stats->contention_point[i],
- ip, (void *)class->contention_point[i]);
- }
- for (i = 0; i < LOCKSTAT_POINTS; i++) {
- char ip[32];
-
- if (class->contending_point[i] == 0)
- break;
-
- if (!i)
- seq_line(m, '-', 40-namelen, namelen);
-
- snprintf(ip, sizeof(ip), "[<%p>]",
- (void *)class->contending_point[i]);
- seq_printf(m, "%40s %14lu %29s %pS\n",
- name, stats->contending_point[i],
- ip, (void *)class->contending_point[i]);
- }
- if (i) {
- seq_puts(m, "\n");
- seq_line(m, '.', 0, 40 + 1 + 12 * (14 + 1));
- seq_puts(m, "\n");
- }
-}
-
-static void seq_header(struct seq_file *m)
-{
- seq_puts(m, "lock_stat version 0.4\n");
-
- if (unlikely(!debug_locks))
- seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n");
-
- seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1));
- seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s %14s %14s "
- "%14s %14s\n",
- "class name",
- "con-bounces",
- "contentions",
- "waittime-min",
- "waittime-max",
- "waittime-total",
- "waittime-avg",
- "acq-bounces",
- "acquisitions",
- "holdtime-min",
- "holdtime-max",
- "holdtime-total",
- "holdtime-avg");
- seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1));
- seq_printf(m, "\n");
-}
-
-static void *ls_start(struct seq_file *m, loff_t *pos)
-{
- struct lock_stat_seq *data = m->private;
- struct lock_stat_data *iter;
-
- if (*pos == 0)
- return SEQ_START_TOKEN;
-
- iter = data->stats + (*pos - 1);
- if (iter >= data->iter_end)
- iter = NULL;
-
- return iter;
-}
-
-static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
-{
- (*pos)++;
- return ls_start(m, pos);
-}
-
-static void ls_stop(struct seq_file *m, void *v)
-{
-}
-
-static int ls_show(struct seq_file *m, void *v)
-{
- if (v == SEQ_START_TOKEN)
- seq_header(m);
- else
- seq_stats(m, v);
-
- return 0;
-}
-
-static const struct seq_operations lockstat_ops = {
- .start = ls_start,
- .next = ls_next,
- .stop = ls_stop,
- .show = ls_show,
-};
-
-static int lock_stat_open(struct inode *inode, struct file *file)
-{
- int res;
- struct lock_class *class;
- struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
-
- if (!data)
- return -ENOMEM;
-
- res = seq_open(file, &lockstat_ops);
- if (!res) {
- struct lock_stat_data *iter = data->stats;
- struct seq_file *m = file->private_data;
-
- list_for_each_entry(class, &all_lock_classes, lock_entry) {
- iter->class = class;
- iter->stats = lock_stats(class);
- iter++;
- }
- data->iter_end = iter;
-
- sort(data->stats, data->iter_end - data->stats,
- sizeof(struct lock_stat_data),
- lock_stat_cmp, NULL);
-
- m->private = data;
- } else
- vfree(data);
-
- return res;
-}
-
-static ssize_t lock_stat_write(struct file *file, const char __user *buf,
- size_t count, loff_t *ppos)
-{
- struct lock_class *class;
- char c;
-
- if (count) {
- if (get_user(c, buf))
- return -EFAULT;
-
- if (c != '0')
- return count;
-
- list_for_each_entry(class, &all_lock_classes, lock_entry)
- clear_lock_stats(class);
- }
- return count;
-}
-
-static int lock_stat_release(struct inode *inode, struct file *file)
-{
- struct seq_file *seq = file->private_data;
-
- vfree(seq->private);
- return seq_release(inode, file);
-}
-
-static const struct file_operations proc_lock_stat_operations = {
- .open = lock_stat_open,
- .write = lock_stat_write,
- .read = seq_read,
- .llseek = seq_lseek,
- .release = lock_stat_release,
-};
-#endif /* CONFIG_LOCK_STAT */
-
-static int __init lockdep_proc_init(void)
-{
- proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations);
-#ifdef CONFIG_PROVE_LOCKING
- proc_create("lockdep_chains", S_IRUSR, NULL,
- &proc_lockdep_chains_operations);
-#endif
- proc_create("lockdep_stats", S_IRUSR, NULL,
- &proc_lockdep_stats_operations);
-
-#ifdef CONFIG_LOCK_STAT
- proc_create("lock_stat", S_IRUSR | S_IWUSR, NULL,
- &proc_lock_stat_operations);
-#endif
-
- return 0;
-}
-
-__initcall(lockdep_proc_init);
-
Index: linux-2.6/kernel/lockdep_states.h
===================================================================
--- linux-2.6.orig/kernel/lockdep_states.h
+++ /dev/null
@@ -1,9 +0,0 @@
-/*
- * Lockdep states,
- *
- * please update XXX_LOCK_USAGE_STATES in include/linux/lockdep.h whenever
- * you add one, or come up with a nice dynamic solution.
- */
-LOCKDEP_STATE(HARDIRQ)
-LOCKDEP_STATE(SOFTIRQ)
-LOCKDEP_STATE(RECLAIM_FS)
Index: linux-2.6/kernel/locking/Makefile
===================================================================
--- linux-2.6.orig/kernel/locking/Makefile
+++ linux-2.6/kernel/locking/Makefile
@@ -2,8 +2,14 @@
obj-y += mutex.o
ifdef CONFIG_FUNCTION_TRACER
+CFLAGS_REMOVE_lockdep.o = -pg
+CFLAGS_REMOVE_lockdep_proc.o = -pg
CFLAGS_REMOVE_mutex-debug.o = -pg
CFLAGS_REMOVE_rtmutex-debug.o = -pg
endif
obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
+obj-$(CONFIG_LOCKDEP) += lockdep.o
+ifeq ($(CONFIG_PROC_FS),y)
+obj-$(CONFIG_LOCKDEP) += lockdep_proc.o
+endif
Index: linux-2.6/kernel/locking/lockdep.c
===================================================================
--- /dev/null
+++ linux-2.6/kernel/locking/lockdep.c
@@ -0,0 +1,4257 @@
+/*
+ * kernel/lockdep.c
+ *
+ * Runtime locking correctness validator
+ *
+ * Started by Ingo Molnar:
+ *
+ * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
+ *
+ * this code maps all the lock dependencies as they occur in a live kernel
+ * and will warn about the following classes of locking bugs:
+ *
+ * - lock inversion scenarios
+ * - circular lock dependencies
+ * - hardirq/softirq safe/unsafe locking bugs
+ *
+ * Bugs are reported even if the current locking scenario does not cause
+ * any deadlock at this point.
+ *
+ * I.e. if anytime in the past two locks were taken in a different order,
+ * even if it happened for another task, even if those were different
+ * locks (but of the same class as this lock), this code will detect it.
+ *
+ * Thanks to Arjan van de Ven for coming up with the initial idea of
+ * mapping lock dependencies runtime.
+ */
+#define DISABLE_BRANCH_PROFILING
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/spinlock.h>
+#include <linux/kallsyms.h>
+#include <linux/interrupt.h>
+#include <linux/stacktrace.h>
+#include <linux/debug_locks.h>
+#include <linux/irqflags.h>
+#include <linux/utsname.h>
+#include <linux/hash.h>
+#include <linux/ftrace.h>
+#include <linux/stringify.h>
+#include <linux/bitops.h>
+#include <linux/gfp.h>
+#include <linux/kmemcheck.h>
+
+#include <asm/sections.h>
+
+#include "lockdep_internals.h"
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/lock.h>
+
+#ifdef CONFIG_PROVE_LOCKING
+int prove_locking = 1;
+module_param(prove_locking, int, 0644);
+#else
+#define prove_locking 0
+#endif
+
+#ifdef CONFIG_LOCK_STAT
+int lock_stat = 1;
+module_param(lock_stat, int, 0644);
+#else
+#define lock_stat 0
+#endif
+
+/*
+ * lockdep_lock: protects the lockdep graph, the hashes and the
+ * class/list/hash allocators.
+ *
+ * This is one of the rare exceptions where it's justified
+ * to use a raw spinlock - we really dont want the spinlock
+ * code to recurse back into the lockdep code...
+ */
+static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
+
+static int graph_lock(void)
+{
+ arch_spin_lock(&lockdep_lock);
+ /*
+ * Make sure that if another CPU detected a bug while
+ * walking the graph we dont change it (while the other
+ * CPU is busy printing out stuff with the graph lock
+ * dropped already)
+ */
+ if (!debug_locks) {
+ arch_spin_unlock(&lockdep_lock);
+ return 0;
+ }
+ /* prevent any recursions within lockdep from causing deadlocks */
+ current->lockdep_recursion++;
+ return 1;
+}
+
+static inline int graph_unlock(void)
+{
+ if (debug_locks && !arch_spin_is_locked(&lockdep_lock)) {
+ /*
+ * The lockdep graph lock isn't locked while we expect it to
+ * be, we're confused now, bye!
+ */
+ return DEBUG_LOCKS_WARN_ON(1);
+ }
+
+ current->lockdep_recursion--;
+ arch_spin_unlock(&lockdep_lock);
+ return 0;
+}
+
+/*
+ * Turn lock debugging off and return with 0 if it was off already,
+ * and also release the graph lock:
+ */
+static inline int debug_locks_off_graph_unlock(void)
+{
+ int ret = debug_locks_off();
+
+ arch_spin_unlock(&lockdep_lock);
+
+ return ret;
+}
+
+static int lockdep_initialized;
+
+unsigned long nr_list_entries;
+static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
+
+/*
+ * All data structures here are protected by the global debug_lock.
+ *
+ * Mutex key structs only get allocated, once during bootup, and never
+ * get freed - this significantly simplifies the debugging code.
+ */
+unsigned long nr_lock_classes;
+static struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
+
+static inline struct lock_class *hlock_class(struct held_lock *hlock)
+{
+ if (!hlock->class_idx) {
+ /*
+ * Someone passed in garbage, we give up.
+ */
+ DEBUG_LOCKS_WARN_ON(1);
+ return NULL;
+ }
+ return lock_classes + hlock->class_idx - 1;
+}
+
+#ifdef CONFIG_LOCK_STAT
+static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS],
+ cpu_lock_stats);
+
+static inline u64 lockstat_clock(void)
+{
+ return local_clock();
+}
+
+static int lock_point(unsigned long points[], unsigned long ip)
+{
+ int i;
+
+ for (i = 0; i < LOCKSTAT_POINTS; i++) {
+ if (points[i] == 0) {
+ points[i] = ip;
+ break;
+ }
+ if (points[i] == ip)
+ break;
+ }
+
+ return i;
+}
+
+static void lock_time_inc(struct lock_time *lt, u64 time)
+{
+ if (time > lt->max)
+ lt->max = time;
+
+ if (time < lt->min || !lt->nr)
+ lt->min = time;
+
+ lt->total += time;
+ lt->nr++;
+}
+
+static inline void lock_time_add(struct lock_time *src, struct lock_time *dst)
+{
+ if (!src->nr)
+ return;
+
+ if (src->max > dst->max)
+ dst->max = src->max;
+
+ if (src->min < dst->min || !dst->nr)
+ dst->min = src->min;
+
+ dst->total += src->total;
+ dst->nr += src->nr;
+}
+
+struct lock_class_stats lock_stats(struct lock_class *class)
+{
+ struct lock_class_stats stats;
+ int cpu, i;
+
+ memset(&stats, 0, sizeof(struct lock_class_stats));
+ for_each_possible_cpu(cpu) {
+ struct lock_class_stats *pcs =
+ &per_cpu(cpu_lock_stats, cpu)[class - lock_classes];
+
+ for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++)
+ stats.contention_point[i] += pcs->contention_point[i];
+
+ for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++)
+ stats.contending_point[i] += pcs->contending_point[i];
+
+ lock_time_add(&pcs->read_waittime, &stats.read_waittime);
+ lock_time_add(&pcs->write_waittime, &stats.write_waittime);
+
+ lock_time_add(&pcs->read_holdtime, &stats.read_holdtime);
+ lock_time_add(&pcs->write_holdtime, &stats.write_holdtime);
+
+ for (i = 0; i < ARRAY_SIZE(stats.bounces); i++)
+ stats.bounces[i] += pcs->bounces[i];
+ }
+
+ return stats;
+}
+
+void clear_lock_stats(struct lock_class *class)
+{
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ struct lock_class_stats *cpu_stats =
+ &per_cpu(cpu_lock_stats, cpu)[class - lock_classes];
+
+ memset(cpu_stats, 0, sizeof(struct lock_class_stats));
+ }
+ memset(class->contention_point, 0, sizeof(class->contention_point));
+ memset(class->contending_point, 0, sizeof(class->contending_point));
+}
+
+static struct lock_class_stats *get_lock_stats(struct lock_class *class)
+{
+ return &get_cpu_var(cpu_lock_stats)[class - lock_classes];
+}
+
+static void put_lock_stats(struct lock_class_stats *stats)
+{
+ put_cpu_var(cpu_lock_stats);
+}
+
+static void lock_release_holdtime(struct held_lock *hlock)
+{
+ struct lock_class_stats *stats;
+ u64 holdtime;
+
+ if (!lock_stat)
+ return;
+
+ holdtime = lockstat_clock() - hlock->holdtime_stamp;
+
+ stats = get_lock_stats(hlock_class(hlock));
+ if (hlock->read)
+ lock_time_inc(&stats->read_holdtime, holdtime);
+ else
+ lock_time_inc(&stats->write_holdtime, holdtime);
+ put_lock_stats(stats);
+}
+#else
+static inline void lock_release_holdtime(struct held_lock *hlock)
+{
+}
+#endif
+
+/*
+ * We keep a global list of all lock classes. The list only grows,
+ * never shrinks. The list is only accessed with the lockdep
+ * spinlock lock held.
+ */
+LIST_HEAD(all_lock_classes);
+
+/*
+ * The lockdep classes are in a hash-table as well, for fast lookup:
+ */
+#define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1)
+#define CLASSHASH_SIZE (1UL << CLASSHASH_BITS)
+#define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS)
+#define classhashentry(key) (classhash_table + __classhashfn((key)))
+
+static struct list_head classhash_table[CLASSHASH_SIZE];
+
+/*
+ * We put the lock dependency chains into a hash-table as well, to cache
+ * their existence:
+ */
+#define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1)
+#define CHAINHASH_SIZE (1UL << CHAINHASH_BITS)
+#define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS)
+#define chainhashentry(chain) (chainhash_table + __chainhashfn((chain)))
+
+static struct list_head chainhash_table[CHAINHASH_SIZE];
+
+/*
+ * The hash key of the lock dependency chains is a hash itself too:
+ * it's a hash of all locks taken up to that lock, including that lock.
+ * It's a 64-bit hash, because it's important for the keys to be
+ * unique.
+ */
+#define iterate_chain_key(key1, key2) \
+ (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \
+ ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \
+ (key2))
+
+void lockdep_off(void)
+{
+ current->lockdep_recursion++;
+}
+EXPORT_SYMBOL(lockdep_off);
+
+void lockdep_on(void)
+{
+ current->lockdep_recursion--;
+}
+EXPORT_SYMBOL(lockdep_on);
+
+/*
+ * Debugging switches:
+ */
+
+#define VERBOSE 0
+#define VERY_VERBOSE 0
+
+#if VERBOSE
+# define HARDIRQ_VERBOSE 1
+# define SOFTIRQ_VERBOSE 1
+# define RECLAIM_VERBOSE 1
+#else
+# define HARDIRQ_VERBOSE 0
+# define SOFTIRQ_VERBOSE 0
+# define RECLAIM_VERBOSE 0
+#endif
+
+#if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE
+/*
+ * Quick filtering for interesting events:
+ */
+static int class_filter(struct lock_class *class)
+{
+#if 0
+ /* Example */
+ if (class->name_version == 1 &&
+ !strcmp(class->name, "lockname"))
+ return 1;
+ if (class->name_version == 1 &&
+ !strcmp(class->name, "&struct->lockfield"))
+ return 1;
+#endif
+ /* Filter everything else. 1 would be to allow everything else */
+ return 0;
+}
+#endif
+
+static int verbose(struct lock_class *class)
+{
+#if VERBOSE
+ return class_filter(class);
+#endif
+ return 0;
+}
+
+/*
+ * Stack-trace: tightly packed array of stack backtrace
+ * addresses. Protected by the graph_lock.
+ */
+unsigned long nr_stack_trace_entries;
+static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES];
+
+static void print_lockdep_off(const char *bug_msg)
+{
+ printk(KERN_DEBUG "%s\n", bug_msg);
+ printk(KERN_DEBUG "turning off the locking correctness validator.\n");
+ printk(KERN_DEBUG "Please attach the output of /proc/lock_stat to the bug report\n");
+}
+
+static int save_trace(struct stack_trace *trace)
+{
+ trace->nr_entries = 0;
+ trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries;
+ trace->entries = stack_trace + nr_stack_trace_entries;
+
+ trace->skip = 3;
+
+ save_stack_trace(trace);
+
+ /*
+ * Some daft arches put -1 at the end to indicate its a full trace.
+ *
+ * <rant> this is buggy anyway, since it takes a whole extra entry so a
+ * complete trace that maxes out the entries provided will be reported
+ * as incomplete, friggin useless </rant>
+ */
+ if (trace->nr_entries != 0 &&
+ trace->entries[trace->nr_entries-1] == ULONG_MAX)
+ trace->nr_entries--;
+
+ trace->max_entries = trace->nr_entries;
+
+ nr_stack_trace_entries += trace->nr_entries;
+
+ if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) {
+ if (!debug_locks_off_graph_unlock())
+ return 0;
+
+ print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!");
+ dump_stack();
+
+ return 0;
+ }
+
+ return 1;
+}
+
+unsigned int nr_hardirq_chains;
+unsigned int nr_softirq_chains;
+unsigned int nr_process_chains;
+unsigned int max_lockdep_depth;
+
+#ifdef CONFIG_DEBUG_LOCKDEP
+/*
+ * We cannot printk in early bootup code. Not even early_printk()
+ * might work. So we mark any initialization errors and printk
+ * about it later on, in lockdep_info().
+ */
+static int lockdep_init_error;
+static const char *lock_init_error;
+static unsigned long lockdep_init_trace_data[20];
+static struct stack_trace lockdep_init_trace = {
+ .max_entries = ARRAY_SIZE(lockdep_init_trace_data),
+ .entries = lockdep_init_trace_data,
+};
+
+/*
+ * Various lockdep statistics:
+ */
+DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats);
+#endif
+
+/*
+ * Locking printouts:
+ */
+
+#define __USAGE(__STATE) \
+ [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \
+ [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \
+ [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\
+ [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R",
+
+static const char *usage_str[] =
+{
+#define LOCKDEP_STATE(__STATE) __USAGE(__STATE)
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+ [LOCK_USED] = "INITIAL USE",
+};
+
+const char * __get_key_name(struct lockdep_subclass_key *key, char *str)
+{
+ return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str);
+}
+
+static inline unsigned long lock_flag(enum lock_usage_bit bit)
+{
+ return 1UL << bit;
+}
+
+static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit)
+{
+ char c = '.';
+
+ if (class->usage_mask & lock_flag(bit + 2))
+ c = '+';
+ if (class->usage_mask & lock_flag(bit)) {
+ c = '-';
+ if (class->usage_mask & lock_flag(bit + 2))
+ c = '?';
+ }
+
+ return c;
+}
+
+void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS])
+{
+ int i = 0;
+
+#define LOCKDEP_STATE(__STATE) \
+ usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \
+ usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ);
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+
+ usage[i] = '\0';
+}
+
+static void __print_lock_name(struct lock_class *class)
+{
+ char str[KSYM_NAME_LEN];
+ const char *name;
+
+ name = class->name;
+ if (!name) {
+ name = __get_key_name(class->key, str);
+ printk("%s", name);
+ } else {
+ printk("%s", name);
+ if (class->name_version > 1)
+ printk("#%d", class->name_version);
+ if (class->subclass)
+ printk("/%d", class->subclass);
+ }
+}
+
+static void print_lock_name(struct lock_class *class)
+{
+ char usage[LOCK_USAGE_CHARS];
+
+ get_usage_chars(class, usage);
+
+ printk(" (");
+ __print_lock_name(class);
+ printk("){%s}", usage);
+}
+
+static void print_lockdep_cache(struct lockdep_map *lock)
+{
+ const char *name;
+ char str[KSYM_NAME_LEN];
+
+ name = lock->name;
+ if (!name)
+ name = __get_key_name(lock->key->subkeys, str);
+
+ printk("%s", name);
+}
+
+static void print_lock(struct held_lock *hlock)
+{
+ print_lock_name(hlock_class(hlock));
+ printk(", at: ");
+ print_ip_sym(hlock->acquire_ip);
+}
+
+static void lockdep_print_held_locks(struct task_struct *curr)
+{
+ int i, depth = curr->lockdep_depth;
+
+ if (!depth) {
+ printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr));
+ return;
+ }
+ printk("%d lock%s held by %s/%d:\n",
+ depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr));
+
+ for (i = 0; i < depth; i++) {
+ printk(" #%d: ", i);
+ print_lock(curr->held_locks + i);
+ }
+}
+
+static void print_kernel_ident(void)
+{
+ printk("%s %.*s %s\n", init_utsname()->release,
+ (int)strcspn(init_utsname()->version, " "),
+ init_utsname()->version,
+ print_tainted());
+}
+
+static int very_verbose(struct lock_class *class)
+{
+#if VERY_VERBOSE
+ return class_filter(class);
+#endif
+ return 0;
+}
+
+/*
+ * Is this the address of a static object:
+ */
+static int static_obj(void *obj)
+{
+ unsigned long start = (unsigned long) &_stext,
+ end = (unsigned long) &_end,
+ addr = (unsigned long) obj;
+
+ /*
+ * static variable?
+ */
+ if ((addr >= start) && (addr < end))
+ return 1;
+
+ if (arch_is_kernel_data(addr))
+ return 1;
+
+ /*
+ * in-kernel percpu var?
+ */
+ if (is_kernel_percpu_address(addr))
+ return 1;
+
+ /*
+ * module static or percpu var?
+ */
+ return is_module_address(addr) || is_module_percpu_address(addr);
+}
+
+/*
+ * To make lock name printouts unique, we calculate a unique
+ * class->name_version generation counter:
+ */
+static int count_matching_names(struct lock_class *new_class)
+{
+ struct lock_class *class;
+ int count = 0;
+
+ if (!new_class->name)
+ return 0;
+
+ list_for_each_entry(class, &all_lock_classes, lock_entry) {
+ if (new_class->key - new_class->subclass == class->key)
+ return class->name_version;
+ if (class->name && !strcmp(class->name, new_class->name))
+ count = max(count, class->name_version);
+ }
+
+ return count + 1;
+}
+
+/*
+ * Register a lock's class in the hash-table, if the class is not present
+ * yet. Otherwise we look it up. We cache the result in the lock object
+ * itself, so actual lookup of the hash should be once per lock object.
+ */
+static inline struct lock_class *
+look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
+{
+ struct lockdep_subclass_key *key;
+ struct list_head *hash_head;
+ struct lock_class *class;
+
+#ifdef CONFIG_DEBUG_LOCKDEP
+ /*
+ * If the architecture calls into lockdep before initializing
+ * the hashes then we'll warn about it later. (we cannot printk
+ * right now)
+ */
+ if (unlikely(!lockdep_initialized)) {
+ lockdep_init();
+ lockdep_init_error = 1;
+ lock_init_error = lock->name;
+ save_stack_trace(&lockdep_init_trace);
+ }
+#endif
+
+ if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) {
+ debug_locks_off();
+ printk(KERN_ERR
+ "BUG: looking up invalid subclass: %u\n", subclass);
+ printk(KERN_ERR
+ "turning off the locking correctness validator.\n");
+ dump_stack();
+ return NULL;
+ }
+
+ /*
+ * Static locks do not have their class-keys yet - for them the key
+ * is the lock object itself:
+ */
+ if (unlikely(!lock->key))
+ lock->key = (void *)lock;
+
+ /*
+ * NOTE: the class-key must be unique. For dynamic locks, a static
+ * lock_class_key variable is passed in through the mutex_init()
+ * (or spin_lock_init()) call - which acts as the key. For static
+ * locks we use the lock object itself as the key.
+ */
+ BUILD_BUG_ON(sizeof(struct lock_class_key) >
+ sizeof(struct lockdep_map));
+
+ key = lock->key->subkeys + subclass;
+
+ hash_head = classhashentry(key);
+
+ /*
+ * We can walk the hash lockfree, because the hash only
+ * grows, and we are careful when adding entries to the end:
+ */
+ list_for_each_entry(class, hash_head, hash_entry) {
+ if (class->key == key) {
+ /*
+ * Huh! same key, different name? Did someone trample
+ * on some memory? We're most confused.
+ */
+ WARN_ON_ONCE(class->name != lock->name);
+ return class;
+ }
+ }
+
+ return NULL;
+}
+
+/*
+ * Register a lock's class in the hash-table, if the class is not present
+ * yet. Otherwise we look it up. We cache the result in the lock object
+ * itself, so actual lookup of the hash should be once per lock object.
+ */
+static inline struct lock_class *
+register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
+{
+ struct lockdep_subclass_key *key;
+ struct list_head *hash_head;
+ struct lock_class *class;
+ unsigned long flags;
+
+ class = look_up_lock_class(lock, subclass);
+ if (likely(class))
+ goto out_set_class_cache;
+
+ /*
+ * Debug-check: all keys must be persistent!
+ */
+ if (!static_obj(lock->key)) {
+ debug_locks_off();
+ printk("INFO: trying to register non-static key.\n");
+ printk("the code is fine but needs lockdep annotation.\n");
+ printk("turning off the locking correctness validator.\n");
+ dump_stack();
+
+ return NULL;
+ }
+
+ key = lock->key->subkeys + subclass;
+ hash_head = classhashentry(key);
+
+ raw_local_irq_save(flags);
+ if (!graph_lock()) {
+ raw_local_irq_restore(flags);
+ return NULL;
+ }
+ /*
+ * We have to do the hash-walk again, to avoid races
+ * with another CPU:
+ */
+ list_for_each_entry(class, hash_head, hash_entry)
+ if (class->key == key)
+ goto out_unlock_set;
+ /*
+ * Allocate a new key from the static array, and add it to
+ * the hash:
+ */
+ if (nr_lock_classes >= MAX_LOCKDEP_KEYS) {
+ if (!debug_locks_off_graph_unlock()) {
+ raw_local_irq_restore(flags);
+ return NULL;
+ }
+ raw_local_irq_restore(flags);
+
+ print_lockdep_off("BUG: MAX_LOCKDEP_KEYS too low!");
+ dump_stack();
+ return NULL;
+ }
+ class = lock_classes + nr_lock_classes++;
+ debug_atomic_inc(nr_unused_locks);
+ class->key = key;
+ class->name = lock->name;
+ class->subclass = subclass;
+ INIT_LIST_HEAD(&class->lock_entry);
+ INIT_LIST_HEAD(&class->locks_before);
+ INIT_LIST_HEAD(&class->locks_after);
+ class->name_version = count_matching_names(class);
+ /*
+ * We use RCU's safe list-add method to make
+ * parallel walking of the hash-list safe:
+ */
+ list_add_tail_rcu(&class->hash_entry, hash_head);
+ /*
+ * Add it to the global list of classes:
+ */
+ list_add_tail_rcu(&class->lock_entry, &all_lock_classes);
+
+ if (verbose(class)) {
+ graph_unlock();
+ raw_local_irq_restore(flags);
+
+ printk("\nnew class %p: %s", class->key, class->name);
+ if (class->name_version > 1)
+ printk("#%d", class->name_version);
+ printk("\n");
+ dump_stack();
+
+ raw_local_irq_save(flags);
+ if (!graph_lock()) {
+ raw_local_irq_restore(flags);
+ return NULL;
+ }
+ }
+out_unlock_set:
+ graph_unlock();
+ raw_local_irq_restore(flags);
+
+out_set_class_cache:
+ if (!subclass || force)
+ lock->class_cache[0] = class;
+ else if (subclass < NR_LOCKDEP_CACHING_CLASSES)
+ lock->class_cache[subclass] = class;
+
+ /*
+ * Hash collision, did we smoke some? We found a class with a matching
+ * hash but the subclass -- which is hashed in -- didn't match.
+ */
+ if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass))
+ return NULL;
+
+ return class;
+}
+
+#ifdef CONFIG_PROVE_LOCKING
+/*
+ * Allocate a lockdep entry. (assumes the graph_lock held, returns
+ * with NULL on failure)
+ */
+static struct lock_list *alloc_list_entry(void)
+{
+ if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) {
+ if (!debug_locks_off_graph_unlock())
+ return NULL;
+
+ print_lockdep_off("BUG: MAX_LOCKDEP_ENTRIES too low!");
+ dump_stack();
+ return NULL;
+ }
+ return list_entries + nr_list_entries++;
+}
+
+/*
+ * Add a new dependency to the head of the list:
+ */
+static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
+ struct list_head *head, unsigned long ip,
+ int distance, struct stack_trace *trace)
+{
+ struct lock_list *entry;
+ /*
+ * Lock not present yet - get a new dependency struct and
+ * add it to the list:
+ */
+ entry = alloc_list_entry();
+ if (!entry)
+ return 0;
+
+ entry->class = this;
+ entry->distance = distance;
+ entry->trace = *trace;
+ /*
+ * Since we never remove from the dependency list, the list can
+ * be walked lockless by other CPUs, it's only allocation
+ * that must be protected by the spinlock. But this also means
+ * we must make new entries visible only once writes to the
+ * entry become visible - hence the RCU op:
+ */
+ list_add_tail_rcu(&entry->entry, head);
+
+ return 1;
+}
+
+/*
+ * For good efficiency of modular, we use power of 2
+ */
+#define MAX_CIRCULAR_QUEUE_SIZE 4096UL
+#define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1)
+
+/*
+ * The circular_queue and helpers is used to implement the
+ * breadth-first search(BFS)algorithem, by which we can build
+ * the shortest path from the next lock to be acquired to the
+ * previous held lock if there is a circular between them.
+ */
+struct circular_queue {
+ unsigned long element[MAX_CIRCULAR_QUEUE_SIZE];
+ unsigned int front, rear;
+};
+
+static struct circular_queue lock_cq;
+
+unsigned int max_bfs_queue_depth;
+
+static unsigned int lockdep_dependency_gen_id;
+
+static inline void __cq_init(struct circular_queue *cq)
+{
+ cq->front = cq->rear = 0;
+ lockdep_dependency_gen_id++;
+}
+
+static inline int __cq_empty(struct circular_queue *cq)
+{
+ return (cq->front == cq->rear);
+}
+
+static inline int __cq_full(struct circular_queue *cq)
+{
+ return ((cq->rear + 1) & CQ_MASK) == cq->front;
+}
+
+static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem)
+{
+ if (__cq_full(cq))
+ return -1;
+
+ cq->element[cq->rear] = elem;
+ cq->rear = (cq->rear + 1) & CQ_MASK;
+ return 0;
+}
+
+static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem)
+{
+ if (__cq_empty(cq))
+ return -1;
+
+ *elem = cq->element[cq->front];
+ cq->front = (cq->front + 1) & CQ_MASK;
+ return 0;
+}
+
+static inline unsigned int __cq_get_elem_count(struct circular_queue *cq)
+{
+ return (cq->rear - cq->front) & CQ_MASK;
+}
+
+static inline void mark_lock_accessed(struct lock_list *lock,
+ struct lock_list *parent)
+{
+ unsigned long nr;
+
+ nr = lock - list_entries;
+ WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */
+ lock->parent = parent;
+ lock->class->dep_gen_id = lockdep_dependency_gen_id;
+}
+
+static inline unsigned long lock_accessed(struct lock_list *lock)
+{
+ unsigned long nr;
+
+ nr = lock - list_entries;
+ WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */
+ return lock->class->dep_gen_id == lockdep_dependency_gen_id;
+}
+
+static inline struct lock_list *get_lock_parent(struct lock_list *child)
+{
+ return child->parent;
+}
+
+static inline int get_lock_depth(struct lock_list *child)
+{
+ int depth = 0;
+ struct lock_list *parent;
+
+ while ((parent = get_lock_parent(child))) {
+ child = parent;
+ depth++;
+ }
+ return depth;
+}
+
+static int __bfs(struct lock_list *source_entry,
+ void *data,
+ int (*match)(struct lock_list *entry, void *data),
+ struct lock_list **target_entry,
+ int forward)
+{
+ struct lock_list *entry;
+ struct list_head *head;
+ struct circular_queue *cq = &lock_cq;
+ int ret = 1;
+
+ if (match(source_entry, data)) {
+ *target_entry = source_entry;
+ ret = 0;
+ goto exit;
+ }
+
+ if (forward)
+ head = &source_entry->class->locks_after;
+ else
+ head = &source_entry->class->locks_before;
+
+ if (list_empty(head))
+ goto exit;
+
+ __cq_init(cq);
+ __cq_enqueue(cq, (unsigned long)source_entry);
+
+ while (!__cq_empty(cq)) {
+ struct lock_list *lock;
+
+ __cq_dequeue(cq, (unsigned long *)&lock);
+
+ if (!lock->class) {
+ ret = -2;
+ goto exit;
+ }
+
+ if (forward)
+ head = &lock->class->locks_after;
+ else
+ head = &lock->class->locks_before;
+
+ list_for_each_entry(entry, head, entry) {
+ if (!lock_accessed(entry)) {
+ unsigned int cq_depth;
+ mark_lock_accessed(entry, lock);
+ if (match(entry, data)) {
+ *target_entry = entry;
+ ret = 0;
+ goto exit;
+ }
+
+ if (__cq_enqueue(cq, (unsigned long)entry)) {
+ ret = -1;
+ goto exit;
+ }
+ cq_depth = __cq_get_elem_count(cq);
+ if (max_bfs_queue_depth < cq_depth)
+ max_bfs_queue_depth = cq_depth;
+ }
+ }
+ }
+exit:
+ return ret;
+}
+
+static inline int __bfs_forwards(struct lock_list *src_entry,
+ void *data,
+ int (*match)(struct lock_list *entry, void *data),
+ struct lock_list **target_entry)
+{
+ return __bfs(src_entry, data, match, target_entry, 1);
+
+}
+
+static inline int __bfs_backwards(struct lock_list *src_entry,
+ void *data,
+ int (*match)(struct lock_list *entry, void *data),
+ struct lock_list **target_entry)
+{
+ return __bfs(src_entry, data, match, target_entry, 0);
+
+}
+
+/*
+ * Recursive, forwards-direction lock-dependency checking, used for
+ * both noncyclic checking and for hardirq-unsafe/softirq-unsafe
+ * checking.
+ */
+
+/*
+ * Print a dependency chain entry (this is only done when a deadlock
+ * has been detected):
+ */
+static noinline int
+print_circular_bug_entry(struct lock_list *target, int depth)
+{
+ if (debug_locks_silent)
+ return 0;
+ printk("\n-> #%u", depth);
+ print_lock_name(target->class);
+ printk(":\n");
+ print_stack_trace(&target->trace, 6);
+
+ return 0;
+}
+
+static void
+print_circular_lock_scenario(struct held_lock *src,
+ struct held_lock *tgt,
+ struct lock_list *prt)
+{
+ struct lock_class *source = hlock_class(src);
+ struct lock_class *target = hlock_class(tgt);
+ struct lock_class *parent = prt->class;
+
+ /*
+ * A direct locking problem where unsafe_class lock is taken
+ * directly by safe_class lock, then all we need to show
+ * is the deadlock scenario, as it is obvious that the
+ * unsafe lock is taken under the safe lock.
+ *
+ * But if there is a chain instead, where the safe lock takes
+ * an intermediate lock (middle_class) where this lock is
+ * not the same as the safe lock, then the lock chain is
+ * used to describe the problem. Otherwise we would need
+ * to show a different CPU case for each link in the chain
+ * from the safe_class lock to the unsafe_class lock.
+ */
+ if (parent != source) {
+ printk("Chain exists of:\n ");
+ __print_lock_name(source);
+ printk(" --> ");
+ __print_lock_name(parent);
+ printk(" --> ");
+ __print_lock_name(target);
+ printk("\n\n");
+ }
+
+ printk(" Possible unsafe locking scenario:\n\n");
+ printk(" CPU0 CPU1\n");
+ printk(" ---- ----\n");
+ printk(" lock(");
+ __print_lock_name(target);
+ printk(");\n");
+ printk(" lock(");
+ __print_lock_name(parent);
+ printk(");\n");
+ printk(" lock(");
+ __print_lock_name(target);
+ printk(");\n");
+ printk(" lock(");
+ __print_lock_name(source);
+ printk(");\n");
+ printk("\n *** DEADLOCK ***\n\n");
+}
+
+/*
+ * When a circular dependency is detected, print the
+ * header first:
+ */
+static noinline int
+print_circular_bug_header(struct lock_list *entry, unsigned int depth,
+ struct held_lock *check_src,
+ struct held_lock *check_tgt)
+{
+ struct task_struct *curr = current;
+
+ if (debug_locks_silent)
+ return 0;
+
+ printk("\n");
+ printk("======================================================\n");
+ printk("[ INFO: possible circular locking dependency detected ]\n");
+ print_kernel_ident();
+ printk("-------------------------------------------------------\n");
+ printk("%s/%d is trying to acquire lock:\n",
+ curr->comm, task_pid_nr(curr));
+ print_lock(check_src);
+ printk("\nbut task is already holding lock:\n");
+ print_lock(check_tgt);
+ printk("\nwhich lock already depends on the new lock.\n\n");
+ printk("\nthe existing dependency chain (in reverse order) is:\n");
+
+ print_circular_bug_entry(entry, depth);
+
+ return 0;
+}
+
+static inline int class_equal(struct lock_list *entry, void *data)
+{
+ return entry->class == data;
+}
+
+static noinline int print_circular_bug(struct lock_list *this,
+ struct lock_list *target,
+ struct held_lock *check_src,
+ struct held_lock *check_tgt)
+{
+ struct task_struct *curr = current;
+ struct lock_list *parent;
+ struct lock_list *first_parent;
+ int depth;
+
+ if (!debug_locks_off_graph_unlock() || debug_locks_silent)
+ return 0;
+
+ if (!save_trace(&this->trace))
+ return 0;
+
+ depth = get_lock_depth(target);
+
+ print_circular_bug_header(target, depth, check_src, check_tgt);
+
+ parent = get_lock_parent(target);
+ first_parent = parent;
+
+ while (parent) {
+ print_circular_bug_entry(parent, --depth);
+ parent = get_lock_parent(parent);
+ }
+
+ printk("\nother info that might help us debug this:\n\n");
+ print_circular_lock_scenario(check_src, check_tgt,
+ first_parent);
+
+ lockdep_print_held_locks(curr);
+
+ printk("\nstack backtrace:\n");
+ dump_stack();
+
+ return 0;
+}
+
+static noinline int print_bfs_bug(int ret)
+{
+ if (!debug_locks_off_graph_unlock())
+ return 0;
+
+ /*
+ * Breadth-first-search failed, graph got corrupted?
+ */
+ WARN(1, "lockdep bfs error:%d\n", ret);
+
+ return 0;
+}
+
+static int noop_count(struct lock_list *entry, void *data)
+{
+ (*(unsigned long *)data)++;
+ return 0;
+}
+
+unsigned long __lockdep_count_forward_deps(struct lock_list *this)
+{
+ unsigned long count = 0;
+ struct lock_list *uninitialized_var(target_entry);
+
+ __bfs_forwards(this, (void *)&count, noop_count, &target_entry);
+
+ return count;
+}
+unsigned long lockdep_count_forward_deps(struct lock_class *class)
+{
+ unsigned long ret, flags;
+ struct lock_list this;
+
+ this.parent = NULL;
+ this.class = class;
+
+ local_irq_save(flags);
+ arch_spin_lock(&lockdep_lock);
+ ret = __lockdep_count_forward_deps(&this);
+ arch_spin_unlock(&lockdep_lock);
+ local_irq_restore(flags);
+
+ return ret;
+}
+
+unsigned long __lockdep_count_backward_deps(struct lock_list *this)
+{
+ unsigned long count = 0;
+ struct lock_list *uninitialized_var(target_entry);
+
+ __bfs_backwards(this, (void *)&count, noop_count, &target_entry);
+
+ return count;
+}
+
+unsigned long lockdep_count_backward_deps(struct lock_class *class)
+{
+ unsigned long ret, flags;
+ struct lock_list this;
+
+ this.parent = NULL;
+ this.class = class;
+
+ local_irq_save(flags);
+ arch_spin_lock(&lockdep_lock);
+ ret = __lockdep_count_backward_deps(&this);
+ arch_spin_unlock(&lockdep_lock);
+ local_irq_restore(flags);
+
+ return ret;
+}
+
+/*
+ * Prove that the dependency graph starting at <entry> can not
+ * lead to <target>. Print an error and return 0 if it does.
+ */
+static noinline int
+check_noncircular(struct lock_list *root, struct lock_class *target,
+ struct lock_list **target_entry)
+{
+ int result;
+
+ debug_atomic_inc(nr_cyclic_checks);
+
+ result = __bfs_forwards(root, target, class_equal, target_entry);
+
+ return result;
+}
+
+#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
+/*
+ * Forwards and backwards subgraph searching, for the purposes of
+ * proving that two subgraphs can be connected by a new dependency
+ * without creating any illegal irq-safe -> irq-unsafe lock dependency.
+ */
+
+static inline int usage_match(struct lock_list *entry, void *bit)
+{
+ return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit);
+}
+
+
+
+/*
+ * Find a node in the forwards-direction dependency sub-graph starting
+ * at @root->class that matches @bit.
+ *
+ * Return 0 if such a node exists in the subgraph, and put that node
+ * into *@target_entry.
+ *
+ * Return 1 otherwise and keep *@target_entry unchanged.
+ * Return <0 on error.
+ */
+static int
+find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit,
+ struct lock_list **target_entry)
+{
+ int result;
+
+ debug_atomic_inc(nr_find_usage_forwards_checks);
+
+ result = __bfs_forwards(root, (void *)bit, usage_match, target_entry);
+
+ return result;
+}
+
+/*
+ * Find a node in the backwards-direction dependency sub-graph starting
+ * at @root->class that matches @bit.
+ *
+ * Return 0 if such a node exists in the subgraph, and put that node
+ * into *@target_entry.
+ *
+ * Return 1 otherwise and keep *@target_entry unchanged.
+ * Return <0 on error.
+ */
+static int
+find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit,
+ struct lock_list **target_entry)
+{
+ int result;
+
+ debug_atomic_inc(nr_find_usage_backwards_checks);
+
+ result = __bfs_backwards(root, (void *)bit, usage_match, target_entry);
+
+ return result;
+}
+
+static void print_lock_class_header(struct lock_class *class, int depth)
+{
+ int bit;
+
+ printk("%*s->", depth, "");
+ print_lock_name(class);
+ printk(" ops: %lu", class->ops);
+ printk(" {\n");
+
+ for (bit = 0; bit < LOCK_USAGE_STATES; bit++) {
+ if (class->usage_mask & (1 << bit)) {
+ int len = depth;
+
+ len += printk("%*s %s", depth, "", usage_str[bit]);
+ len += printk(" at:\n");
+ print_stack_trace(class->usage_traces + bit, len);
+ }
+ }
+ printk("%*s }\n", depth, "");
+
+ printk("%*s ... key at: ",depth,"");
+ print_ip_sym((unsigned long)class->key);
+}
+
+/*
+ * printk the shortest lock dependencies from @start to @end in reverse order:
+ */
+static void __used
+print_shortest_lock_dependencies(struct lock_list *leaf,
+ struct lock_list *root)
+{
+ struct lock_list *entry = leaf;
+ int depth;
+
+ /*compute depth from generated tree by BFS*/
+ depth = get_lock_depth(leaf);
+
+ do {
+ print_lock_class_header(entry->class, depth);
+ printk("%*s ... acquired at:\n", depth, "");
+ print_stack_trace(&entry->trace, 2);
+ printk("\n");
+
+ if (depth == 0 && (entry != root)) {
+ printk("lockdep:%s bad path found in chain graph\n", __func__);
+ break;
+ }
+
+ entry = get_lock_parent(entry);
+ depth--;
+ } while (entry && (depth >= 0));
+
+ return;
+}
+
+static void
+print_irq_lock_scenario(struct lock_list *safe_entry,
+ struct lock_list *unsafe_entry,
+ struct lock_class *prev_class,
+ struct lock_class *next_class)
+{
+ struct lock_class *safe_class = safe_entry->class;
+ struct lock_class *unsafe_class = unsafe_entry->class;
+ struct lock_class *middle_class = prev_class;
+
+ if (middle_class == safe_class)
+ middle_class = next_class;
+
+ /*
+ * A direct locking problem where unsafe_class lock is taken
+ * directly by safe_class lock, then all we need to show
+ * is the deadlock scenario, as it is obvious that the
+ * unsafe lock is taken under the safe lock.
+ *
+ * But if there is a chain instead, where the safe lock takes
+ * an intermediate lock (middle_class) where this lock is
+ * not the same as the safe lock, then the lock chain is
+ * used to describe the problem. Otherwise we would need
+ * to show a different CPU case for each link in the chain
+ * from the safe_class lock to the unsafe_class lock.
+ */
+ if (middle_class != unsafe_class) {
+ printk("Chain exists of:\n ");
+ __print_lock_name(safe_class);
+ printk(" --> ");
+ __print_lock_name(middle_class);
+ printk(" --> ");
+ __print_lock_name(unsafe_class);
+ printk("\n\n");
+ }
+
+ printk(" Possible interrupt unsafe locking scenario:\n\n");
+ printk(" CPU0 CPU1\n");
+ printk(" ---- ----\n");
+ printk(" lock(");
+ __print_lock_name(unsafe_class);
+ printk(");\n");
+ printk(" local_irq_disable();\n");
+ printk(" lock(");
+ __print_lock_name(safe_class);
+ printk(");\n");
+ printk(" lock(");
+ __print_lock_name(middle_class);
+ printk(");\n");
+ printk(" <Interrupt>\n");
+ printk(" lock(");
+ __print_lock_name(safe_class);
+ printk(");\n");
+ printk("\n *** DEADLOCK ***\n\n");
+}
+
+static int
+print_bad_irq_dependency(struct task_struct *curr,
+ struct lock_list *prev_root,
+ struct lock_list *next_root,
+ struct lock_list *backwards_entry,
+ struct lock_list *forwards_entry,
+ struct held_lock *prev,
+ struct held_lock *next,
+ enum lock_usage_bit bit1,
+ enum lock_usage_bit bit2,
+ const char *irqclass)
+{
+ if (!debug_locks_off_graph_unlock() || debug_locks_silent)
+ return 0;
+
+ printk("\n");
+ printk("======================================================\n");
+ printk("[ INFO: %s-safe -> %s-unsafe lock order detected ]\n",
+ irqclass, irqclass);
+ print_kernel_ident();
+ printk("------------------------------------------------------\n");
+ printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n",
+ curr->comm, task_pid_nr(curr),
+ curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT,
+ curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT,
+ curr->hardirqs_enabled,
+ curr->softirqs_enabled);
+ print_lock(next);
+
+ printk("\nand this task is already holding:\n");
+ print_lock(prev);
+ printk("which would create a new lock dependency:\n");
+ print_lock_name(hlock_class(prev));
+ printk(" ->");
+ print_lock_name(hlock_class(next));
+ printk("\n");
+
+ printk("\nbut this new dependency connects a %s-irq-safe lock:\n",
+ irqclass);
+ print_lock_name(backwards_entry->class);
+ printk("\n... which became %s-irq-safe at:\n", irqclass);
+
+ print_stack_trace(backwards_entry->class->usage_traces + bit1, 1);
+
+ printk("\nto a %s-irq-unsafe lock:\n", irqclass);
+ print_lock_name(forwards_entry->class);
+ printk("\n... which became %s-irq-unsafe at:\n", irqclass);
+ printk("...");
+
+ print_stack_trace(forwards_entry->class->usage_traces + bit2, 1);
+
+ printk("\nother info that might help us debug this:\n\n");
+ print_irq_lock_scenario(backwards_entry, forwards_entry,
+ hlock_class(prev), hlock_class(next));
+
+ lockdep_print_held_locks(curr);
+
+ printk("\nthe dependencies between %s-irq-safe lock", irqclass);
+ printk(" and the holding lock:\n");
+ if (!save_trace(&prev_root->trace))
+ return 0;
+ print_shortest_lock_dependencies(backwards_entry, prev_root);
+
+ printk("\nthe dependencies between the lock to be acquired");
+ printk(" and %s-irq-unsafe lock:\n", irqclass);
+ if (!save_trace(&next_root->trace))
+ return 0;
+ print_shortest_lock_dependencies(forwards_entry, next_root);
+
+ printk("\nstack backtrace:\n");
+ dump_stack();
+
+ return 0;
+}
+
+static int
+check_usage(struct task_struct *curr, struct held_lock *prev,
+ struct held_lock *next, enum lock_usage_bit bit_backwards,
+ enum lock_usage_bit bit_forwards, const char *irqclass)
+{
+ int ret;
+ struct lock_list this, that;
+ struct lock_list *uninitialized_var(target_entry);
+ struct lock_list *uninitialized_var(target_entry1);
+
+ this.parent = NULL;
+
+ this.class = hlock_class(prev);
+ ret = find_usage_backwards(&this, bit_backwards, &target_entry);
+ if (ret < 0)
+ return print_bfs_bug(ret);
+ if (ret == 1)
+ return ret;
+
+ that.parent = NULL;
+ that.class = hlock_class(next);
+ ret = find_usage_forwards(&that, bit_forwards, &target_entry1);
+ if (ret < 0)
+ return print_bfs_bug(ret);
+ if (ret == 1)
+ return ret;
+
+ return print_bad_irq_dependency(curr, &this, &that,
+ target_entry, target_entry1,
+ prev, next,
+ bit_backwards, bit_forwards, irqclass);
+}
+
+static const char *state_names[] = {
+#define LOCKDEP_STATE(__STATE) \
+ __stringify(__STATE),
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+};
+
+static const char *state_rnames[] = {
+#define LOCKDEP_STATE(__STATE) \
+ __stringify(__STATE)"-READ",
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+};
+
+static inline const char *state_name(enum lock_usage_bit bit)
+{
+ return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2];
+}
+
+static int exclusive_bit(int new_bit)
+{
+ /*
+ * USED_IN
+ * USED_IN_READ
+ * ENABLED
+ * ENABLED_READ
+ *
+ * bit 0 - write/read
+ * bit 1 - used_in/enabled
+ * bit 2+ state
+ */
+
+ int state = new_bit & ~3;
+ int dir = new_bit & 2;
+
+ /*
+ * keep state, bit flip the direction and strip read.
+ */
+ return state | (dir ^ 2);
+}
+
+static int check_irq_usage(struct task_struct *curr, struct held_lock *prev,
+ struct held_lock *next, enum lock_usage_bit bit)
+{
+ /*
+ * Prove that the new dependency does not connect a hardirq-safe
+ * lock with a hardirq-unsafe lock - to achieve this we search
+ * the backwards-subgraph starting at <prev>, and the
+ * forwards-subgraph starting at <next>:
+ */
+ if (!check_usage(curr, prev, next, bit,
+ exclusive_bit(bit), state_name(bit)))
+ return 0;
+
+ bit++; /* _READ */
+
+ /*
+ * Prove that the new dependency does not connect a hardirq-safe-read
+ * lock with a hardirq-unsafe lock - to achieve this we search
+ * the backwards-subgraph starting at <prev>, and the
+ * forwards-subgraph starting at <next>:
+ */
+ if (!check_usage(curr, prev, next, bit,
+ exclusive_bit(bit), state_name(bit)))
+ return 0;
+
+ return 1;
+}
+
+static int
+check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
+ struct held_lock *next)
+{
+#define LOCKDEP_STATE(__STATE) \
+ if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \
+ return 0;
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+
+ return 1;
+}
+
+static void inc_chains(void)
+{
+ if (current->hardirq_context)
+ nr_hardirq_chains++;
+ else {
+ if (current->softirq_context)
+ nr_softirq_chains++;
+ else
+ nr_process_chains++;
+ }
+}
+
+#else
+
+static inline int
+check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
+ struct held_lock *next)
+{
+ return 1;
+}
+
+static inline void inc_chains(void)
+{
+ nr_process_chains++;
+}
+
+#endif
+
+static void
+print_deadlock_scenario(struct held_lock *nxt,
+ struct held_lock *prv)
+{
+ struct lock_class *next = hlock_class(nxt);
+ struct lock_class *prev = hlock_class(prv);
+
+ printk(" Possible unsafe locking scenario:\n\n");
+ printk(" CPU0\n");
+ printk(" ----\n");
+ printk(" lock(");
+ __print_lock_name(prev);
+ printk(");\n");
+ printk(" lock(");
+ __print_lock_name(next);
+ printk(");\n");
+ printk("\n *** DEADLOCK ***\n\n");
+ printk(" May be due to missing lock nesting notation\n\n");
+}
+
+static int
+print_deadlock_bug(struct task_struct *curr, struct held_lock *prev,
+ struct held_lock *next)
+{
+ if (!debug_locks_off_graph_unlock() || debug_locks_silent)
+ return 0;
+
+ printk("\n");
+ printk("=============================================\n");
+ printk("[ INFO: possible recursive locking detected ]\n");
+ print_kernel_ident();
+ printk("---------------------------------------------\n");
+ printk("%s/%d is trying to acquire lock:\n",
+ curr->comm, task_pid_nr(curr));
+ print_lock(next);
+ printk("\nbut task is already holding lock:\n");
+ print_lock(prev);
+
+ printk("\nother info that might help us debug this:\n");
+ print_deadlock_scenario(next, prev);
+ lockdep_print_held_locks(curr);
+
+ printk("\nstack backtrace:\n");
+ dump_stack();
+
+ return 0;
+}
+
+/*
+ * Check whether we are holding such a class already.
+ *
+ * (Note that this has to be done separately, because the graph cannot
+ * detect such classes of deadlocks.)
+ *
+ * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read
+ */
+static int
+check_deadlock(struct task_struct *curr, struct held_lock *next,
+ struct lockdep_map *next_instance, int read)
+{
+ struct held_lock *prev;
+ struct held_lock *nest = NULL;
+ int i;
+
+ for (i = 0; i < curr->lockdep_depth; i++) {
+ prev = curr->held_locks + i;
+
+ if (prev->instance == next->nest_lock)
+ nest = prev;
+
+ if (hlock_class(prev) != hlock_class(next))
+ continue;
+
+ /*
+ * Allow read-after-read recursion of the same
+ * lock class (i.e. read_lock(lock)+read_lock(lock)):
+ */
+ if ((read == 2) && prev->read)
+ return 2;
+
+ /*
+ * We're holding the nest_lock, which serializes this lock's
+ * nesting behaviour.
+ */
+ if (nest)
+ return 2;
+
+ return print_deadlock_bug(curr, prev, next);
+ }
+ return 1;
+}
+
+/*
+ * There was a chain-cache miss, and we are about to add a new dependency
+ * to a previous lock. We recursively validate the following rules:
+ *
+ * - would the adding of the <prev> -> <next> dependency create a
+ * circular dependency in the graph? [== circular deadlock]
+ *
+ * - does the new prev->next dependency connect any hardirq-safe lock
+ * (in the full backwards-subgraph starting at <prev>) with any
+ * hardirq-unsafe lock (in the full forwards-subgraph starting at
+ * <next>)? [== illegal lock inversion with hardirq contexts]
+ *
+ * - does the new prev->next dependency connect any softirq-safe lock
+ * (in the full backwards-subgraph starting at <prev>) with any
+ * softirq-unsafe lock (in the full forwards-subgraph starting at
+ * <next>)? [== illegal lock inversion with softirq contexts]
+ *
+ * any of these scenarios could lead to a deadlock.
+ *
+ * Then if all the validations pass, we add the forwards and backwards
+ * dependency.
+ */
+static int
+check_prev_add(struct task_struct *curr, struct held_lock *prev,
+ struct held_lock *next, int distance, int trylock_loop)
+{
+ struct lock_list *entry;
+ int ret;
+ struct lock_list this;
+ struct lock_list *uninitialized_var(target_entry);
+ /*
+ * Static variable, serialized by the graph_lock().
+ *
+ * We use this static variable to save the stack trace in case
+ * we call into this function multiple times due to encountering
+ * trylocks in the held lock stack.
+ */
+ static struct stack_trace trace;
+
+ /*
+ * Prove that the new <prev> -> <next> dependency would not
+ * create a circular dependency in the graph. (We do this by
+ * forward-recursing into the graph starting at <next>, and
+ * checking whether we can reach <prev>.)
+ *
+ * We are using global variables to control the recursion, to
+ * keep the stackframe size of the recursive functions low:
+ */
+ this.class = hlock_class(next);
+ this.parent = NULL;
+ ret = check_noncircular(&this, hlock_class(prev), &target_entry);
+ if (unlikely(!ret))
+ return print_circular_bug(&this, target_entry, next, prev);
+ else if (unlikely(ret < 0))
+ return print_bfs_bug(ret);
+
+ if (!check_prev_add_irq(curr, prev, next))
+ return 0;
+
+ /*
+ * For recursive read-locks we do all the dependency checks,
+ * but we dont store read-triggered dependencies (only
+ * write-triggered dependencies). This ensures that only the
+ * write-side dependencies matter, and that if for example a
+ * write-lock never takes any other locks, then the reads are
+ * equivalent to a NOP.
+ */
+ if (next->read == 2 || prev->read == 2)
+ return 1;
+ /*
+ * Is the <prev> -> <next> dependency already present?
+ *
+ * (this may occur even though this is a new chain: consider
+ * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3
+ * chains - the second one will be new, but L1 already has
+ * L2 added to its dependency list, due to the first chain.)
+ */
+ list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) {
+ if (entry->class == hlock_class(next)) {
+ if (distance == 1)
+ entry->distance = 1;
+ return 2;
+ }
+ }
+
+ if (!trylock_loop && !save_trace(&trace))
+ return 0;
+
+ /*
+ * Ok, all validations passed, add the new lock
+ * to the previous lock's dependency list:
+ */
+ ret = add_lock_to_list(hlock_class(prev), hlock_class(next),
+ &hlock_class(prev)->locks_after,
+ next->acquire_ip, distance, &trace);
+
+ if (!ret)
+ return 0;
+
+ ret = add_lock_to_list(hlock_class(next), hlock_class(prev),
+ &hlock_class(next)->locks_before,
+ next->acquire_ip, distance, &trace);
+ if (!ret)
+ return 0;
+
+ /*
+ * Debugging printouts:
+ */
+ if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) {
+ graph_unlock();
+ printk("\n new dependency: ");
+ print_lock_name(hlock_class(prev));
+ printk(" => ");
+ print_lock_name(hlock_class(next));
+ printk("\n");
+ dump_stack();
+ return graph_lock();
+ }
+ return 1;
+}
+
+/*
+ * Add the dependency to all directly-previous locks that are 'relevant'.
+ * The ones that are relevant are (in increasing distance from curr):
+ * all consecutive trylock entries and the final non-trylock entry - or
+ * the end of this context's lock-chain - whichever comes first.
+ */
+static int
+check_prevs_add(struct task_struct *curr, struct held_lock *next)
+{
+ int depth = curr->lockdep_depth;
+ int trylock_loop = 0;
+ struct held_lock *hlock;
+
+ /*
+ * Debugging checks.
+ *
+ * Depth must not be zero for a non-head lock:
+ */
+ if (!depth)
+ goto out_bug;
+ /*
+ * At least two relevant locks must exist for this
+ * to be a head:
+ */
+ if (curr->held_locks[depth].irq_context !=
+ curr->held_locks[depth-1].irq_context)
+ goto out_bug;
+
+ for (;;) {
+ int distance = curr->lockdep_depth - depth + 1;
+ hlock = curr->held_locks + depth-1;
+ /*
+ * Only non-recursive-read entries get new dependencies
+ * added:
+ */
+ if (hlock->read != 2) {
+ if (!check_prev_add(curr, hlock, next,
+ distance, trylock_loop))
+ return 0;
+ /*
+ * Stop after the first non-trylock entry,
+ * as non-trylock entries have added their
+ * own direct dependencies already, so this
+ * lock is connected to them indirectly:
+ */
+ if (!hlock->trylock)
+ break;
+ }
+ depth--;
+ /*
+ * End of lock-stack?
+ */
+ if (!depth)
+ break;
+ /*
+ * Stop the search if we cross into another context:
+ */
+ if (curr->held_locks[depth].irq_context !=
+ curr->held_locks[depth-1].irq_context)
+ break;
+ trylock_loop = 1;
+ }
+ return 1;
+out_bug:
+ if (!debug_locks_off_graph_unlock())
+ return 0;
+
+ /*
+ * Clearly we all shouldn't be here, but since we made it we
+ * can reliable say we messed up our state. See the above two
+ * gotos for reasons why we could possibly end up here.
+ */
+ WARN_ON(1);
+
+ return 0;
+}
+
+unsigned long nr_lock_chains;
+struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
+int nr_chain_hlocks;
+static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS];
+
+struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i)
+{
+ return lock_classes + chain_hlocks[chain->base + i];
+}
+
+/*
+ * Look up a dependency chain. If the key is not present yet then
+ * add it and return 1 - in this case the new dependency chain is
+ * validated. If the key is already hashed, return 0.
+ * (On return with 1 graph_lock is held.)
+ */
+static inline int lookup_chain_cache(struct task_struct *curr,
+ struct held_lock *hlock,
+ u64 chain_key)
+{
+ struct lock_class *class = hlock_class(hlock);
+ struct list_head *hash_head = chainhashentry(chain_key);
+ struct lock_chain *chain;
+ struct held_lock *hlock_curr;
+ int i, j;
+
+ /*
+ * We might need to take the graph lock, ensure we've got IRQs
+ * disabled to make this an IRQ-safe lock.. for recursion reasons
+ * lockdep won't complain about its own locking errors.
+ */
+ if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+ return 0;
+ /*
+ * We can walk it lock-free, because entries only get added
+ * to the hash:
+ */
+ list_for_each_entry(chain, hash_head, entry) {
+ if (chain->chain_key == chain_key) {
+cache_hit:
+ debug_atomic_inc(chain_lookup_hits);
+ if (very_verbose(class))
+ printk("\nhash chain already cached, key: "
+ "%016Lx tail class: [%p] %s\n",
+ (unsigned long long)chain_key,
+ class->key, class->name);
+ return 0;
+ }
+ }
+ if (very_verbose(class))
+ printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n",
+ (unsigned long long)chain_key, class->key, class->name);
+ /*
+ * Allocate a new chain entry from the static array, and add
+ * it to the hash:
+ */
+ if (!graph_lock())
+ return 0;
+ /*
+ * We have to walk the chain again locked - to avoid duplicates:
+ */
+ list_for_each_entry(chain, hash_head, entry) {
+ if (chain->chain_key == chain_key) {
+ graph_unlock();
+ goto cache_hit;
+ }
+ }
+ if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) {
+ if (!debug_locks_off_graph_unlock())
+ return 0;
+
+ print_lockdep_off("BUG: MAX_LOCKDEP_CHAINS too low!");
+ dump_stack();
+ return 0;
+ }
+ chain = lock_chains + nr_lock_chains++;
+ chain->chain_key = chain_key;
+ chain->irq_context = hlock->irq_context;
+ /* Find the first held_lock of current chain */
+ for (i = curr->lockdep_depth - 1; i >= 0; i--) {
+ hlock_curr = curr->held_locks + i;
+ if (hlock_curr->irq_context != hlock->irq_context)
+ break;
+ }
+ i++;
+ chain->depth = curr->lockdep_depth + 1 - i;
+ if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) {
+ chain->base = nr_chain_hlocks;
+ nr_chain_hlocks += chain->depth;
+ for (j = 0; j < chain->depth - 1; j++, i++) {
+ int lock_id = curr->held_locks[i].class_idx - 1;
+ chain_hlocks[chain->base + j] = lock_id;
+ }
+ chain_hlocks[chain->base + j] = class - lock_classes;
+ }
+ list_add_tail_rcu(&chain->entry, hash_head);
+ debug_atomic_inc(chain_lookup_misses);
+ inc_chains();
+
+ return 1;
+}
+
+static int validate_chain(struct task_struct *curr, struct lockdep_map *lock,
+ struct held_lock *hlock, int chain_head, u64 chain_key)
+{
+ /*
+ * Trylock needs to maintain the stack of held locks, but it
+ * does not add new dependencies, because trylock can be done
+ * in any order.
+ *
+ * We look up the chain_key and do the O(N^2) check and update of
+ * the dependencies only if this is a new dependency chain.
+ * (If lookup_chain_cache() returns with 1 it acquires
+ * graph_lock for us)
+ */
+ if (!hlock->trylock && (hlock->check == 2) &&
+ lookup_chain_cache(curr, hlock, chain_key)) {
+ /*
+ * Check whether last held lock:
+ *
+ * - is irq-safe, if this lock is irq-unsafe
+ * - is softirq-safe, if this lock is hardirq-unsafe
+ *
+ * And check whether the new lock's dependency graph
+ * could lead back to the previous lock.
+ *
+ * any of these scenarios could lead to a deadlock. If
+ * All validations
+ */
+ int ret = check_deadlock(curr, hlock, lock, hlock->read);
+
+ if (!ret)
+ return 0;
+ /*
+ * Mark recursive read, as we jump over it when
+ * building dependencies (just like we jump over
+ * trylock entries):
+ */
+ if (ret == 2)
+ hlock->read = 2;
+ /*
+ * Add dependency only if this lock is not the head
+ * of the chain, and if it's not a secondary read-lock:
+ */
+ if (!chain_head && ret != 2)
+ if (!check_prevs_add(curr, hlock))
+ return 0;
+ graph_unlock();
+ } else
+ /* after lookup_chain_cache(): */
+ if (unlikely(!debug_locks))
+ return 0;
+
+ return 1;
+}
+#else
+static inline int validate_chain(struct task_struct *curr,
+ struct lockdep_map *lock, struct held_lock *hlock,
+ int chain_head, u64 chain_key)
+{
+ return 1;
+}
+#endif
+
+/*
+ * We are building curr_chain_key incrementally, so double-check
+ * it from scratch, to make sure that it's done correctly:
+ */
+static void check_chain_key(struct task_struct *curr)
+{
+#ifdef CONFIG_DEBUG_LOCKDEP
+ struct held_lock *hlock, *prev_hlock = NULL;
+ unsigned int i, id;
+ u64 chain_key = 0;
+
+ for (i = 0; i < curr->lockdep_depth; i++) {
+ hlock = curr->held_locks + i;
+ if (chain_key != hlock->prev_chain_key) {
+ debug_locks_off();
+ /*
+ * We got mighty confused, our chain keys don't match
+ * with what we expect, someone trample on our task state?
+ */
+ WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n",
+ curr->lockdep_depth, i,
+ (unsigned long long)chain_key,
+ (unsigned long long)hlock->prev_chain_key);
+ return;
+ }
+ id = hlock->class_idx - 1;
+ /*
+ * Whoops ran out of static storage again?
+ */
+ if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
+ return;
+
+ if (prev_hlock && (prev_hlock->irq_context !=
+ hlock->irq_context))
+ chain_key = 0;
+ chain_key = iterate_chain_key(chain_key, id);
+ prev_hlock = hlock;
+ }
+ if (chain_key != curr->curr_chain_key) {
+ debug_locks_off();
+ /*
+ * More smoking hash instead of calculating it, damn see these
+ * numbers float.. I bet that a pink elephant stepped on my memory.
+ */
+ WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n",
+ curr->lockdep_depth, i,
+ (unsigned long long)chain_key,
+ (unsigned long long)curr->curr_chain_key);
+ }
+#endif
+}
+
+static void
+print_usage_bug_scenario(struct held_lock *lock)
+{
+ struct lock_class *class = hlock_class(lock);
+
+ printk(" Possible unsafe locking scenario:\n\n");
+ printk(" CPU0\n");
+ printk(" ----\n");
+ printk(" lock(");
+ __print_lock_name(class);
+ printk(");\n");
+ printk(" <Interrupt>\n");
+ printk(" lock(");
+ __print_lock_name(class);
+ printk(");\n");
+ printk("\n *** DEADLOCK ***\n\n");
+}
+
+static int
+print_usage_bug(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit)
+{
+ if (!debug_locks_off_graph_unlock() || debug_locks_silent)
+ return 0;
+
+ printk("\n");
+ printk("=================================\n");
+ printk("[ INFO: inconsistent lock state ]\n");
+ print_kernel_ident();
+ printk("---------------------------------\n");
+
+ printk("inconsistent {%s} -> {%s} usage.\n",
+ usage_str[prev_bit], usage_str[new_bit]);
+
+ printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n",
+ curr->comm, task_pid_nr(curr),
+ trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT,
+ trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT,
+ trace_hardirqs_enabled(curr),
+ trace_softirqs_enabled(curr));
+ print_lock(this);
+
+ printk("{%s} state was registered at:\n", usage_str[prev_bit]);
+ print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1);
+
+ print_irqtrace_events(curr);
+ printk("\nother info that might help us debug this:\n");
+ print_usage_bug_scenario(this);
+
+ lockdep_print_held_locks(curr);
+
+ printk("\nstack backtrace:\n");
+ dump_stack();
+
+ return 0;
+}
+
+/*
+ * Print out an error if an invalid bit is set:
+ */
+static inline int
+valid_state(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit)
+{
+ if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit)))
+ return print_usage_bug(curr, this, bad_bit, new_bit);
+ return 1;
+}
+
+static int mark_lock(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit new_bit);
+
+#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
+
+/*
+ * print irq inversion bug:
+ */
+static int
+print_irq_inversion_bug(struct task_struct *curr,
+ struct lock_list *root, struct lock_list *other,
+ struct held_lock *this, int forwards,
+ const char *irqclass)
+{
+ struct lock_list *entry = other;
+ struct lock_list *middle = NULL;
+ int depth;
+
+ if (!debug_locks_off_graph_unlock() || debug_locks_silent)
+ return 0;
+
+ printk("\n");
+ printk("=========================================================\n");
+ printk("[ INFO: possible irq lock inversion dependency detected ]\n");
+ print_kernel_ident();
+ printk("---------------------------------------------------------\n");
+ printk("%s/%d just changed the state of lock:\n",
+ curr->comm, task_pid_nr(curr));
+ print_lock(this);
+ if (forwards)
+ printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass);
+ else
+ printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass);
+ print_lock_name(other->class);
+ printk("\n\nand interrupts could create inverse lock ordering between them.\n\n");
+
+ printk("\nother info that might help us debug this:\n");
+
+ /* Find a middle lock (if one exists) */
+ depth = get_lock_depth(other);
+ do {
+ if (depth == 0 && (entry != root)) {
+ printk("lockdep:%s bad path found in chain graph\n", __func__);
+ break;
+ }
+ middle = entry;
+ entry = get_lock_parent(entry);
+ depth--;
+ } while (entry && entry != root && (depth >= 0));
+ if (forwards)
+ print_irq_lock_scenario(root, other,
+ middle ? middle->class : root->class, other->class);
+ else
+ print_irq_lock_scenario(other, root,
+ middle ? middle->class : other->class, root->class);
+
+ lockdep_print_held_locks(curr);
+
+ printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n");
+ if (!save_trace(&root->trace))
+ return 0;
+ print_shortest_lock_dependencies(other, root);
+
+ printk("\nstack backtrace:\n");
+ dump_stack();
+
+ return 0;
+}
+
+/*
+ * Prove that in the forwards-direction subgraph starting at <this>
+ * there is no lock matching <mask>:
+ */
+static int
+check_usage_forwards(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit bit, const char *irqclass)
+{
+ int ret;
+ struct lock_list root;
+ struct lock_list *uninitialized_var(target_entry);
+
+ root.parent = NULL;
+ root.class = hlock_class(this);
+ ret = find_usage_forwards(&root, bit, &target_entry);
+ if (ret < 0)
+ return print_bfs_bug(ret);
+ if (ret == 1)
+ return ret;
+
+ return print_irq_inversion_bug(curr, &root, target_entry,
+ this, 1, irqclass);
+}
+
+/*
+ * Prove that in the backwards-direction subgraph starting at <this>
+ * there is no lock matching <mask>:
+ */
+static int
+check_usage_backwards(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit bit, const char *irqclass)
+{
+ int ret;
+ struct lock_list root;
+ struct lock_list *uninitialized_var(target_entry);
+
+ root.parent = NULL;
+ root.class = hlock_class(this);
+ ret = find_usage_backwards(&root, bit, &target_entry);
+ if (ret < 0)
+ return print_bfs_bug(ret);
+ if (ret == 1)
+ return ret;
+
+ return print_irq_inversion_bug(curr, &root, target_entry,
+ this, 0, irqclass);
+}
+
+void print_irqtrace_events(struct task_struct *curr)
+{
+ printk("irq event stamp: %u\n", curr->irq_events);
+ printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event);
+ print_ip_sym(curr->hardirq_enable_ip);
+ printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event);
+ print_ip_sym(curr->hardirq_disable_ip);
+ printk("softirqs last enabled at (%u): ", curr->softirq_enable_event);
+ print_ip_sym(curr->softirq_enable_ip);
+ printk("softirqs last disabled at (%u): ", curr->softirq_disable_event);
+ print_ip_sym(curr->softirq_disable_ip);
+}
+
+static int HARDIRQ_verbose(struct lock_class *class)
+{
+#if HARDIRQ_VERBOSE
+ return class_filter(class);
+#endif
+ return 0;
+}
+
+static int SOFTIRQ_verbose(struct lock_class *class)
+{
+#if SOFTIRQ_VERBOSE
+ return class_filter(class);
+#endif
+ return 0;
+}
+
+static int RECLAIM_FS_verbose(struct lock_class *class)
+{
+#if RECLAIM_VERBOSE
+ return class_filter(class);
+#endif
+ return 0;
+}
+
+#define STRICT_READ_CHECKS 1
+
+static int (*state_verbose_f[])(struct lock_class *class) = {
+#define LOCKDEP_STATE(__STATE) \
+ __STATE##_verbose,
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+};
+
+static inline int state_verbose(enum lock_usage_bit bit,
+ struct lock_class *class)
+{
+ return state_verbose_f[bit >> 2](class);
+}
+
+typedef int (*check_usage_f)(struct task_struct *, struct held_lock *,
+ enum lock_usage_bit bit, const char *name);
+
+static int
+mark_lock_irq(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit new_bit)
+{
+ int excl_bit = exclusive_bit(new_bit);
+ int read = new_bit & 1;
+ int dir = new_bit & 2;
+
+ /*
+ * mark USED_IN has to look forwards -- to ensure no dependency
+ * has ENABLED state, which would allow recursion deadlocks.
+ *
+ * mark ENABLED has to look backwards -- to ensure no dependee
+ * has USED_IN state, which, again, would allow recursion deadlocks.
+ */
+ check_usage_f usage = dir ?
+ check_usage_backwards : check_usage_forwards;
+
+ /*
+ * Validate that this particular lock does not have conflicting
+ * usage states.
+ */
+ if (!valid_state(curr, this, new_bit, excl_bit))
+ return 0;
+
+ /*
+ * Validate that the lock dependencies don't have conflicting usage
+ * states.
+ */
+ if ((!read || !dir || STRICT_READ_CHECKS) &&
+ !usage(curr, this, excl_bit, state_name(new_bit & ~1)))
+ return 0;
+
+ /*
+ * Check for read in write conflicts
+ */
+ if (!read) {
+ if (!valid_state(curr, this, new_bit, excl_bit + 1))
+ return 0;
+
+ if (STRICT_READ_CHECKS &&
+ !usage(curr, this, excl_bit + 1,
+ state_name(new_bit + 1)))
+ return 0;
+ }
+
+ if (state_verbose(new_bit, hlock_class(this)))
+ return 2;
+
+ return 1;
+}
+
+enum mark_type {
+#define LOCKDEP_STATE(__STATE) __STATE,
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+};
+
+/*
+ * Mark all held locks with a usage bit:
+ */
+static int
+mark_held_locks(struct task_struct *curr, enum mark_type mark)
+{
+ enum lock_usage_bit usage_bit;
+ struct held_lock *hlock;
+ int i;
+
+ for (i = 0; i < curr->lockdep_depth; i++) {
+ hlock = curr->held_locks + i;
+
+ usage_bit = 2 + (mark << 2); /* ENABLED */
+ if (hlock->read)
+ usage_bit += 1; /* READ */
+
+ BUG_ON(usage_bit >= LOCK_USAGE_STATES);
+
+ if (hlock_class(hlock)->key == __lockdep_no_validate__.subkeys)
+ continue;
+
+ if (!mark_lock(curr, hlock, usage_bit))
+ return 0;
+ }
+
+ return 1;
+}
+
+/*
+ * Hardirqs will be enabled:
+ */
+static void __trace_hardirqs_on_caller(unsigned long ip)
+{
+ struct task_struct *curr = current;
+
+ /* we'll do an OFF -> ON transition: */
+ curr->hardirqs_enabled = 1;
+
+ /*
+ * We are going to turn hardirqs on, so set the
+ * usage bit for all held locks:
+ */
+ if (!mark_held_locks(curr, HARDIRQ))
+ return;
+ /*
+ * If we have softirqs enabled, then set the usage
+ * bit for all held locks. (disabled hardirqs prevented
+ * this bit from being set before)
+ */
+ if (curr->softirqs_enabled)
+ if (!mark_held_locks(curr, SOFTIRQ))
+ return;
+
+ curr->hardirq_enable_ip = ip;
+ curr->hardirq_enable_event = ++curr->irq_events;
+ debug_atomic_inc(hardirqs_on_events);
+}
+
+void trace_hardirqs_on_caller(unsigned long ip)
+{
+ time_hardirqs_on(CALLER_ADDR0, ip);
+
+ if (unlikely(!debug_locks || current->lockdep_recursion))
+ return;
+
+ if (unlikely(current->hardirqs_enabled)) {
+ /*
+ * Neither irq nor preemption are disabled here
+ * so this is racy by nature but losing one hit
+ * in a stat is not a big deal.
+ */
+ __debug_atomic_inc(redundant_hardirqs_on);
+ return;
+ }
+
+ /*
+ * We're enabling irqs and according to our state above irqs weren't
+ * already enabled, yet we find the hardware thinks they are in fact
+ * enabled.. someone messed up their IRQ state tracing.
+ */
+ if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+ return;
+
+ /*
+ * See the fine text that goes along with this variable definition.
+ */
+ if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled)))
+ return;
+
+ /*
+ * Can't allow enabling interrupts while in an interrupt handler,
+ * that's general bad form and such. Recursion, limited stack etc..
+ */
+ if (DEBUG_LOCKS_WARN_ON(current->hardirq_context))
+ return;
+
+ current->lockdep_recursion = 1;
+ __trace_hardirqs_on_caller(ip);
+ current->lockdep_recursion = 0;
+}
+EXPORT_SYMBOL(trace_hardirqs_on_caller);
+
+void trace_hardirqs_on(void)
+{
+ trace_hardirqs_on_caller(CALLER_ADDR0);
+}
+EXPORT_SYMBOL(trace_hardirqs_on);
+
+/*
+ * Hardirqs were disabled:
+ */
+void trace_hardirqs_off_caller(unsigned long ip)
+{
+ struct task_struct *curr = current;
+
+ time_hardirqs_off(CALLER_ADDR0, ip);
+
+ if (unlikely(!debug_locks || current->lockdep_recursion))
+ return;
+
+ /*
+ * So we're supposed to get called after you mask local IRQs, but for
+ * some reason the hardware doesn't quite think you did a proper job.
+ */
+ if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+ return;
+
+ if (curr->hardirqs_enabled) {
+ /*
+ * We have done an ON -> OFF transition:
+ */
+ curr->hardirqs_enabled = 0;
+ curr->hardirq_disable_ip = ip;
+ curr->hardirq_disable_event = ++curr->irq_events;
+ debug_atomic_inc(hardirqs_off_events);
+ } else
+ debug_atomic_inc(redundant_hardirqs_off);
+}
+EXPORT_SYMBOL(trace_hardirqs_off_caller);
+
+void trace_hardirqs_off(void)
+{
+ trace_hardirqs_off_caller(CALLER_ADDR0);
+}
+EXPORT_SYMBOL(trace_hardirqs_off);
+
+/*
+ * Softirqs will be enabled:
+ */
+void trace_softirqs_on(unsigned long ip)
+{
+ struct task_struct *curr = current;
+
+ if (unlikely(!debug_locks || current->lockdep_recursion))
+ return;
+
+ /*
+ * We fancy IRQs being disabled here, see softirq.c, avoids
+ * funny state and nesting things.
+ */
+ if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+ return;
+
+ if (curr->softirqs_enabled) {
+ debug_atomic_inc(redundant_softirqs_on);
+ return;
+ }
+
+ current->lockdep_recursion = 1;
+ /*
+ * We'll do an OFF -> ON transition:
+ */
+ curr->softirqs_enabled = 1;
+ curr->softirq_enable_ip = ip;
+ curr->softirq_enable_event = ++curr->irq_events;
+ debug_atomic_inc(softirqs_on_events);
+ /*
+ * We are going to turn softirqs on, so set the
+ * usage bit for all held locks, if hardirqs are
+ * enabled too:
+ */
+ if (curr->hardirqs_enabled)
+ mark_held_locks(curr, SOFTIRQ);
+ current->lockdep_recursion = 0;
+}
+
+/*
+ * Softirqs were disabled:
+ */
+void trace_softirqs_off(unsigned long ip)
+{
+ struct task_struct *curr = current;
+
+ if (unlikely(!debug_locks || current->lockdep_recursion))
+ return;
+
+ /*
+ * We fancy IRQs being disabled here, see softirq.c
+ */
+ if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+ return;
+
+ if (curr->softirqs_enabled) {
+ /*
+ * We have done an ON -> OFF transition:
+ */
+ curr->softirqs_enabled = 0;
+ curr->softirq_disable_ip = ip;
+ curr->softirq_disable_event = ++curr->irq_events;
+ debug_atomic_inc(softirqs_off_events);
+ /*
+ * Whoops, we wanted softirqs off, so why aren't they?
+ */
+ DEBUG_LOCKS_WARN_ON(!softirq_count());
+ } else
+ debug_atomic_inc(redundant_softirqs_off);
+}
+
+static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags)
+{
+ struct task_struct *curr = current;
+
+ if (unlikely(!debug_locks))
+ return;
+
+ /* no reclaim without waiting on it */
+ if (!(gfp_mask & __GFP_WAIT))
+ return;
+
+ /* this guy won't enter reclaim */
+ if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC))
+ return;
+
+ /* We're only interested __GFP_FS allocations for now */
+ if (!(gfp_mask & __GFP_FS))
+ return;
+
+ /*
+ * Oi! Can't be having __GFP_FS allocations with IRQs disabled.
+ */
+ if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags)))
+ return;
+
+ mark_held_locks(curr, RECLAIM_FS);
+}
+
+static void check_flags(unsigned long flags);
+
+void lockdep_trace_alloc(gfp_t gfp_mask)
+{
+ unsigned long flags;
+
+ if (unlikely(current->lockdep_recursion))
+ return;
+
+ raw_local_irq_save(flags);
+ check_flags(flags);
+ current->lockdep_recursion = 1;
+ __lockdep_trace_alloc(gfp_mask, flags);
+ current->lockdep_recursion = 0;
+ raw_local_irq_restore(flags);
+}
+
+static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
+{
+ /*
+ * If non-trylock use in a hardirq or softirq context, then
+ * mark the lock as used in these contexts:
+ */
+ if (!hlock->trylock) {
+ if (hlock->read) {
+ if (curr->hardirq_context)
+ if (!mark_lock(curr, hlock,
+ LOCK_USED_IN_HARDIRQ_READ))
+ return 0;
+ if (curr->softirq_context)
+ if (!mark_lock(curr, hlock,
+ LOCK_USED_IN_SOFTIRQ_READ))
+ return 0;
+ } else {
+ if (curr->hardirq_context)
+ if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ))
+ return 0;
+ if (curr->softirq_context)
+ if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ))
+ return 0;
+ }
+ }
+ if (!hlock->hardirqs_off) {
+ if (hlock->read) {
+ if (!mark_lock(curr, hlock,
+ LOCK_ENABLED_HARDIRQ_READ))
+ return 0;
+ if (curr->softirqs_enabled)
+ if (!mark_lock(curr, hlock,
+ LOCK_ENABLED_SOFTIRQ_READ))
+ return 0;
+ } else {
+ if (!mark_lock(curr, hlock,
+ LOCK_ENABLED_HARDIRQ))
+ return 0;
+ if (curr->softirqs_enabled)
+ if (!mark_lock(curr, hlock,
+ LOCK_ENABLED_SOFTIRQ))
+ return 0;
+ }
+ }
+
+ /*
+ * We reuse the irq context infrastructure more broadly as a general
+ * context checking code. This tests GFP_FS recursion (a lock taken
+ * during reclaim for a GFP_FS allocation is held over a GFP_FS
+ * allocation).
+ */
+ if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) {
+ if (hlock->read) {
+ if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ))
+ return 0;
+ } else {
+ if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS))
+ return 0;
+ }
+ }
+
+ return 1;
+}
+
+static int separate_irq_context(struct task_struct *curr,
+ struct held_lock *hlock)
+{
+ unsigned int depth = curr->lockdep_depth;
+
+ /*
+ * Keep track of points where we cross into an interrupt context:
+ */
+ hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) +
+ curr->softirq_context;
+ if (depth) {
+ struct held_lock *prev_hlock;
+
+ prev_hlock = curr->held_locks + depth-1;
+ /*
+ * If we cross into another context, reset the
+ * hash key (this also prevents the checking and the
+ * adding of the dependency to 'prev'):
+ */
+ if (prev_hlock->irq_context != hlock->irq_context)
+ return 1;
+ }
+ return 0;
+}
+
+#else /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */
+
+static inline
+int mark_lock_irq(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit new_bit)
+{
+ WARN_ON(1); /* Impossible innit? when we don't have TRACE_IRQFLAG */
+ return 1;
+}
+
+static inline int mark_irqflags(struct task_struct *curr,
+ struct held_lock *hlock)
+{
+ return 1;
+}
+
+static inline int separate_irq_context(struct task_struct *curr,
+ struct held_lock *hlock)
+{
+ return 0;
+}
+
+void lockdep_trace_alloc(gfp_t gfp_mask)
+{
+}
+
+#endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */
+
+/*
+ * Mark a lock with a usage bit, and validate the state transition:
+ */
+static int mark_lock(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit new_bit)
+{
+ unsigned int new_mask = 1 << new_bit, ret = 1;
+
+ /*
+ * If already set then do not dirty the cacheline,
+ * nor do any checks:
+ */
+ if (likely(hlock_class(this)->usage_mask & new_mask))
+ return 1;
+
+ if (!graph_lock())
+ return 0;
+ /*
+ * Make sure we didn't race:
+ */
+ if (unlikely(hlock_class(this)->usage_mask & new_mask)) {
+ graph_unlock();
+ return 1;
+ }
+
+ hlock_class(this)->usage_mask |= new_mask;
+
+ if (!save_trace(hlock_class(this)->usage_traces + new_bit))
+ return 0;
+
+ switch (new_bit) {
+#define LOCKDEP_STATE(__STATE) \
+ case LOCK_USED_IN_##__STATE: \
+ case LOCK_USED_IN_##__STATE##_READ: \
+ case LOCK_ENABLED_##__STATE: \
+ case LOCK_ENABLED_##__STATE##_READ:
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+ ret = mark_lock_irq(curr, this, new_bit);
+ if (!ret)
+ return 0;
+ break;
+ case LOCK_USED:
+ debug_atomic_dec(nr_unused_locks);
+ break;
+ default:
+ if (!debug_locks_off_graph_unlock())
+ return 0;
+ WARN_ON(1);
+ return 0;
+ }
+
+ graph_unlock();
+
+ /*
+ * We must printk outside of the graph_lock:
+ */
+ if (ret == 2) {
+ printk("\nmarked lock as {%s}:\n", usage_str[new_bit]);
+ print_lock(this);
+ print_irqtrace_events(curr);
+ dump_stack();
+ }
+
+ return ret;
+}
+
+/*
+ * Initialize a lock instance's lock-class mapping info:
+ */
+void lockdep_init_map(struct lockdep_map *lock, const char *name,
+ struct lock_class_key *key, int subclass)
+{
+ int i;
+
+ kmemcheck_mark_initialized(lock, sizeof(*lock));
+
+ for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
+ lock->class_cache[i] = NULL;
+
+#ifdef CONFIG_LOCK_STAT
+ lock->cpu = raw_smp_processor_id();
+#endif
+
+ /*
+ * Can't be having no nameless bastards around this place!
+ */
+ if (DEBUG_LOCKS_WARN_ON(!name)) {
+ lock->name = "NULL";
+ return;
+ }
+
+ lock->name = name;
+
+ /*
+ * No key, no joy, we need to hash something.
+ */
+ if (DEBUG_LOCKS_WARN_ON(!key))
+ return;
+ /*
+ * Sanity check, the lock-class key must be persistent:
+ */
+ if (!static_obj(key)) {
+ printk("BUG: key %p not in .data!\n", key);
+ /*
+ * What it says above ^^^^^, I suggest you read it.
+ */
+ DEBUG_LOCKS_WARN_ON(1);
+ return;
+ }
+ lock->key = key;
+
+ if (unlikely(!debug_locks))
+ return;
+
+ if (subclass)
+ register_lock_class(lock, subclass, 1);
+}
+EXPORT_SYMBOL_GPL(lockdep_init_map);
+
+struct lock_class_key __lockdep_no_validate__;
+EXPORT_SYMBOL_GPL(__lockdep_no_validate__);
+
+static int
+print_lock_nested_lock_not_held(struct task_struct *curr,
+ struct held_lock *hlock,
+ unsigned long ip)
+{
+ if (!debug_locks_off())
+ return 0;
+ if (debug_locks_silent)
+ return 0;
+
+ printk("\n");
+ printk("==================================\n");
+ printk("[ BUG: Nested lock was not taken ]\n");
+ print_kernel_ident();
+ printk("----------------------------------\n");
+
+ printk("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr));
+ print_lock(hlock);
+
+ printk("\nbut this task is not holding:\n");
+ printk("%s\n", hlock->nest_lock->name);
+
+ printk("\nstack backtrace:\n");
+ dump_stack();
+
+ printk("\nother info that might help us debug this:\n");
+ lockdep_print_held_locks(curr);
+
+ printk("\nstack backtrace:\n");
+ dump_stack();
+
+ return 0;
+}
+
+static int __lock_is_held(struct lockdep_map *lock);
+
+/*
+ * This gets called for every mutex_lock*()/spin_lock*() operation.
+ * We maintain the dependency maps and validate the locking attempt:
+ */
+static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
+ int trylock, int read, int check, int hardirqs_off,
+ struct lockdep_map *nest_lock, unsigned long ip,
+ int references)
+{
+ struct task_struct *curr = current;
+ struct lock_class *class = NULL;
+ struct held_lock *hlock;
+ unsigned int depth, id;
+ int chain_head = 0;
+ int class_idx;
+ u64 chain_key;
+
+ if (!prove_locking)
+ check = 1;
+
+ if (unlikely(!debug_locks))
+ return 0;
+
+ /*
+ * Lockdep should run with IRQs disabled, otherwise we could
+ * get an interrupt which would want to take locks, which would
+ * end up in lockdep and have you got a head-ache already?
+ */
+ if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+ return 0;
+
+ if (lock->key == &__lockdep_no_validate__)
+ check = 1;
+
+ if (subclass < NR_LOCKDEP_CACHING_CLASSES)
+ class = lock->class_cache[subclass];
+ /*
+ * Not cached?
+ */
+ if (unlikely(!class)) {
+ class = register_lock_class(lock, subclass, 0);
+ if (!class)
+ return 0;
+ }
+ atomic_inc((atomic_t *)&class->ops);
+ if (very_verbose(class)) {
+ printk("\nacquire class [%p] %s", class->key, class->name);
+ if (class->name_version > 1)
+ printk("#%d", class->name_version);
+ printk("\n");
+ dump_stack();
+ }
+
+ /*
+ * Add the lock to the list of currently held locks.
+ * (we dont increase the depth just yet, up until the
+ * dependency checks are done)
+ */
+ depth = curr->lockdep_depth;
+ /*
+ * Ran out of static storage for our per-task lock stack again have we?
+ */
+ if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH))
+ return 0;
+
+ class_idx = class - lock_classes + 1;
+
+ if (depth) {
+ hlock = curr->held_locks + depth - 1;
+ if (hlock->class_idx == class_idx && nest_lock) {
+ if (hlock->references)
+ hlock->references++;
+ else
+ hlock->references = 2;
+
+ return 1;
+ }
+ }
+
+ hlock = curr->held_locks + depth;
+ /*
+ * Plain impossible, we just registered it and checked it weren't no
+ * NULL like.. I bet this mushroom I ate was good!
+ */
+ if (DEBUG_LOCKS_WARN_ON(!class))
+ return 0;
+ hlock->class_idx = class_idx;
+ hlock->acquire_ip = ip;
+ hlock->instance = lock;
+ hlock->nest_lock = nest_lock;
+ hlock->trylock = trylock;
+ hlock->read = read;
+ hlock->check = check;
+ hlock->hardirqs_off = !!hardirqs_off;
+ hlock->references = references;
+#ifdef CONFIG_LOCK_STAT
+ hlock->waittime_stamp = 0;
+ hlock->holdtime_stamp = lockstat_clock();
+#endif
+
+ if (check == 2 && !mark_irqflags(curr, hlock))
+ return 0;
+
+ /* mark it as used: */
+ if (!mark_lock(curr, hlock, LOCK_USED))
+ return 0;
+
+ /*
+ * Calculate the chain hash: it's the combined hash of all the
+ * lock keys along the dependency chain. We save the hash value
+ * at every step so that we can get the current hash easily
+ * after unlock. The chain hash is then used to cache dependency
+ * results.
+ *
+ * The 'key ID' is what is the most compact key value to drive
+ * the hash, not class->key.
+ */
+ id = class - lock_classes;
+ /*
+ * Whoops, we did it again.. ran straight out of our static allocation.
+ */
+ if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
+ return 0;
+
+ chain_key = curr->curr_chain_key;
+ if (!depth) {
+ /*
+ * How can we have a chain hash when we ain't got no keys?!
+ */
+ if (DEBUG_LOCKS_WARN_ON(chain_key != 0))
+ return 0;
+ chain_head = 1;
+ }
+
+ hlock->prev_chain_key = chain_key;
+ if (separate_irq_context(curr, hlock)) {
+ chain_key = 0;
+ chain_head = 1;
+ }
+ chain_key = iterate_chain_key(chain_key, id);
+
+ if (nest_lock && !__lock_is_held(nest_lock))
+ return print_lock_nested_lock_not_held(curr, hlock, ip);
+
+ if (!validate_chain(curr, lock, hlock, chain_head, chain_key))
+ return 0;
+
+ curr->curr_chain_key = chain_key;
+ curr->lockdep_depth++;
+ check_chain_key(curr);
+#ifdef CONFIG_DEBUG_LOCKDEP
+ if (unlikely(!debug_locks))
+ return 0;
+#endif
+ if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) {
+ debug_locks_off();
+ print_lockdep_off("BUG: MAX_LOCK_DEPTH too low!");
+ printk(KERN_DEBUG "depth: %i max: %lu!\n",
+ curr->lockdep_depth, MAX_LOCK_DEPTH);
+
+ lockdep_print_held_locks(current);
+ debug_show_all_locks();
+ dump_stack();
+
+ return 0;
+ }
+
+ if (unlikely(curr->lockdep_depth > max_lockdep_depth))
+ max_lockdep_depth = curr->lockdep_depth;
+
+ return 1;
+}
+
+static int
+print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock,
+ unsigned long ip)
+{
+ if (!debug_locks_off())
+ return 0;
+ if (debug_locks_silent)
+ return 0;
+
+ printk("\n");
+ printk("=====================================\n");
+ printk("[ BUG: bad unlock balance detected! ]\n");
+ print_kernel_ident();
+ printk("-------------------------------------\n");
+ printk("%s/%d is trying to release lock (",
+ curr->comm, task_pid_nr(curr));
+ print_lockdep_cache(lock);
+ printk(") at:\n");
+ print_ip_sym(ip);
+ printk("but there are no more locks to release!\n");
+ printk("\nother info that might help us debug this:\n");
+ lockdep_print_held_locks(curr);
+
+ printk("\nstack backtrace:\n");
+ dump_stack();
+
+ return 0;
+}
+
+/*
+ * Common debugging checks for both nested and non-nested unlock:
+ */
+static int check_unlock(struct task_struct *curr, struct lockdep_map *lock,
+ unsigned long ip)
+{
+ if (unlikely(!debug_locks))
+ return 0;
+ /*
+ * Lockdep should run with IRQs disabled, recursion, head-ache, etc..
+ */
+ if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+ return 0;
+
+ if (curr->lockdep_depth <= 0)
+ return print_unlock_imbalance_bug(curr, lock, ip);
+
+ return 1;
+}
+
+static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock)
+{
+ if (hlock->instance == lock)
+ return 1;
+
+ if (hlock->references) {
+ struct lock_class *class = lock->class_cache[0];
+
+ if (!class)
+ class = look_up_lock_class(lock, 0);
+
+ /*
+ * If look_up_lock_class() failed to find a class, we're trying
+ * to test if we hold a lock that has never yet been acquired.
+ * Clearly if the lock hasn't been acquired _ever_, we're not
+ * holding it either, so report failure.
+ */
+ if (!class)
+ return 0;
+
+ /*
+ * References, but not a lock we're actually ref-counting?
+ * State got messed up, follow the sites that change ->references
+ * and try to make sense of it.
+ */
+ if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock))
+ return 0;
+
+ if (hlock->class_idx == class - lock_classes + 1)
+ return 1;
+ }
+
+ return 0;
+}
+
+static int
+__lock_set_class(struct lockdep_map *lock, const char *name,
+ struct lock_class_key *key, unsigned int subclass,
+ unsigned long ip)
+{
+ struct task_struct *curr = current;
+ struct held_lock *hlock, *prev_hlock;
+ struct lock_class *class;
+ unsigned int depth;
+ int i;
+
+ depth = curr->lockdep_depth;
+ /*
+ * This function is about (re)setting the class of a held lock,
+ * yet we're not actually holding any locks. Naughty user!
+ */
+ if (DEBUG_LOCKS_WARN_ON(!depth))
+ return 0;
+
+ prev_hlock = NULL;
+ for (i = depth-1; i >= 0; i--) {
+ hlock = curr->held_locks + i;
+ /*
+ * We must not cross into another context:
+ */
+ if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
+ break;
+ if (match_held_lock(hlock, lock))
+ goto found_it;
+ prev_hlock = hlock;
+ }
+ return print_unlock_imbalance_bug(curr, lock, ip);
+
+found_it:
+ lockdep_init_map(lock, name, key, 0);
+ class = register_lock_class(lock, subclass, 0);
+ hlock->class_idx = class - lock_classes + 1;
+
+ curr->lockdep_depth = i;
+ curr->curr_chain_key = hlock->prev_chain_key;
+
+ for (; i < depth; i++) {
+ hlock = curr->held_locks + i;
+ if (!__lock_acquire(hlock->instance,
+ hlock_class(hlock)->subclass, hlock->trylock,
+ hlock->read, hlock->check, hlock->hardirqs_off,
+ hlock->nest_lock, hlock->acquire_ip,
+ hlock->references))
+ return 0;
+ }
+
+ /*
+ * I took it apart and put it back together again, except now I have
+ * these 'spare' parts.. where shall I put them.
+ */
+ if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth))
+ return 0;
+ return 1;
+}
+
+/*
+ * Remove the lock to the list of currently held locks in a
+ * potentially non-nested (out of order) manner. This is a
+ * relatively rare operation, as all the unlock APIs default
+ * to nested mode (which uses lock_release()):
+ */
+static int
+lock_release_non_nested(struct task_struct *curr,
+ struct lockdep_map *lock, unsigned long ip)
+{
+ struct held_lock *hlock, *prev_hlock;
+ unsigned int depth;
+ int i;
+
+ /*
+ * Check whether the lock exists in the current stack
+ * of held locks:
+ */
+ depth = curr->lockdep_depth;
+ /*
+ * So we're all set to release this lock.. wait what lock? We don't
+ * own any locks, you've been drinking again?
+ */
+ if (DEBUG_LOCKS_WARN_ON(!depth))
+ return 0;
+
+ prev_hlock = NULL;
+ for (i = depth-1; i >= 0; i--) {
+ hlock = curr->held_locks + i;
+ /*
+ * We must not cross into another context:
+ */
+ if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
+ break;
+ if (match_held_lock(hlock, lock))
+ goto found_it;
+ prev_hlock = hlock;
+ }
+ return print_unlock_imbalance_bug(curr, lock, ip);
+
+found_it:
+ if (hlock->instance == lock)
+ lock_release_holdtime(hlock);
+
+ if (hlock->references) {
+ hlock->references--;
+ if (hlock->references) {
+ /*
+ * We had, and after removing one, still have
+ * references, the current lock stack is still
+ * valid. We're done!
+ */
+ return 1;
+ }
+ }
+
+ /*
+ * We have the right lock to unlock, 'hlock' points to it.
+ * Now we remove it from the stack, and add back the other
+ * entries (if any), recalculating the hash along the way:
+ */
+
+ curr->lockdep_depth = i;
+ curr->curr_chain_key = hlock->prev_chain_key;
+
+ for (i++; i < depth; i++) {
+ hlock = curr->held_locks + i;
+ if (!__lock_acquire(hlock->instance,
+ hlock_class(hlock)->subclass, hlock->trylock,
+ hlock->read, hlock->check, hlock->hardirqs_off,
+ hlock->nest_lock, hlock->acquire_ip,
+ hlock->references))
+ return 0;
+ }
+
+ /*
+ * We had N bottles of beer on the wall, we drank one, but now
+ * there's not N-1 bottles of beer left on the wall...
+ */
+ if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1))
+ return 0;
+ return 1;
+}
+
+/*
+ * Remove the lock to the list of currently held locks - this gets
+ * called on mutex_unlock()/spin_unlock*() (or on a failed
+ * mutex_lock_interruptible()). This is done for unlocks that nest
+ * perfectly. (i.e. the current top of the lock-stack is unlocked)
+ */
+static int lock_release_nested(struct task_struct *curr,
+ struct lockdep_map *lock, unsigned long ip)
+{
+ struct held_lock *hlock;
+ unsigned int depth;
+
+ /*
+ * Pop off the top of the lock stack:
+ */
+ depth = curr->lockdep_depth - 1;
+ hlock = curr->held_locks + depth;
+
+ /*
+ * Is the unlock non-nested:
+ */
+ if (hlock->instance != lock || hlock->references)
+ return lock_release_non_nested(curr, lock, ip);
+ curr->lockdep_depth--;
+
+ /*
+ * No more locks, but somehow we've got hash left over, who left it?
+ */
+ if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0)))
+ return 0;
+
+ curr->curr_chain_key = hlock->prev_chain_key;
+
+ lock_release_holdtime(hlock);
+
+#ifdef CONFIG_DEBUG_LOCKDEP
+ hlock->prev_chain_key = 0;
+ hlock->class_idx = 0;
+ hlock->acquire_ip = 0;
+ hlock->irq_context = 0;
+#endif
+ return 1;
+}
+
+/*
+ * Remove the lock to the list of currently held locks - this gets
+ * called on mutex_unlock()/spin_unlock*() (or on a failed
+ * mutex_lock_interruptible()). This is done for unlocks that nest
+ * perfectly. (i.e. the current top of the lock-stack is unlocked)
+ */
+static void
+__lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
+{
+ struct task_struct *curr = current;
+
+ if (!check_unlock(curr, lock, ip))
+ return;
+
+ if (nested) {
+ if (!lock_release_nested(curr, lock, ip))
+ return;
+ } else {
+ if (!lock_release_non_nested(curr, lock, ip))
+ return;
+ }
+
+ check_chain_key(curr);
+}
+
+static int __lock_is_held(struct lockdep_map *lock)
+{
+ struct task_struct *curr = current;
+ int i;
+
+ for (i = 0; i < curr->lockdep_depth; i++) {
+ struct held_lock *hlock = curr->held_locks + i;
+
+ if (match_held_lock(hlock, lock))
+ return 1;
+ }
+
+ return 0;
+}
+
+/*
+ * Check whether we follow the irq-flags state precisely:
+ */
+static void check_flags(unsigned long flags)
+{
+#if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \
+ defined(CONFIG_TRACE_IRQFLAGS)
+ if (!debug_locks)
+ return;
+
+ if (irqs_disabled_flags(flags)) {
+ if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) {
+ printk("possible reason: unannotated irqs-off.\n");
+ }
+ } else {
+ if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) {
+ printk("possible reason: unannotated irqs-on.\n");
+ }
+ }
+
+ /*
+ * We dont accurately track softirq state in e.g.
+ * hardirq contexts (such as on 4KSTACKS), so only
+ * check if not in hardirq contexts:
+ */
+ if (!hardirq_count()) {
+ if (softirq_count()) {
+ /* like the above, but with softirqs */
+ DEBUG_LOCKS_WARN_ON(current->softirqs_enabled);
+ } else {
+ /* lick the above, does it taste good? */
+ DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled);
+ }
+ }
+
+ if (!debug_locks)
+ print_irqtrace_events(current);
+#endif
+}
+
+void lock_set_class(struct lockdep_map *lock, const char *name,
+ struct lock_class_key *key, unsigned int subclass,
+ unsigned long ip)
+{
+ unsigned long flags;
+
+ if (unlikely(current->lockdep_recursion))
+ return;
+
+ raw_local_irq_save(flags);
+ current->lockdep_recursion = 1;
+ check_flags(flags);
+ if (__lock_set_class(lock, name, key, subclass, ip))
+ check_chain_key(current);
+ current->lockdep_recursion = 0;
+ raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lock_set_class);
+
+/*
+ * We are not always called with irqs disabled - do that here,
+ * and also avoid lockdep recursion:
+ */
+void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
+ int trylock, int read, int check,
+ struct lockdep_map *nest_lock, unsigned long ip)
+{
+ unsigned long flags;
+
+ if (unlikely(current->lockdep_recursion))
+ return;
+
+ raw_local_irq_save(flags);
+ check_flags(flags);
+
+ current->lockdep_recursion = 1;
+ trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip);
+ __lock_acquire(lock, subclass, trylock, read, check,
+ irqs_disabled_flags(flags), nest_lock, ip, 0);
+ current->lockdep_recursion = 0;
+ raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lock_acquire);
+
+void lock_release(struct lockdep_map *lock, int nested,
+ unsigned long ip)
+{
+ unsigned long flags;
+
+ if (unlikely(current->lockdep_recursion))
+ return;
+
+ raw_local_irq_save(flags);
+ check_flags(flags);
+ current->lockdep_recursion = 1;
+ trace_lock_release(lock, ip);
+ __lock_release(lock, nested, ip);
+ current->lockdep_recursion = 0;
+ raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lock_release);
+
+int lock_is_held(struct lockdep_map *lock)
+{
+ unsigned long flags;
+ int ret = 0;
+
+ if (unlikely(current->lockdep_recursion))
+ return 1; /* avoid false negative lockdep_assert_held() */
+
+ raw_local_irq_save(flags);
+ check_flags(flags);
+
+ current->lockdep_recursion = 1;
+ ret = __lock_is_held(lock);
+ current->lockdep_recursion = 0;
+ raw_local_irq_restore(flags);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(lock_is_held);
+
+void lockdep_set_current_reclaim_state(gfp_t gfp_mask)
+{
+ current->lockdep_reclaim_gfp = gfp_mask;
+}
+
+void lockdep_clear_current_reclaim_state(void)
+{
+ current->lockdep_reclaim_gfp = 0;
+}
+
+#ifdef CONFIG_LOCK_STAT
+static int
+print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock,
+ unsigned long ip)
+{
+ if (!debug_locks_off())
+ return 0;
+ if (debug_locks_silent)
+ return 0;
+
+ printk("\n");
+ printk("=================================\n");
+ printk("[ BUG: bad contention detected! ]\n");
+ print_kernel_ident();
+ printk("---------------------------------\n");
+ printk("%s/%d is trying to contend lock (",
+ curr->comm, task_pid_nr(curr));
+ print_lockdep_cache(lock);
+ printk(") at:\n");
+ print_ip_sym(ip);
+ printk("but there are no locks held!\n");
+ printk("\nother info that might help us debug this:\n");
+ lockdep_print_held_locks(curr);
+
+ printk("\nstack backtrace:\n");
+ dump_stack();
+
+ return 0;
+}
+
+static void
+__lock_contended(struct lockdep_map *lock, unsigned long ip)
+{
+ struct task_struct *curr = current;
+ struct held_lock *hlock, *prev_hlock;
+ struct lock_class_stats *stats;
+ unsigned int depth;
+ int i, contention_point, contending_point;
+
+ depth = curr->lockdep_depth;
+ /*
+ * Whee, we contended on this lock, except it seems we're not
+ * actually trying to acquire anything much at all..
+ */
+ if (DEBUG_LOCKS_WARN_ON(!depth))
+ return;
+
+ prev_hlock = NULL;
+ for (i = depth-1; i >= 0; i--) {
+ hlock = curr->held_locks + i;
+ /*
+ * We must not cross into another context:
+ */
+ if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
+ break;
+ if (match_held_lock(hlock, lock))
+ goto found_it;
+ prev_hlock = hlock;
+ }
+ print_lock_contention_bug(curr, lock, ip);
+ return;
+
+found_it:
+ if (hlock->instance != lock)
+ return;
+
+ hlock->waittime_stamp = lockstat_clock();
+
+ contention_point = lock_point(hlock_class(hlock)->contention_point, ip);
+ contending_point = lock_point(hlock_class(hlock)->contending_point,
+ lock->ip);
+
+ stats = get_lock_stats(hlock_class(hlock));
+ if (contention_point < LOCKSTAT_POINTS)
+ stats->contention_point[contention_point]++;
+ if (contending_point < LOCKSTAT_POINTS)
+ stats->contending_point[contending_point]++;
+ if (lock->cpu != smp_processor_id())
+ stats->bounces[bounce_contended + !!hlock->read]++;
+ put_lock_stats(stats);
+}
+
+static void
+__lock_acquired(struct lockdep_map *lock, unsigned long ip)
+{
+ struct task_struct *curr = current;
+ struct held_lock *hlock, *prev_hlock;
+ struct lock_class_stats *stats;
+ unsigned int depth;
+ u64 now, waittime = 0;
+ int i, cpu;
+
+ depth = curr->lockdep_depth;
+ /*
+ * Yay, we acquired ownership of this lock we didn't try to
+ * acquire, how the heck did that happen?
+ */
+ if (DEBUG_LOCKS_WARN_ON(!depth))
+ return;
+
+ prev_hlock = NULL;
+ for (i = depth-1; i >= 0; i--) {
+ hlock = curr->held_locks + i;
+ /*
+ * We must not cross into another context:
+ */
+ if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
+ break;
+ if (match_held_lock(hlock, lock))
+ goto found_it;
+ prev_hlock = hlock;
+ }
+ print_lock_contention_bug(curr, lock, _RET_IP_);
+ return;
+
+found_it:
+ if (hlock->instance != lock)
+ return;
+
+ cpu = smp_processor_id();
+ if (hlock->waittime_stamp) {
+ now = lockstat_clock();
+ waittime = now - hlock->waittime_stamp;
+ hlock->holdtime_stamp = now;
+ }
+
+ trace_lock_acquired(lock, ip);
+
+ stats = get_lock_stats(hlock_class(hlock));
+ if (waittime) {
+ if (hlock->read)
+ lock_time_inc(&stats->read_waittime, waittime);
+ else
+ lock_time_inc(&stats->write_waittime, waittime);
+ }
+ if (lock->cpu != cpu)
+ stats->bounces[bounce_acquired + !!hlock->read]++;
+ put_lock_stats(stats);
+
+ lock->cpu = cpu;
+ lock->ip = ip;
+}
+
+void lock_contended(struct lockdep_map *lock, unsigned long ip)
+{
+ unsigned long flags;
+
+ if (unlikely(!lock_stat))
+ return;
+
+ if (unlikely(current->lockdep_recursion))
+ return;
+
+ raw_local_irq_save(flags);
+ check_flags(flags);
+ current->lockdep_recursion = 1;
+ trace_lock_contended(lock, ip);
+ __lock_contended(lock, ip);
+ current->lockdep_recursion = 0;
+ raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lock_contended);
+
+void lock_acquired(struct lockdep_map *lock, unsigned long ip)
+{
+ unsigned long flags;
+
+ if (unlikely(!lock_stat))
+ return;
+
+ if (unlikely(current->lockdep_recursion))
+ return;
+
+ raw_local_irq_save(flags);
+ check_flags(flags);
+ current->lockdep_recursion = 1;
+ __lock_acquired(lock, ip);
+ current->lockdep_recursion = 0;
+ raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lock_acquired);
+#endif
+
+/*
+ * Used by the testsuite, sanitize the validator state
+ * after a simulated failure:
+ */
+
+void lockdep_reset(void)
+{
+ unsigned long flags;
+ int i;
+
+ raw_local_irq_save(flags);
+ current->curr_chain_key = 0;
+ current->lockdep_depth = 0;
+ current->lockdep_recursion = 0;
+ memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock));
+ nr_hardirq_chains = 0;
+ nr_softirq_chains = 0;
+ nr_process_chains = 0;
+ debug_locks = 1;
+ for (i = 0; i < CHAINHASH_SIZE; i++)
+ INIT_LIST_HEAD(chainhash_table + i);
+ raw_local_irq_restore(flags);
+}
+
+static void zap_class(struct lock_class *class)
+{
+ int i;
+
+ /*
+ * Remove all dependencies this lock is
+ * involved in:
+ */
+ for (i = 0; i < nr_list_entries; i++) {
+ if (list_entries[i].class == class)
+ list_del_rcu(&list_entries[i].entry);
+ }
+ /*
+ * Unhash the class and remove it from the all_lock_classes list:
+ */
+ list_del_rcu(&class->hash_entry);
+ list_del_rcu(&class->lock_entry);
+
+ class->key = NULL;
+}
+
+static inline int within(const void *addr, void *start, unsigned long size)
+{
+ return addr >= start && addr < start + size;
+}
+
+void lockdep_free_key_range(void *start, unsigned long size)
+{
+ struct lock_class *class, *next;
+ struct list_head *head;
+ unsigned long flags;
+ int i;
+ int locked;
+
+ raw_local_irq_save(flags);
+ locked = graph_lock();
+
+ /*
+ * Unhash all classes that were created by this module:
+ */
+ for (i = 0; i < CLASSHASH_SIZE; i++) {
+ head = classhash_table + i;
+ if (list_empty(head))
+ continue;
+ list_for_each_entry_safe(class, next, head, hash_entry) {
+ if (within(class->key, start, size))
+ zap_class(class);
+ else if (within(class->name, start, size))
+ zap_class(class);
+ }
+ }
+
+ if (locked)
+ graph_unlock();
+ raw_local_irq_restore(flags);
+}
+
+void lockdep_reset_lock(struct lockdep_map *lock)
+{
+ struct lock_class *class, *next;
+ struct list_head *head;
+ unsigned long flags;
+ int i, j;
+ int locked;
+
+ raw_local_irq_save(flags);
+
+ /*
+ * Remove all classes this lock might have:
+ */
+ for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) {
+ /*
+ * If the class exists we look it up and zap it:
+ */
+ class = look_up_lock_class(lock, j);
+ if (class)
+ zap_class(class);
+ }
+ /*
+ * Debug check: in the end all mapped classes should
+ * be gone.
+ */
+ locked = graph_lock();
+ for (i = 0; i < CLASSHASH_SIZE; i++) {
+ head = classhash_table + i;
+ if (list_empty(head))
+ continue;
+ list_for_each_entry_safe(class, next, head, hash_entry) {
+ int match = 0;
+
+ for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++)
+ match |= class == lock->class_cache[j];
+
+ if (unlikely(match)) {
+ if (debug_locks_off_graph_unlock()) {
+ /*
+ * We all just reset everything, how did it match?
+ */
+ WARN_ON(1);
+ }
+ goto out_restore;
+ }
+ }
+ }
+ if (locked)
+ graph_unlock();
+
+out_restore:
+ raw_local_irq_restore(flags);
+}
+
+void lockdep_init(void)
+{
+ int i;
+
+ /*
+ * Some architectures have their own start_kernel()
+ * code which calls lockdep_init(), while we also
+ * call lockdep_init() from the start_kernel() itself,
+ * and we want to initialize the hashes only once:
+ */
+ if (lockdep_initialized)
+ return;
+
+ for (i = 0; i < CLASSHASH_SIZE; i++)
+ INIT_LIST_HEAD(classhash_table + i);
+
+ for (i = 0; i < CHAINHASH_SIZE; i++)
+ INIT_LIST_HEAD(chainhash_table + i);
+
+ lockdep_initialized = 1;
+}
+
+void __init lockdep_info(void)
+{
+ printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n");
+
+ printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES);
+ printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH);
+ printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS);
+ printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE);
+ printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES);
+ printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS);
+ printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE);
+
+ printk(" memory used by lock dependency info: %lu kB\n",
+ (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS +
+ sizeof(struct list_head) * CLASSHASH_SIZE +
+ sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES +
+ sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS +
+ sizeof(struct list_head) * CHAINHASH_SIZE
+#ifdef CONFIG_PROVE_LOCKING
+ + sizeof(struct circular_queue)
+#endif
+ ) / 1024
+ );
+
+ printk(" per task-struct memory footprint: %lu bytes\n",
+ sizeof(struct held_lock) * MAX_LOCK_DEPTH);
+
+#ifdef CONFIG_DEBUG_LOCKDEP
+ if (lockdep_init_error) {
+ printk("WARNING: lockdep init error! lock-%s was acquired"
+ "before lockdep_init\n", lock_init_error);
+ printk("Call stack leading to lockdep invocation was:\n");
+ print_stack_trace(&lockdep_init_trace, 0);
+ }
+#endif
+}
+
+static void
+print_freed_lock_bug(struct task_struct *curr, const void *mem_from,
+ const void *mem_to, struct held_lock *hlock)
+{
+ if (!debug_locks_off())
+ return;
+ if (debug_locks_silent)
+ return;
+
+ printk("\n");
+ printk("=========================\n");
+ printk("[ BUG: held lock freed! ]\n");
+ print_kernel_ident();
+ printk("-------------------------\n");
+ printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n",
+ curr->comm, task_pid_nr(curr), mem_from, mem_to-1);
+ print_lock(hlock);
+ lockdep_print_held_locks(curr);
+
+ printk("\nstack backtrace:\n");
+ dump_stack();
+}
+
+static inline int not_in_range(const void* mem_from, unsigned long mem_len,
+ const void* lock_from, unsigned long lock_len)
+{
+ return lock_from + lock_len <= mem_from ||
+ mem_from + mem_len <= lock_from;
+}
+
+/*
+ * Called when kernel memory is freed (or unmapped), or if a lock
+ * is destroyed or reinitialized - this code checks whether there is
+ * any held lock in the memory range of <from> to <to>:
+ */
+void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len)
+{
+ struct task_struct *curr = current;
+ struct held_lock *hlock;
+ unsigned long flags;
+ int i;
+
+ if (unlikely(!debug_locks))
+ return;
+
+ local_irq_save(flags);
+ for (i = 0; i < curr->lockdep_depth; i++) {
+ hlock = curr->held_locks + i;
+
+ if (not_in_range(mem_from, mem_len, hlock->instance,
+ sizeof(*hlock->instance)))
+ continue;
+
+ print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock);
+ break;
+ }
+ local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(debug_check_no_locks_freed);
+
+static void print_held_locks_bug(void)
+{
+ if (!debug_locks_off())
+ return;
+ if (debug_locks_silent)
+ return;
+
+ printk("\n");
+ printk("=====================================\n");
+ printk("[ BUG: %s/%d still has locks held! ]\n",
+ current->comm, task_pid_nr(current));
+ print_kernel_ident();
+ printk("-------------------------------------\n");
+ lockdep_print_held_locks(current);
+ printk("\nstack backtrace:\n");
+ dump_stack();
+}
+
+void debug_check_no_locks_held(void)
+{
+ if (unlikely(current->lockdep_depth > 0))
+ print_held_locks_bug();
+}
+EXPORT_SYMBOL_GPL(debug_check_no_locks_held);
+
+void debug_show_all_locks(void)
+{
+ struct task_struct *g, *p;
+ int count = 10;
+ int unlock = 1;
+
+ if (unlikely(!debug_locks)) {
+ printk("INFO: lockdep is turned off.\n");
+ return;
+ }
+ printk("\nShowing all locks held in the system:\n");
+
+ /*
+ * Here we try to get the tasklist_lock as hard as possible,
+ * if not successful after 2 seconds we ignore it (but keep
+ * trying). This is to enable a debug printout even if a
+ * tasklist_lock-holding task deadlocks or crashes.
+ */
+retry:
+ if (!read_trylock(&tasklist_lock)) {
+ if (count == 10)
+ printk("hm, tasklist_lock locked, retrying... ");
+ if (count) {
+ count--;
+ printk(" #%d", 10-count);
+ mdelay(200);
+ goto retry;
+ }
+ printk(" ignoring it.\n");
+ unlock = 0;
+ } else {
+ if (count != 10)
+ printk(KERN_CONT " locked it.\n");
+ }
+
+ do_each_thread(g, p) {
+ /*
+ * It's not reliable to print a task's held locks
+ * if it's not sleeping (or if it's not the current
+ * task):
+ */
+ if (p->state == TASK_RUNNING && p != current)
+ continue;
+ if (p->lockdep_depth)
+ lockdep_print_held_locks(p);
+ if (!unlock)
+ if (read_trylock(&tasklist_lock))
+ unlock = 1;
+ } while_each_thread(g, p);
+
+ printk("\n");
+ printk("=============================================\n\n");
+
+ if (unlock)
+ read_unlock(&tasklist_lock);
+}
+EXPORT_SYMBOL_GPL(debug_show_all_locks);
+
+/*
+ * Careful: only use this function if you are sure that
+ * the task cannot run in parallel!
+ */
+void debug_show_held_locks(struct task_struct *task)
+{
+ if (unlikely(!debug_locks)) {
+ printk("INFO: lockdep is turned off.\n");
+ return;
+ }
+ lockdep_print_held_locks(task);
+}
+EXPORT_SYMBOL_GPL(debug_show_held_locks);
+
+void lockdep_sys_exit(void)
+{
+ struct task_struct *curr = current;
+
+ if (unlikely(curr->lockdep_depth)) {
+ if (!debug_locks_off())
+ return;
+ printk("\n");
+ printk("================================================\n");
+ printk("[ BUG: lock held when returning to user space! ]\n");
+ print_kernel_ident();
+ printk("------------------------------------------------\n");
+ printk("%s/%d is leaving the kernel with locks still held!\n",
+ curr->comm, curr->pid);
+ lockdep_print_held_locks(curr);
+ }
+}
+
+void lockdep_rcu_suspicious(const char *file, const int line, const char *s)
+{
+ struct task_struct *curr = current;
+
+#ifndef CONFIG_PROVE_RCU_REPEATEDLY
+ if (!debug_locks_off())
+ return;
+#endif /* #ifdef CONFIG_PROVE_RCU_REPEATEDLY */
+ /* Note: the following can be executed concurrently, so be careful. */
+ printk("\n");
+ printk("===============================\n");
+ printk("[ INFO: suspicious RCU usage. ]\n");
+ print_kernel_ident();
+ printk("-------------------------------\n");
+ printk("%s:%d %s!\n", file, line, s);
+ printk("\nother info that might help us debug this:\n\n");
+ printk("\n%srcu_scheduler_active = %d, debug_locks = %d\n",
+ !rcu_lockdep_current_cpu_online()
+ ? "RCU used illegally from offline CPU!\n"
+ : !rcu_is_watching()
+ ? "RCU used illegally from idle CPU!\n"
+ : "",
+ rcu_scheduler_active, debug_locks);
+
+ /*
+ * If a CPU is in the RCU-free window in idle (ie: in the section
+ * between rcu_idle_enter() and rcu_idle_exit(), then RCU
+ * considers that CPU to be in an "extended quiescent state",
+ * which means that RCU will be completely ignoring that CPU.
+ * Therefore, rcu_read_lock() and friends have absolutely no
+ * effect on a CPU running in that state. In other words, even if
+ * such an RCU-idle CPU has called rcu_read_lock(), RCU might well
+ * delete data structures out from under it. RCU really has no
+ * choice here: we need to keep an RCU-free window in idle where
+ * the CPU may possibly enter into low power mode. This way we can
+ * notice an extended quiescent state to other CPUs that started a grace
+ * period. Otherwise we would delay any grace period as long as we run
+ * in the idle task.
+ *
+ * So complain bitterly if someone does call rcu_read_lock(),
+ * rcu_read_lock_bh() and so on from extended quiescent states.
+ */
+ if (!rcu_is_watching())
+ printk("RCU used illegally from extended quiescent state!\n");
+
+ lockdep_print_held_locks(curr);
+ printk("\nstack backtrace:\n");
+ dump_stack();
+}
+EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious);
Index: linux-2.6/kernel/locking/lockdep_internals.h
===================================================================
--- /dev/null
+++ linux-2.6/kernel/locking/lockdep_internals.h
@@ -0,0 +1,170 @@
+/*
+ * kernel/lockdep_internals.h
+ *
+ * Runtime locking correctness validator
+ *
+ * lockdep subsystem internal functions and variables.
+ */
+
+/*
+ * Lock-class usage-state bits:
+ */
+enum lock_usage_bit {
+#define LOCKDEP_STATE(__STATE) \
+ LOCK_USED_IN_##__STATE, \
+ LOCK_USED_IN_##__STATE##_READ, \
+ LOCK_ENABLED_##__STATE, \
+ LOCK_ENABLED_##__STATE##_READ,
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+ LOCK_USED,
+ LOCK_USAGE_STATES
+};
+
+/*
+ * Usage-state bitmasks:
+ */
+#define __LOCKF(__STATE) LOCKF_##__STATE = (1 << LOCK_##__STATE),
+
+enum {
+#define LOCKDEP_STATE(__STATE) \
+ __LOCKF(USED_IN_##__STATE) \
+ __LOCKF(USED_IN_##__STATE##_READ) \
+ __LOCKF(ENABLED_##__STATE) \
+ __LOCKF(ENABLED_##__STATE##_READ)
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+ __LOCKF(USED)
+};
+
+#define LOCKF_ENABLED_IRQ (LOCKF_ENABLED_HARDIRQ | LOCKF_ENABLED_SOFTIRQ)
+#define LOCKF_USED_IN_IRQ (LOCKF_USED_IN_HARDIRQ | LOCKF_USED_IN_SOFTIRQ)
+
+#define LOCKF_ENABLED_IRQ_READ \
+ (LOCKF_ENABLED_HARDIRQ_READ | LOCKF_ENABLED_SOFTIRQ_READ)
+#define LOCKF_USED_IN_IRQ_READ \
+ (LOCKF_USED_IN_HARDIRQ_READ | LOCKF_USED_IN_SOFTIRQ_READ)
+
+/*
+ * MAX_LOCKDEP_ENTRIES is the maximum number of lock dependencies
+ * we track.
+ *
+ * We use the per-lock dependency maps in two ways: we grow it by adding
+ * every to-be-taken lock to all currently held lock's own dependency
+ * table (if it's not there yet), and we check it for lock order
+ * conflicts and deadlocks.
+ */
+#define MAX_LOCKDEP_ENTRIES 16384UL
+
+#define MAX_LOCKDEP_CHAINS_BITS 15
+#define MAX_LOCKDEP_CHAINS (1UL << MAX_LOCKDEP_CHAINS_BITS)
+
+#define MAX_LOCKDEP_CHAIN_HLOCKS (MAX_LOCKDEP_CHAINS*5)
+
+/*
+ * Stack-trace: tightly packed array of stack backtrace
+ * addresses. Protected by the hash_lock.
+ */
+#define MAX_STACK_TRACE_ENTRIES 262144UL
+
+extern struct list_head all_lock_classes;
+extern struct lock_chain lock_chains[];
+
+#define LOCK_USAGE_CHARS (1+LOCK_USAGE_STATES/2)
+
+extern void get_usage_chars(struct lock_class *class,
+ char usage[LOCK_USAGE_CHARS]);
+
+extern const char * __get_key_name(struct lockdep_subclass_key *key, char *str);
+
+struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i);
+
+extern unsigned long nr_lock_classes;
+extern unsigned long nr_list_entries;
+extern unsigned long nr_lock_chains;
+extern int nr_chain_hlocks;
+extern unsigned long nr_stack_trace_entries;
+
+extern unsigned int nr_hardirq_chains;
+extern unsigned int nr_softirq_chains;
+extern unsigned int nr_process_chains;
+extern unsigned int max_lockdep_depth;
+extern unsigned int max_recursion_depth;
+
+extern unsigned int max_bfs_queue_depth;
+
+#ifdef CONFIG_PROVE_LOCKING
+extern unsigned long lockdep_count_forward_deps(struct lock_class *);
+extern unsigned long lockdep_count_backward_deps(struct lock_class *);
+#else
+static inline unsigned long
+lockdep_count_forward_deps(struct lock_class *class)
+{
+ return 0;
+}
+static inline unsigned long
+lockdep_count_backward_deps(struct lock_class *class)
+{
+ return 0;
+}
+#endif
+
+#ifdef CONFIG_DEBUG_LOCKDEP
+
+#include <asm/local.h>
+/*
+ * Various lockdep statistics.
+ * We want them per cpu as they are often accessed in fast path
+ * and we want to avoid too much cache bouncing.
+ */
+struct lockdep_stats {
+ int chain_lookup_hits;
+ int chain_lookup_misses;
+ int hardirqs_on_events;
+ int hardirqs_off_events;
+ int redundant_hardirqs_on;
+ int redundant_hardirqs_off;
+ int softirqs_on_events;
+ int softirqs_off_events;
+ int redundant_softirqs_on;
+ int redundant_softirqs_off;
+ int nr_unused_locks;
+ int nr_cyclic_checks;
+ int nr_cyclic_check_recursions;
+ int nr_find_usage_forwards_checks;
+ int nr_find_usage_forwards_recursions;
+ int nr_find_usage_backwards_checks;
+ int nr_find_usage_backwards_recursions;
+};
+
+DECLARE_PER_CPU(struct lockdep_stats, lockdep_stats);
+
+#define __debug_atomic_inc(ptr) \
+ this_cpu_inc(lockdep_stats.ptr);
+
+#define debug_atomic_inc(ptr) { \
+ WARN_ON_ONCE(!irqs_disabled()); \
+ __this_cpu_inc(lockdep_stats.ptr); \
+}
+
+#define debug_atomic_dec(ptr) { \
+ WARN_ON_ONCE(!irqs_disabled()); \
+ __this_cpu_dec(lockdep_stats.ptr); \
+}
+
+#define debug_atomic_read(ptr) ({ \
+ struct lockdep_stats *__cpu_lockdep_stats; \
+ unsigned long long __total = 0; \
+ int __cpu; \
+ for_each_possible_cpu(__cpu) { \
+ __cpu_lockdep_stats = &per_cpu(lockdep_stats, __cpu); \
+ __total += __cpu_lockdep_stats->ptr; \
+ } \
+ __total; \
+})
+#else
+# define __debug_atomic_inc(ptr) do { } while (0)
+# define debug_atomic_inc(ptr) do { } while (0)
+# define debug_atomic_dec(ptr) do { } while (0)
+# define debug_atomic_read(ptr) 0
+#endif
Index: linux-2.6/kernel/locking/lockdep_proc.c
===================================================================
--- /dev/null
+++ linux-2.6/kernel/locking/lockdep_proc.c
@@ -0,0 +1,683 @@
+/*
+ * kernel/lockdep_proc.c
+ *
+ * Runtime locking correctness validator
+ *
+ * Started by Ingo Molnar:
+ *
+ * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
+ *
+ * Code for /proc/lockdep and /proc/lockdep_stats:
+ *
+ */
+#include <linux/export.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/kallsyms.h>
+#include <linux/debug_locks.h>
+#include <linux/vmalloc.h>
+#include <linux/sort.h>
+#include <asm/uaccess.h>
+#include <asm/div64.h>
+
+#include "lockdep_internals.h"
+
+static void *l_next(struct seq_file *m, void *v, loff_t *pos)
+{
+ return seq_list_next(v, &all_lock_classes, pos);
+}
+
+static void *l_start(struct seq_file *m, loff_t *pos)
+{
+ return seq_list_start_head(&all_lock_classes, *pos);
+}
+
+static void l_stop(struct seq_file *m, void *v)
+{
+}
+
+static void print_name(struct seq_file *m, struct lock_class *class)
+{
+ char str[KSYM_NAME_LEN];
+ const char *name = class->name;
+
+ if (!name) {
+ name = __get_key_name(class->key, str);
+ seq_printf(m, "%s", name);
+ } else{
+ seq_printf(m, "%s", name);
+ if (class->name_version > 1)
+ seq_printf(m, "#%d", class->name_version);
+ if (class->subclass)
+ seq_printf(m, "/%d", class->subclass);
+ }
+}
+
+static int l_show(struct seq_file *m, void *v)
+{
+ struct lock_class *class = list_entry(v, struct lock_class, lock_entry);
+ struct lock_list *entry;
+ char usage[LOCK_USAGE_CHARS];
+
+ if (v == &all_lock_classes) {
+ seq_printf(m, "all lock classes:\n");
+ return 0;
+ }
+
+ seq_printf(m, "%p", class->key);
+#ifdef CONFIG_DEBUG_LOCKDEP
+ seq_printf(m, " OPS:%8ld", class->ops);
+#endif
+#ifdef CONFIG_PROVE_LOCKING
+ seq_printf(m, " FD:%5ld", lockdep_count_forward_deps(class));
+ seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class));
+#endif
+
+ get_usage_chars(class, usage);
+ seq_printf(m, " %s", usage);
+
+ seq_printf(m, ": ");
+ print_name(m, class);
+ seq_puts(m, "\n");
+
+ list_for_each_entry(entry, &class->locks_after, entry) {
+ if (entry->distance == 1) {
+ seq_printf(m, " -> [%p] ", entry->class->key);
+ print_name(m, entry->class);
+ seq_puts(m, "\n");
+ }
+ }
+ seq_puts(m, "\n");
+
+ return 0;
+}
+
+static const struct seq_operations lockdep_ops = {
+ .start = l_start,
+ .next = l_next,
+ .stop = l_stop,
+ .show = l_show,
+};
+
+static int lockdep_open(struct inode *inode, struct file *file)
+{
+ return seq_open(file, &lockdep_ops);
+}
+
+static const struct file_operations proc_lockdep_operations = {
+ .open = lockdep_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
+#ifdef CONFIG_PROVE_LOCKING
+static void *lc_start(struct seq_file *m, loff_t *pos)
+{
+ if (*pos == 0)
+ return SEQ_START_TOKEN;
+
+ if (*pos - 1 < nr_lock_chains)
+ return lock_chains + (*pos - 1);
+
+ return NULL;
+}
+
+static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
+{
+ (*pos)++;
+ return lc_start(m, pos);
+}
+
+static void lc_stop(struct seq_file *m, void *v)
+{
+}
+
+static int lc_show(struct seq_file *m, void *v)
+{
+ struct lock_chain *chain = v;
+ struct lock_class *class;
+ int i;
+
+ if (v == SEQ_START_TOKEN) {
+ seq_printf(m, "all lock chains:\n");
+ return 0;
+ }
+
+ seq_printf(m, "irq_context: %d\n", chain->irq_context);
+
+ for (i = 0; i < chain->depth; i++) {
+ class = lock_chain_get_class(chain, i);
+ if (!class->key)
+ continue;
+
+ seq_printf(m, "[%p] ", class->key);
+ print_name(m, class);
+ seq_puts(m, "\n");
+ }
+ seq_puts(m, "\n");
+
+ return 0;
+}
+
+static const struct seq_operations lockdep_chains_ops = {
+ .start = lc_start,
+ .next = lc_next,
+ .stop = lc_stop,
+ .show = lc_show,
+};
+
+static int lockdep_chains_open(struct inode *inode, struct file *file)
+{
+ return seq_open(file, &lockdep_chains_ops);
+}
+
+static const struct file_operations proc_lockdep_chains_operations = {
+ .open = lockdep_chains_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+#endif /* CONFIG_PROVE_LOCKING */
+
+static void lockdep_stats_debug_show(struct seq_file *m)
+{
+#ifdef CONFIG_DEBUG_LOCKDEP
+ unsigned long long hi1 = debug_atomic_read(hardirqs_on_events),
+ hi2 = debug_atomic_read(hardirqs_off_events),
+ hr1 = debug_atomic_read(redundant_hardirqs_on),
+ hr2 = debug_atomic_read(redundant_hardirqs_off),
+ si1 = debug_atomic_read(softirqs_on_events),
+ si2 = debug_atomic_read(softirqs_off_events),
+ sr1 = debug_atomic_read(redundant_softirqs_on),
+ sr2 = debug_atomic_read(redundant_softirqs_off);
+
+ seq_printf(m, " chain lookup misses: %11llu\n",
+ debug_atomic_read(chain_lookup_misses));
+ seq_printf(m, " chain lookup hits: %11llu\n",
+ debug_atomic_read(chain_lookup_hits));
+ seq_printf(m, " cyclic checks: %11llu\n",
+ debug_atomic_read(nr_cyclic_checks));
+ seq_printf(m, " find-mask forwards checks: %11llu\n",
+ debug_atomic_read(nr_find_usage_forwards_checks));
+ seq_printf(m, " find-mask backwards checks: %11llu\n",
+ debug_atomic_read(nr_find_usage_backwards_checks));
+
+ seq_printf(m, " hardirq on events: %11llu\n", hi1);
+ seq_printf(m, " hardirq off events: %11llu\n", hi2);
+ seq_printf(m, " redundant hardirq ons: %11llu\n", hr1);
+ seq_printf(m, " redundant hardirq offs: %11llu\n", hr2);
+ seq_printf(m, " softirq on events: %11llu\n", si1);
+ seq_printf(m, " softirq off events: %11llu\n", si2);
+ seq_printf(m, " redundant softirq ons: %11llu\n", sr1);
+ seq_printf(m, " redundant softirq offs: %11llu\n", sr2);
+#endif
+}
+
+static int lockdep_stats_show(struct seq_file *m, void *v)
+{
+ struct lock_class *class;
+ unsigned long nr_unused = 0, nr_uncategorized = 0,
+ nr_irq_safe = 0, nr_irq_unsafe = 0,
+ nr_softirq_safe = 0, nr_softirq_unsafe = 0,
+ nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
+ nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
+ nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
+ nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
+ sum_forward_deps = 0;
+
+ list_for_each_entry(class, &all_lock_classes, lock_entry) {
+
+ if (class->usage_mask == 0)
+ nr_unused++;
+ if (class->usage_mask == LOCKF_USED)
+ nr_uncategorized++;
+ if (class->usage_mask & LOCKF_USED_IN_IRQ)
+ nr_irq_safe++;
+ if (class->usage_mask & LOCKF_ENABLED_IRQ)
+ nr_irq_unsafe++;
+ if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
+ nr_softirq_safe++;
+ if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ)
+ nr_softirq_unsafe++;
+ if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
+ nr_hardirq_safe++;
+ if (class->usage_mask & LOCKF_ENABLED_HARDIRQ)
+ nr_hardirq_unsafe++;
+ if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
+ nr_irq_read_safe++;
+ if (class->usage_mask & LOCKF_ENABLED_IRQ_READ)
+ nr_irq_read_unsafe++;
+ if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
+ nr_softirq_read_safe++;
+ if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ)
+ nr_softirq_read_unsafe++;
+ if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
+ nr_hardirq_read_safe++;
+ if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ)
+ nr_hardirq_read_unsafe++;
+
+#ifdef CONFIG_PROVE_LOCKING
+ sum_forward_deps += lockdep_count_forward_deps(class);
+#endif
+ }
+#ifdef CONFIG_DEBUG_LOCKDEP
+ DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused);
+#endif
+ seq_printf(m, " lock-classes: %11lu [max: %lu]\n",
+ nr_lock_classes, MAX_LOCKDEP_KEYS);
+ seq_printf(m, " direct dependencies: %11lu [max: %lu]\n",
+ nr_list_entries, MAX_LOCKDEP_ENTRIES);
+ seq_printf(m, " indirect dependencies: %11lu\n",
+ sum_forward_deps);
+
+ /*
+ * Total number of dependencies:
+ *
+ * All irq-safe locks may nest inside irq-unsafe locks,
+ * plus all the other known dependencies:
+ */
+ seq_printf(m, " all direct dependencies: %11lu\n",
+ nr_irq_unsafe * nr_irq_safe +
+ nr_hardirq_unsafe * nr_hardirq_safe +
+ nr_list_entries);
+
+#ifdef CONFIG_PROVE_LOCKING
+ seq_printf(m, " dependency chains: %11lu [max: %lu]\n",
+ nr_lock_chains, MAX_LOCKDEP_CHAINS);
+ seq_printf(m, " dependency chain hlocks: %11d [max: %lu]\n",
+ nr_chain_hlocks, MAX_LOCKDEP_CHAIN_HLOCKS);
+#endif
+
+#ifdef CONFIG_TRACE_IRQFLAGS
+ seq_printf(m, " in-hardirq chains: %11u\n",
+ nr_hardirq_chains);
+ seq_printf(m, " in-softirq chains: %11u\n",
+ nr_softirq_chains);
+#endif
+ seq_printf(m, " in-process chains: %11u\n",
+ nr_process_chains);
+ seq_printf(m, " stack-trace entries: %11lu [max: %lu]\n",
+ nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
+ seq_printf(m, " combined max dependencies: %11u\n",
+ (nr_hardirq_chains + 1) *
+ (nr_softirq_chains + 1) *
+ (nr_process_chains + 1)
+ );
+ seq_printf(m, " hardirq-safe locks: %11lu\n",
+ nr_hardirq_safe);
+ seq_printf(m, " hardirq-unsafe locks: %11lu\n",
+ nr_hardirq_unsafe);
+ seq_printf(m, " softirq-safe locks: %11lu\n",
+ nr_softirq_safe);
+ seq_printf(m, " softirq-unsafe locks: %11lu\n",
+ nr_softirq_unsafe);
+ seq_printf(m, " irq-safe locks: %11lu\n",
+ nr_irq_safe);
+ seq_printf(m, " irq-unsafe locks: %11lu\n",
+ nr_irq_unsafe);
+
+ seq_printf(m, " hardirq-read-safe locks: %11lu\n",
+ nr_hardirq_read_safe);
+ seq_printf(m, " hardirq-read-unsafe locks: %11lu\n",
+ nr_hardirq_read_unsafe);
+ seq_printf(m, " softirq-read-safe locks: %11lu\n",
+ nr_softirq_read_safe);
+ seq_printf(m, " softirq-read-unsafe locks: %11lu\n",
+ nr_softirq_read_unsafe);
+ seq_printf(m, " irq-read-safe locks: %11lu\n",
+ nr_irq_read_safe);
+ seq_printf(m, " irq-read-unsafe locks: %11lu\n",
+ nr_irq_read_unsafe);
+
+ seq_printf(m, " uncategorized locks: %11lu\n",
+ nr_uncategorized);
+ seq_printf(m, " unused locks: %11lu\n",
+ nr_unused);
+ seq_printf(m, " max locking depth: %11u\n",
+ max_lockdep_depth);
+#ifdef CONFIG_PROVE_LOCKING
+ seq_printf(m, " max bfs queue depth: %11u\n",
+ max_bfs_queue_depth);
+#endif
+ lockdep_stats_debug_show(m);
+ seq_printf(m, " debug_locks: %11u\n",
+ debug_locks);
+
+ return 0;
+}
+
+static int lockdep_stats_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, lockdep_stats_show, NULL);
+}
+
+static const struct file_operations proc_lockdep_stats_operations = {
+ .open = lockdep_stats_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+#ifdef CONFIG_LOCK_STAT
+
+struct lock_stat_data {
+ struct lock_class *class;
+ struct lock_class_stats stats;
+};
+
+struct lock_stat_seq {
+ struct lock_stat_data *iter_end;
+ struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
+};
+
+/*
+ * sort on absolute number of contentions
+ */
+static int lock_stat_cmp(const void *l, const void *r)
+{
+ const struct lock_stat_data *dl = l, *dr = r;
+ unsigned long nl, nr;
+
+ nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
+ nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
+
+ return nr - nl;
+}
+
+static void seq_line(struct seq_file *m, char c, int offset, int length)
+{
+ int i;
+
+ for (i = 0; i < offset; i++)
+ seq_puts(m, " ");
+ for (i = 0; i < length; i++)
+ seq_printf(m, "%c", c);
+ seq_puts(m, "\n");
+}
+
+static void snprint_time(char *buf, size_t bufsiz, s64 nr)
+{
+ s64 div;
+ s32 rem;
+
+ nr += 5; /* for display rounding */
+ div = div_s64_rem(nr, 1000, &rem);
+ snprintf(buf, bufsiz, "%lld.%02d", (long long)div, (int)rem/10);
+}
+
+static void seq_time(struct seq_file *m, s64 time)
+{
+ char num[15];
+
+ snprint_time(num, sizeof(num), time);
+ seq_printf(m, " %14s", num);
+}
+
+static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
+{
+ seq_printf(m, "%14lu", lt->nr);
+ seq_time(m, lt->min);
+ seq_time(m, lt->max);
+ seq_time(m, lt->total);
+ seq_time(m, lt->nr ? do_div(lt->total, lt->nr) : 0);
+}
+
+static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
+{
+ char name[39];
+ struct lock_class *class;
+ struct lock_class_stats *stats;
+ int i, namelen;
+
+ class = data->class;
+ stats = &data->stats;
+
+ namelen = 38;
+ if (class->name_version > 1)
+ namelen -= 2; /* XXX truncates versions > 9 */
+ if (class->subclass)
+ namelen -= 2;
+
+ if (!class->name) {
+ char str[KSYM_NAME_LEN];
+ const char *key_name;
+
+ key_name = __get_key_name(class->key, str);
+ snprintf(name, namelen, "%s", key_name);
+ } else {
+ snprintf(name, namelen, "%s", class->name);
+ }
+ namelen = strlen(name);
+ if (class->name_version > 1) {
+ snprintf(name+namelen, 3, "#%d", class->name_version);
+ namelen += 2;
+ }
+ if (class->subclass) {
+ snprintf(name+namelen, 3, "/%d", class->subclass);
+ namelen += 2;
+ }
+
+ if (stats->write_holdtime.nr) {
+ if (stats->read_holdtime.nr)
+ seq_printf(m, "%38s-W:", name);
+ else
+ seq_printf(m, "%40s:", name);
+
+ seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
+ seq_lock_time(m, &stats->write_waittime);
+ seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
+ seq_lock_time(m, &stats->write_holdtime);
+ seq_puts(m, "\n");
+ }
+
+ if (stats->read_holdtime.nr) {
+ seq_printf(m, "%38s-R:", name);
+ seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
+ seq_lock_time(m, &stats->read_waittime);
+ seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
+ seq_lock_time(m, &stats->read_holdtime);
+ seq_puts(m, "\n");
+ }
+
+ if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
+ return;
+
+ if (stats->read_holdtime.nr)
+ namelen += 2;
+
+ for (i = 0; i < LOCKSTAT_POINTS; i++) {
+ char ip[32];
+
+ if (class->contention_point[i] == 0)
+ break;
+
+ if (!i)
+ seq_line(m, '-', 40-namelen, namelen);
+
+ snprintf(ip, sizeof(ip), "[<%p>]",
+ (void *)class->contention_point[i]);
+ seq_printf(m, "%40s %14lu %29s %pS\n",
+ name, stats->contention_point[i],
+ ip, (void *)class->contention_point[i]);
+ }
+ for (i = 0; i < LOCKSTAT_POINTS; i++) {
+ char ip[32];
+
+ if (class->contending_point[i] == 0)
+ break;
+
+ if (!i)
+ seq_line(m, '-', 40-namelen, namelen);
+
+ snprintf(ip, sizeof(ip), "[<%p>]",
+ (void *)class->contending_point[i]);
+ seq_printf(m, "%40s %14lu %29s %pS\n",
+ name, stats->contending_point[i],
+ ip, (void *)class->contending_point[i]);
+ }
+ if (i) {
+ seq_puts(m, "\n");
+ seq_line(m, '.', 0, 40 + 1 + 12 * (14 + 1));
+ seq_puts(m, "\n");
+ }
+}
+
+static void seq_header(struct seq_file *m)
+{
+ seq_puts(m, "lock_stat version 0.4\n");
+
+ if (unlikely(!debug_locks))
+ seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n");
+
+ seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1));
+ seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s %14s %14s "
+ "%14s %14s\n",
+ "class name",
+ "con-bounces",
+ "contentions",
+ "waittime-min",
+ "waittime-max",
+ "waittime-total",
+ "waittime-avg",
+ "acq-bounces",
+ "acquisitions",
+ "holdtime-min",
+ "holdtime-max",
+ "holdtime-total",
+ "holdtime-avg");
+ seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1));
+ seq_printf(m, "\n");
+}
+
+static void *ls_start(struct seq_file *m, loff_t *pos)
+{
+ struct lock_stat_seq *data = m->private;
+ struct lock_stat_data *iter;
+
+ if (*pos == 0)
+ return SEQ_START_TOKEN;
+
+ iter = data->stats + (*pos - 1);
+ if (iter >= data->iter_end)
+ iter = NULL;
+
+ return iter;
+}
+
+static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
+{
+ (*pos)++;
+ return ls_start(m, pos);
+}
+
+static void ls_stop(struct seq_file *m, void *v)
+{
+}
+
+static int ls_show(struct seq_file *m, void *v)
+{
+ if (v == SEQ_START_TOKEN)
+ seq_header(m);
+ else
+ seq_stats(m, v);
+
+ return 0;
+}
+
+static const struct seq_operations lockstat_ops = {
+ .start = ls_start,
+ .next = ls_next,
+ .stop = ls_stop,
+ .show = ls_show,
+};
+
+static int lock_stat_open(struct inode *inode, struct file *file)
+{
+ int res;
+ struct lock_class *class;
+ struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
+
+ if (!data)
+ return -ENOMEM;
+
+ res = seq_open(file, &lockstat_ops);
+ if (!res) {
+ struct lock_stat_data *iter = data->stats;
+ struct seq_file *m = file->private_data;
+
+ list_for_each_entry(class, &all_lock_classes, lock_entry) {
+ iter->class = class;
+ iter->stats = lock_stats(class);
+ iter++;
+ }
+ data->iter_end = iter;
+
+ sort(data->stats, data->iter_end - data->stats,
+ sizeof(struct lock_stat_data),
+ lock_stat_cmp, NULL);
+
+ m->private = data;
+ } else
+ vfree(data);
+
+ return res;
+}
+
+static ssize_t lock_stat_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct lock_class *class;
+ char c;
+
+ if (count) {
+ if (get_user(c, buf))
+ return -EFAULT;
+
+ if (c != '0')
+ return count;
+
+ list_for_each_entry(class, &all_lock_classes, lock_entry)
+ clear_lock_stats(class);
+ }
+ return count;
+}
+
+static int lock_stat_release(struct inode *inode, struct file *file)
+{
+ struct seq_file *seq = file->private_data;
+
+ vfree(seq->private);
+ return seq_release(inode, file);
+}
+
+static const struct file_operations proc_lock_stat_operations = {
+ .open = lock_stat_open,
+ .write = lock_stat_write,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = lock_stat_release,
+};
+#endif /* CONFIG_LOCK_STAT */
+
+static int __init lockdep_proc_init(void)
+{
+ proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations);
+#ifdef CONFIG_PROVE_LOCKING
+ proc_create("lockdep_chains", S_IRUSR, NULL,
+ &proc_lockdep_chains_operations);
+#endif
+ proc_create("lockdep_stats", S_IRUSR, NULL,
+ &proc_lockdep_stats_operations);
+
+#ifdef CONFIG_LOCK_STAT
+ proc_create("lock_stat", S_IRUSR | S_IWUSR, NULL,
+ &proc_lock_stat_operations);
+#endif
+
+ return 0;
+}
+
+__initcall(lockdep_proc_init);
+
Index: linux-2.6/kernel/locking/lockdep_states.h
===================================================================
--- /dev/null
+++ linux-2.6/kernel/locking/lockdep_states.h
@@ -0,0 +1,9 @@
+/*
+ * Lockdep states,
+ *
+ * please update XXX_LOCK_USAGE_STATES in include/linux/lockdep.h whenever
+ * you add one, or come up with a nice dynamic solution.
+ */
+LOCKDEP_STATE(HARDIRQ)
+LOCKDEP_STATE(SOFTIRQ)
+LOCKDEP_STATE(RECLAIM_FS)
^ permalink raw reply [flat|nested] 23+ messages in thread* [RFC 5/8] locking: Move rtmutex into kernel/locking/
2013-11-05 12:10 [RFC 0/8] Move locking primitives into kernel/locking/ Peter Zijlstra
` (3 preceding siblings ...)
2013-11-05 12:10 ` [RFC 4/8] locking: Move semaphore " Peter Zijlstra
@ 2013-11-05 12:10 ` Peter Zijlstra
2013-11-05 12:10 ` [RFC 6/8] locking: Move rwsem " Peter Zijlstra
` (5 subsequent siblings)
10 siblings, 0 replies; 23+ messages in thread
From: Peter Zijlstra @ 2013-11-05 12:10 UTC (permalink / raw)
To: torvalds, akpm
Cc: paulmck, oleg, dhowells, willy, tglx, rostedt, airlied,
maarten.lankhorst, walken, linux-kernel, Ingo Molnar,
Peter Zijlstra
[-- Attachment #1: peterz-move-locking-rtmutex.patch --]
[-- Type: text/plain, Size: 101024 bytes --]
Cc: tglx@linutronix.de
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
---
kernel/Makefile | 3
kernel/futex.c | 2
kernel/locking/Makefile | 3
kernel/locking/rtmutex-debug.c | 187 +++++++
kernel/locking/rtmutex-debug.h | 33 +
kernel/locking/rtmutex-tester.c | 420 +++++++++++++++
kernel/locking/rtmutex.c | 1060 ++++++++++++++++++++++++++++++++++++++++
kernel/locking/rtmutex.h | 26
kernel/locking/rtmutex_common.h | 126 ++++
kernel/rtmutex-debug.c | 187 -------
kernel/rtmutex-debug.h | 33 -
kernel/rtmutex-tester.c | 420 ---------------
kernel/rtmutex.c | 1060 ----------------------------------------
kernel/rtmutex.h | 26
kernel/rtmutex_common.h | 126 ----
15 files changed, 1856 insertions(+), 1856 deletions(-)
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -35,9 +35,6 @@ obj-$(CONFIG_FUTEX) += futex.o
ifeq ($(CONFIG_COMPAT),y)
obj-$(CONFIG_FUTEX) += futex_compat.o
endif
-obj-$(CONFIG_RT_MUTEXES) += rtmutex.o
-obj-$(CONFIG_DEBUG_RT_MUTEXES) += rtmutex-debug.o
-obj-$(CONFIG_RT_MUTEX_TESTER) += rtmutex-tester.o
obj-$(CONFIG_GENERIC_ISA_DMA) += dma.o
obj-$(CONFIG_SMP) += smp.o
ifneq ($(CONFIG_SMP),y)
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -66,7 +66,7 @@
#include <asm/futex.h>
-#include "rtmutex_common.h"
+#include "locking/rtmutex_common.h"
int __read_mostly futex_cmpxchg_enabled;
--- a/kernel/locking/Makefile
+++ b/kernel/locking/Makefile
@@ -15,5 +15,8 @@ obj-$(CONFIG_LOCKDEP) += lockdep_proc.o
endif
obj-$(CONFIG_SMP) += spinlock.o
obj-$(CONFIG_PROVE_LOCKING) += spinlock.o
+obj-$(CONFIG_RT_MUTEXES) += rtmutex.o
+obj-$(CONFIG_DEBUG_RT_MUTEXES) += rtmutex-debug.o
+obj-$(CONFIG_RT_MUTEX_TESTER) += rtmutex-tester.o
obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
--- /dev/null
+++ b/kernel/locking/rtmutex-debug.c
@@ -0,0 +1,187 @@
+/*
+ * RT-Mutexes: blocking mutual exclusion locks with PI support
+ *
+ * started by Ingo Molnar and Thomas Gleixner:
+ *
+ * Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ * Copyright (C) 2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
+ *
+ * This code is based on the rt.c implementation in the preempt-rt tree.
+ * Portions of said code are
+ *
+ * Copyright (C) 2004 LynuxWorks, Inc., Igor Manyilov, Bill Huey
+ * Copyright (C) 2006 Esben Nielsen
+ * Copyright (C) 2006 Kihon Technologies Inc.,
+ * Steven Rostedt <rostedt@goodmis.org>
+ *
+ * See rt.c in preempt-rt for proper credits and further information
+ */
+#include <linux/sched.h>
+#include <linux/sched/rt.h>
+#include <linux/delay.h>
+#include <linux/export.h>
+#include <linux/spinlock.h>
+#include <linux/kallsyms.h>
+#include <linux/syscalls.h>
+#include <linux/interrupt.h>
+#include <linux/plist.h>
+#include <linux/fs.h>
+#include <linux/debug_locks.h>
+
+#include "rtmutex_common.h"
+
+static void printk_task(struct task_struct *p)
+{
+ if (p)
+ printk("%16s:%5d [%p, %3d]", p->comm, task_pid_nr(p), p, p->prio);
+ else
+ printk("<none>");
+}
+
+static void printk_lock(struct rt_mutex *lock, int print_owner)
+{
+ if (lock->name)
+ printk(" [%p] {%s}\n",
+ lock, lock->name);
+ else
+ printk(" [%p] {%s:%d}\n",
+ lock, lock->file, lock->line);
+
+ if (print_owner && rt_mutex_owner(lock)) {
+ printk(".. ->owner: %p\n", lock->owner);
+ printk(".. held by: ");
+ printk_task(rt_mutex_owner(lock));
+ printk("\n");
+ }
+}
+
+void rt_mutex_debug_task_free(struct task_struct *task)
+{
+ DEBUG_LOCKS_WARN_ON(!plist_head_empty(&task->pi_waiters));
+ DEBUG_LOCKS_WARN_ON(task->pi_blocked_on);
+}
+
+/*
+ * We fill out the fields in the waiter to store the information about
+ * the deadlock. We print when we return. act_waiter can be NULL in
+ * case of a remove waiter operation.
+ */
+void debug_rt_mutex_deadlock(int detect, struct rt_mutex_waiter *act_waiter,
+ struct rt_mutex *lock)
+{
+ struct task_struct *task;
+
+ if (!debug_locks || detect || !act_waiter)
+ return;
+
+ task = rt_mutex_owner(act_waiter->lock);
+ if (task && task != current) {
+ act_waiter->deadlock_task_pid = get_pid(task_pid(task));
+ act_waiter->deadlock_lock = lock;
+ }
+}
+
+void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter)
+{
+ struct task_struct *task;
+
+ if (!waiter->deadlock_lock || !debug_locks)
+ return;
+
+ rcu_read_lock();
+ task = pid_task(waiter->deadlock_task_pid, PIDTYPE_PID);
+ if (!task) {
+ rcu_read_unlock();
+ return;
+ }
+
+ if (!debug_locks_off()) {
+ rcu_read_unlock();
+ return;
+ }
+
+ printk("\n============================================\n");
+ printk( "[ BUG: circular locking deadlock detected! ]\n");
+ printk("%s\n", print_tainted());
+ printk( "--------------------------------------------\n");
+ printk("%s/%d is deadlocking current task %s/%d\n\n",
+ task->comm, task_pid_nr(task),
+ current->comm, task_pid_nr(current));
+
+ printk("\n1) %s/%d is trying to acquire this lock:\n",
+ current->comm, task_pid_nr(current));
+ printk_lock(waiter->lock, 1);
+
+ printk("\n2) %s/%d is blocked on this lock:\n",
+ task->comm, task_pid_nr(task));
+ printk_lock(waiter->deadlock_lock, 1);
+
+ debug_show_held_locks(current);
+ debug_show_held_locks(task);
+
+ printk("\n%s/%d's [blocked] stackdump:\n\n",
+ task->comm, task_pid_nr(task));
+ show_stack(task, NULL);
+ printk("\n%s/%d's [current] stackdump:\n\n",
+ current->comm, task_pid_nr(current));
+ dump_stack();
+ debug_show_all_locks();
+ rcu_read_unlock();
+
+ printk("[ turning off deadlock detection."
+ "Please report this trace. ]\n\n");
+}
+
+void debug_rt_mutex_lock(struct rt_mutex *lock)
+{
+}
+
+void debug_rt_mutex_unlock(struct rt_mutex *lock)
+{
+ DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current);
+}
+
+void
+debug_rt_mutex_proxy_lock(struct rt_mutex *lock, struct task_struct *powner)
+{
+}
+
+void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock)
+{
+ DEBUG_LOCKS_WARN_ON(!rt_mutex_owner(lock));
+}
+
+void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
+{
+ memset(waiter, 0x11, sizeof(*waiter));
+ plist_node_init(&waiter->list_entry, MAX_PRIO);
+ plist_node_init(&waiter->pi_list_entry, MAX_PRIO);
+ waiter->deadlock_task_pid = NULL;
+}
+
+void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter)
+{
+ put_pid(waiter->deadlock_task_pid);
+ DEBUG_LOCKS_WARN_ON(!plist_node_empty(&waiter->list_entry));
+ DEBUG_LOCKS_WARN_ON(!plist_node_empty(&waiter->pi_list_entry));
+ memset(waiter, 0x22, sizeof(*waiter));
+}
+
+void debug_rt_mutex_init(struct rt_mutex *lock, const char *name)
+{
+ /*
+ * Make sure we are not reinitializing a held lock:
+ */
+ debug_check_no_locks_freed((void *)lock, sizeof(*lock));
+ lock->name = name;
+}
+
+void
+rt_mutex_deadlock_account_lock(struct rt_mutex *lock, struct task_struct *task)
+{
+}
+
+void rt_mutex_deadlock_account_unlock(struct task_struct *task)
+{
+}
+
--- /dev/null
+++ b/kernel/locking/rtmutex-debug.h
@@ -0,0 +1,33 @@
+/*
+ * RT-Mutexes: blocking mutual exclusion locks with PI support
+ *
+ * started by Ingo Molnar and Thomas Gleixner:
+ *
+ * Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ * Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
+ *
+ * This file contains macros used solely by rtmutex.c. Debug version.
+ */
+
+extern void
+rt_mutex_deadlock_account_lock(struct rt_mutex *lock, struct task_struct *task);
+extern void rt_mutex_deadlock_account_unlock(struct task_struct *task);
+extern void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter);
+extern void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter);
+extern void debug_rt_mutex_init(struct rt_mutex *lock, const char *name);
+extern void debug_rt_mutex_lock(struct rt_mutex *lock);
+extern void debug_rt_mutex_unlock(struct rt_mutex *lock);
+extern void debug_rt_mutex_proxy_lock(struct rt_mutex *lock,
+ struct task_struct *powner);
+extern void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock);
+extern void debug_rt_mutex_deadlock(int detect, struct rt_mutex_waiter *waiter,
+ struct rt_mutex *lock);
+extern void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter);
+# define debug_rt_mutex_reset_waiter(w) \
+ do { (w)->deadlock_lock = NULL; } while (0)
+
+static inline int debug_rt_mutex_detect_deadlock(struct rt_mutex_waiter *waiter,
+ int detect)
+{
+ return (waiter != NULL);
+}
--- /dev/null
+++ b/kernel/locking/rtmutex-tester.c
@@ -0,0 +1,420 @@
+/*
+ * RT-Mutex-tester: scriptable tester for rt mutexes
+ *
+ * started by Thomas Gleixner:
+ *
+ * Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
+ *
+ */
+#include <linux/device.h>
+#include <linux/kthread.h>
+#include <linux/export.h>
+#include <linux/sched.h>
+#include <linux/sched/rt.h>
+#include <linux/spinlock.h>
+#include <linux/timer.h>
+#include <linux/freezer.h>
+#include <linux/stat.h>
+
+#include "rtmutex.h"
+
+#define MAX_RT_TEST_THREADS 8
+#define MAX_RT_TEST_MUTEXES 8
+
+static spinlock_t rttest_lock;
+static atomic_t rttest_event;
+
+struct test_thread_data {
+ int opcode;
+ int opdata;
+ int mutexes[MAX_RT_TEST_MUTEXES];
+ int event;
+ struct device dev;
+};
+
+static struct test_thread_data thread_data[MAX_RT_TEST_THREADS];
+static struct task_struct *threads[MAX_RT_TEST_THREADS];
+static struct rt_mutex mutexes[MAX_RT_TEST_MUTEXES];
+
+enum test_opcodes {
+ RTTEST_NOP = 0,
+ RTTEST_SCHEDOT, /* 1 Sched other, data = nice */
+ RTTEST_SCHEDRT, /* 2 Sched fifo, data = prio */
+ RTTEST_LOCK, /* 3 Lock uninterruptible, data = lockindex */
+ RTTEST_LOCKNOWAIT, /* 4 Lock uninterruptible no wait in wakeup, data = lockindex */
+ RTTEST_LOCKINT, /* 5 Lock interruptible, data = lockindex */
+ RTTEST_LOCKINTNOWAIT, /* 6 Lock interruptible no wait in wakeup, data = lockindex */
+ RTTEST_LOCKCONT, /* 7 Continue locking after the wakeup delay */
+ RTTEST_UNLOCK, /* 8 Unlock, data = lockindex */
+ /* 9, 10 - reserved for BKL commemoration */
+ RTTEST_SIGNAL = 11, /* 11 Signal other test thread, data = thread id */
+ RTTEST_RESETEVENT = 98, /* 98 Reset event counter */
+ RTTEST_RESET = 99, /* 99 Reset all pending operations */
+};
+
+static int handle_op(struct test_thread_data *td, int lockwakeup)
+{
+ int i, id, ret = -EINVAL;
+
+ switch(td->opcode) {
+
+ case RTTEST_NOP:
+ return 0;
+
+ case RTTEST_LOCKCONT:
+ td->mutexes[td->opdata] = 1;
+ td->event = atomic_add_return(1, &rttest_event);
+ return 0;
+
+ case RTTEST_RESET:
+ for (i = 0; i < MAX_RT_TEST_MUTEXES; i++) {
+ if (td->mutexes[i] == 4) {
+ rt_mutex_unlock(&mutexes[i]);
+ td->mutexes[i] = 0;
+ }
+ }
+ return 0;
+
+ case RTTEST_RESETEVENT:
+ atomic_set(&rttest_event, 0);
+ return 0;
+
+ default:
+ if (lockwakeup)
+ return ret;
+ }
+
+ switch(td->opcode) {
+
+ case RTTEST_LOCK:
+ case RTTEST_LOCKNOWAIT:
+ id = td->opdata;
+ if (id < 0 || id >= MAX_RT_TEST_MUTEXES)
+ return ret;
+
+ td->mutexes[id] = 1;
+ td->event = atomic_add_return(1, &rttest_event);
+ rt_mutex_lock(&mutexes[id]);
+ td->event = atomic_add_return(1, &rttest_event);
+ td->mutexes[id] = 4;
+ return 0;
+
+ case RTTEST_LOCKINT:
+ case RTTEST_LOCKINTNOWAIT:
+ id = td->opdata;
+ if (id < 0 || id >= MAX_RT_TEST_MUTEXES)
+ return ret;
+
+ td->mutexes[id] = 1;
+ td->event = atomic_add_return(1, &rttest_event);
+ ret = rt_mutex_lock_interruptible(&mutexes[id], 0);
+ td->event = atomic_add_return(1, &rttest_event);
+ td->mutexes[id] = ret ? 0 : 4;
+ return ret ? -EINTR : 0;
+
+ case RTTEST_UNLOCK:
+ id = td->opdata;
+ if (id < 0 || id >= MAX_RT_TEST_MUTEXES || td->mutexes[id] != 4)
+ return ret;
+
+ td->event = atomic_add_return(1, &rttest_event);
+ rt_mutex_unlock(&mutexes[id]);
+ td->event = atomic_add_return(1, &rttest_event);
+ td->mutexes[id] = 0;
+ return 0;
+
+ default:
+ break;
+ }
+ return ret;
+}
+
+/*
+ * Schedule replacement for rtsem_down(). Only called for threads with
+ * PF_MUTEX_TESTER set.
+ *
+ * This allows us to have finegrained control over the event flow.
+ *
+ */
+void schedule_rt_mutex_test(struct rt_mutex *mutex)
+{
+ int tid, op, dat;
+ struct test_thread_data *td;
+
+ /* We have to lookup the task */
+ for (tid = 0; tid < MAX_RT_TEST_THREADS; tid++) {
+ if (threads[tid] == current)
+ break;
+ }
+
+ BUG_ON(tid == MAX_RT_TEST_THREADS);
+
+ td = &thread_data[tid];
+
+ op = td->opcode;
+ dat = td->opdata;
+
+ switch (op) {
+ case RTTEST_LOCK:
+ case RTTEST_LOCKINT:
+ case RTTEST_LOCKNOWAIT:
+ case RTTEST_LOCKINTNOWAIT:
+ if (mutex != &mutexes[dat])
+ break;
+
+ if (td->mutexes[dat] != 1)
+ break;
+
+ td->mutexes[dat] = 2;
+ td->event = atomic_add_return(1, &rttest_event);
+ break;
+
+ default:
+ break;
+ }
+
+ schedule();
+
+
+ switch (op) {
+ case RTTEST_LOCK:
+ case RTTEST_LOCKINT:
+ if (mutex != &mutexes[dat])
+ return;
+
+ if (td->mutexes[dat] != 2)
+ return;
+
+ td->mutexes[dat] = 3;
+ td->event = atomic_add_return(1, &rttest_event);
+ break;
+
+ case RTTEST_LOCKNOWAIT:
+ case RTTEST_LOCKINTNOWAIT:
+ if (mutex != &mutexes[dat])
+ return;
+
+ if (td->mutexes[dat] != 2)
+ return;
+
+ td->mutexes[dat] = 1;
+ td->event = atomic_add_return(1, &rttest_event);
+ return;
+
+ default:
+ return;
+ }
+
+ td->opcode = 0;
+
+ for (;;) {
+ set_current_state(TASK_INTERRUPTIBLE);
+
+ if (td->opcode > 0) {
+ int ret;
+
+ set_current_state(TASK_RUNNING);
+ ret = handle_op(td, 1);
+ set_current_state(TASK_INTERRUPTIBLE);
+ if (td->opcode == RTTEST_LOCKCONT)
+ break;
+ td->opcode = ret;
+ }
+
+ /* Wait for the next command to be executed */
+ schedule();
+ }
+
+ /* Restore previous command and data */
+ td->opcode = op;
+ td->opdata = dat;
+}
+
+static int test_func(void *data)
+{
+ struct test_thread_data *td = data;
+ int ret;
+
+ current->flags |= PF_MUTEX_TESTER;
+ set_freezable();
+ allow_signal(SIGHUP);
+
+ for(;;) {
+
+ set_current_state(TASK_INTERRUPTIBLE);
+
+ if (td->opcode > 0) {
+ set_current_state(TASK_RUNNING);
+ ret = handle_op(td, 0);
+ set_current_state(TASK_INTERRUPTIBLE);
+ td->opcode = ret;
+ }
+
+ /* Wait for the next command to be executed */
+ schedule();
+ try_to_freeze();
+
+ if (signal_pending(current))
+ flush_signals(current);
+
+ if(kthread_should_stop())
+ break;
+ }
+ return 0;
+}
+
+/**
+ * sysfs_test_command - interface for test commands
+ * @dev: thread reference
+ * @buf: command for actual step
+ * @count: length of buffer
+ *
+ * command syntax:
+ *
+ * opcode:data
+ */
+static ssize_t sysfs_test_command(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct sched_param schedpar;
+ struct test_thread_data *td;
+ char cmdbuf[32];
+ int op, dat, tid, ret;
+
+ td = container_of(dev, struct test_thread_data, dev);
+ tid = td->dev.id;
+
+ /* strings from sysfs write are not 0 terminated! */
+ if (count >= sizeof(cmdbuf))
+ return -EINVAL;
+
+ /* strip of \n: */
+ if (buf[count-1] == '\n')
+ count--;
+ if (count < 1)
+ return -EINVAL;
+
+ memcpy(cmdbuf, buf, count);
+ cmdbuf[count] = 0;
+
+ if (sscanf(cmdbuf, "%d:%d", &op, &dat) != 2)
+ return -EINVAL;
+
+ switch (op) {
+ case RTTEST_SCHEDOT:
+ schedpar.sched_priority = 0;
+ ret = sched_setscheduler(threads[tid], SCHED_NORMAL, &schedpar);
+ if (ret)
+ return ret;
+ set_user_nice(current, 0);
+ break;
+
+ case RTTEST_SCHEDRT:
+ schedpar.sched_priority = dat;
+ ret = sched_setscheduler(threads[tid], SCHED_FIFO, &schedpar);
+ if (ret)
+ return ret;
+ break;
+
+ case RTTEST_SIGNAL:
+ send_sig(SIGHUP, threads[tid], 0);
+ break;
+
+ default:
+ if (td->opcode > 0)
+ return -EBUSY;
+ td->opdata = dat;
+ td->opcode = op;
+ wake_up_process(threads[tid]);
+ }
+
+ return count;
+}
+
+/**
+ * sysfs_test_status - sysfs interface for rt tester
+ * @dev: thread to query
+ * @buf: char buffer to be filled with thread status info
+ */
+static ssize_t sysfs_test_status(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct test_thread_data *td;
+ struct task_struct *tsk;
+ char *curr = buf;
+ int i;
+
+ td = container_of(dev, struct test_thread_data, dev);
+ tsk = threads[td->dev.id];
+
+ spin_lock(&rttest_lock);
+
+ curr += sprintf(curr,
+ "O: %4d, E:%8d, S: 0x%08lx, P: %4d, N: %4d, B: %p, M:",
+ td->opcode, td->event, tsk->state,
+ (MAX_RT_PRIO - 1) - tsk->prio,
+ (MAX_RT_PRIO - 1) - tsk->normal_prio,
+ tsk->pi_blocked_on);
+
+ for (i = MAX_RT_TEST_MUTEXES - 1; i >=0 ; i--)
+ curr += sprintf(curr, "%d", td->mutexes[i]);
+
+ spin_unlock(&rttest_lock);
+
+ curr += sprintf(curr, ", T: %p, R: %p\n", tsk,
+ mutexes[td->dev.id].owner);
+
+ return curr - buf;
+}
+
+static DEVICE_ATTR(status, S_IRUSR, sysfs_test_status, NULL);
+static DEVICE_ATTR(command, S_IWUSR, NULL, sysfs_test_command);
+
+static struct bus_type rttest_subsys = {
+ .name = "rttest",
+ .dev_name = "rttest",
+};
+
+static int init_test_thread(int id)
+{
+ thread_data[id].dev.bus = &rttest_subsys;
+ thread_data[id].dev.id = id;
+
+ threads[id] = kthread_run(test_func, &thread_data[id], "rt-test-%d", id);
+ if (IS_ERR(threads[id]))
+ return PTR_ERR(threads[id]);
+
+ return device_register(&thread_data[id].dev);
+}
+
+static int init_rttest(void)
+{
+ int ret, i;
+
+ spin_lock_init(&rttest_lock);
+
+ for (i = 0; i < MAX_RT_TEST_MUTEXES; i++)
+ rt_mutex_init(&mutexes[i]);
+
+ ret = subsys_system_register(&rttest_subsys, NULL);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < MAX_RT_TEST_THREADS; i++) {
+ ret = init_test_thread(i);
+ if (ret)
+ break;
+ ret = device_create_file(&thread_data[i].dev, &dev_attr_status);
+ if (ret)
+ break;
+ ret = device_create_file(&thread_data[i].dev, &dev_attr_command);
+ if (ret)
+ break;
+ }
+
+ printk("Initializing RT-Tester: %s\n", ret ? "Failed" : "OK" );
+
+ return ret;
+}
+
+device_initcall(init_rttest);
--- /dev/null
+++ b/kernel/locking/rtmutex.c
@@ -0,0 +1,1060 @@
+/*
+ * RT-Mutexes: simple blocking mutual exclusion locks with PI support
+ *
+ * started by Ingo Molnar and Thomas Gleixner.
+ *
+ * Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ * Copyright (C) 2005-2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
+ * Copyright (C) 2005 Kihon Technologies Inc., Steven Rostedt
+ * Copyright (C) 2006 Esben Nielsen
+ *
+ * See Documentation/rt-mutex-design.txt for details.
+ */
+#include <linux/spinlock.h>
+#include <linux/export.h>
+#include <linux/sched.h>
+#include <linux/sched/rt.h>
+#include <linux/timer.h>
+
+#include "rtmutex_common.h"
+
+/*
+ * lock->owner state tracking:
+ *
+ * lock->owner holds the task_struct pointer of the owner. Bit 0
+ * is used to keep track of the "lock has waiters" state.
+ *
+ * owner bit0
+ * NULL 0 lock is free (fast acquire possible)
+ * NULL 1 lock is free and has waiters and the top waiter
+ * is going to take the lock*
+ * taskpointer 0 lock is held (fast release possible)
+ * taskpointer 1 lock is held and has waiters**
+ *
+ * The fast atomic compare exchange based acquire and release is only
+ * possible when bit 0 of lock->owner is 0.
+ *
+ * (*) It also can be a transitional state when grabbing the lock
+ * with ->wait_lock is held. To prevent any fast path cmpxchg to the lock,
+ * we need to set the bit0 before looking at the lock, and the owner may be
+ * NULL in this small time, hence this can be a transitional state.
+ *
+ * (**) There is a small time when bit 0 is set but there are no
+ * waiters. This can happen when grabbing the lock in the slow path.
+ * To prevent a cmpxchg of the owner releasing the lock, we need to
+ * set this bit before looking at the lock.
+ */
+
+static void
+rt_mutex_set_owner(struct rt_mutex *lock, struct task_struct *owner)
+{
+ unsigned long val = (unsigned long)owner;
+
+ if (rt_mutex_has_waiters(lock))
+ val |= RT_MUTEX_HAS_WAITERS;
+
+ lock->owner = (struct task_struct *)val;
+}
+
+static inline void clear_rt_mutex_waiters(struct rt_mutex *lock)
+{
+ lock->owner = (struct task_struct *)
+ ((unsigned long)lock->owner & ~RT_MUTEX_HAS_WAITERS);
+}
+
+static void fixup_rt_mutex_waiters(struct rt_mutex *lock)
+{
+ if (!rt_mutex_has_waiters(lock))
+ clear_rt_mutex_waiters(lock);
+}
+
+/*
+ * We can speed up the acquire/release, if the architecture
+ * supports cmpxchg and if there's no debugging state to be set up
+ */
+#if defined(__HAVE_ARCH_CMPXCHG) && !defined(CONFIG_DEBUG_RT_MUTEXES)
+# define rt_mutex_cmpxchg(l,c,n) (cmpxchg(&l->owner, c, n) == c)
+static inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
+{
+ unsigned long owner, *p = (unsigned long *) &lock->owner;
+
+ do {
+ owner = *p;
+ } while (cmpxchg(p, owner, owner | RT_MUTEX_HAS_WAITERS) != owner);
+}
+#else
+# define rt_mutex_cmpxchg(l,c,n) (0)
+static inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
+{
+ lock->owner = (struct task_struct *)
+ ((unsigned long)lock->owner | RT_MUTEX_HAS_WAITERS);
+}
+#endif
+
+/*
+ * Calculate task priority from the waiter list priority
+ *
+ * Return task->normal_prio when the waiter list is empty or when
+ * the waiter is not allowed to do priority boosting
+ */
+int rt_mutex_getprio(struct task_struct *task)
+{
+ if (likely(!task_has_pi_waiters(task)))
+ return task->normal_prio;
+
+ return min(task_top_pi_waiter(task)->pi_list_entry.prio,
+ task->normal_prio);
+}
+
+/*
+ * Adjust the priority of a task, after its pi_waiters got modified.
+ *
+ * This can be both boosting and unboosting. task->pi_lock must be held.
+ */
+static void __rt_mutex_adjust_prio(struct task_struct *task)
+{
+ int prio = rt_mutex_getprio(task);
+
+ if (task->prio != prio)
+ rt_mutex_setprio(task, prio);
+}
+
+/*
+ * Adjust task priority (undo boosting). Called from the exit path of
+ * rt_mutex_slowunlock() and rt_mutex_slowlock().
+ *
+ * (Note: We do this outside of the protection of lock->wait_lock to
+ * allow the lock to be taken while or before we readjust the priority
+ * of task. We do not use the spin_xx_mutex() variants here as we are
+ * outside of the debug path.)
+ */
+static void rt_mutex_adjust_prio(struct task_struct *task)
+{
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&task->pi_lock, flags);
+ __rt_mutex_adjust_prio(task);
+ raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+}
+
+/*
+ * Max number of times we'll walk the boosting chain:
+ */
+int max_lock_depth = 1024;
+
+/*
+ * Adjust the priority chain. Also used for deadlock detection.
+ * Decreases task's usage by one - may thus free the task.
+ *
+ * @task: the task owning the mutex (owner) for which a chain walk is probably
+ * needed
+ * @deadlock_detect: do we have to carry out deadlock detection?
+ * @orig_lock: the mutex (can be NULL if we are walking the chain to recheck
+ * things for a task that has just got its priority adjusted, and
+ * is waiting on a mutex)
+ * @orig_waiter: rt_mutex_waiter struct for the task that has just donated
+ * its priority to the mutex owner (can be NULL in the case
+ * depicted above or if the top waiter is gone away and we are
+ * actually deboosting the owner)
+ * @top_task: the current top waiter
+ *
+ * Returns 0 or -EDEADLK.
+ */
+static int rt_mutex_adjust_prio_chain(struct task_struct *task,
+ int deadlock_detect,
+ struct rt_mutex *orig_lock,
+ struct rt_mutex_waiter *orig_waiter,
+ struct task_struct *top_task)
+{
+ struct rt_mutex *lock;
+ struct rt_mutex_waiter *waiter, *top_waiter = orig_waiter;
+ int detect_deadlock, ret = 0, depth = 0;
+ unsigned long flags;
+
+ detect_deadlock = debug_rt_mutex_detect_deadlock(orig_waiter,
+ deadlock_detect);
+
+ /*
+ * The (de)boosting is a step by step approach with a lot of
+ * pitfalls. We want this to be preemptible and we want hold a
+ * maximum of two locks per step. So we have to check
+ * carefully whether things change under us.
+ */
+ again:
+ if (++depth > max_lock_depth) {
+ static int prev_max;
+
+ /*
+ * Print this only once. If the admin changes the limit,
+ * print a new message when reaching the limit again.
+ */
+ if (prev_max != max_lock_depth) {
+ prev_max = max_lock_depth;
+ printk(KERN_WARNING "Maximum lock depth %d reached "
+ "task: %s (%d)\n", max_lock_depth,
+ top_task->comm, task_pid_nr(top_task));
+ }
+ put_task_struct(task);
+
+ return deadlock_detect ? -EDEADLK : 0;
+ }
+ retry:
+ /*
+ * Task can not go away as we did a get_task() before !
+ */
+ raw_spin_lock_irqsave(&task->pi_lock, flags);
+
+ waiter = task->pi_blocked_on;
+ /*
+ * Check whether the end of the boosting chain has been
+ * reached or the state of the chain has changed while we
+ * dropped the locks.
+ */
+ if (!waiter)
+ goto out_unlock_pi;
+
+ /*
+ * Check the orig_waiter state. After we dropped the locks,
+ * the previous owner of the lock might have released the lock.
+ */
+ if (orig_waiter && !rt_mutex_owner(orig_lock))
+ goto out_unlock_pi;
+
+ /*
+ * Drop out, when the task has no waiters. Note,
+ * top_waiter can be NULL, when we are in the deboosting
+ * mode!
+ */
+ if (top_waiter && (!task_has_pi_waiters(task) ||
+ top_waiter != task_top_pi_waiter(task)))
+ goto out_unlock_pi;
+
+ /*
+ * When deadlock detection is off then we check, if further
+ * priority adjustment is necessary.
+ */
+ if (!detect_deadlock && waiter->list_entry.prio == task->prio)
+ goto out_unlock_pi;
+
+ lock = waiter->lock;
+ if (!raw_spin_trylock(&lock->wait_lock)) {
+ raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+ cpu_relax();
+ goto retry;
+ }
+
+ /* Deadlock detection */
+ if (lock == orig_lock || rt_mutex_owner(lock) == top_task) {
+ debug_rt_mutex_deadlock(deadlock_detect, orig_waiter, lock);
+ raw_spin_unlock(&lock->wait_lock);
+ ret = deadlock_detect ? -EDEADLK : 0;
+ goto out_unlock_pi;
+ }
+
+ top_waiter = rt_mutex_top_waiter(lock);
+
+ /* Requeue the waiter */
+ plist_del(&waiter->list_entry, &lock->wait_list);
+ waiter->list_entry.prio = task->prio;
+ plist_add(&waiter->list_entry, &lock->wait_list);
+
+ /* Release the task */
+ raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+ if (!rt_mutex_owner(lock)) {
+ /*
+ * If the requeue above changed the top waiter, then we need
+ * to wake the new top waiter up to try to get the lock.
+ */
+
+ if (top_waiter != rt_mutex_top_waiter(lock))
+ wake_up_process(rt_mutex_top_waiter(lock)->task);
+ raw_spin_unlock(&lock->wait_lock);
+ goto out_put_task;
+ }
+ put_task_struct(task);
+
+ /* Grab the next task */
+ task = rt_mutex_owner(lock);
+ get_task_struct(task);
+ raw_spin_lock_irqsave(&task->pi_lock, flags);
+
+ if (waiter == rt_mutex_top_waiter(lock)) {
+ /* Boost the owner */
+ plist_del(&top_waiter->pi_list_entry, &task->pi_waiters);
+ waiter->pi_list_entry.prio = waiter->list_entry.prio;
+ plist_add(&waiter->pi_list_entry, &task->pi_waiters);
+ __rt_mutex_adjust_prio(task);
+
+ } else if (top_waiter == waiter) {
+ /* Deboost the owner */
+ plist_del(&waiter->pi_list_entry, &task->pi_waiters);
+ waiter = rt_mutex_top_waiter(lock);
+ waiter->pi_list_entry.prio = waiter->list_entry.prio;
+ plist_add(&waiter->pi_list_entry, &task->pi_waiters);
+ __rt_mutex_adjust_prio(task);
+ }
+
+ raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+
+ top_waiter = rt_mutex_top_waiter(lock);
+ raw_spin_unlock(&lock->wait_lock);
+
+ if (!detect_deadlock && waiter != top_waiter)
+ goto out_put_task;
+
+ goto again;
+
+ out_unlock_pi:
+ raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+ out_put_task:
+ put_task_struct(task);
+
+ return ret;
+}
+
+/*
+ * Try to take an rt-mutex
+ *
+ * Must be called with lock->wait_lock held.
+ *
+ * @lock: the lock to be acquired.
+ * @task: the task which wants to acquire the lock
+ * @waiter: the waiter that is queued to the lock's wait list. (could be NULL)
+ */
+static int try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
+ struct rt_mutex_waiter *waiter)
+{
+ /*
+ * We have to be careful here if the atomic speedups are
+ * enabled, such that, when
+ * - no other waiter is on the lock
+ * - the lock has been released since we did the cmpxchg
+ * the lock can be released or taken while we are doing the
+ * checks and marking the lock with RT_MUTEX_HAS_WAITERS.
+ *
+ * The atomic acquire/release aware variant of
+ * mark_rt_mutex_waiters uses a cmpxchg loop. After setting
+ * the WAITERS bit, the atomic release / acquire can not
+ * happen anymore and lock->wait_lock protects us from the
+ * non-atomic case.
+ *
+ * Note, that this might set lock->owner =
+ * RT_MUTEX_HAS_WAITERS in the case the lock is not contended
+ * any more. This is fixed up when we take the ownership.
+ * This is the transitional state explained at the top of this file.
+ */
+ mark_rt_mutex_waiters(lock);
+
+ if (rt_mutex_owner(lock))
+ return 0;
+
+ /*
+ * It will get the lock because of one of these conditions:
+ * 1) there is no waiter
+ * 2) higher priority than waiters
+ * 3) it is top waiter
+ */
+ if (rt_mutex_has_waiters(lock)) {
+ if (task->prio >= rt_mutex_top_waiter(lock)->list_entry.prio) {
+ if (!waiter || waiter != rt_mutex_top_waiter(lock))
+ return 0;
+ }
+ }
+
+ if (waiter || rt_mutex_has_waiters(lock)) {
+ unsigned long flags;
+ struct rt_mutex_waiter *top;
+
+ raw_spin_lock_irqsave(&task->pi_lock, flags);
+
+ /* remove the queued waiter. */
+ if (waiter) {
+ plist_del(&waiter->list_entry, &lock->wait_list);
+ task->pi_blocked_on = NULL;
+ }
+
+ /*
+ * We have to enqueue the top waiter(if it exists) into
+ * task->pi_waiters list.
+ */
+ if (rt_mutex_has_waiters(lock)) {
+ top = rt_mutex_top_waiter(lock);
+ top->pi_list_entry.prio = top->list_entry.prio;
+ plist_add(&top->pi_list_entry, &task->pi_waiters);
+ }
+ raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+ }
+
+ /* We got the lock. */
+ debug_rt_mutex_lock(lock);
+
+ rt_mutex_set_owner(lock, task);
+
+ rt_mutex_deadlock_account_lock(lock, task);
+
+ return 1;
+}
+
+/*
+ * Task blocks on lock.
+ *
+ * Prepare waiter and propagate pi chain
+ *
+ * This must be called with lock->wait_lock held.
+ */
+static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
+ struct rt_mutex_waiter *waiter,
+ struct task_struct *task,
+ int detect_deadlock)
+{
+ struct task_struct *owner = rt_mutex_owner(lock);
+ struct rt_mutex_waiter *top_waiter = waiter;
+ unsigned long flags;
+ int chain_walk = 0, res;
+
+ raw_spin_lock_irqsave(&task->pi_lock, flags);
+ __rt_mutex_adjust_prio(task);
+ waiter->task = task;
+ waiter->lock = lock;
+ plist_node_init(&waiter->list_entry, task->prio);
+ plist_node_init(&waiter->pi_list_entry, task->prio);
+
+ /* Get the top priority waiter on the lock */
+ if (rt_mutex_has_waiters(lock))
+ top_waiter = rt_mutex_top_waiter(lock);
+ plist_add(&waiter->list_entry, &lock->wait_list);
+
+ task->pi_blocked_on = waiter;
+
+ raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+
+ if (!owner)
+ return 0;
+
+ if (waiter == rt_mutex_top_waiter(lock)) {
+ raw_spin_lock_irqsave(&owner->pi_lock, flags);
+ plist_del(&top_waiter->pi_list_entry, &owner->pi_waiters);
+ plist_add(&waiter->pi_list_entry, &owner->pi_waiters);
+
+ __rt_mutex_adjust_prio(owner);
+ if (owner->pi_blocked_on)
+ chain_walk = 1;
+ raw_spin_unlock_irqrestore(&owner->pi_lock, flags);
+ }
+ else if (debug_rt_mutex_detect_deadlock(waiter, detect_deadlock))
+ chain_walk = 1;
+
+ if (!chain_walk)
+ return 0;
+
+ /*
+ * The owner can't disappear while holding a lock,
+ * so the owner struct is protected by wait_lock.
+ * Gets dropped in rt_mutex_adjust_prio_chain()!
+ */
+ get_task_struct(owner);
+
+ raw_spin_unlock(&lock->wait_lock);
+
+ res = rt_mutex_adjust_prio_chain(owner, detect_deadlock, lock, waiter,
+ task);
+
+ raw_spin_lock(&lock->wait_lock);
+
+ return res;
+}
+
+/*
+ * Wake up the next waiter on the lock.
+ *
+ * Remove the top waiter from the current tasks waiter list and wake it up.
+ *
+ * Called with lock->wait_lock held.
+ */
+static void wakeup_next_waiter(struct rt_mutex *lock)
+{
+ struct rt_mutex_waiter *waiter;
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(¤t->pi_lock, flags);
+
+ waiter = rt_mutex_top_waiter(lock);
+
+ /*
+ * Remove it from current->pi_waiters. We do not adjust a
+ * possible priority boost right now. We execute wakeup in the
+ * boosted mode and go back to normal after releasing
+ * lock->wait_lock.
+ */
+ plist_del(&waiter->pi_list_entry, ¤t->pi_waiters);
+
+ rt_mutex_set_owner(lock, NULL);
+
+ raw_spin_unlock_irqrestore(¤t->pi_lock, flags);
+
+ wake_up_process(waiter->task);
+}
+
+/*
+ * Remove a waiter from a lock and give up
+ *
+ * Must be called with lock->wait_lock held and
+ * have just failed to try_to_take_rt_mutex().
+ */
+static void remove_waiter(struct rt_mutex *lock,
+ struct rt_mutex_waiter *waiter)
+{
+ int first = (waiter == rt_mutex_top_waiter(lock));
+ struct task_struct *owner = rt_mutex_owner(lock);
+ unsigned long flags;
+ int chain_walk = 0;
+
+ raw_spin_lock_irqsave(¤t->pi_lock, flags);
+ plist_del(&waiter->list_entry, &lock->wait_list);
+ current->pi_blocked_on = NULL;
+ raw_spin_unlock_irqrestore(¤t->pi_lock, flags);
+
+ if (!owner)
+ return;
+
+ if (first) {
+
+ raw_spin_lock_irqsave(&owner->pi_lock, flags);
+
+ plist_del(&waiter->pi_list_entry, &owner->pi_waiters);
+
+ if (rt_mutex_has_waiters(lock)) {
+ struct rt_mutex_waiter *next;
+
+ next = rt_mutex_top_waiter(lock);
+ plist_add(&next->pi_list_entry, &owner->pi_waiters);
+ }
+ __rt_mutex_adjust_prio(owner);
+
+ if (owner->pi_blocked_on)
+ chain_walk = 1;
+
+ raw_spin_unlock_irqrestore(&owner->pi_lock, flags);
+ }
+
+ WARN_ON(!plist_node_empty(&waiter->pi_list_entry));
+
+ if (!chain_walk)
+ return;
+
+ /* gets dropped in rt_mutex_adjust_prio_chain()! */
+ get_task_struct(owner);
+
+ raw_spin_unlock(&lock->wait_lock);
+
+ rt_mutex_adjust_prio_chain(owner, 0, lock, NULL, current);
+
+ raw_spin_lock(&lock->wait_lock);
+}
+
+/*
+ * Recheck the pi chain, in case we got a priority setting
+ *
+ * Called from sched_setscheduler
+ */
+void rt_mutex_adjust_pi(struct task_struct *task)
+{
+ struct rt_mutex_waiter *waiter;
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&task->pi_lock, flags);
+
+ waiter = task->pi_blocked_on;
+ if (!waiter || waiter->list_entry.prio == task->prio) {
+ raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+ return;
+ }
+
+ raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+
+ /* gets dropped in rt_mutex_adjust_prio_chain()! */
+ get_task_struct(task);
+ rt_mutex_adjust_prio_chain(task, 0, NULL, NULL, task);
+}
+
+/**
+ * __rt_mutex_slowlock() - Perform the wait-wake-try-to-take loop
+ * @lock: the rt_mutex to take
+ * @state: the state the task should block in (TASK_INTERRUPTIBLE
+ * or TASK_UNINTERRUPTIBLE)
+ * @timeout: the pre-initialized and started timer, or NULL for none
+ * @waiter: the pre-initialized rt_mutex_waiter
+ *
+ * lock->wait_lock must be held by the caller.
+ */
+static int __sched
+__rt_mutex_slowlock(struct rt_mutex *lock, int state,
+ struct hrtimer_sleeper *timeout,
+ struct rt_mutex_waiter *waiter)
+{
+ int ret = 0;
+
+ for (;;) {
+ /* Try to acquire the lock: */
+ if (try_to_take_rt_mutex(lock, current, waiter))
+ break;
+
+ /*
+ * TASK_INTERRUPTIBLE checks for signals and
+ * timeout. Ignored otherwise.
+ */
+ if (unlikely(state == TASK_INTERRUPTIBLE)) {
+ /* Signal pending? */
+ if (signal_pending(current))
+ ret = -EINTR;
+ if (timeout && !timeout->task)
+ ret = -ETIMEDOUT;
+ if (ret)
+ break;
+ }
+
+ raw_spin_unlock(&lock->wait_lock);
+
+ debug_rt_mutex_print_deadlock(waiter);
+
+ schedule_rt_mutex(lock);
+
+ raw_spin_lock(&lock->wait_lock);
+ set_current_state(state);
+ }
+
+ return ret;
+}
+
+/*
+ * Slow path lock function:
+ */
+static int __sched
+rt_mutex_slowlock(struct rt_mutex *lock, int state,
+ struct hrtimer_sleeper *timeout,
+ int detect_deadlock)
+{
+ struct rt_mutex_waiter waiter;
+ int ret = 0;
+
+ debug_rt_mutex_init_waiter(&waiter);
+
+ raw_spin_lock(&lock->wait_lock);
+
+ /* Try to acquire the lock again: */
+ if (try_to_take_rt_mutex(lock, current, NULL)) {
+ raw_spin_unlock(&lock->wait_lock);
+ return 0;
+ }
+
+ set_current_state(state);
+
+ /* Setup the timer, when timeout != NULL */
+ if (unlikely(timeout)) {
+ hrtimer_start_expires(&timeout->timer, HRTIMER_MODE_ABS);
+ if (!hrtimer_active(&timeout->timer))
+ timeout->task = NULL;
+ }
+
+ ret = task_blocks_on_rt_mutex(lock, &waiter, current, detect_deadlock);
+
+ if (likely(!ret))
+ ret = __rt_mutex_slowlock(lock, state, timeout, &waiter);
+
+ set_current_state(TASK_RUNNING);
+
+ if (unlikely(ret))
+ remove_waiter(lock, &waiter);
+
+ /*
+ * try_to_take_rt_mutex() sets the waiter bit
+ * unconditionally. We might have to fix that up.
+ */
+ fixup_rt_mutex_waiters(lock);
+
+ raw_spin_unlock(&lock->wait_lock);
+
+ /* Remove pending timer: */
+ if (unlikely(timeout))
+ hrtimer_cancel(&timeout->timer);
+
+ debug_rt_mutex_free_waiter(&waiter);
+
+ return ret;
+}
+
+/*
+ * Slow path try-lock function:
+ */
+static inline int
+rt_mutex_slowtrylock(struct rt_mutex *lock)
+{
+ int ret = 0;
+
+ raw_spin_lock(&lock->wait_lock);
+
+ if (likely(rt_mutex_owner(lock) != current)) {
+
+ ret = try_to_take_rt_mutex(lock, current, NULL);
+ /*
+ * try_to_take_rt_mutex() sets the lock waiters
+ * bit unconditionally. Clean this up.
+ */
+ fixup_rt_mutex_waiters(lock);
+ }
+
+ raw_spin_unlock(&lock->wait_lock);
+
+ return ret;
+}
+
+/*
+ * Slow path to release a rt-mutex:
+ */
+static void __sched
+rt_mutex_slowunlock(struct rt_mutex *lock)
+{
+ raw_spin_lock(&lock->wait_lock);
+
+ debug_rt_mutex_unlock(lock);
+
+ rt_mutex_deadlock_account_unlock(current);
+
+ if (!rt_mutex_has_waiters(lock)) {
+ lock->owner = NULL;
+ raw_spin_unlock(&lock->wait_lock);
+ return;
+ }
+
+ wakeup_next_waiter(lock);
+
+ raw_spin_unlock(&lock->wait_lock);
+
+ /* Undo pi boosting if necessary: */
+ rt_mutex_adjust_prio(current);
+}
+
+/*
+ * debug aware fast / slowpath lock,trylock,unlock
+ *
+ * The atomic acquire/release ops are compiled away, when either the
+ * architecture does not support cmpxchg or when debugging is enabled.
+ */
+static inline int
+rt_mutex_fastlock(struct rt_mutex *lock, int state,
+ int detect_deadlock,
+ int (*slowfn)(struct rt_mutex *lock, int state,
+ struct hrtimer_sleeper *timeout,
+ int detect_deadlock))
+{
+ if (!detect_deadlock && likely(rt_mutex_cmpxchg(lock, NULL, current))) {
+ rt_mutex_deadlock_account_lock(lock, current);
+ return 0;
+ } else
+ return slowfn(lock, state, NULL, detect_deadlock);
+}
+
+static inline int
+rt_mutex_timed_fastlock(struct rt_mutex *lock, int state,
+ struct hrtimer_sleeper *timeout, int detect_deadlock,
+ int (*slowfn)(struct rt_mutex *lock, int state,
+ struct hrtimer_sleeper *timeout,
+ int detect_deadlock))
+{
+ if (!detect_deadlock && likely(rt_mutex_cmpxchg(lock, NULL, current))) {
+ rt_mutex_deadlock_account_lock(lock, current);
+ return 0;
+ } else
+ return slowfn(lock, state, timeout, detect_deadlock);
+}
+
+static inline int
+rt_mutex_fasttrylock(struct rt_mutex *lock,
+ int (*slowfn)(struct rt_mutex *lock))
+{
+ if (likely(rt_mutex_cmpxchg(lock, NULL, current))) {
+ rt_mutex_deadlock_account_lock(lock, current);
+ return 1;
+ }
+ return slowfn(lock);
+}
+
+static inline void
+rt_mutex_fastunlock(struct rt_mutex *lock,
+ void (*slowfn)(struct rt_mutex *lock))
+{
+ if (likely(rt_mutex_cmpxchg(lock, current, NULL)))
+ rt_mutex_deadlock_account_unlock(current);
+ else
+ slowfn(lock);
+}
+
+/**
+ * rt_mutex_lock - lock a rt_mutex
+ *
+ * @lock: the rt_mutex to be locked
+ */
+void __sched rt_mutex_lock(struct rt_mutex *lock)
+{
+ might_sleep();
+
+ rt_mutex_fastlock(lock, TASK_UNINTERRUPTIBLE, 0, rt_mutex_slowlock);
+}
+EXPORT_SYMBOL_GPL(rt_mutex_lock);
+
+/**
+ * rt_mutex_lock_interruptible - lock a rt_mutex interruptible
+ *
+ * @lock: the rt_mutex to be locked
+ * @detect_deadlock: deadlock detection on/off
+ *
+ * Returns:
+ * 0 on success
+ * -EINTR when interrupted by a signal
+ * -EDEADLK when the lock would deadlock (when deadlock detection is on)
+ */
+int __sched rt_mutex_lock_interruptible(struct rt_mutex *lock,
+ int detect_deadlock)
+{
+ might_sleep();
+
+ return rt_mutex_fastlock(lock, TASK_INTERRUPTIBLE,
+ detect_deadlock, rt_mutex_slowlock);
+}
+EXPORT_SYMBOL_GPL(rt_mutex_lock_interruptible);
+
+/**
+ * rt_mutex_timed_lock - lock a rt_mutex interruptible
+ * the timeout structure is provided
+ * by the caller
+ *
+ * @lock: the rt_mutex to be locked
+ * @timeout: timeout structure or NULL (no timeout)
+ * @detect_deadlock: deadlock detection on/off
+ *
+ * Returns:
+ * 0 on success
+ * -EINTR when interrupted by a signal
+ * -ETIMEDOUT when the timeout expired
+ * -EDEADLK when the lock would deadlock (when deadlock detection is on)
+ */
+int
+rt_mutex_timed_lock(struct rt_mutex *lock, struct hrtimer_sleeper *timeout,
+ int detect_deadlock)
+{
+ might_sleep();
+
+ return rt_mutex_timed_fastlock(lock, TASK_INTERRUPTIBLE, timeout,
+ detect_deadlock, rt_mutex_slowlock);
+}
+EXPORT_SYMBOL_GPL(rt_mutex_timed_lock);
+
+/**
+ * rt_mutex_trylock - try to lock a rt_mutex
+ *
+ * @lock: the rt_mutex to be locked
+ *
+ * Returns 1 on success and 0 on contention
+ */
+int __sched rt_mutex_trylock(struct rt_mutex *lock)
+{
+ return rt_mutex_fasttrylock(lock, rt_mutex_slowtrylock);
+}
+EXPORT_SYMBOL_GPL(rt_mutex_trylock);
+
+/**
+ * rt_mutex_unlock - unlock a rt_mutex
+ *
+ * @lock: the rt_mutex to be unlocked
+ */
+void __sched rt_mutex_unlock(struct rt_mutex *lock)
+{
+ rt_mutex_fastunlock(lock, rt_mutex_slowunlock);
+}
+EXPORT_SYMBOL_GPL(rt_mutex_unlock);
+
+/**
+ * rt_mutex_destroy - mark a mutex unusable
+ * @lock: the mutex to be destroyed
+ *
+ * This function marks the mutex uninitialized, and any subsequent
+ * use of the mutex is forbidden. The mutex must not be locked when
+ * this function is called.
+ */
+void rt_mutex_destroy(struct rt_mutex *lock)
+{
+ WARN_ON(rt_mutex_is_locked(lock));
+#ifdef CONFIG_DEBUG_RT_MUTEXES
+ lock->magic = NULL;
+#endif
+}
+
+EXPORT_SYMBOL_GPL(rt_mutex_destroy);
+
+/**
+ * __rt_mutex_init - initialize the rt lock
+ *
+ * @lock: the rt lock to be initialized
+ *
+ * Initialize the rt lock to unlocked state.
+ *
+ * Initializing of a locked rt lock is not allowed
+ */
+void __rt_mutex_init(struct rt_mutex *lock, const char *name)
+{
+ lock->owner = NULL;
+ raw_spin_lock_init(&lock->wait_lock);
+ plist_head_init(&lock->wait_list);
+
+ debug_rt_mutex_init(lock, name);
+}
+EXPORT_SYMBOL_GPL(__rt_mutex_init);
+
+/**
+ * rt_mutex_init_proxy_locked - initialize and lock a rt_mutex on behalf of a
+ * proxy owner
+ *
+ * @lock: the rt_mutex to be locked
+ * @proxy_owner:the task to set as owner
+ *
+ * No locking. Caller has to do serializing itself
+ * Special API call for PI-futex support
+ */
+void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
+ struct task_struct *proxy_owner)
+{
+ __rt_mutex_init(lock, NULL);
+ debug_rt_mutex_proxy_lock(lock, proxy_owner);
+ rt_mutex_set_owner(lock, proxy_owner);
+ rt_mutex_deadlock_account_lock(lock, proxy_owner);
+}
+
+/**
+ * rt_mutex_proxy_unlock - release a lock on behalf of owner
+ *
+ * @lock: the rt_mutex to be locked
+ *
+ * No locking. Caller has to do serializing itself
+ * Special API call for PI-futex support
+ */
+void rt_mutex_proxy_unlock(struct rt_mutex *lock,
+ struct task_struct *proxy_owner)
+{
+ debug_rt_mutex_proxy_unlock(lock);
+ rt_mutex_set_owner(lock, NULL);
+ rt_mutex_deadlock_account_unlock(proxy_owner);
+}
+
+/**
+ * rt_mutex_start_proxy_lock() - Start lock acquisition for another task
+ * @lock: the rt_mutex to take
+ * @waiter: the pre-initialized rt_mutex_waiter
+ * @task: the task to prepare
+ * @detect_deadlock: perform deadlock detection (1) or not (0)
+ *
+ * Returns:
+ * 0 - task blocked on lock
+ * 1 - acquired the lock for task, caller should wake it up
+ * <0 - error
+ *
+ * Special API call for FUTEX_REQUEUE_PI support.
+ */
+int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
+ struct rt_mutex_waiter *waiter,
+ struct task_struct *task, int detect_deadlock)
+{
+ int ret;
+
+ raw_spin_lock(&lock->wait_lock);
+
+ if (try_to_take_rt_mutex(lock, task, NULL)) {
+ raw_spin_unlock(&lock->wait_lock);
+ return 1;
+ }
+
+ ret = task_blocks_on_rt_mutex(lock, waiter, task, detect_deadlock);
+
+ if (ret && !rt_mutex_owner(lock)) {
+ /*
+ * Reset the return value. We might have
+ * returned with -EDEADLK and the owner
+ * released the lock while we were walking the
+ * pi chain. Let the waiter sort it out.
+ */
+ ret = 0;
+ }
+
+ if (unlikely(ret))
+ remove_waiter(lock, waiter);
+
+ raw_spin_unlock(&lock->wait_lock);
+
+ debug_rt_mutex_print_deadlock(waiter);
+
+ return ret;
+}
+
+/**
+ * rt_mutex_next_owner - return the next owner of the lock
+ *
+ * @lock: the rt lock query
+ *
+ * Returns the next owner of the lock or NULL
+ *
+ * Caller has to serialize against other accessors to the lock
+ * itself.
+ *
+ * Special API call for PI-futex support
+ */
+struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock)
+{
+ if (!rt_mutex_has_waiters(lock))
+ return NULL;
+
+ return rt_mutex_top_waiter(lock)->task;
+}
+
+/**
+ * rt_mutex_finish_proxy_lock() - Complete lock acquisition
+ * @lock: the rt_mutex we were woken on
+ * @to: the timeout, null if none. hrtimer should already have
+ * been started.
+ * @waiter: the pre-initialized rt_mutex_waiter
+ * @detect_deadlock: perform deadlock detection (1) or not (0)
+ *
+ * Complete the lock acquisition started our behalf by another thread.
+ *
+ * Returns:
+ * 0 - success
+ * <0 - error, one of -EINTR, -ETIMEDOUT, or -EDEADLK
+ *
+ * Special API call for PI-futex requeue support
+ */
+int rt_mutex_finish_proxy_lock(struct rt_mutex *lock,
+ struct hrtimer_sleeper *to,
+ struct rt_mutex_waiter *waiter,
+ int detect_deadlock)
+{
+ int ret;
+
+ raw_spin_lock(&lock->wait_lock);
+
+ set_current_state(TASK_INTERRUPTIBLE);
+
+ ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter);
+
+ set_current_state(TASK_RUNNING);
+
+ if (unlikely(ret))
+ remove_waiter(lock, waiter);
+
+ /*
+ * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might
+ * have to fix that up.
+ */
+ fixup_rt_mutex_waiters(lock);
+
+ raw_spin_unlock(&lock->wait_lock);
+
+ return ret;
+}
--- /dev/null
+++ b/kernel/locking/rtmutex.h
@@ -0,0 +1,26 @@
+/*
+ * RT-Mutexes: blocking mutual exclusion locks with PI support
+ *
+ * started by Ingo Molnar and Thomas Gleixner:
+ *
+ * Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ * Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
+ *
+ * This file contains macros used solely by rtmutex.c.
+ * Non-debug version.
+ */
+
+#define rt_mutex_deadlock_check(l) (0)
+#define rt_mutex_deadlock_account_lock(m, t) do { } while (0)
+#define rt_mutex_deadlock_account_unlock(l) do { } while (0)
+#define debug_rt_mutex_init_waiter(w) do { } while (0)
+#define debug_rt_mutex_free_waiter(w) do { } while (0)
+#define debug_rt_mutex_lock(l) do { } while (0)
+#define debug_rt_mutex_proxy_lock(l,p) do { } while (0)
+#define debug_rt_mutex_proxy_unlock(l) do { } while (0)
+#define debug_rt_mutex_unlock(l) do { } while (0)
+#define debug_rt_mutex_init(m, n) do { } while (0)
+#define debug_rt_mutex_deadlock(d, a ,l) do { } while (0)
+#define debug_rt_mutex_print_deadlock(w) do { } while (0)
+#define debug_rt_mutex_detect_deadlock(w,d) (d)
+#define debug_rt_mutex_reset_waiter(w) do { } while (0)
--- /dev/null
+++ b/kernel/locking/rtmutex_common.h
@@ -0,0 +1,126 @@
+/*
+ * RT Mutexes: blocking mutual exclusion locks with PI support
+ *
+ * started by Ingo Molnar and Thomas Gleixner:
+ *
+ * Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ * Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
+ *
+ * This file contains the private data structure and API definitions.
+ */
+
+#ifndef __KERNEL_RTMUTEX_COMMON_H
+#define __KERNEL_RTMUTEX_COMMON_H
+
+#include <linux/rtmutex.h>
+
+/*
+ * The rtmutex in kernel tester is independent of rtmutex debugging. We
+ * call schedule_rt_mutex_test() instead of schedule() for the tasks which
+ * belong to the tester. That way we can delay the wakeup path of those
+ * threads to provoke lock stealing and testing of complex boosting scenarios.
+ */
+#ifdef CONFIG_RT_MUTEX_TESTER
+
+extern void schedule_rt_mutex_test(struct rt_mutex *lock);
+
+#define schedule_rt_mutex(_lock) \
+ do { \
+ if (!(current->flags & PF_MUTEX_TESTER)) \
+ schedule(); \
+ else \
+ schedule_rt_mutex_test(_lock); \
+ } while (0)
+
+#else
+# define schedule_rt_mutex(_lock) schedule()
+#endif
+
+/*
+ * This is the control structure for tasks blocked on a rt_mutex,
+ * which is allocated on the kernel stack on of the blocked task.
+ *
+ * @list_entry: pi node to enqueue into the mutex waiters list
+ * @pi_list_entry: pi node to enqueue into the mutex owner waiters list
+ * @task: task reference to the blocked task
+ */
+struct rt_mutex_waiter {
+ struct plist_node list_entry;
+ struct plist_node pi_list_entry;
+ struct task_struct *task;
+ struct rt_mutex *lock;
+#ifdef CONFIG_DEBUG_RT_MUTEXES
+ unsigned long ip;
+ struct pid *deadlock_task_pid;
+ struct rt_mutex *deadlock_lock;
+#endif
+};
+
+/*
+ * Various helpers to access the waiters-plist:
+ */
+static inline int rt_mutex_has_waiters(struct rt_mutex *lock)
+{
+ return !plist_head_empty(&lock->wait_list);
+}
+
+static inline struct rt_mutex_waiter *
+rt_mutex_top_waiter(struct rt_mutex *lock)
+{
+ struct rt_mutex_waiter *w;
+
+ w = plist_first_entry(&lock->wait_list, struct rt_mutex_waiter,
+ list_entry);
+ BUG_ON(w->lock != lock);
+
+ return w;
+}
+
+static inline int task_has_pi_waiters(struct task_struct *p)
+{
+ return !plist_head_empty(&p->pi_waiters);
+}
+
+static inline struct rt_mutex_waiter *
+task_top_pi_waiter(struct task_struct *p)
+{
+ return plist_first_entry(&p->pi_waiters, struct rt_mutex_waiter,
+ pi_list_entry);
+}
+
+/*
+ * lock->owner state tracking:
+ */
+#define RT_MUTEX_HAS_WAITERS 1UL
+#define RT_MUTEX_OWNER_MASKALL 1UL
+
+static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock)
+{
+ return (struct task_struct *)
+ ((unsigned long)lock->owner & ~RT_MUTEX_OWNER_MASKALL);
+}
+
+/*
+ * PI-futex support (proxy locking functions, etc.):
+ */
+extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock);
+extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
+ struct task_struct *proxy_owner);
+extern void rt_mutex_proxy_unlock(struct rt_mutex *lock,
+ struct task_struct *proxy_owner);
+extern int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
+ struct rt_mutex_waiter *waiter,
+ struct task_struct *task,
+ int detect_deadlock);
+extern int rt_mutex_finish_proxy_lock(struct rt_mutex *lock,
+ struct hrtimer_sleeper *to,
+ struct rt_mutex_waiter *waiter,
+ int detect_deadlock);
+
+#ifdef CONFIG_DEBUG_RT_MUTEXES
+# include "rtmutex-debug.h"
+#else
+# include "rtmutex.h"
+#endif
+
+#endif
--- a/kernel/rtmutex-debug.c
+++ /dev/null
@@ -1,187 +0,0 @@
-/*
- * RT-Mutexes: blocking mutual exclusion locks with PI support
- *
- * started by Ingo Molnar and Thomas Gleixner:
- *
- * Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- * Copyright (C) 2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
- *
- * This code is based on the rt.c implementation in the preempt-rt tree.
- * Portions of said code are
- *
- * Copyright (C) 2004 LynuxWorks, Inc., Igor Manyilov, Bill Huey
- * Copyright (C) 2006 Esben Nielsen
- * Copyright (C) 2006 Kihon Technologies Inc.,
- * Steven Rostedt <rostedt@goodmis.org>
- *
- * See rt.c in preempt-rt for proper credits and further information
- */
-#include <linux/sched.h>
-#include <linux/sched/rt.h>
-#include <linux/delay.h>
-#include <linux/export.h>
-#include <linux/spinlock.h>
-#include <linux/kallsyms.h>
-#include <linux/syscalls.h>
-#include <linux/interrupt.h>
-#include <linux/plist.h>
-#include <linux/fs.h>
-#include <linux/debug_locks.h>
-
-#include "rtmutex_common.h"
-
-static void printk_task(struct task_struct *p)
-{
- if (p)
- printk("%16s:%5d [%p, %3d]", p->comm, task_pid_nr(p), p, p->prio);
- else
- printk("<none>");
-}
-
-static void printk_lock(struct rt_mutex *lock, int print_owner)
-{
- if (lock->name)
- printk(" [%p] {%s}\n",
- lock, lock->name);
- else
- printk(" [%p] {%s:%d}\n",
- lock, lock->file, lock->line);
-
- if (print_owner && rt_mutex_owner(lock)) {
- printk(".. ->owner: %p\n", lock->owner);
- printk(".. held by: ");
- printk_task(rt_mutex_owner(lock));
- printk("\n");
- }
-}
-
-void rt_mutex_debug_task_free(struct task_struct *task)
-{
- DEBUG_LOCKS_WARN_ON(!plist_head_empty(&task->pi_waiters));
- DEBUG_LOCKS_WARN_ON(task->pi_blocked_on);
-}
-
-/*
- * We fill out the fields in the waiter to store the information about
- * the deadlock. We print when we return. act_waiter can be NULL in
- * case of a remove waiter operation.
- */
-void debug_rt_mutex_deadlock(int detect, struct rt_mutex_waiter *act_waiter,
- struct rt_mutex *lock)
-{
- struct task_struct *task;
-
- if (!debug_locks || detect || !act_waiter)
- return;
-
- task = rt_mutex_owner(act_waiter->lock);
- if (task && task != current) {
- act_waiter->deadlock_task_pid = get_pid(task_pid(task));
- act_waiter->deadlock_lock = lock;
- }
-}
-
-void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter)
-{
- struct task_struct *task;
-
- if (!waiter->deadlock_lock || !debug_locks)
- return;
-
- rcu_read_lock();
- task = pid_task(waiter->deadlock_task_pid, PIDTYPE_PID);
- if (!task) {
- rcu_read_unlock();
- return;
- }
-
- if (!debug_locks_off()) {
- rcu_read_unlock();
- return;
- }
-
- printk("\n============================================\n");
- printk( "[ BUG: circular locking deadlock detected! ]\n");
- printk("%s\n", print_tainted());
- printk( "--------------------------------------------\n");
- printk("%s/%d is deadlocking current task %s/%d\n\n",
- task->comm, task_pid_nr(task),
- current->comm, task_pid_nr(current));
-
- printk("\n1) %s/%d is trying to acquire this lock:\n",
- current->comm, task_pid_nr(current));
- printk_lock(waiter->lock, 1);
-
- printk("\n2) %s/%d is blocked on this lock:\n",
- task->comm, task_pid_nr(task));
- printk_lock(waiter->deadlock_lock, 1);
-
- debug_show_held_locks(current);
- debug_show_held_locks(task);
-
- printk("\n%s/%d's [blocked] stackdump:\n\n",
- task->comm, task_pid_nr(task));
- show_stack(task, NULL);
- printk("\n%s/%d's [current] stackdump:\n\n",
- current->comm, task_pid_nr(current));
- dump_stack();
- debug_show_all_locks();
- rcu_read_unlock();
-
- printk("[ turning off deadlock detection."
- "Please report this trace. ]\n\n");
-}
-
-void debug_rt_mutex_lock(struct rt_mutex *lock)
-{
-}
-
-void debug_rt_mutex_unlock(struct rt_mutex *lock)
-{
- DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current);
-}
-
-void
-debug_rt_mutex_proxy_lock(struct rt_mutex *lock, struct task_struct *powner)
-{
-}
-
-void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock)
-{
- DEBUG_LOCKS_WARN_ON(!rt_mutex_owner(lock));
-}
-
-void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
-{
- memset(waiter, 0x11, sizeof(*waiter));
- plist_node_init(&waiter->list_entry, MAX_PRIO);
- plist_node_init(&waiter->pi_list_entry, MAX_PRIO);
- waiter->deadlock_task_pid = NULL;
-}
-
-void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter)
-{
- put_pid(waiter->deadlock_task_pid);
- DEBUG_LOCKS_WARN_ON(!plist_node_empty(&waiter->list_entry));
- DEBUG_LOCKS_WARN_ON(!plist_node_empty(&waiter->pi_list_entry));
- memset(waiter, 0x22, sizeof(*waiter));
-}
-
-void debug_rt_mutex_init(struct rt_mutex *lock, const char *name)
-{
- /*
- * Make sure we are not reinitializing a held lock:
- */
- debug_check_no_locks_freed((void *)lock, sizeof(*lock));
- lock->name = name;
-}
-
-void
-rt_mutex_deadlock_account_lock(struct rt_mutex *lock, struct task_struct *task)
-{
-}
-
-void rt_mutex_deadlock_account_unlock(struct task_struct *task)
-{
-}
-
--- a/kernel/rtmutex-debug.h
+++ /dev/null
@@ -1,33 +0,0 @@
-/*
- * RT-Mutexes: blocking mutual exclusion locks with PI support
- *
- * started by Ingo Molnar and Thomas Gleixner:
- *
- * Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- * Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
- *
- * This file contains macros used solely by rtmutex.c. Debug version.
- */
-
-extern void
-rt_mutex_deadlock_account_lock(struct rt_mutex *lock, struct task_struct *task);
-extern void rt_mutex_deadlock_account_unlock(struct task_struct *task);
-extern void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter);
-extern void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter);
-extern void debug_rt_mutex_init(struct rt_mutex *lock, const char *name);
-extern void debug_rt_mutex_lock(struct rt_mutex *lock);
-extern void debug_rt_mutex_unlock(struct rt_mutex *lock);
-extern void debug_rt_mutex_proxy_lock(struct rt_mutex *lock,
- struct task_struct *powner);
-extern void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock);
-extern void debug_rt_mutex_deadlock(int detect, struct rt_mutex_waiter *waiter,
- struct rt_mutex *lock);
-extern void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter);
-# define debug_rt_mutex_reset_waiter(w) \
- do { (w)->deadlock_lock = NULL; } while (0)
-
-static inline int debug_rt_mutex_detect_deadlock(struct rt_mutex_waiter *waiter,
- int detect)
-{
- return (waiter != NULL);
-}
--- a/kernel/rtmutex-tester.c
+++ /dev/null
@@ -1,420 +0,0 @@
-/*
- * RT-Mutex-tester: scriptable tester for rt mutexes
- *
- * started by Thomas Gleixner:
- *
- * Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
- *
- */
-#include <linux/device.h>
-#include <linux/kthread.h>
-#include <linux/export.h>
-#include <linux/sched.h>
-#include <linux/sched/rt.h>
-#include <linux/spinlock.h>
-#include <linux/timer.h>
-#include <linux/freezer.h>
-#include <linux/stat.h>
-
-#include "rtmutex.h"
-
-#define MAX_RT_TEST_THREADS 8
-#define MAX_RT_TEST_MUTEXES 8
-
-static spinlock_t rttest_lock;
-static atomic_t rttest_event;
-
-struct test_thread_data {
- int opcode;
- int opdata;
- int mutexes[MAX_RT_TEST_MUTEXES];
- int event;
- struct device dev;
-};
-
-static struct test_thread_data thread_data[MAX_RT_TEST_THREADS];
-static struct task_struct *threads[MAX_RT_TEST_THREADS];
-static struct rt_mutex mutexes[MAX_RT_TEST_MUTEXES];
-
-enum test_opcodes {
- RTTEST_NOP = 0,
- RTTEST_SCHEDOT, /* 1 Sched other, data = nice */
- RTTEST_SCHEDRT, /* 2 Sched fifo, data = prio */
- RTTEST_LOCK, /* 3 Lock uninterruptible, data = lockindex */
- RTTEST_LOCKNOWAIT, /* 4 Lock uninterruptible no wait in wakeup, data = lockindex */
- RTTEST_LOCKINT, /* 5 Lock interruptible, data = lockindex */
- RTTEST_LOCKINTNOWAIT, /* 6 Lock interruptible no wait in wakeup, data = lockindex */
- RTTEST_LOCKCONT, /* 7 Continue locking after the wakeup delay */
- RTTEST_UNLOCK, /* 8 Unlock, data = lockindex */
- /* 9, 10 - reserved for BKL commemoration */
- RTTEST_SIGNAL = 11, /* 11 Signal other test thread, data = thread id */
- RTTEST_RESETEVENT = 98, /* 98 Reset event counter */
- RTTEST_RESET = 99, /* 99 Reset all pending operations */
-};
-
-static int handle_op(struct test_thread_data *td, int lockwakeup)
-{
- int i, id, ret = -EINVAL;
-
- switch(td->opcode) {
-
- case RTTEST_NOP:
- return 0;
-
- case RTTEST_LOCKCONT:
- td->mutexes[td->opdata] = 1;
- td->event = atomic_add_return(1, &rttest_event);
- return 0;
-
- case RTTEST_RESET:
- for (i = 0; i < MAX_RT_TEST_MUTEXES; i++) {
- if (td->mutexes[i] == 4) {
- rt_mutex_unlock(&mutexes[i]);
- td->mutexes[i] = 0;
- }
- }
- return 0;
-
- case RTTEST_RESETEVENT:
- atomic_set(&rttest_event, 0);
- return 0;
-
- default:
- if (lockwakeup)
- return ret;
- }
-
- switch(td->opcode) {
-
- case RTTEST_LOCK:
- case RTTEST_LOCKNOWAIT:
- id = td->opdata;
- if (id < 0 || id >= MAX_RT_TEST_MUTEXES)
- return ret;
-
- td->mutexes[id] = 1;
- td->event = atomic_add_return(1, &rttest_event);
- rt_mutex_lock(&mutexes[id]);
- td->event = atomic_add_return(1, &rttest_event);
- td->mutexes[id] = 4;
- return 0;
-
- case RTTEST_LOCKINT:
- case RTTEST_LOCKINTNOWAIT:
- id = td->opdata;
- if (id < 0 || id >= MAX_RT_TEST_MUTEXES)
- return ret;
-
- td->mutexes[id] = 1;
- td->event = atomic_add_return(1, &rttest_event);
- ret = rt_mutex_lock_interruptible(&mutexes[id], 0);
- td->event = atomic_add_return(1, &rttest_event);
- td->mutexes[id] = ret ? 0 : 4;
- return ret ? -EINTR : 0;
-
- case RTTEST_UNLOCK:
- id = td->opdata;
- if (id < 0 || id >= MAX_RT_TEST_MUTEXES || td->mutexes[id] != 4)
- return ret;
-
- td->event = atomic_add_return(1, &rttest_event);
- rt_mutex_unlock(&mutexes[id]);
- td->event = atomic_add_return(1, &rttest_event);
- td->mutexes[id] = 0;
- return 0;
-
- default:
- break;
- }
- return ret;
-}
-
-/*
- * Schedule replacement for rtsem_down(). Only called for threads with
- * PF_MUTEX_TESTER set.
- *
- * This allows us to have finegrained control over the event flow.
- *
- */
-void schedule_rt_mutex_test(struct rt_mutex *mutex)
-{
- int tid, op, dat;
- struct test_thread_data *td;
-
- /* We have to lookup the task */
- for (tid = 0; tid < MAX_RT_TEST_THREADS; tid++) {
- if (threads[tid] == current)
- break;
- }
-
- BUG_ON(tid == MAX_RT_TEST_THREADS);
-
- td = &thread_data[tid];
-
- op = td->opcode;
- dat = td->opdata;
-
- switch (op) {
- case RTTEST_LOCK:
- case RTTEST_LOCKINT:
- case RTTEST_LOCKNOWAIT:
- case RTTEST_LOCKINTNOWAIT:
- if (mutex != &mutexes[dat])
- break;
-
- if (td->mutexes[dat] != 1)
- break;
-
- td->mutexes[dat] = 2;
- td->event = atomic_add_return(1, &rttest_event);
- break;
-
- default:
- break;
- }
-
- schedule();
-
-
- switch (op) {
- case RTTEST_LOCK:
- case RTTEST_LOCKINT:
- if (mutex != &mutexes[dat])
- return;
-
- if (td->mutexes[dat] != 2)
- return;
-
- td->mutexes[dat] = 3;
- td->event = atomic_add_return(1, &rttest_event);
- break;
-
- case RTTEST_LOCKNOWAIT:
- case RTTEST_LOCKINTNOWAIT:
- if (mutex != &mutexes[dat])
- return;
-
- if (td->mutexes[dat] != 2)
- return;
-
- td->mutexes[dat] = 1;
- td->event = atomic_add_return(1, &rttest_event);
- return;
-
- default:
- return;
- }
-
- td->opcode = 0;
-
- for (;;) {
- set_current_state(TASK_INTERRUPTIBLE);
-
- if (td->opcode > 0) {
- int ret;
-
- set_current_state(TASK_RUNNING);
- ret = handle_op(td, 1);
- set_current_state(TASK_INTERRUPTIBLE);
- if (td->opcode == RTTEST_LOCKCONT)
- break;
- td->opcode = ret;
- }
-
- /* Wait for the next command to be executed */
- schedule();
- }
-
- /* Restore previous command and data */
- td->opcode = op;
- td->opdata = dat;
-}
-
-static int test_func(void *data)
-{
- struct test_thread_data *td = data;
- int ret;
-
- current->flags |= PF_MUTEX_TESTER;
- set_freezable();
- allow_signal(SIGHUP);
-
- for(;;) {
-
- set_current_state(TASK_INTERRUPTIBLE);
-
- if (td->opcode > 0) {
- set_current_state(TASK_RUNNING);
- ret = handle_op(td, 0);
- set_current_state(TASK_INTERRUPTIBLE);
- td->opcode = ret;
- }
-
- /* Wait for the next command to be executed */
- schedule();
- try_to_freeze();
-
- if (signal_pending(current))
- flush_signals(current);
-
- if(kthread_should_stop())
- break;
- }
- return 0;
-}
-
-/**
- * sysfs_test_command - interface for test commands
- * @dev: thread reference
- * @buf: command for actual step
- * @count: length of buffer
- *
- * command syntax:
- *
- * opcode:data
- */
-static ssize_t sysfs_test_command(struct device *dev, struct device_attribute *attr,
- const char *buf, size_t count)
-{
- struct sched_param schedpar;
- struct test_thread_data *td;
- char cmdbuf[32];
- int op, dat, tid, ret;
-
- td = container_of(dev, struct test_thread_data, dev);
- tid = td->dev.id;
-
- /* strings from sysfs write are not 0 terminated! */
- if (count >= sizeof(cmdbuf))
- return -EINVAL;
-
- /* strip of \n: */
- if (buf[count-1] == '\n')
- count--;
- if (count < 1)
- return -EINVAL;
-
- memcpy(cmdbuf, buf, count);
- cmdbuf[count] = 0;
-
- if (sscanf(cmdbuf, "%d:%d", &op, &dat) != 2)
- return -EINVAL;
-
- switch (op) {
- case RTTEST_SCHEDOT:
- schedpar.sched_priority = 0;
- ret = sched_setscheduler(threads[tid], SCHED_NORMAL, &schedpar);
- if (ret)
- return ret;
- set_user_nice(current, 0);
- break;
-
- case RTTEST_SCHEDRT:
- schedpar.sched_priority = dat;
- ret = sched_setscheduler(threads[tid], SCHED_FIFO, &schedpar);
- if (ret)
- return ret;
- break;
-
- case RTTEST_SIGNAL:
- send_sig(SIGHUP, threads[tid], 0);
- break;
-
- default:
- if (td->opcode > 0)
- return -EBUSY;
- td->opdata = dat;
- td->opcode = op;
- wake_up_process(threads[tid]);
- }
-
- return count;
-}
-
-/**
- * sysfs_test_status - sysfs interface for rt tester
- * @dev: thread to query
- * @buf: char buffer to be filled with thread status info
- */
-static ssize_t sysfs_test_status(struct device *dev, struct device_attribute *attr,
- char *buf)
-{
- struct test_thread_data *td;
- struct task_struct *tsk;
- char *curr = buf;
- int i;
-
- td = container_of(dev, struct test_thread_data, dev);
- tsk = threads[td->dev.id];
-
- spin_lock(&rttest_lock);
-
- curr += sprintf(curr,
- "O: %4d, E:%8d, S: 0x%08lx, P: %4d, N: %4d, B: %p, M:",
- td->opcode, td->event, tsk->state,
- (MAX_RT_PRIO - 1) - tsk->prio,
- (MAX_RT_PRIO - 1) - tsk->normal_prio,
- tsk->pi_blocked_on);
-
- for (i = MAX_RT_TEST_MUTEXES - 1; i >=0 ; i--)
- curr += sprintf(curr, "%d", td->mutexes[i]);
-
- spin_unlock(&rttest_lock);
-
- curr += sprintf(curr, ", T: %p, R: %p\n", tsk,
- mutexes[td->dev.id].owner);
-
- return curr - buf;
-}
-
-static DEVICE_ATTR(status, S_IRUSR, sysfs_test_status, NULL);
-static DEVICE_ATTR(command, S_IWUSR, NULL, sysfs_test_command);
-
-static struct bus_type rttest_subsys = {
- .name = "rttest",
- .dev_name = "rttest",
-};
-
-static int init_test_thread(int id)
-{
- thread_data[id].dev.bus = &rttest_subsys;
- thread_data[id].dev.id = id;
-
- threads[id] = kthread_run(test_func, &thread_data[id], "rt-test-%d", id);
- if (IS_ERR(threads[id]))
- return PTR_ERR(threads[id]);
-
- return device_register(&thread_data[id].dev);
-}
-
-static int init_rttest(void)
-{
- int ret, i;
-
- spin_lock_init(&rttest_lock);
-
- for (i = 0; i < MAX_RT_TEST_MUTEXES; i++)
- rt_mutex_init(&mutexes[i]);
-
- ret = subsys_system_register(&rttest_subsys, NULL);
- if (ret)
- return ret;
-
- for (i = 0; i < MAX_RT_TEST_THREADS; i++) {
- ret = init_test_thread(i);
- if (ret)
- break;
- ret = device_create_file(&thread_data[i].dev, &dev_attr_status);
- if (ret)
- break;
- ret = device_create_file(&thread_data[i].dev, &dev_attr_command);
- if (ret)
- break;
- }
-
- printk("Initializing RT-Tester: %s\n", ret ? "Failed" : "OK" );
-
- return ret;
-}
-
-device_initcall(init_rttest);
--- a/kernel/rtmutex.c
+++ /dev/null
@@ -1,1060 +0,0 @@
-/*
- * RT-Mutexes: simple blocking mutual exclusion locks with PI support
- *
- * started by Ingo Molnar and Thomas Gleixner.
- *
- * Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- * Copyright (C) 2005-2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
- * Copyright (C) 2005 Kihon Technologies Inc., Steven Rostedt
- * Copyright (C) 2006 Esben Nielsen
- *
- * See Documentation/rt-mutex-design.txt for details.
- */
-#include <linux/spinlock.h>
-#include <linux/export.h>
-#include <linux/sched.h>
-#include <linux/sched/rt.h>
-#include <linux/timer.h>
-
-#include "rtmutex_common.h"
-
-/*
- * lock->owner state tracking:
- *
- * lock->owner holds the task_struct pointer of the owner. Bit 0
- * is used to keep track of the "lock has waiters" state.
- *
- * owner bit0
- * NULL 0 lock is free (fast acquire possible)
- * NULL 1 lock is free and has waiters and the top waiter
- * is going to take the lock*
- * taskpointer 0 lock is held (fast release possible)
- * taskpointer 1 lock is held and has waiters**
- *
- * The fast atomic compare exchange based acquire and release is only
- * possible when bit 0 of lock->owner is 0.
- *
- * (*) It also can be a transitional state when grabbing the lock
- * with ->wait_lock is held. To prevent any fast path cmpxchg to the lock,
- * we need to set the bit0 before looking at the lock, and the owner may be
- * NULL in this small time, hence this can be a transitional state.
- *
- * (**) There is a small time when bit 0 is set but there are no
- * waiters. This can happen when grabbing the lock in the slow path.
- * To prevent a cmpxchg of the owner releasing the lock, we need to
- * set this bit before looking at the lock.
- */
-
-static void
-rt_mutex_set_owner(struct rt_mutex *lock, struct task_struct *owner)
-{
- unsigned long val = (unsigned long)owner;
-
- if (rt_mutex_has_waiters(lock))
- val |= RT_MUTEX_HAS_WAITERS;
-
- lock->owner = (struct task_struct *)val;
-}
-
-static inline void clear_rt_mutex_waiters(struct rt_mutex *lock)
-{
- lock->owner = (struct task_struct *)
- ((unsigned long)lock->owner & ~RT_MUTEX_HAS_WAITERS);
-}
-
-static void fixup_rt_mutex_waiters(struct rt_mutex *lock)
-{
- if (!rt_mutex_has_waiters(lock))
- clear_rt_mutex_waiters(lock);
-}
-
-/*
- * We can speed up the acquire/release, if the architecture
- * supports cmpxchg and if there's no debugging state to be set up
- */
-#if defined(__HAVE_ARCH_CMPXCHG) && !defined(CONFIG_DEBUG_RT_MUTEXES)
-# define rt_mutex_cmpxchg(l,c,n) (cmpxchg(&l->owner, c, n) == c)
-static inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
-{
- unsigned long owner, *p = (unsigned long *) &lock->owner;
-
- do {
- owner = *p;
- } while (cmpxchg(p, owner, owner | RT_MUTEX_HAS_WAITERS) != owner);
-}
-#else
-# define rt_mutex_cmpxchg(l,c,n) (0)
-static inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
-{
- lock->owner = (struct task_struct *)
- ((unsigned long)lock->owner | RT_MUTEX_HAS_WAITERS);
-}
-#endif
-
-/*
- * Calculate task priority from the waiter list priority
- *
- * Return task->normal_prio when the waiter list is empty or when
- * the waiter is not allowed to do priority boosting
- */
-int rt_mutex_getprio(struct task_struct *task)
-{
- if (likely(!task_has_pi_waiters(task)))
- return task->normal_prio;
-
- return min(task_top_pi_waiter(task)->pi_list_entry.prio,
- task->normal_prio);
-}
-
-/*
- * Adjust the priority of a task, after its pi_waiters got modified.
- *
- * This can be both boosting and unboosting. task->pi_lock must be held.
- */
-static void __rt_mutex_adjust_prio(struct task_struct *task)
-{
- int prio = rt_mutex_getprio(task);
-
- if (task->prio != prio)
- rt_mutex_setprio(task, prio);
-}
-
-/*
- * Adjust task priority (undo boosting). Called from the exit path of
- * rt_mutex_slowunlock() and rt_mutex_slowlock().
- *
- * (Note: We do this outside of the protection of lock->wait_lock to
- * allow the lock to be taken while or before we readjust the priority
- * of task. We do not use the spin_xx_mutex() variants here as we are
- * outside of the debug path.)
- */
-static void rt_mutex_adjust_prio(struct task_struct *task)
-{
- unsigned long flags;
-
- raw_spin_lock_irqsave(&task->pi_lock, flags);
- __rt_mutex_adjust_prio(task);
- raw_spin_unlock_irqrestore(&task->pi_lock, flags);
-}
-
-/*
- * Max number of times we'll walk the boosting chain:
- */
-int max_lock_depth = 1024;
-
-/*
- * Adjust the priority chain. Also used for deadlock detection.
- * Decreases task's usage by one - may thus free the task.
- *
- * @task: the task owning the mutex (owner) for which a chain walk is probably
- * needed
- * @deadlock_detect: do we have to carry out deadlock detection?
- * @orig_lock: the mutex (can be NULL if we are walking the chain to recheck
- * things for a task that has just got its priority adjusted, and
- * is waiting on a mutex)
- * @orig_waiter: rt_mutex_waiter struct for the task that has just donated
- * its priority to the mutex owner (can be NULL in the case
- * depicted above or if the top waiter is gone away and we are
- * actually deboosting the owner)
- * @top_task: the current top waiter
- *
- * Returns 0 or -EDEADLK.
- */
-static int rt_mutex_adjust_prio_chain(struct task_struct *task,
- int deadlock_detect,
- struct rt_mutex *orig_lock,
- struct rt_mutex_waiter *orig_waiter,
- struct task_struct *top_task)
-{
- struct rt_mutex *lock;
- struct rt_mutex_waiter *waiter, *top_waiter = orig_waiter;
- int detect_deadlock, ret = 0, depth = 0;
- unsigned long flags;
-
- detect_deadlock = debug_rt_mutex_detect_deadlock(orig_waiter,
- deadlock_detect);
-
- /*
- * The (de)boosting is a step by step approach with a lot of
- * pitfalls. We want this to be preemptible and we want hold a
- * maximum of two locks per step. So we have to check
- * carefully whether things change under us.
- */
- again:
- if (++depth > max_lock_depth) {
- static int prev_max;
-
- /*
- * Print this only once. If the admin changes the limit,
- * print a new message when reaching the limit again.
- */
- if (prev_max != max_lock_depth) {
- prev_max = max_lock_depth;
- printk(KERN_WARNING "Maximum lock depth %d reached "
- "task: %s (%d)\n", max_lock_depth,
- top_task->comm, task_pid_nr(top_task));
- }
- put_task_struct(task);
-
- return deadlock_detect ? -EDEADLK : 0;
- }
- retry:
- /*
- * Task can not go away as we did a get_task() before !
- */
- raw_spin_lock_irqsave(&task->pi_lock, flags);
-
- waiter = task->pi_blocked_on;
- /*
- * Check whether the end of the boosting chain has been
- * reached or the state of the chain has changed while we
- * dropped the locks.
- */
- if (!waiter)
- goto out_unlock_pi;
-
- /*
- * Check the orig_waiter state. After we dropped the locks,
- * the previous owner of the lock might have released the lock.
- */
- if (orig_waiter && !rt_mutex_owner(orig_lock))
- goto out_unlock_pi;
-
- /*
- * Drop out, when the task has no waiters. Note,
- * top_waiter can be NULL, when we are in the deboosting
- * mode!
- */
- if (top_waiter && (!task_has_pi_waiters(task) ||
- top_waiter != task_top_pi_waiter(task)))
- goto out_unlock_pi;
-
- /*
- * When deadlock detection is off then we check, if further
- * priority adjustment is necessary.
- */
- if (!detect_deadlock && waiter->list_entry.prio == task->prio)
- goto out_unlock_pi;
-
- lock = waiter->lock;
- if (!raw_spin_trylock(&lock->wait_lock)) {
- raw_spin_unlock_irqrestore(&task->pi_lock, flags);
- cpu_relax();
- goto retry;
- }
-
- /* Deadlock detection */
- if (lock == orig_lock || rt_mutex_owner(lock) == top_task) {
- debug_rt_mutex_deadlock(deadlock_detect, orig_waiter, lock);
- raw_spin_unlock(&lock->wait_lock);
- ret = deadlock_detect ? -EDEADLK : 0;
- goto out_unlock_pi;
- }
-
- top_waiter = rt_mutex_top_waiter(lock);
-
- /* Requeue the waiter */
- plist_del(&waiter->list_entry, &lock->wait_list);
- waiter->list_entry.prio = task->prio;
- plist_add(&waiter->list_entry, &lock->wait_list);
-
- /* Release the task */
- raw_spin_unlock_irqrestore(&task->pi_lock, flags);
- if (!rt_mutex_owner(lock)) {
- /*
- * If the requeue above changed the top waiter, then we need
- * to wake the new top waiter up to try to get the lock.
- */
-
- if (top_waiter != rt_mutex_top_waiter(lock))
- wake_up_process(rt_mutex_top_waiter(lock)->task);
- raw_spin_unlock(&lock->wait_lock);
- goto out_put_task;
- }
- put_task_struct(task);
-
- /* Grab the next task */
- task = rt_mutex_owner(lock);
- get_task_struct(task);
- raw_spin_lock_irqsave(&task->pi_lock, flags);
-
- if (waiter == rt_mutex_top_waiter(lock)) {
- /* Boost the owner */
- plist_del(&top_waiter->pi_list_entry, &task->pi_waiters);
- waiter->pi_list_entry.prio = waiter->list_entry.prio;
- plist_add(&waiter->pi_list_entry, &task->pi_waiters);
- __rt_mutex_adjust_prio(task);
-
- } else if (top_waiter == waiter) {
- /* Deboost the owner */
- plist_del(&waiter->pi_list_entry, &task->pi_waiters);
- waiter = rt_mutex_top_waiter(lock);
- waiter->pi_list_entry.prio = waiter->list_entry.prio;
- plist_add(&waiter->pi_list_entry, &task->pi_waiters);
- __rt_mutex_adjust_prio(task);
- }
-
- raw_spin_unlock_irqrestore(&task->pi_lock, flags);
-
- top_waiter = rt_mutex_top_waiter(lock);
- raw_spin_unlock(&lock->wait_lock);
-
- if (!detect_deadlock && waiter != top_waiter)
- goto out_put_task;
-
- goto again;
-
- out_unlock_pi:
- raw_spin_unlock_irqrestore(&task->pi_lock, flags);
- out_put_task:
- put_task_struct(task);
-
- return ret;
-}
-
-/*
- * Try to take an rt-mutex
- *
- * Must be called with lock->wait_lock held.
- *
- * @lock: the lock to be acquired.
- * @task: the task which wants to acquire the lock
- * @waiter: the waiter that is queued to the lock's wait list. (could be NULL)
- */
-static int try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
- struct rt_mutex_waiter *waiter)
-{
- /*
- * We have to be careful here if the atomic speedups are
- * enabled, such that, when
- * - no other waiter is on the lock
- * - the lock has been released since we did the cmpxchg
- * the lock can be released or taken while we are doing the
- * checks and marking the lock with RT_MUTEX_HAS_WAITERS.
- *
- * The atomic acquire/release aware variant of
- * mark_rt_mutex_waiters uses a cmpxchg loop. After setting
- * the WAITERS bit, the atomic release / acquire can not
- * happen anymore and lock->wait_lock protects us from the
- * non-atomic case.
- *
- * Note, that this might set lock->owner =
- * RT_MUTEX_HAS_WAITERS in the case the lock is not contended
- * any more. This is fixed up when we take the ownership.
- * This is the transitional state explained at the top of this file.
- */
- mark_rt_mutex_waiters(lock);
-
- if (rt_mutex_owner(lock))
- return 0;
-
- /*
- * It will get the lock because of one of these conditions:
- * 1) there is no waiter
- * 2) higher priority than waiters
- * 3) it is top waiter
- */
- if (rt_mutex_has_waiters(lock)) {
- if (task->prio >= rt_mutex_top_waiter(lock)->list_entry.prio) {
- if (!waiter || waiter != rt_mutex_top_waiter(lock))
- return 0;
- }
- }
-
- if (waiter || rt_mutex_has_waiters(lock)) {
- unsigned long flags;
- struct rt_mutex_waiter *top;
-
- raw_spin_lock_irqsave(&task->pi_lock, flags);
-
- /* remove the queued waiter. */
- if (waiter) {
- plist_del(&waiter->list_entry, &lock->wait_list);
- task->pi_blocked_on = NULL;
- }
-
- /*
- * We have to enqueue the top waiter(if it exists) into
- * task->pi_waiters list.
- */
- if (rt_mutex_has_waiters(lock)) {
- top = rt_mutex_top_waiter(lock);
- top->pi_list_entry.prio = top->list_entry.prio;
- plist_add(&top->pi_list_entry, &task->pi_waiters);
- }
- raw_spin_unlock_irqrestore(&task->pi_lock, flags);
- }
-
- /* We got the lock. */
- debug_rt_mutex_lock(lock);
-
- rt_mutex_set_owner(lock, task);
-
- rt_mutex_deadlock_account_lock(lock, task);
-
- return 1;
-}
-
-/*
- * Task blocks on lock.
- *
- * Prepare waiter and propagate pi chain
- *
- * This must be called with lock->wait_lock held.
- */
-static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
- struct rt_mutex_waiter *waiter,
- struct task_struct *task,
- int detect_deadlock)
-{
- struct task_struct *owner = rt_mutex_owner(lock);
- struct rt_mutex_waiter *top_waiter = waiter;
- unsigned long flags;
- int chain_walk = 0, res;
-
- raw_spin_lock_irqsave(&task->pi_lock, flags);
- __rt_mutex_adjust_prio(task);
- waiter->task = task;
- waiter->lock = lock;
- plist_node_init(&waiter->list_entry, task->prio);
- plist_node_init(&waiter->pi_list_entry, task->prio);
-
- /* Get the top priority waiter on the lock */
- if (rt_mutex_has_waiters(lock))
- top_waiter = rt_mutex_top_waiter(lock);
- plist_add(&waiter->list_entry, &lock->wait_list);
-
- task->pi_blocked_on = waiter;
-
- raw_spin_unlock_irqrestore(&task->pi_lock, flags);
-
- if (!owner)
- return 0;
-
- if (waiter == rt_mutex_top_waiter(lock)) {
- raw_spin_lock_irqsave(&owner->pi_lock, flags);
- plist_del(&top_waiter->pi_list_entry, &owner->pi_waiters);
- plist_add(&waiter->pi_list_entry, &owner->pi_waiters);
-
- __rt_mutex_adjust_prio(owner);
- if (owner->pi_blocked_on)
- chain_walk = 1;
- raw_spin_unlock_irqrestore(&owner->pi_lock, flags);
- }
- else if (debug_rt_mutex_detect_deadlock(waiter, detect_deadlock))
- chain_walk = 1;
-
- if (!chain_walk)
- return 0;
-
- /*
- * The owner can't disappear while holding a lock,
- * so the owner struct is protected by wait_lock.
- * Gets dropped in rt_mutex_adjust_prio_chain()!
- */
- get_task_struct(owner);
-
- raw_spin_unlock(&lock->wait_lock);
-
- res = rt_mutex_adjust_prio_chain(owner, detect_deadlock, lock, waiter,
- task);
-
- raw_spin_lock(&lock->wait_lock);
-
- return res;
-}
-
-/*
- * Wake up the next waiter on the lock.
- *
- * Remove the top waiter from the current tasks waiter list and wake it up.
- *
- * Called with lock->wait_lock held.
- */
-static void wakeup_next_waiter(struct rt_mutex *lock)
-{
- struct rt_mutex_waiter *waiter;
- unsigned long flags;
-
- raw_spin_lock_irqsave(¤t->pi_lock, flags);
-
- waiter = rt_mutex_top_waiter(lock);
-
- /*
- * Remove it from current->pi_waiters. We do not adjust a
- * possible priority boost right now. We execute wakeup in the
- * boosted mode and go back to normal after releasing
- * lock->wait_lock.
- */
- plist_del(&waiter->pi_list_entry, ¤t->pi_waiters);
-
- rt_mutex_set_owner(lock, NULL);
-
- raw_spin_unlock_irqrestore(¤t->pi_lock, flags);
-
- wake_up_process(waiter->task);
-}
-
-/*
- * Remove a waiter from a lock and give up
- *
- * Must be called with lock->wait_lock held and
- * have just failed to try_to_take_rt_mutex().
- */
-static void remove_waiter(struct rt_mutex *lock,
- struct rt_mutex_waiter *waiter)
-{
- int first = (waiter == rt_mutex_top_waiter(lock));
- struct task_struct *owner = rt_mutex_owner(lock);
- unsigned long flags;
- int chain_walk = 0;
-
- raw_spin_lock_irqsave(¤t->pi_lock, flags);
- plist_del(&waiter->list_entry, &lock->wait_list);
- current->pi_blocked_on = NULL;
- raw_spin_unlock_irqrestore(¤t->pi_lock, flags);
-
- if (!owner)
- return;
-
- if (first) {
-
- raw_spin_lock_irqsave(&owner->pi_lock, flags);
-
- plist_del(&waiter->pi_list_entry, &owner->pi_waiters);
-
- if (rt_mutex_has_waiters(lock)) {
- struct rt_mutex_waiter *next;
-
- next = rt_mutex_top_waiter(lock);
- plist_add(&next->pi_list_entry, &owner->pi_waiters);
- }
- __rt_mutex_adjust_prio(owner);
-
- if (owner->pi_blocked_on)
- chain_walk = 1;
-
- raw_spin_unlock_irqrestore(&owner->pi_lock, flags);
- }
-
- WARN_ON(!plist_node_empty(&waiter->pi_list_entry));
-
- if (!chain_walk)
- return;
-
- /* gets dropped in rt_mutex_adjust_prio_chain()! */
- get_task_struct(owner);
-
- raw_spin_unlock(&lock->wait_lock);
-
- rt_mutex_adjust_prio_chain(owner, 0, lock, NULL, current);
-
- raw_spin_lock(&lock->wait_lock);
-}
-
-/*
- * Recheck the pi chain, in case we got a priority setting
- *
- * Called from sched_setscheduler
- */
-void rt_mutex_adjust_pi(struct task_struct *task)
-{
- struct rt_mutex_waiter *waiter;
- unsigned long flags;
-
- raw_spin_lock_irqsave(&task->pi_lock, flags);
-
- waiter = task->pi_blocked_on;
- if (!waiter || waiter->list_entry.prio == task->prio) {
- raw_spin_unlock_irqrestore(&task->pi_lock, flags);
- return;
- }
-
- raw_spin_unlock_irqrestore(&task->pi_lock, flags);
-
- /* gets dropped in rt_mutex_adjust_prio_chain()! */
- get_task_struct(task);
- rt_mutex_adjust_prio_chain(task, 0, NULL, NULL, task);
-}
-
-/**
- * __rt_mutex_slowlock() - Perform the wait-wake-try-to-take loop
- * @lock: the rt_mutex to take
- * @state: the state the task should block in (TASK_INTERRUPTIBLE
- * or TASK_UNINTERRUPTIBLE)
- * @timeout: the pre-initialized and started timer, or NULL for none
- * @waiter: the pre-initialized rt_mutex_waiter
- *
- * lock->wait_lock must be held by the caller.
- */
-static int __sched
-__rt_mutex_slowlock(struct rt_mutex *lock, int state,
- struct hrtimer_sleeper *timeout,
- struct rt_mutex_waiter *waiter)
-{
- int ret = 0;
-
- for (;;) {
- /* Try to acquire the lock: */
- if (try_to_take_rt_mutex(lock, current, waiter))
- break;
-
- /*
- * TASK_INTERRUPTIBLE checks for signals and
- * timeout. Ignored otherwise.
- */
- if (unlikely(state == TASK_INTERRUPTIBLE)) {
- /* Signal pending? */
- if (signal_pending(current))
- ret = -EINTR;
- if (timeout && !timeout->task)
- ret = -ETIMEDOUT;
- if (ret)
- break;
- }
-
- raw_spin_unlock(&lock->wait_lock);
-
- debug_rt_mutex_print_deadlock(waiter);
-
- schedule_rt_mutex(lock);
-
- raw_spin_lock(&lock->wait_lock);
- set_current_state(state);
- }
-
- return ret;
-}
-
-/*
- * Slow path lock function:
- */
-static int __sched
-rt_mutex_slowlock(struct rt_mutex *lock, int state,
- struct hrtimer_sleeper *timeout,
- int detect_deadlock)
-{
- struct rt_mutex_waiter waiter;
- int ret = 0;
-
- debug_rt_mutex_init_waiter(&waiter);
-
- raw_spin_lock(&lock->wait_lock);
-
- /* Try to acquire the lock again: */
- if (try_to_take_rt_mutex(lock, current, NULL)) {
- raw_spin_unlock(&lock->wait_lock);
- return 0;
- }
-
- set_current_state(state);
-
- /* Setup the timer, when timeout != NULL */
- if (unlikely(timeout)) {
- hrtimer_start_expires(&timeout->timer, HRTIMER_MODE_ABS);
- if (!hrtimer_active(&timeout->timer))
- timeout->task = NULL;
- }
-
- ret = task_blocks_on_rt_mutex(lock, &waiter, current, detect_deadlock);
-
- if (likely(!ret))
- ret = __rt_mutex_slowlock(lock, state, timeout, &waiter);
-
- set_current_state(TASK_RUNNING);
-
- if (unlikely(ret))
- remove_waiter(lock, &waiter);
-
- /*
- * try_to_take_rt_mutex() sets the waiter bit
- * unconditionally. We might have to fix that up.
- */
- fixup_rt_mutex_waiters(lock);
-
- raw_spin_unlock(&lock->wait_lock);
-
- /* Remove pending timer: */
- if (unlikely(timeout))
- hrtimer_cancel(&timeout->timer);
-
- debug_rt_mutex_free_waiter(&waiter);
-
- return ret;
-}
-
-/*
- * Slow path try-lock function:
- */
-static inline int
-rt_mutex_slowtrylock(struct rt_mutex *lock)
-{
- int ret = 0;
-
- raw_spin_lock(&lock->wait_lock);
-
- if (likely(rt_mutex_owner(lock) != current)) {
-
- ret = try_to_take_rt_mutex(lock, current, NULL);
- /*
- * try_to_take_rt_mutex() sets the lock waiters
- * bit unconditionally. Clean this up.
- */
- fixup_rt_mutex_waiters(lock);
- }
-
- raw_spin_unlock(&lock->wait_lock);
-
- return ret;
-}
-
-/*
- * Slow path to release a rt-mutex:
- */
-static void __sched
-rt_mutex_slowunlock(struct rt_mutex *lock)
-{
- raw_spin_lock(&lock->wait_lock);
-
- debug_rt_mutex_unlock(lock);
-
- rt_mutex_deadlock_account_unlock(current);
-
- if (!rt_mutex_has_waiters(lock)) {
- lock->owner = NULL;
- raw_spin_unlock(&lock->wait_lock);
- return;
- }
-
- wakeup_next_waiter(lock);
-
- raw_spin_unlock(&lock->wait_lock);
-
- /* Undo pi boosting if necessary: */
- rt_mutex_adjust_prio(current);
-}
-
-/*
- * debug aware fast / slowpath lock,trylock,unlock
- *
- * The atomic acquire/release ops are compiled away, when either the
- * architecture does not support cmpxchg or when debugging is enabled.
- */
-static inline int
-rt_mutex_fastlock(struct rt_mutex *lock, int state,
- int detect_deadlock,
- int (*slowfn)(struct rt_mutex *lock, int state,
- struct hrtimer_sleeper *timeout,
- int detect_deadlock))
-{
- if (!detect_deadlock && likely(rt_mutex_cmpxchg(lock, NULL, current))) {
- rt_mutex_deadlock_account_lock(lock, current);
- return 0;
- } else
- return slowfn(lock, state, NULL, detect_deadlock);
-}
-
-static inline int
-rt_mutex_timed_fastlock(struct rt_mutex *lock, int state,
- struct hrtimer_sleeper *timeout, int detect_deadlock,
- int (*slowfn)(struct rt_mutex *lock, int state,
- struct hrtimer_sleeper *timeout,
- int detect_deadlock))
-{
- if (!detect_deadlock && likely(rt_mutex_cmpxchg(lock, NULL, current))) {
- rt_mutex_deadlock_account_lock(lock, current);
- return 0;
- } else
- return slowfn(lock, state, timeout, detect_deadlock);
-}
-
-static inline int
-rt_mutex_fasttrylock(struct rt_mutex *lock,
- int (*slowfn)(struct rt_mutex *lock))
-{
- if (likely(rt_mutex_cmpxchg(lock, NULL, current))) {
- rt_mutex_deadlock_account_lock(lock, current);
- return 1;
- }
- return slowfn(lock);
-}
-
-static inline void
-rt_mutex_fastunlock(struct rt_mutex *lock,
- void (*slowfn)(struct rt_mutex *lock))
-{
- if (likely(rt_mutex_cmpxchg(lock, current, NULL)))
- rt_mutex_deadlock_account_unlock(current);
- else
- slowfn(lock);
-}
-
-/**
- * rt_mutex_lock - lock a rt_mutex
- *
- * @lock: the rt_mutex to be locked
- */
-void __sched rt_mutex_lock(struct rt_mutex *lock)
-{
- might_sleep();
-
- rt_mutex_fastlock(lock, TASK_UNINTERRUPTIBLE, 0, rt_mutex_slowlock);
-}
-EXPORT_SYMBOL_GPL(rt_mutex_lock);
-
-/**
- * rt_mutex_lock_interruptible - lock a rt_mutex interruptible
- *
- * @lock: the rt_mutex to be locked
- * @detect_deadlock: deadlock detection on/off
- *
- * Returns:
- * 0 on success
- * -EINTR when interrupted by a signal
- * -EDEADLK when the lock would deadlock (when deadlock detection is on)
- */
-int __sched rt_mutex_lock_interruptible(struct rt_mutex *lock,
- int detect_deadlock)
-{
- might_sleep();
-
- return rt_mutex_fastlock(lock, TASK_INTERRUPTIBLE,
- detect_deadlock, rt_mutex_slowlock);
-}
-EXPORT_SYMBOL_GPL(rt_mutex_lock_interruptible);
-
-/**
- * rt_mutex_timed_lock - lock a rt_mutex interruptible
- * the timeout structure is provided
- * by the caller
- *
- * @lock: the rt_mutex to be locked
- * @timeout: timeout structure or NULL (no timeout)
- * @detect_deadlock: deadlock detection on/off
- *
- * Returns:
- * 0 on success
- * -EINTR when interrupted by a signal
- * -ETIMEDOUT when the timeout expired
- * -EDEADLK when the lock would deadlock (when deadlock detection is on)
- */
-int
-rt_mutex_timed_lock(struct rt_mutex *lock, struct hrtimer_sleeper *timeout,
- int detect_deadlock)
-{
- might_sleep();
-
- return rt_mutex_timed_fastlock(lock, TASK_INTERRUPTIBLE, timeout,
- detect_deadlock, rt_mutex_slowlock);
-}
-EXPORT_SYMBOL_GPL(rt_mutex_timed_lock);
-
-/**
- * rt_mutex_trylock - try to lock a rt_mutex
- *
- * @lock: the rt_mutex to be locked
- *
- * Returns 1 on success and 0 on contention
- */
-int __sched rt_mutex_trylock(struct rt_mutex *lock)
-{
- return rt_mutex_fasttrylock(lock, rt_mutex_slowtrylock);
-}
-EXPORT_SYMBOL_GPL(rt_mutex_trylock);
-
-/**
- * rt_mutex_unlock - unlock a rt_mutex
- *
- * @lock: the rt_mutex to be unlocked
- */
-void __sched rt_mutex_unlock(struct rt_mutex *lock)
-{
- rt_mutex_fastunlock(lock, rt_mutex_slowunlock);
-}
-EXPORT_SYMBOL_GPL(rt_mutex_unlock);
-
-/**
- * rt_mutex_destroy - mark a mutex unusable
- * @lock: the mutex to be destroyed
- *
- * This function marks the mutex uninitialized, and any subsequent
- * use of the mutex is forbidden. The mutex must not be locked when
- * this function is called.
- */
-void rt_mutex_destroy(struct rt_mutex *lock)
-{
- WARN_ON(rt_mutex_is_locked(lock));
-#ifdef CONFIG_DEBUG_RT_MUTEXES
- lock->magic = NULL;
-#endif
-}
-
-EXPORT_SYMBOL_GPL(rt_mutex_destroy);
-
-/**
- * __rt_mutex_init - initialize the rt lock
- *
- * @lock: the rt lock to be initialized
- *
- * Initialize the rt lock to unlocked state.
- *
- * Initializing of a locked rt lock is not allowed
- */
-void __rt_mutex_init(struct rt_mutex *lock, const char *name)
-{
- lock->owner = NULL;
- raw_spin_lock_init(&lock->wait_lock);
- plist_head_init(&lock->wait_list);
-
- debug_rt_mutex_init(lock, name);
-}
-EXPORT_SYMBOL_GPL(__rt_mutex_init);
-
-/**
- * rt_mutex_init_proxy_locked - initialize and lock a rt_mutex on behalf of a
- * proxy owner
- *
- * @lock: the rt_mutex to be locked
- * @proxy_owner:the task to set as owner
- *
- * No locking. Caller has to do serializing itself
- * Special API call for PI-futex support
- */
-void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
- struct task_struct *proxy_owner)
-{
- __rt_mutex_init(lock, NULL);
- debug_rt_mutex_proxy_lock(lock, proxy_owner);
- rt_mutex_set_owner(lock, proxy_owner);
- rt_mutex_deadlock_account_lock(lock, proxy_owner);
-}
-
-/**
- * rt_mutex_proxy_unlock - release a lock on behalf of owner
- *
- * @lock: the rt_mutex to be locked
- *
- * No locking. Caller has to do serializing itself
- * Special API call for PI-futex support
- */
-void rt_mutex_proxy_unlock(struct rt_mutex *lock,
- struct task_struct *proxy_owner)
-{
- debug_rt_mutex_proxy_unlock(lock);
- rt_mutex_set_owner(lock, NULL);
- rt_mutex_deadlock_account_unlock(proxy_owner);
-}
-
-/**
- * rt_mutex_start_proxy_lock() - Start lock acquisition for another task
- * @lock: the rt_mutex to take
- * @waiter: the pre-initialized rt_mutex_waiter
- * @task: the task to prepare
- * @detect_deadlock: perform deadlock detection (1) or not (0)
- *
- * Returns:
- * 0 - task blocked on lock
- * 1 - acquired the lock for task, caller should wake it up
- * <0 - error
- *
- * Special API call for FUTEX_REQUEUE_PI support.
- */
-int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
- struct rt_mutex_waiter *waiter,
- struct task_struct *task, int detect_deadlock)
-{
- int ret;
-
- raw_spin_lock(&lock->wait_lock);
-
- if (try_to_take_rt_mutex(lock, task, NULL)) {
- raw_spin_unlock(&lock->wait_lock);
- return 1;
- }
-
- ret = task_blocks_on_rt_mutex(lock, waiter, task, detect_deadlock);
-
- if (ret && !rt_mutex_owner(lock)) {
- /*
- * Reset the return value. We might have
- * returned with -EDEADLK and the owner
- * released the lock while we were walking the
- * pi chain. Let the waiter sort it out.
- */
- ret = 0;
- }
-
- if (unlikely(ret))
- remove_waiter(lock, waiter);
-
- raw_spin_unlock(&lock->wait_lock);
-
- debug_rt_mutex_print_deadlock(waiter);
-
- return ret;
-}
-
-/**
- * rt_mutex_next_owner - return the next owner of the lock
- *
- * @lock: the rt lock query
- *
- * Returns the next owner of the lock or NULL
- *
- * Caller has to serialize against other accessors to the lock
- * itself.
- *
- * Special API call for PI-futex support
- */
-struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock)
-{
- if (!rt_mutex_has_waiters(lock))
- return NULL;
-
- return rt_mutex_top_waiter(lock)->task;
-}
-
-/**
- * rt_mutex_finish_proxy_lock() - Complete lock acquisition
- * @lock: the rt_mutex we were woken on
- * @to: the timeout, null if none. hrtimer should already have
- * been started.
- * @waiter: the pre-initialized rt_mutex_waiter
- * @detect_deadlock: perform deadlock detection (1) or not (0)
- *
- * Complete the lock acquisition started our behalf by another thread.
- *
- * Returns:
- * 0 - success
- * <0 - error, one of -EINTR, -ETIMEDOUT, or -EDEADLK
- *
- * Special API call for PI-futex requeue support
- */
-int rt_mutex_finish_proxy_lock(struct rt_mutex *lock,
- struct hrtimer_sleeper *to,
- struct rt_mutex_waiter *waiter,
- int detect_deadlock)
-{
- int ret;
-
- raw_spin_lock(&lock->wait_lock);
-
- set_current_state(TASK_INTERRUPTIBLE);
-
- ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter);
-
- set_current_state(TASK_RUNNING);
-
- if (unlikely(ret))
- remove_waiter(lock, waiter);
-
- /*
- * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might
- * have to fix that up.
- */
- fixup_rt_mutex_waiters(lock);
-
- raw_spin_unlock(&lock->wait_lock);
-
- return ret;
-}
--- a/kernel/rtmutex.h
+++ /dev/null
@@ -1,26 +0,0 @@
-/*
- * RT-Mutexes: blocking mutual exclusion locks with PI support
- *
- * started by Ingo Molnar and Thomas Gleixner:
- *
- * Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- * Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
- *
- * This file contains macros used solely by rtmutex.c.
- * Non-debug version.
- */
-
-#define rt_mutex_deadlock_check(l) (0)
-#define rt_mutex_deadlock_account_lock(m, t) do { } while (0)
-#define rt_mutex_deadlock_account_unlock(l) do { } while (0)
-#define debug_rt_mutex_init_waiter(w) do { } while (0)
-#define debug_rt_mutex_free_waiter(w) do { } while (0)
-#define debug_rt_mutex_lock(l) do { } while (0)
-#define debug_rt_mutex_proxy_lock(l,p) do { } while (0)
-#define debug_rt_mutex_proxy_unlock(l) do { } while (0)
-#define debug_rt_mutex_unlock(l) do { } while (0)
-#define debug_rt_mutex_init(m, n) do { } while (0)
-#define debug_rt_mutex_deadlock(d, a ,l) do { } while (0)
-#define debug_rt_mutex_print_deadlock(w) do { } while (0)
-#define debug_rt_mutex_detect_deadlock(w,d) (d)
-#define debug_rt_mutex_reset_waiter(w) do { } while (0)
--- a/kernel/rtmutex_common.h
+++ /dev/null
@@ -1,126 +0,0 @@
-/*
- * RT Mutexes: blocking mutual exclusion locks with PI support
- *
- * started by Ingo Molnar and Thomas Gleixner:
- *
- * Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- * Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
- *
- * This file contains the private data structure and API definitions.
- */
-
-#ifndef __KERNEL_RTMUTEX_COMMON_H
-#define __KERNEL_RTMUTEX_COMMON_H
-
-#include <linux/rtmutex.h>
-
-/*
- * The rtmutex in kernel tester is independent of rtmutex debugging. We
- * call schedule_rt_mutex_test() instead of schedule() for the tasks which
- * belong to the tester. That way we can delay the wakeup path of those
- * threads to provoke lock stealing and testing of complex boosting scenarios.
- */
-#ifdef CONFIG_RT_MUTEX_TESTER
-
-extern void schedule_rt_mutex_test(struct rt_mutex *lock);
-
-#define schedule_rt_mutex(_lock) \
- do { \
- if (!(current->flags & PF_MUTEX_TESTER)) \
- schedule(); \
- else \
- schedule_rt_mutex_test(_lock); \
- } while (0)
-
-#else
-# define schedule_rt_mutex(_lock) schedule()
-#endif
-
-/*
- * This is the control structure for tasks blocked on a rt_mutex,
- * which is allocated on the kernel stack on of the blocked task.
- *
- * @list_entry: pi node to enqueue into the mutex waiters list
- * @pi_list_entry: pi node to enqueue into the mutex owner waiters list
- * @task: task reference to the blocked task
- */
-struct rt_mutex_waiter {
- struct plist_node list_entry;
- struct plist_node pi_list_entry;
- struct task_struct *task;
- struct rt_mutex *lock;
-#ifdef CONFIG_DEBUG_RT_MUTEXES
- unsigned long ip;
- struct pid *deadlock_task_pid;
- struct rt_mutex *deadlock_lock;
-#endif
-};
-
-/*
- * Various helpers to access the waiters-plist:
- */
-static inline int rt_mutex_has_waiters(struct rt_mutex *lock)
-{
- return !plist_head_empty(&lock->wait_list);
-}
-
-static inline struct rt_mutex_waiter *
-rt_mutex_top_waiter(struct rt_mutex *lock)
-{
- struct rt_mutex_waiter *w;
-
- w = plist_first_entry(&lock->wait_list, struct rt_mutex_waiter,
- list_entry);
- BUG_ON(w->lock != lock);
-
- return w;
-}
-
-static inline int task_has_pi_waiters(struct task_struct *p)
-{
- return !plist_head_empty(&p->pi_waiters);
-}
-
-static inline struct rt_mutex_waiter *
-task_top_pi_waiter(struct task_struct *p)
-{
- return plist_first_entry(&p->pi_waiters, struct rt_mutex_waiter,
- pi_list_entry);
-}
-
-/*
- * lock->owner state tracking:
- */
-#define RT_MUTEX_HAS_WAITERS 1UL
-#define RT_MUTEX_OWNER_MASKALL 1UL
-
-static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock)
-{
- return (struct task_struct *)
- ((unsigned long)lock->owner & ~RT_MUTEX_OWNER_MASKALL);
-}
-
-/*
- * PI-futex support (proxy locking functions, etc.):
- */
-extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock);
-extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
- struct task_struct *proxy_owner);
-extern void rt_mutex_proxy_unlock(struct rt_mutex *lock,
- struct task_struct *proxy_owner);
-extern int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
- struct rt_mutex_waiter *waiter,
- struct task_struct *task,
- int detect_deadlock);
-extern int rt_mutex_finish_proxy_lock(struct rt_mutex *lock,
- struct hrtimer_sleeper *to,
- struct rt_mutex_waiter *waiter,
- int detect_deadlock);
-
-#ifdef CONFIG_DEBUG_RT_MUTEXES
-# include "rtmutex-debug.h"
-#else
-# include "rtmutex.h"
-#endif
-
-#endif
^ permalink raw reply [flat|nested] 23+ messages in thread