[patch] generic rwsems

Nick Piggin
2007-04-13T10:04:16Z

OK, this patch is against 2.6.21-rc6 + Mathieu's atomic_long patches.

Last time this came up I was asked to get some numbers, so here are
some in the changelog, captured with a simple kernel module tester.
I got motivated again because of the MySQL/glibc/mmap_sem issue.

This patch converts all architectures to a generic rwsem implementation,
which will compile down to the same code for i386, or powerpc, for
example, and will allow some (eg. x86-64) to move away from spinlock
based rwsems.

Comments?
--

Move to an architecture independent rwsem implementation, using the
better of the two rwsem implementations (ie. the one which doesn't
take a spinlock to take an uncontested rwsem) as a basis. This gives
us a single rwsem design instead of two.

Use high level atomic primitives for the implementation, rather than
open coded assembly. This gives us a single implementation, rather
than a handful.

Use atomic_long_t rather than atomic_t for the count, which solves
the parallelism limitation for those architectures (actually found
to be a problem with ia64, powerpc and x86-64 may not be far behind).

Remove one level of indirection (kernel/rwsem.c -> lib/rwsem.c), and
give a bit of a cleanup (eg remove the fastcall junk) to make the
code a bit easier to read.

Out-of-line the fastpaths, to bring rw-semaphores into line with
mutexes and spinlocks WRT our icache vs function call policy.

Test system is a 16 core 8 socket Opteron. Numbers are the total
number of lock/unlock pairs performed in a given time -- 10s for
single-thread tests, 30s for others. 1r/0w means 1 read locker
and 0 write locker threads, "generic" is patched kernel, and "irq"
is plain kernel but with _irq* removed from rwsem spinlocks because
otherwise all the multi-threaded tests start losing timer interrupts
due to spinlock contention and measurements go silly.

Spinlock based rwsems are inferior to atomic based ones one most
architectures that can do atomic ops without spinlocks:

- The atomic version is faster (on x86_64) by more than 2 times in
single threaded performance.

1r/0w 0r/1w
irq 115577784 131483401
generic 270112870 264038942

- The spinlock based rwsem can gather a lot of spinlock contention
even when only rwsem readers are present (eg. threaded malloc/free
workload after glibc gets converted to use MADV_DONTNEED).
Throughput is improved by a factor of 4 with 16 cores.

16r/0w 0r/16w
irq 52793019 7752277
generic 199174486 7750554

- At high concurrencies, with both readers and writers, the spinlock
in the fastpath can get tangled up with the spinlock in the slow
wakeup path. This is also a reason why atomic based rwsems will be
better even for architectures that do atomics with hashed spinlocks.

At 16 readers and 1 writer, reader throughput goes up by an order of
magnitude and writer throughput increases significantly. At 128
readers and 4 writers, throughput goes up by more than double for both
readers and writers.

16r/1w 128r/4w
irq 13084481/265663 5233988/256034
generic 104505771/349811 11963683/554682

Signed-off-by: Nick Piggin <npiggin@suse.de>

arch/alpha/Kconfig | 7
arch/arm/Kconfig | 7
arch/arm26/Kconfig | 7
arch/cris/Kconfig | 7
arch/frv/Kconfig | 7
arch/h8300/Kconfig | 8
arch/i386/Kconfig.cpu | 10
arch/ia64/Kconfig | 4
arch/m32r/Kconfig | 9
arch/m68k/Kconfig | 7
arch/m68knommu/Kconfig | 8
arch/mips/Kconfig | 11 -
arch/parisc/Kconfig | 6
arch/powerpc/Kconfig | 7
arch/ppc/Kconfig | 7
arch/s390/Kconfig | 7
arch/sh/Kconfig | 7
arch/sh64/Kconfig | 7
arch/sparc/Kconfig | 7
arch/sparc/lib/rwsem.S | 204 --------------------
arch/sparc64/Kconfig | 7
arch/sparc64/lib/rwsem.S | 170 ----------------
arch/um/Kconfig.x86_64 | 4
arch/v850/Kconfig | 6
arch/x86_64/Kconfig | 7
arch/xtensa/Kconfig | 4
include/asm-alpha/rwsem.h | 259 -------------------------
include/asm-i386/rwsem.h | 258 -------------------------
include/asm-ia64/rwsem.h | 178 -----------------
include/asm-powerpc/rwsem.h | 152 --------------
include/asm-s390/rwsem.h | 387 --------------------------------------
include/asm-sh/rwsem.h | 184 ------------------
include/asm-sparc64/rwsem-const.h | 12 -
include/asm-sparc64/rwsem.h | 84 --------
include/asm-um/rwsem.h | 6
include/asm-xtensa/rwsem.h | 164 ----------------
include/linux/rwsem-spinlock.h | 78 -------
include/linux/rwsem.h | 62 +++++-
kernel/rwsem.c | 320 ++++++++++++++++++++++++++++++-
lib/Makefile | 2
lib/rwsem-spinlock.c | 316 -------------------------------
lib/rwsem.c | 257 -------------------------
42 files changed, 364 insertions(+), 2897 deletions(-)

Index: linux-2.6/include/asm-powerpc/rwsem.h
===================================================================
--- linux-2.6.orig/include/asm-powerpc/rwsem.h
+++ /dev/null
@@ -1,152 +0,0 @@
-#ifndef _ASM_POWERPC_RWSEM_H
-#define _ASM_POWERPC_RWSEM_H
-
-#ifdef __KERNEL__
-
-/*
- * include/asm-powerpc/rwsem.h: R/W semaphores for PPC using the stuff
- * in lib/rwsem.c. Adapted largely from include/asm-i386/rwsem.h
- * by Paul Mackerras <paulus@samba.org>.
- */
-
-#include <linux/list.h>
-#include <linux/spinlock.h>
-#include <asm/atomic.h>
-#include <asm/system.h>
-
-/*
- * the semaphore definition
- */
-struct rw_semaphore {
- /* XXX this should be able to be an atomic_t -- paulus */
- signed int count;
-#define RWSEM_UNLOCKED_VALUE 0x00000000
-#define RWSEM_ACTIVE_BIAS 0x00000001
-#define RWSEM_ACTIVE_MASK 0x0000ffff
-#define RWSEM_WAITING_BIAS (-0x00010000)
-#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS
-#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)
- spinlock_t wait_lock;
- struct list_head wait_list;
-};
-
-#define __RWSEM_INITIALIZER(name) \
- { RWSEM_UNLOCKED_VALUE, SPIN_LOCK_UNLOCKED, \
- LIST_HEAD_INIT((name).wait_list) }
-
-#define DECLARE_RWSEM(name) \
- struct rw_semaphore name = __RWSEM_INITIALIZER(name)
-
-extern struct rw_semaphore *rwsem_down_read_failed(struct rw_semaphore *sem);
-extern struct rw_semaphore *rwsem_down_write_failed(struct rw_semaphore *sem);
-extern struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem);
-extern struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem);
-
-static inline void init_rwsem(struct rw_semaphore *sem)
-{
- sem->count = RWSEM_UNLOCKED_VALUE;
- spin_lock_init(&sem->wait_lock);
- INIT_LIST_HEAD(&sem->wait_list);
-}
-
-/*
- * lock for reading
- */
-static inline void __down_read(struct rw_semaphore *sem)
-{
- if (unlikely(atomic_inc_return((atomic_t *)(&sem->count)) <= 0))
- rwsem_down_read_failed(sem);
-}
-
-static inline int __down_read_trylock(struct rw_semaphore *sem)
-{
- int tmp;
-
- while ((tmp = sem->count) >= 0) {
- if (tmp == cmpxchg(&sem->count, tmp,
- tmp + RWSEM_ACTIVE_READ_BIAS)) {
- return 1;
- }
- }
- return 0;
-}
-
-/*
- * lock for writing
- */
-static inline void __down_write(struct rw_semaphore *sem)
-{
- int tmp;
-
- tmp = atomic_add_return(RWSEM_ACTIVE_WRITE_BIAS,
- (atomic_t *)(&sem->count));
- if (unlikely(tmp != RWSEM_ACTIVE_WRITE_BIAS))
- rwsem_down_write_failed(sem);
-}
-
-static inline int __down_write_trylock(struct rw_semaphore *sem)
-{
- int tmp;
-
- tmp = cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE,
- RWSEM_ACTIVE_WRITE_BIAS);
- return tmp == RWSEM_UNLOCKED_VALUE;
-}
-
-/*
- * unlock after reading
- */
-static inline void __up_read(struct rw_semaphore *sem)
-{
- int tmp;
-
- tmp = atomic_dec_return((atomic_t *)(&sem->count));
- if (unlikely(tmp < -1 && (tmp & RWSEM_ACTIVE_MASK) == 0))
- rwsem_wake(sem);
-}
-
-/*
- * unlock after writing
- */
-static inline void __up_write(struct rw_semaphore *sem)
-{
- if (unlikely(atomic_sub_return(RWSEM_ACTIVE_WRITE_BIAS,
- (atomic_t *)(&sem->count)) < 0))
- rwsem_wake(sem);
-}
-
-/*
- * implement atomic add functionality
- */
-static inline void rwsem_atomic_add(int delta, struct rw_semaphore *sem)
-{
- atomic_add(delta, (atomic_t *)(&sem->count));
-}
-
-/*
- * downgrade write lock to read lock
- */
-static inline void __downgrade_write(struct rw_semaphore *sem)
-{
- int tmp;
-
- tmp = atomic_add_return(-RWSEM_WAITING_BIAS, (atomic_t *)(&sem->count));
- if (tmp < 0)
- rwsem_downgrade_wake(sem);
-}
-
-/*
- * implement exchange and add functionality
- */
-static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem)
-{
- return atomic_add_return(delta, (atomic_t *)(&sem->count));
-}
-
-static inline int rwsem_is_locked(struct rw_semaphore *sem)
-{
- return (sem->count != 0);
-}
-
-#endif /* __KERNEL__ */
-#endif /* _ASM_POWERPC_RWSEM_H */
Index: linux-2.6/include/linux/rwsem.h
===================================================================
--- linux-2.6.orig/include/linux/rwsem.h
+++ linux-2.6/include/linux/rwsem.h
@@ -1,9 +1,19 @@
-/* rwsem.h: R/W semaphores, public interface
+/*
+ * rwsem.h: R/W semaphores, public interface
*
* Written by David Howells (dhowells@redhat.com).
* Derived from asm-i386/semaphore.h
+ *
+ * Also by:
+ * Paul Mackerras <paulus@samba.org>
+ * Nick Piggin <npiggin@suse.de>
+ *
+ * These semaphores are strictly FIFO - if anything is waiting, a process that
+ * wants a lock will go to the back of the queue. When the currently active
+ * lock is released, if there's a writer at the front of the queue, then that
+ * and only that will be woken up; if there's a bunch of consecutive readers at
+ * the front, then they'll all be woken up, but no other readers will be.
*/
-
#ifndef _LINUX_RWSEM_H
#define _LINUX_RWSEM_H

@@ -13,17 +23,57 @@

#include <linux/types.h>
#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/lockdep.h>
+#include <linux/spinlock.h>
#include <asm/system.h>
#include <asm/atomic.h>

-struct rw_semaphore;
+#define RWSEM_UNLOCKED_VALUE 0x00000000L
+
+/*
+ * the semaphore definition
+ */
+struct rw_semaphore {
+ atomic_long_t count;
+ spinlock_t wait_lock;
+ struct list_head wait_list;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ struct lockdep_map dep_map;
+#endif
+};

-#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
-#include <linux/rwsem-spinlock.h> /* use a generic implementation */
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+# define __RWSEM_DEP_MAP_INIT(lockname) .dep_map = { .name = #lockname }
#else
-#include <asm/rwsem.h> /* use an arch-specific implementation */
+# define __RWSEM_DEP_MAP_INIT(lockname)
#endif

+
+#define __RWSEM_INITIALIZER(name) \
+{ ATOMIC_LONG_INIT(RWSEM_UNLOCKED_VALUE), \
+ __SPIN_LOCK_UNLOCKED((name).wait_lock), \
+ LIST_HEAD_INIT((name).wait_list), \
+ __RWSEM_DEP_MAP_INIT(name) }
+
+#define DECLARE_RWSEM(name) \
+ struct rw_semaphore name = __RWSEM_INITIALIZER(name)
+
+extern void __init_rwsem(struct rw_semaphore *sem, const char *name,
+ struct lock_class_key *key);
+
+#define init_rwsem(sem) \
+do { \
+ static struct lock_class_key __key; \
+ \
+ __init_rwsem((sem), #sem, &__key); \
+} while (0)
+
+static inline int rwsem_is_locked(struct rw_semaphore *sem)
+{
+ return (atomic_long_read(&sem->count) != 0);
+}
+
/*
* lock for reading
*/
Index: linux-2.6/lib/rwsem-spinlock.c
===================================================================
--- linux-2.6.orig/lib/rwsem-spinlock.c
+++ /dev/null
@@ -1,316 +0,0 @@
-/* rwsem-spinlock.c: R/W semaphores: contention handling functions for
- * generic spinlock implementation
- *
- * Copyright (c) 2001 David Howells (dhowells@redhat.com).
- * - Derived partially from idea by Andrea Arcangeli <andrea@suse.de>
- * - Derived also from comments by Linus
- */
-#include <linux/rwsem.h>
-#include <linux/sched.h>
-#include <linux/module.h>
-
-struct rwsem_waiter {
- struct list_head list;
- struct task_struct *task;
- unsigned int flags;
-#define RWSEM_WAITING_FOR_READ 0x00000001
-#define RWSEM_WAITING_FOR_WRITE 0x00000002
-};
-
-/*
- * initialise the semaphore
- */
-void __init_rwsem(struct rw_semaphore *sem, const char *name,
- struct lock_class_key *key)
-{
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
- /*
- * Make sure we are not reinitializing a held semaphore:
- */
- debug_check_no_locks_freed((void *)sem, sizeof(*sem));
- lockdep_init_map(&sem->dep_map, name, key, 0);
-#endif
- sem->activity = 0;
- spin_lock_init(&sem->wait_lock);
- INIT_LIST_HEAD(&sem->wait_list);
-}
-
-/*
- * handle the lock release when processes blocked on it that can now run
- * - if we come here, then:
- * - the 'active count' _reached_ zero
- * - the 'waiting count' is non-zero
- * - the spinlock must be held by the caller
- * - woken process blocks are discarded from the list after having task zeroed
- * - writers are only woken if wakewrite is non-zero
- */
-static inline struct rw_semaphore *
-__rwsem_do_wake(struct rw_semaphore *sem, int wakewrite)
-{
- struct rwsem_waiter *waiter;
- struct task_struct *tsk;
- int woken;
-
- waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list);
-
- if (!wakewrite) {
- if (waiter->flags & RWSEM_WAITING_FOR_WRITE)
- goto out;
- goto dont_wake_writers;
- }
-
- /* if we are allowed to wake writers try to grant a single write lock
- * if there's a writer at the front of the queue
- * - we leave the 'waiting count' incremented to signify potential
- * contention
- */
- if (waiter->flags & RWSEM_WAITING_FOR_WRITE) {
- sem->activity = -1;
- list_del(&waiter->list);
- tsk = waiter->task;
- /* Don't touch waiter after ->task has been NULLed */
- smp_mb();
- waiter->task = NULL;
- wake_up_process(tsk);
- put_task_struct(tsk);
- goto out;
- }
-
- /* grant an infinite number of read locks to the front of the queue */
- dont_wake_writers:
- woken = 0;
- while (waiter->flags & RWSEM_WAITING_FOR_READ) {
- struct list_head *next = waiter->list.next;
-
- list_del(&waiter->list);
- tsk = waiter->task;
- smp_mb();
- waiter->task = NULL;
- wake_up_process(tsk);
- put_task_struct(tsk);
- woken++;
- if (list_empty(&sem->wait_list))
- break;
- waiter = list_entry(next, struct rwsem_waiter, list);
- }
-
- sem->activity += woken;
-
- out:
- return sem;
-}
-
-/*
- * wake a single writer
- */
-static inline struct rw_semaphore *
-__rwsem_wake_one_writer(struct rw_semaphore *sem)
-{
- struct rwsem_waiter *waiter;
- struct task_struct *tsk;
-
- sem->activity = -1;
-
- waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list);
- list_del(&waiter->list);
-
- tsk = waiter->task;
- smp_mb();
- waiter->task = NULL;
- wake_up_process(tsk);
- put_task_struct(tsk);
- return sem;
-}
-
-/*
- * get a read lock on the semaphore
- */
-void fastcall __sched __down_read(struct rw_semaphore *sem)
-{
- struct rwsem_waiter waiter;
- struct task_struct *tsk;
-
- spin_lock_irq(&sem->wait_lock);
-
- if (sem->activity >= 0 && list_empty(&sem->wait_list)) {
- /* granted */
- sem->activity++;
- spin_unlock_irq(&sem->wait_lock);
- goto out;
- }
-
- tsk = current;
- set_task_state(tsk, TASK_UNINTERRUPTIBLE);
-
- /* set up my own style of waitqueue */
- waiter.task = tsk;
- waiter.flags = RWSEM_WAITING_FOR_READ;
- get_task_struct(tsk);
-
- list_add_tail(&waiter.list, &sem->wait_list);
-
- /* we don't need to touch the semaphore struct anymore */
- spin_unlock_irq(&sem->wait_lock);
-
- /* wait to be given the lock */
- for (;;) {
- if (!waiter.task)
- break;
- schedule();
- set_task_state(tsk, TASK_UNINTERRUPTIBLE);
- }
-
- tsk->state = TASK_RUNNING;
- out:
- ;
-}
-
-/*
- * trylock for reading -- returns 1 if successful, 0 if contention
- */
-int fastcall __down_read_trylock(struct rw_semaphore *sem)
-{
- unsigned long flags;
- int ret = 0;
-
-
- spin_lock_irqsave(&sem->wait_lock, flags);
-
- if (sem->activity >= 0 && list_empty(&sem->wait_list)) {
- /* granted */
- sem->activity++;
- ret = 1;
- }
-
- spin_unlock_irqrestore(&sem->wait_lock, flags);
-
- return ret;
-}
-
-/*
- * get a write lock on the semaphore
- * - we increment the waiting count anyway to indicate an exclusive lock
- */
-void fastcall __sched __down_write_nested(struct rw_semaphore *sem, int subclass)
-{
- struct rwsem_waiter waiter;
- struct task_struct *tsk;
-
- spin_lock_irq(&sem->wait_lock);
-
- if (sem->activity == 0 && list_empty(&sem->wait_list)) {
- /* granted */
- sem->activity = -1;
- spin_unlock_irq(&sem->wait_lock);
- goto out;
- }
-
- tsk = current;
- set_task_state(tsk, TASK_UNINTERRUPTIBLE);
-
- /* set up my own style of waitqueue */
- waiter.task = tsk;
- waiter.flags = RWSEM_WAITING_FOR_WRITE;
- get_task_struct(tsk);
-
- list_add_tail(&waiter.list, &sem->wait_list);
-
- /* we don't need to touch the semaphore struct anymore */
- spin_unlock_irq(&sem->wait_lock);
-
- /* wait to be given the lock */
- for (;;) {
- if (!waiter.task)
- break;
- schedule();
- set_task_state(tsk, TASK_UNINTERRUPTIBLE);
- }
-
- tsk->state = TASK_RUNNING;
- out:
- ;
-}
-
-void fastcall __sched __down_write(struct rw_semaphore *sem)
-{
- __down_write_nested(sem, 0);
-}
-
-/*
- * trylock for writing -- returns 1 if successful, 0 if contention
- */
-int fastcall __down_write_trylock(struct rw_semaphore *sem)
-{
- unsigned long flags;
- int ret = 0;
-
- spin_lock_irqsave(&sem->wait_lock, flags);
-
- if (sem->activity == 0 && list_empty(&sem->wait_list)) {
- /* granted */
- sem->activity = -1;
- ret = 1;
- }
-
- spin_unlock_irqrestore(&sem->wait_lock, flags);
-
- return ret;
-}
-
-/*
- * release a read lock on the semaphore
- */
-void fastcall __up_read(struct rw_semaphore *sem)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&sem->wait_lock, flags);
-
- if (--sem->activity == 0 && !list_empty(&sem->wait_list))
- sem = __rwsem_wake_one_writer(sem);
-
- spin_unlock_irqrestore(&sem->wait_lock, flags);
-}
-
-/*
- * release a write lock on the semaphore
- */
-void fastcall __up_write(struct rw_semaphore *sem)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&sem->wait_lock, flags);
-
- sem->activity = 0;
- if (!list_empty(&sem->wait_list))
- sem = __rwsem_do_wake(sem, 1);
-
- spin_unlock_irqrestore(&sem->wait_lock, flags);
-}
-
-/*
- * downgrade a write lock into a read lock
- * - just wake up any readers at the front of the queue
- */
-void fastcall __downgrade_write(struct rw_semaphore *sem)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&sem->wait_lock, flags);
-
- sem->activity = 1;
- if (!list_empty(&sem->wait_list))
- sem = __rwsem_do_wake(sem, 0);
-
- spin_unlock_irqrestore(&sem->wait_lock, flags);
-}
-
-EXPORT_SYMBOL(__init_rwsem);
-EXPORT_SYMBOL(__down_read);
-EXPORT_SYMBOL(__down_read_trylock);
-EXPORT_SYMBOL(__down_write_nested);
-EXPORT_SYMBOL(__down_write);
-EXPORT_SYMBOL(__down_write_trylock);
-EXPORT_SYMBOL(__up_read);
-EXPORT_SYMBOL(__up_write);
-EXPORT_SYMBOL(__downgrade_write);
Index: linux-2.6/include/asm-alpha/rwsem.h
===================================================================
--- linux-2.6.orig/include/asm-alpha/rwsem.h
+++ /dev/null
@@ -1,259 +0,0 @@
-#ifndef _ALPHA_RWSEM_H
-#define _ALPHA_RWSEM_H
-
-/*
- * Written by Ivan Kokshaysky <ink@jurassic.park.msu.ru>, 2001.
- * Based on asm-alpha/semaphore.h and asm-i386/rwsem.h
- */
-
-#ifndef _LINUX_RWSEM_H
-#error "please don't include asm/rwsem.h directly, use linux/rwsem.h instead"
-#endif
-
-#ifdef __KERNEL__
-
-#include <linux/compiler.h>
-#include <linux/list.h>
-#include <linux/spinlock.h>
-
-struct rwsem_waiter;
-
-extern struct rw_semaphore *rwsem_down_read_failed(struct rw_semaphore *sem);
-extern struct rw_semaphore *rwsem_down_write_failed(struct rw_semaphore *sem);
-extern struct rw_semaphore *rwsem_wake(struct rw_semaphore *);
-extern struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem);
-
-/*
- * the semaphore definition
- */
-struct rw_semaphore {
- long count;
-#define RWSEM_UNLOCKED_VALUE 0x0000000000000000L
-#define RWSEM_ACTIVE_BIAS 0x0000000000000001L
-#define RWSEM_ACTIVE_MASK 0x00000000ffffffffL
-#define RWSEM_WAITING_BIAS (-0x0000000100000000L)
-#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS
-#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)
- spinlock_t wait_lock;
- struct list_head wait_list;
-};
-
-#define __RWSEM_INITIALIZER(name) \
- { RWSEM_UNLOCKED_VALUE, SPIN_LOCK_UNLOCKED, \
- LIST_HEAD_INIT((name).wait_list) }
-
-#define DECLARE_RWSEM(name) \
- struct rw_semaphore name = __RWSEM_INITIALIZER(name)
-
-static inline void init_rwsem(struct rw_semaphore *sem)
-{
- sem->count = RWSEM_UNLOCKED_VALUE;
- spin_lock_init(&sem->wait_lock);
- INIT_LIST_HEAD(&sem->wait_list);
-}
-
-static inline void __down_read(struct rw_semaphore *sem)
-{
- long oldcount;
-#ifndef CONFIG_SMP
- oldcount = sem->count;
- sem->count += RWSEM_ACTIVE_READ_BIAS;
-#else
- long temp;
- __asm__ __volatile__(
- "1: ldq_l %0,%1\n"
- " addq %0,%3,%2\n"
- " stq_c %2,%1\n"
- " beq %2,2f\n"
- " mb\n"
- ".subsection 2\n"
- "2: br 1b\n"
- ".previous"
- :"=&r" (oldcount), "=m" (sem->count), "=&r" (temp)
- :"Ir" (RWSEM_ACTIVE_READ_BIAS), "m" (sem->count) : "memory");
-#endif
- if (unlikely(oldcount < 0))
- rwsem_down_read_failed(sem);
-}
-
-/*
- * trylock for reading -- returns 1 if successful, 0 if contention
- */
-static inline int __down_read_trylock(struct rw_semaphore *sem)
-{
- long old, new, res;
-
- res = sem->count;
- do {
- new = res + RWSEM_ACTIVE_READ_BIAS;
- if (new <= 0)
- break;
- old = res;
- res = cmpxchg(&sem->count, old, new);
- } while (res != old);
- return res >= 0 ? 1 : 0;
-}
-
-static inline void __down_write(struct rw_semaphore *sem)
-{
- long oldcount;
-#ifndef CONFIG_SMP
- oldcount = sem->count;
- sem->count += RWSEM_ACTIVE_WRITE_BIAS;
-#else
- long temp;
- __asm__ __volatile__(
- "1: ldq_l %0,%1\n"
- " addq %0,%3,%2\n"
- " stq_c %2,%1\n"
- " beq %2,2f\n"
- " mb\n"
- ".subsection 2\n"
- "2: br 1b\n"
- ".previous"
- :"=&r" (oldcount), "=m" (sem->count), "=&r" (temp)
- :"Ir" (RWSEM_ACTIVE_WRITE_BIAS), "m" (sem->count) : "memory");
-#endif
- if (unlikely(oldcount))
- rwsem_down_write_failed(sem);
-}
-
-/*
- * trylock for writing -- returns 1 if successful, 0 if contention
- */
-static inline int __down_write_trylock(struct rw_semaphore *sem)
-{
- long ret = cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE,
- RWSEM_ACTIVE_WRITE_BIAS);
- if (ret == RWSEM_UNLOCKED_VALUE)
- return 1;
- return 0;
-}
-
-static inline void __up_read(struct rw_semaphore *sem)
-{
- long oldcount;
-#ifndef CONFIG_SMP
- oldcount = sem->count;
- sem->count -= RWSEM_ACTIVE_READ_BIAS;
-#else
- long temp;
- __asm__ __volatile__(
- " mb\n"
- "1: ldq_l %0,%1\n"
- " subq %0,%3,%2\n"
- " stq_c %2,%1\n"
- " beq %2,2f\n"
- ".subsection 2\n"
- "2: br 1b\n"
- ".previous"
- :"=&r" (oldcount), "=m" (sem->count), "=&r" (temp)
- :"Ir" (RWSEM_ACTIVE_READ_BIAS), "m" (sem->count) : "memory");
-#endif
- if (unlikely(oldcount < 0))
- if ((int)oldcount - RWSEM_ACTIVE_READ_BIAS == 0)
- rwsem_wake(sem);
-}
-
-static inline void __up_write(struct rw_semaphore *sem)
-{
- long count;
-#ifndef CONFIG_SMP
- sem->count -= RWSEM_ACTIVE_WRITE_BIAS;
- count = sem->count;
-#else
- long temp;
- __asm__ __volatile__(
- " mb\n"
- "1: ldq_l %0,%1\n"
- " subq %0,%3,%2\n"
- " stq_c %2,%1\n"
- " beq %2,2f\n"
- " subq %0,%3,%0\n"
- ".subsection 2\n"
- "2: br 1b\n"
- ".previous"
- :"=&r" (count), "=m" (sem->count), "=&r" (temp)
- :"Ir" (RWSEM_ACTIVE_WRITE_BIAS), "m" (sem->count) : "memory");
-#endif
- if (unlikely(count))
- if ((int)count == 0)
- rwsem_wake(sem);
-}
-
-/*
- * downgrade write lock to read lock
- */
-static inline void __downgrade_write(struct rw_semaphore *sem)
-{
- long oldcount;
-#ifndef CONFIG_SMP
- oldcount = sem->count;
- sem->count -= RWSEM_WAITING_BIAS;
-#else
- long temp;
- __asm__ __volatile__(
- "1: ldq_l %0,%1\n"
- " addq %0,%3,%2\n"
- " stq_c %2,%1\n"
- " beq %2,2f\n"
- " mb\n"
- ".subsection 2\n"
- "2: br 1b\n"
- ".previous"
- :"=&r" (oldcount), "=m" (sem->count), "=&r" (temp)
- :"Ir" (-RWSEM_WAITING_BIAS), "m" (sem->count) : "memory");
-#endif
- if (unlikely(oldcount < 0))
- rwsem_downgrade_wake(sem);
-}
-
-static inline void rwsem_atomic_add(long val, struct rw_semaphore *sem)
-{
-#ifndef CONFIG_SMP
- sem->count += val;
-#else
- long temp;
- __asm__ __volatile__(
- "1: ldq_l %0,%1\n"
- " addq %0,%2,%0\n"
- " stq_c %0,%1\n"
- " beq %0,2f\n"
- ".subsection 2\n"
- "2: br 1b\n"
- ".previous"
- :"=&r" (temp), "=m" (sem->count)
- :"Ir" (val), "m" (sem->count));
-#endif
-}
-
-static inline long rwsem_atomic_update(long val, struct rw_semaphore *sem)
-{
-#ifndef CONFIG_SMP
- sem->count += val;
- return sem->count;
-#else
- long ret, temp;
- __asm__ __volatile__(
- "1: ldq_l %0,%1\n"
- " addq %0,%3,%2\n"
- " addq %0,%3,%0\n"
- " stq_c %2,%1\n"
- " beq %2,2f\n"
- ".subsection 2\n"
- "2: br 1b\n"
- ".previous"
- :"=&r" (ret), "=m" (sem->count), "=&r" (temp)
- :"Ir" (val), "m" (sem->count));
-
- return ret;
-#endif
-}
-
-static inline int rwsem_is_locked(struct rw_semaphore *sem)
-{
- return (sem->count != 0);
-}
-
-#endif /* __KERNEL__ */
-#endif /* _ALPHA_RWSEM_H */
Index: linux-2.6/include/asm-i386/rwsem.h
===================================================================
--- linux-2.6.orig/include/asm-i386/rwsem.h
+++ /dev/null
@@ -1,258 +0,0 @@
-/* rwsem.h: R/W semaphores implemented using XADD/CMPXCHG for i486+
- *
- * Written by David Howells (dhowells@redhat.com).
- *
- * Derived from asm-i386/semaphore.h
- *
- *
- * The MSW of the count is the negated number of active writers and waiting
- * lockers, and the LSW is the total number of active locks
- *
- * The lock count is initialized to 0 (no active and no waiting lockers).
- *
- * When a writer subtracts WRITE_BIAS, it'll get 0xffff0001 for the case of an
- * uncontended lock. This can be determined because XADD returns the old value.
- * Readers increment by 1 and see a positive value when uncontended, negative
- * if there are writers (and maybe) readers waiting (in which case it goes to
- * sleep).
- *
- * The value of WAITING_BIAS supports up to 32766 waiting processes. This can
- * be extended to 65534 by manually checking the whole MSW rather than relying
- * on the S flag.
- *
- * The value of ACTIVE_BIAS supports up to 65535 active processes.
- *
- * This should be totally fair - if anything is waiting, a process that wants a
- * lock will go to the back of the queue. When the currently active lock is
- * released, if there's a writer at the front of the queue, then that and only
- * that will be woken up; if there's a bunch of consequtive readers at the
- * front, then they'll all be woken up, but no other readers will be.
- */
-
-#ifndef _I386_RWSEM_H
-#define _I386_RWSEM_H
-
-#ifndef _LINUX_RWSEM_H
-#error "please don't include asm/rwsem.h directly, use linux/rwsem.h instead"
-#endif
-
-#ifdef __KERNEL__
-
-#include <linux/list.h>
-#include <linux/spinlock.h>
-#include <linux/lockdep.h>
-
-struct rwsem_waiter;
-
-extern struct rw_semaphore *FASTCALL(rwsem_down_read_failed(struct rw_semaphore *sem));
-extern struct rw_semaphore *FASTCALL(rwsem_down_write_failed(struct rw_semaphore *sem));
-extern struct rw_semaphore *FASTCALL(rwsem_wake(struct rw_semaphore *));
-extern struct rw_semaphore *FASTCALL(rwsem_downgrade_wake(struct rw_semaphore *sem));
-
-/*
- * the semaphore definition
- */
-struct rw_semaphore {
- signed long count;
-#define RWSEM_UNLOCKED_VALUE 0x00000000
-#define RWSEM_ACTIVE_BIAS 0x00000001
-#define RWSEM_ACTIVE_MASK 0x0000ffff
-#define RWSEM_WAITING_BIAS (-0x00010000)
-#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS
-#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)
- spinlock_t wait_lock;
- struct list_head wait_list;
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
- struct lockdep_map dep_map;
-#endif
-};
-
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-# define __RWSEM_DEP_MAP_INIT(lockname) , .dep_map = { .name = #lockname }
-#else
-# define __RWSEM_DEP_MAP_INIT(lockname)
-#endif
-
-
-#define __RWSEM_INITIALIZER(name) \
-{ RWSEM_UNLOCKED_VALUE, __SPIN_LOCK_UNLOCKED((name).wait_lock), \
- LIST_HEAD_INIT((name).wait_list) __RWSEM_DEP_MAP_INIT(name) }
-
-#define DECLARE_RWSEM(name) \
- struct rw_semaphore name = __RWSEM_INITIALIZER(name)
-
-extern void __init_rwsem(struct rw_semaphore *sem, const char *name,
- struct lock_class_key *key);
-
-#define init_rwsem(sem) \
-do { \
- static struct lock_class_key __key; \
- \
- __init_rwsem((sem), #sem, &__key); \
-} while (0)
-
-/*
- * lock for reading
- */
-static inline void __down_read(struct rw_semaphore *sem)
-{
- __asm__ __volatile__(
- "# beginning down_read\n\t"
-LOCK_PREFIX " incl (%%eax)\n\t" /* adds 0x00000001, returns the old value */
- " jns 1f\n"
- " call call_rwsem_down_read_failed\n"
- "1:\n\t"
- "# ending down_read\n\t"
- : "+m" (sem->count)
- : "a" (sem)
- : "memory", "cc");
-}
-
-/*
- * trylock for reading -- returns 1 if successful, 0 if contention
- */
-static inline int __down_read_trylock(struct rw_semaphore *sem)
-{
- __s32 result, tmp;
- __asm__ __volatile__(
- "# beginning __down_read_trylock\n\t"
- " movl %0,%1\n\t"
- "1:\n\t"
- " movl %1,%2\n\t"
- " addl %3,%2\n\t"
- " jle 2f\n\t"
-LOCK_PREFIX " cmpxchgl %2,%0\n\t"
- " jnz 1b\n\t"
- "2:\n\t"
- "# ending __down_read_trylock\n\t"
- : "+m" (sem->count), "=&a" (result), "=&r" (tmp)
- : "i" (RWSEM_ACTIVE_READ_BIAS)
- : "memory", "cc");
- return result>=0 ? 1 : 0;
-}
-
-/*
- * lock for writing
- */
-static inline void __down_write_nested(struct rw_semaphore *sem, int subclass)
-{
- int tmp;
-
- tmp = RWSEM_ACTIVE_WRITE_BIAS;
- __asm__ __volatile__(
- "# beginning down_write\n\t"
-LOCK_PREFIX " xadd %%edx,(%%eax)\n\t" /* subtract 0x0000ffff, returns the old value */
- " testl %%edx,%%edx\n\t" /* was the count 0 before? */
- " jz 1f\n"
- " call call_rwsem_down_write_failed\n"
- "1:\n"
- "# ending down_write"
- : "+m" (sem->count), "=d" (tmp)
- : "a" (sem), "1" (tmp)
- : "memory", "cc");
-}
-
-static inline void __down_write(struct rw_semaphore *sem)
-{
- __down_write_nested(sem, 0);
-}
-
-/*
- * trylock for writing -- returns 1 if successful, 0 if contention
- */
-static inline int __down_write_trylock(struct rw_semaphore *sem)
-{
- signed long ret = cmpxchg(&sem->count,
- RWSEM_UNLOCKED_VALUE,
- RWSEM_ACTIVE_WRITE_BIAS);
- if (ret == RWSEM_UNLOCKED_VALUE)
- return 1;
- return 0;
-}
-
-/*
- * unlock after reading
- */
-static inline void __up_read(struct rw_semaphore *sem)
-{
- __s32 tmp = -RWSEM_ACTIVE_READ_BIAS;
- __asm__ __volatile__(
- "# beginning __up_read\n\t"
-LOCK_PREFIX " xadd %%edx,(%%eax)\n\t" /* subtracts 1, returns the old value */
- " jns 1f\n\t"
- " call call_rwsem_wake\n"
- "1:\n"
- "# ending __up_read\n"
- : "+m" (sem->count), "=d" (tmp)
- : "a" (sem), "1" (tmp)
- : "memory", "cc");
-}
-
-/*
- * unlock after writing
- */
-static inline void __up_write(struct rw_semaphore *sem)
-{
- __asm__ __volatile__(
- "# beginning __up_write\n\t"
- " movl %2,%%edx\n\t"
-LOCK_PREFIX " xaddl %%edx,(%%eax)\n\t" /* tries to transition 0xffff0001 -> 0x00000000 */
- " jz 1f\n"
- " call call_rwsem_wake\n"
- "1:\n\t"
- "# ending __up_write\n"
- : "+m" (sem->count)
- : "a" (sem), "i" (-RWSEM_ACTIVE_WRITE_BIAS)
- : "memory", "cc", "edx");
-}
-
-/*
- * downgrade write lock to read lock
- */
-static inline void __downgrade_write(struct rw_semaphore *sem)
-{
- __asm__ __volatile__(
- "# beginning __downgrade_write\n\t"
-LOCK_PREFIX " addl %2,(%%eax)\n\t" /* transitions 0xZZZZ0001 -> 0xYYYY0001 */
- " jns 1f\n\t"
- " call call_rwsem_downgrade_wake\n"
- "1:\n\t"
- "# ending __downgrade_write\n"
- : "+m" (sem->count)
- : "a" (sem), "i" (-RWSEM_WAITING_BIAS)
- : "memory", "cc");
-}
-
-/*
- * implement atomic add functionality
- */
-static inline void rwsem_atomic_add(int delta, struct rw_semaphore *sem)
-{
- __asm__ __volatile__(
-LOCK_PREFIX "addl %1,%0"
- : "+m" (sem->count)
- : "ir" (delta));
-}
-
-/*
- * implement exchange and add functionality
- */
-static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem)
-{
- int tmp = delta;
-
- __asm__ __volatile__(
-LOCK_PREFIX "xadd %0,%1"
- : "+r" (tmp), "+m" (sem->count)
- : : "memory");
-
- return tmp+delta;
-}
-
-static inline int rwsem_is_locked(struct rw_semaphore *sem)
-{
- return (sem->count != 0);
-}
-
-#endif /* __KERNEL__ */
-#endif /* _I386_RWSEM_H */
Index: linux-2.6/include/asm-ia64/rwsem.h
===================================================================
--- linux-2.6.orig/include/asm-ia64/rwsem.h
+++ /dev/null
@@ -1,178 +0,0 @@
-/*
- * asm-ia64/rwsem.h: R/W semaphores for ia64
- *
- * Copyright (C) 2003 Ken Chen <kenneth.w.chen@intel.com>
- * Copyright (C) 2003 Asit Mallick <asit.k.mallick@intel.com>
- * Copyright (C) 2005 Christoph Lameter <clameter@sgi.com>
- *
- * Based on asm-i386/rwsem.h and other architecture implementation.
- *
- * The MSW of the count is the negated number of active writers and
- * waiting lockers, and the LSW is the total number of active locks.
- *
- * The lock count is initialized to 0 (no active and no waiting lockers).
- *
- * When a writer subtracts WRITE_BIAS, it'll get 0xffffffff00000001 for
- * the case of an uncontended lock. Readers increment by 1 and see a positive
- * value when uncontended, negative if there are writers (and maybe) readers
- * waiting (in which case it goes to sleep).
- */
-
-#ifndef _ASM_IA64_RWSEM_H
-#define _ASM_IA64_RWSEM_H
-
-#include <linux/list.h>
-#include <linux/spinlock.h>
-
-#include <asm/intrinsics.h>
-
-/*
- * the semaphore definition
- */
-struct rw_semaphore {
- signed long count;
- spinlock_t wait_lock;
- struct list_head wait_list;
-};
-
-#define RWSEM_UNLOCKED_VALUE __IA64_UL_CONST(0x0000000000000000)
-#define RWSEM_ACTIVE_BIAS __IA64_UL_CONST(0x0000000000000001)
-#define RWSEM_ACTIVE_MASK __IA64_UL_CONST(0x00000000ffffffff)
-#define RWSEM_WAITING_BIAS -__IA64_UL_CONST(0x0000000100000000)
-#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS
-#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)
-
-#define __RWSEM_INITIALIZER(name) \
- { RWSEM_UNLOCKED_VALUE, SPIN_LOCK_UNLOCKED, \
- LIST_HEAD_INIT((name).wait_list) }
-
-#define DECLARE_RWSEM(name) \
- struct rw_semaphore name = __RWSEM_INITIALIZER(name)
-
-extern struct rw_semaphore *rwsem_down_read_failed(struct rw_semaphore *sem);
-extern struct rw_semaphore *rwsem_down_write_failed(struct rw_semaphore *sem);
-extern struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem);
-extern struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem);
-
-static inline void
-init_rwsem (struct rw_semaphore *sem)
-{
- sem->count = RWSEM_UNLOCKED_VALUE;
- spin_lock_init(&sem->wait_lock);
- INIT_LIST_HEAD(&sem->wait_list);
-}
-
-/*
- * lock for reading
- */
-static inline void
-__down_read (struct rw_semaphore *sem)
-{
- long result = ia64_fetchadd8_acq((unsigned long *)&sem->count, 1);
-
- if (result < 0)
- rwsem_down_read_failed(sem);
-}
-
-/*
- * lock for writing
- */
-static inline void
-__down_write (struct rw_semaphore *sem)
-{
- long old, new;
-
- do {
- old = sem->count;
- new = old + RWSEM_ACTIVE_WRITE_BIAS;
- } while (cmpxchg_acq(&sem->count, old, new) != old);
-
- if (old != 0)
- rwsem_down_write_failed(sem);
-}
-
-/*
- * unlock after reading
- */
-static inline void
-__up_read (struct rw_semaphore *sem)
-{
- long result = ia64_fetchadd8_rel((unsigned long *)&sem->count, -1);
-
- if (result < 0 && (--result & RWSEM_ACTIVE_MASK) == 0)
- rwsem_wake(sem);
-}
-
-/*
- * unlock after writing
- */
-static inline void
-__up_write (struct rw_semaphore *sem)
-{
- long old, new;
-
- do {
- old = sem->count;
- new = old - RWSEM_ACTIVE_WRITE_BIAS;
- } while (cmpxchg_rel(&sem->count, old, new) != old);
-
- if (new < 0 && (new & RWSEM_ACTIVE_MASK) == 0)
- rwsem_wake(sem);
-}
-
-/*
- * trylock for reading -- returns 1 if successful, 0 if contention
- */
-static inline int
-__down_read_trylock (struct rw_semaphore *sem)
-{
- long tmp;
- while ((tmp = sem->count) >= 0) {
- if (tmp == cmpxchg_acq(&sem->count, tmp, tmp+1)) {
- return 1;
- }
- }
- return 0;
-}
-
-/*
- * trylock for writing -- returns 1 if successful, 0 if contention
- */
-static inline int
-__down_write_trylock (struct rw_semaphore *sem)
-{
- long tmp = cmpxchg_acq(&sem->count, RWSEM_UNLOCKED_VALUE,
- RWSEM_ACTIVE_WRITE_BIAS);
- return tmp == RWSEM_UNLOCKED_VALUE;
-}
-
-/*
- * downgrade write lock to read lock
- */
-static inline void
-__downgrade_write (struct rw_semaphore *sem)
-{
- long old, new;
-
- do {
- old = sem->count;
- new = old - RWSEM_WAITING_BIAS;
- } while (cmpxchg_rel(&sem->count, old, new) != old);
-
- if (old < 0)
- rwsem_downgrade_wake(sem);
-}
-
-/*
- * Implement atomic add functionality. These used to be "inline" functions, but GCC v3.1
- * doesn't quite optimize this stuff right and ends up with bad calls to fetchandadd.
- */
-#define rwsem_atomic_add(delta, sem) atomic64_add(delta, (atomic64_t *)(&(sem)->count))
-#define rwsem_atomic_update(delta, sem) atomic64_add_return(delta, (atomic64_t *)(&(sem)->count))
-
-static inline int rwsem_is_locked(struct rw_semaphore *sem)
-{
- return (sem->count != 0);
-}
-
-#endif /* _ASM_IA64_RWSEM_H */
Index: linux-2.6/include/asm-s390/rwsem.h
===================================================================
--- linux-2.6.orig/include/asm-s390/rwsem.h
+++ /dev/null
@@ -1,387 +0,0 @@
-#ifndef _S390_RWSEM_H
-#define _S390_RWSEM_H
-
-/*
- * include/asm-s390/rwsem.h
- *
- * S390 version
- * Copyright (C) 2002 IBM Deutschland Entwicklung GmbH, IBM Corporation
- * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
- *
- * Based on asm-alpha/semaphore.h and asm-i386/rwsem.h
- */
-
-/*
- *
- * The MSW of the count is the negated number of active writers and waiting
- * lockers, and the LSW is the total number of active locks
- *
- * The lock count is initialized to 0 (no active and no waiting lockers).
- *
- * When a writer subtracts WRITE_BIAS, it'll get 0xffff0001 for the case of an
- * uncontended lock. This can be determined because XADD returns the old value.
- * Readers increment by 1 and see a positive value when uncontended, negative
- * if there are writers (and maybe) readers waiting (in which case it goes to
- * sleep).
- *
- * The value of WAITING_BIAS supports up to 32766 waiting processes. This can
- * be extended to 65534 by manually checking the whole MSW rather than relying
- * on the S flag.
- *
- * The value of ACTIVE_BIAS supports up to 65535 active processes.
- *
- * This should be totally fair - if anything is waiting, a process that wants a
- * lock will go to the back of the queue. When the currently active lock is
- * released, if there's a writer at the front of the queue, then that and only
- * that will be woken up; if there's a bunch of consequtive readers at the
- * front, then they'll all be woken up, but no other readers will be.
- */
-
-#ifndef _LINUX_RWSEM_H
-#error "please don't include asm/rwsem.h directly, use linux/rwsem.h instead"
-#endif
-
-#ifdef __KERNEL__
-
-#include <linux/list.h>
-#include <linux/spinlock.h>
-
-struct rwsem_waiter;
-
-extern struct rw_semaphore *rwsem_down_read_failed(struct rw_semaphore *);
-extern struct rw_semaphore *rwsem_down_write_failed(struct rw_semaphore *);
-extern struct rw_semaphore *rwsem_wake(struct rw_semaphore *);
-extern struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *);
-extern struct rw_semaphore *rwsem_downgrade_write(struct rw_semaphore *);
-
-/*
- * the semaphore definition
- */
-struct rw_semaphore {
- signed long count;
- spinlock_t wait_lock;
- struct list_head wait_list;
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
- struct lockdep_map dep_map;
-#endif
-};
-
-#ifndef __s390x__
-#define RWSEM_UNLOCKED_VALUE 0x00000000
-#define RWSEM_ACTIVE_BIAS 0x00000001
-#define RWSEM_ACTIVE_MASK 0x0000ffff
-#define RWSEM_WAITING_BIAS (-0x00010000)
-#else /* __s390x__ */
-#define RWSEM_UNLOCKED_VALUE 0x0000000000000000L
-#define RWSEM_ACTIVE_BIAS 0x0000000000000001L
-#define RWSEM_ACTIVE_MASK 0x00000000ffffffffL
-#define RWSEM_WAITING_BIAS (-0x0000000100000000L)
-#endif /* __s390x__ */
-#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS
-#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)
-
-/*
- * initialisation
- */
-
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-# define __RWSEM_DEP_MAP_INIT(lockname) , .dep_map = { .name = #lockname }
-#else
-# define __RWSEM_DEP_MAP_INIT(lockname)
-#endif
-
-#define __RWSEM_INITIALIZER(name) \
-{ RWSEM_UNLOCKED_VALUE, SPIN_LOCK_UNLOCKED, LIST_HEAD_INIT((name).wait_list) \
- __RWSEM_DEP_MAP_INIT(name) }
-
-#define DECLARE_RWSEM(name) \
- struct rw_semaphore name = __RWSEM_INITIALIZER(name)
-
-static inline void init_rwsem(struct rw_semaphore *sem)
-{
- sem->count = RWSEM_UNLOCKED_VALUE;
- spin_lock_init(&sem->wait_lock);
- INIT_LIST_HEAD(&sem->wait_list);
-}
-
-extern void __init_rwsem(struct rw_semaphore *sem, const char *name,
- struct lock_class_key *key);
-
-#define init_rwsem(sem) \
-do { \
- static struct lock_class_key __key; \
- \
- __init_rwsem((sem), #sem, &__key); \
-} while (0)
-
-
-/*
- * lock for reading
- */
-static inline void __down_read(struct rw_semaphore *sem)
-{
- signed long old, new;
-
- asm volatile(
-#ifndef __s390x__
- " l %0,0(%3)\n"
- "0: lr %1,%0\n"
- " ahi %1,%5\n"
- " cs %0,%1,0(%3)\n"
- " jl 0b"
-#else /* __s390x__ */
- " lg %0,0(%3)\n"
- "0: lgr %1,%0\n"
- " aghi %1,%5\n"
- " csg %0,%1,0(%3)\n"
- " jl 0b"
-#endif /* __s390x__ */
- : "=&d" (old), "=&d" (new), "=m" (sem->count)
- : "a" (&sem->count), "m" (sem->count),
- "i" (RWSEM_ACTIVE_READ_BIAS) : "cc", "memory");
- if (old < 0)
- rwsem_down_read_failed(sem);
-}
-
-/*
- * trylock for reading -- returns 1 if successful, 0 if contention
- */
-static inline int __down_read_trylock(struct rw_semaphore *sem)
-{
- signed long old, new;
-
- asm volatile(
-#ifndef __s390x__
- " l %0,0(%3)\n"
- "0: ltr %1,%0\n"
- " jm 1f\n"
- " ahi %1,%5\n"
- " cs %0,%1,0(%3)\n"
- " jl 0b\n"
- "1:"
-#else /* __s390x__ */
- " lg %0,0(%3)\n"
- "0: ltgr %1,%0\n"
- " jm 1f\n"
- " aghi %1,%5\n"
- " csg %0,%1,0(%3)\n"
- " jl 0b\n"
- "1:"
-#endif /* __s390x__ */
- : "=&d" (old), "=&d" (new), "=m" (sem->count)
- : "a" (&sem->count), "m" (sem->count),
- "i" (RWSEM_ACTIVE_READ_BIAS) : "cc", "memory");
- return old >= 0 ? 1 : 0;
-}
-
-/*
- * lock for writing
- */
-static inline void __down_write_nested(struct rw_semaphore *sem, int subclass)
-{
- signed long old, new, tmp;
-
- tmp = RWSEM_ACTIVE_WRITE_BIAS;
- asm volatile(
-#ifndef __s390x__
- " l %0,0(%3)\n"
- "0: lr %1,%0\n"
- " a %1,%5\n"
- " cs %0,%1,0(%3)\n"
- " jl 0b"
-#else /* __s390x__ */
- " lg %0,0(%3)\n"
- "0: lgr %1,%0\n"
- " ag %1,%5\n"
- " csg %0,%1,0(%3)\n"
- " jl 0b"
-#endif /* __s390x__ */
- : "=&d" (old), "=&d" (new), "=m" (sem->count)
- : "a" (&sem->count), "m" (sem->count), "m" (tmp)
- : "cc", "memory");
- if (old != 0)
- rwsem_down_write_failed(sem);
-}
-
-static inline void __down_write(struct rw_semaphore *sem)
-{
- __down_write_nested(sem, 0);
-}
-
-/*
- * trylock for writing -- returns 1 if successful, 0 if contention
- */
-static inline int __down_write_trylock(struct rw_semaphore *sem)
-{
- signed long old;
-
- asm volatile(
-#ifndef __s390x__
- " l %0,0(%2)\n"
- "0: ltr %0,%0\n"
- " jnz 1f\n"
- " cs %0,%4,0(%2)\n"
- " jl 0b\n"
-#else /* __s390x__ */
- " lg %0,0(%2)\n"
- "0: ltgr %0,%0\n"
- " jnz 1f\n"
- " csg %0,%4,0(%2)\n"
- " jl 0b\n"
-#endif /* __s390x__ */
- "1:"
- : "=&d" (old), "=m" (sem->count)
- : "a" (&sem->count), "m" (sem->count),
- "d" (RWSEM_ACTIVE_WRITE_BIAS) : "cc", "memory");
- return (old == RWSEM_UNLOCKED_VALUE) ? 1 : 0;
-}
-
-/*
- * unlock after reading
- */
-static inline void __up_read(struct rw_semaphore *sem)
-{
- signed long old, new;
-
- asm volatile(
-#ifndef __s390x__
- " l %0,0(%3)\n"
- "0: lr %1,%0\n"
- " ahi %1,%5\n"
- " cs %0,%1,0(%3)\n"
- " jl 0b"
-#else /* __s390x__ */
- " lg %0,0(%3)\n"
- "0: lgr %1,%0\n"
- " aghi %1,%5\n"
- " csg %0,%1,0(%3)\n"
- " jl 0b"
-#endif /* __s390x__ */
- : "=&d" (old), "=&d" (new), "=m" (sem->count)
- : "a" (&sem->count), "m" (sem->count),
- "i" (-RWSEM_ACTIVE_READ_BIAS)
- : "cc", "memory");
- if (new < 0)
- if ((new & RWSEM_ACTIVE_MASK) == 0)
- rwsem_wake(sem);
-}
-
-/*
- * unlock after writing
- */
-static inline void __up_write(struct rw_semaphore *sem)
-{
- signed long old, new, tmp;
-
- tmp = -RWSEM_ACTIVE_WRITE_BIAS;
- asm volatile(
-#ifndef __s390x__
- " l %0,0(%3)\n"
- "0: lr %1,%0\n"
- " a %1,%5\n"
- " cs %0,%1,0(%3)\n"
- " jl 0b"
-#else /* __s390x__ */
- " lg %0,0(%3)\n"
- "0: lgr %1,%0\n"
- " ag %1,%5\n"
- " csg %0,%1,0(%3)\n"
- " jl 0b"
-#endif /* __s390x__ */
- : "=&d" (old), "=&d" (new), "=m" (sem->count)
- : "a" (&sem->count), "m" (sem->count), "m" (tmp)
- : "cc", "memory");
- if (new < 0)
- if ((new & RWSEM_ACTIVE_MASK) == 0)
- rwsem_wake(sem);
-}
-
-/*
- * downgrade write lock to read lock
- */
-static inline void __downgrade_write(struct rw_semaphore *sem)
-{
- signed long old, new, tmp;
-
- tmp = -RWSEM_WAITING_BIAS;
- asm volatile(
-#ifndef __s390x__
- " l %0,0(%3)\n"
- "0: lr %1,%0\n"
- " a %1,%5\n"
- " cs %0,%1,0(%3)\n"
- " jl 0b"
-#else /* __s390x__ */
- " lg %0,0(%3)\n"
- "0: lgr %1,%0\n"
- " ag %1,%5\n"
- " csg %0,%1,0(%3)\n"
- " jl 0b"
-#endif /* __s390x__ */
- : "=&d" (old), "=&d" (new), "=m" (sem->count)
- : "a" (&sem->count), "m" (sem->count), "m" (tmp)
- : "cc", "memory");
- if (new > 1)
- rwsem_downgrade_wake(sem);
-}
-
-/*
- * implement atomic add functionality
- */
-static inline void rwsem_atomic_add(long delta, struct rw_semaphore *sem)
-{
- signed long old, new;
-
- asm volatile(
-#ifndef __s390x__
- " l %0,0(%3)\n"
- "0: lr %1,%0\n"
- " ar %1,%5\n"
- " cs %0,%1,0(%3)\n"
- " jl 0b"
-#else /* __s390x__ */
- " lg %0,0(%3)\n"
- "0: lgr %1,%0\n"
- " agr %1,%5\n"
- " csg %0,%1,0(%3)\n"
- " jl 0b"
-#endif /* __s390x__ */
- : "=&d" (old), "=&d" (new), "=m" (sem->count)
- : "a" (&sem->count), "m" (sem->count), "d" (delta)
- : "cc", "memory");
-}
-
-/*
- * implement exchange and add functionality
- */
-static inline long rwsem_atomic_update(long delta, struct rw_semaphore *sem)
-{
- signed long old, new;
-
- asm volatile(
-#ifndef __s390x__
- " l %0,0(%3)\n"
- "0: lr %1,%0\n"
- " ar %1,%5\n"
- " cs %0,%1,0(%3)\n"
- " jl 0b"
-#else /* __s390x__ */
- " lg %0,0(%3)\n"
- "0: lgr %1,%0\n"
- " agr %1,%5\n"
- " csg %0,%1,0(%3)\n"
- " jl 0b"
-#endif /* __s390x__ */
- : "=&d" (old), "=&d" (new), "=m" (sem->count)
- : "a" (&sem->count), "m" (sem->count), "d" (delta)
- : "cc", "memory");
- return new;
-}
-
-static inline int rwsem_is_locked(struct rw_semaphore *sem)
-{
- return (sem->count != 0);
-}
-
-#endif /* __KERNEL__ */
-#endif /* _S390_RWSEM_H */
Index: linux-2.6/include/asm-sh/rwsem.h
===================================================================
--- linux-2.6.orig/include/asm-sh/rwsem.h
+++ /dev/null
@@ -1,184 +0,0 @@
-/*
- * include/asm-ppc/rwsem.h: R/W semaphores for SH using the stuff
- * in lib/rwsem.c.
- */
-
-#ifndef _ASM_SH_RWSEM_H
-#define _ASM_SH_RWSEM_H
-
-#ifdef __KERNEL__
-#include <linux/list.h>
-#include <linux/spinlock.h>
-#include <asm/atomic.h>
-#include <asm/system.h>
-
-/*
- * the semaphore definition
- */
-struct rw_semaphore {
- long count;
-#define RWSEM_UNLOCKED_VALUE 0x00000000
-#define RWSEM_ACTIVE_BIAS 0x00000001
-#define RWSEM_ACTIVE_MASK 0x0000ffff
-#define RWSEM_WAITING_BIAS (-0x00010000)
-#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS
-#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)
- spinlock_t wait_lock;
- struct list_head wait_list;
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
- struct lockdep_map dep_map;
-#endif
-};
-
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-# define __RWSEM_DEP_MAP_INIT(lockname) , .dep_map = { .name = #lockname }
-#else
-# define __RWSEM_DEP_MAP_INIT(lockname)
-#endif
-
-#define __RWSEM_INITIALIZER(name) \
- { RWSEM_UNLOCKED_VALUE, SPIN_LOCK_UNLOCKED, \
- LIST_HEAD_INIT((name).wait_list) \
- __RWSEM_DEP_MAP_INIT(name) }
-
-#define DECLARE_RWSEM(name) \
- struct rw_semaphore name = __RWSEM_INITIALIZER(name)
-
-extern struct rw_semaphore *rwsem_down_read_failed(struct rw_semaphore *sem);
-extern struct rw_semaphore *rwsem_down_write_failed(struct rw_semaphore *sem);
-extern struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem);
-extern struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem);
-
-extern void __init_rwsem(struct rw_semaphore *sem, const char *name,
- struct lock_class_key *key);
-
-#define init_rwsem(sem) \
-do { \
- static struct lock_class_key __key; \
- \
- __init_rwsem((sem), #sem, &__key); \
-} while (0)
-
-static inline void init_rwsem(struct rw_semaphore *sem)
-{
- sem->count = RWSEM_UNLOCKED_VALUE;
- spin_lock_init(&sem->wait_lock);
- INIT_LIST_HEAD(&sem->wait_list);
-}
-
-/*
- * lock for reading
- */
-static inline void __down_read(struct rw_semaphore *sem)
-{
- if (atomic_inc_return((atomic_t *)(&sem->count)) > 0)
- smp_wmb();
- else
- rwsem_down_read_failed(sem);
-}
-
-static inline int __down_read_trylock(struct rw_semaphore *sem)
-{
- int tmp;
-
- while ((tmp = sem->count) >= 0) {
- if (tmp == cmpxchg(&sem->count, tmp,
- tmp + RWSEM_ACTIVE_READ_BIAS)) {
- smp_wmb();
- return 1;
- }
- }
- return 0;
-}
-
-/*
- * lock for writing
- */
-static inline void __down_write(struct rw_semaphore *sem)
-{
- int tmp;
-
- tmp = atomic_add_return(RWSEM_ACTIVE_WRITE_BIAS,
- (atomic_t *)(&sem->count));
- if (tmp == RWSEM_ACTIVE_WRITE_BIAS)
- smp_wmb();
- else
- rwsem_down_write_failed(sem);
-}
-
-static inline int __down_write_trylock(struct rw_semaphore *sem)
-{
- int tmp;
-
- tmp = cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE,
- RWSEM_ACTIVE_WRITE_BIAS);
- smp_wmb();
- return tmp == RWSEM_UNLOCKED_VALUE;
-}
-
-/*
- * unlock after reading
- */
-static inline void __up_read(struct rw_semaphore *sem)
-{
- int tmp;
-
- smp_wmb();
- tmp = atomic_dec_return((atomic_t *)(&sem->count));
- if (tmp < -1 && (tmp & RWSEM_ACTIVE_MASK) == 0)
- rwsem_wake(sem);
-}
-
-/*
- * unlock after writing
- */
-static inline void __up_write(struct rw_semaphore *sem)
-{
- smp_wmb();
- if (atomic_sub_return(RWSEM_ACTIVE_WRITE_BIAS,
- (atomic_t *)(&sem->count)) < 0)
- rwsem_wake(sem);
-}
-
-/*
- * implement atomic add functionality
- */
-static inline void rwsem_atomic_add(int delta, struct rw_semaphore *sem)
-{
- atomic_add(delta, (atomic_t *)(&sem->count));
-}
-
-/*
- * downgrade write lock to read lock
- */
-static inline void __downgrade_write(struct rw_semaphore *sem)
-{
- int tmp;
-
- smp_wmb();
- tmp = atomic_add_return(-RWSEM_WAITING_BIAS, (atomic_t *)(&sem->count));
- if (tmp < 0)
- rwsem_downgrade_wake(sem);
-}
-
-static inline void __down_write_nested(struct rw_semaphore *sem, int subclass)
-{
- __down_write(sem);
-}
-
-/*
- * implement exchange and add functionality
- */
-static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem)
-{
- smp_mb();
- return atomic_add_return(delta, (atomic_t *)(&sem->count));
-}
-
-static inline int rwsem_is_locked(struct rw_semaphore *sem)
-{
- return (sem->count != 0);
-}
-
-#endif /* __KERNEL__ */
-#endif /* _ASM_SH_RWSEM_H */
Index: linux-2.6/include/asm-sparc64/rwsem-const.h
===================================================================
--- linux-2.6.orig/include/asm-sparc64/rwsem-const.h
+++ /dev/null
@@ -1,12 +0,0 @@
-/* rwsem-const.h: RW semaphore counter constants. */
-#ifndef _SPARC64_RWSEM_CONST_H
-#define _SPARC64_RWSEM_CONST_H
-
-#define RWSEM_UNLOCKED_VALUE 0x00000000
-#define RWSEM_ACTIVE_BIAS 0x00000001
-#define RWSEM_ACTIVE_MASK 0x0000ffff
-#define RWSEM_WAITING_BIAS 0xffff0000
-#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS
-#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)
-
-#endif /* _SPARC64_RWSEM_CONST_H */
Index: linux-2.6/include/asm-sparc64/rwsem.h
===================================================================
--- linux-2.6.orig/include/asm-sparc64/rwsem.h
+++ /dev/null
@@ -1,84 +0,0 @@
-/* $Id: rwsem.h,v 1.5 2001/11/18 00:12:56 davem Exp $
- * rwsem.h: R/W semaphores implemented using CAS
- *
- * Written by David S. Miller (davem@redhat.com), 2001.
- * Derived from asm-i386/rwsem.h
- */
-#ifndef _SPARC64_RWSEM_H
-#define _SPARC64_RWSEM_H
-
-#ifndef _LINUX_RWSEM_H
-#error "please don't include asm/rwsem.h directly, use linux/rwsem.h instead"
-#endif
-
-#ifdef __KERNEL__
-
-#include <linux/list.h>
-#include <linux/spinlock.h>
-#include <asm/rwsem-const.h>
-
-struct rwsem_waiter;
-
-struct rw_semaphore {
- signed int count;
- spinlock_t wait_lock;
- struct list_head wait_list;
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
- struct lockdep_map dep_map;
-#endif
-};
-
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-# define __RWSEM_DEP_MAP_INIT(lockname) , .dep_map = { .name = #lockname }
-#else
-# define __RWSEM_DEP_MAP_INIT(lockname)
-#endif
-
-#define __RWSEM_INITIALIZER(name) \
-{ RWSEM_UNLOCKED_VALUE, SPIN_LOCK_UNLOCKED, LIST_HEAD_INIT((name).wait_list) \
- __RWSEM_DEP_MAP_INIT(name) }
-
-#define DECLARE_RWSEM(name) \
- struct rw_semaphore name = __RWSEM_INITIALIZER(name)
-
-extern void __init_rwsem(struct rw_semaphore *sem, const char *name,
- struct lock_class_key *key);
-
-#define init_rwsem(sem) \
-do { \
- static struct lock_class_key __key; \
- \
- __init_rwsem((sem), #sem, &__key); \
-} while (0)
-
-extern void __down_read(struct rw_semaphore *sem);
-extern int __down_read_trylock(struct rw_semaphore *sem);
-extern void __down_write(struct rw_semaphore *sem);
-extern int __down_write_trylock(struct rw_semaphore *sem);
-extern void __up_read(struct rw_semaphore *sem);
-extern void __up_write(struct rw_semaphore *sem);
-extern void __downgrade_write(struct rw_semaphore *sem);
-
-static inline void __down_write_nested(struct rw_semaphore *sem, int subclass)
-{
- __down_write(sem);
-}
-
-static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem)
-{
- return atomic_add_return(delta, (atomic_t *)(&sem->count));
-}
-
-static inline void rwsem_atomic_add(int delta, struct rw_semaphore *sem)
-{
- atomic_add(delta, (atomic_t *)(&sem->count));
-}
-
-static inline int rwsem_is_locked(struct rw_semaphore *sem)
-{
- return (sem->count != 0);
-}
-
-#endif /* __KERNEL__ */
-
-#endif /* _SPARC64_RWSEM_H */
Index: linux-2.6/include/asm-um/rwsem.h
===================================================================
--- linux-2.6.orig/include/asm-um/rwsem.h
+++ /dev/null
@@ -1,6 +0,0 @@
-#ifndef __UM_RWSEM_H__
-#define __UM_RWSEM_H__
-
-#include "asm/arch/rwsem.h"
-
-#endif
Index: linux-2.6/include/asm-xtensa/rwsem.h
===================================================================
--- linux-2.6.orig/include/asm-xtensa/rwsem.h
+++ /dev/null
@@ -1,164 +0,0 @@
-/*
- * include/asm-xtensa/rwsem.h
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License. See the file "COPYING" in the main directory of this archive
- * for more details.
- *
- * Largely copied from include/asm-ppc/rwsem.h
- *
- * Copyright (C) 2001 - 2005 Tensilica Inc.
- */
-
-#ifndef _XTENSA_RWSEM_H
-#define _XTENSA_RWSEM_H
-
-#include <linux/list.h>
-#include <linux/spinlock.h>
-#include <asm/atomic.h>
-#include <asm/system.h>
-
-/*
- * the semaphore definition
- */
-struct rw_semaphore {
- signed long count;
-#define RWSEM_UNLOCKED_VALUE 0x00000000
-#define RWSEM_ACTIVE_BIAS 0x00000001
-#define RWSEM_ACTIVE_MASK 0x0000ffff
-#define RWSEM_WAITING_BIAS (-0x00010000)
-#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS
-#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)
- spinlock_t wait_lock;
- struct list_head wait_list;
-};
-
-#define __RWSEM_INITIALIZER(name) \
- { RWSEM_UNLOCKED_VALUE, SPIN_LOCK_UNLOCKED, \
- LIST_HEAD_INIT((name).wait_list) }
-
-#define DECLARE_RWSEM(name) \
- struct rw_semaphore name = __RWSEM_INITIALIZER(name)
-
-extern struct rw_semaphore *rwsem_down_read_failed(struct rw_semaphore *sem);
-extern struct rw_semaphore *rwsem_down_write_failed(struct rw_semaphore *sem);
-extern struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem);
-extern struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem);
-
-static inline void init_rwsem(struct rw_semaphore *sem)
-{
- sem->count = RWSEM_UNLOCKED_VALUE;
- spin_lock_init(&sem->wait_lock);
- INIT_LIST_HEAD(&sem->wait_list);
-}
-
-/*
- * lock for reading
- */
-static inline void __down_read(struct rw_semaphore *sem)
-{
- if (atomic_add_return(1,(atomic_t *)(&sem->count)) > 0)
- smp_wmb();
- else
- rwsem_down_read_failed(sem);
-}
-
-static inline int __down_read_trylock(struct rw_semaphore *sem)
-{
- int tmp;
-
- while ((tmp = sem->count) >= 0) {
- if (tmp == cmpxchg(&sem->count, tmp,
- tmp + RWSEM_ACTIVE_READ_BIAS)) {
- smp_wmb();
- return 1;
- }
- }
- return 0;
-}
-
-/*
- * lock for writing
- */
-static inline void __down_write(struct rw_semaphore *sem)
-{
- int tmp;
-
- tmp = atomic_add_return(RWSEM_ACTIVE_WRITE_BIAS,
- (atomic_t *)(&sem->count));
- if (tmp == RWSEM_ACTIVE_WRITE_BIAS)
- smp_wmb();
- else
- rwsem_down_write_failed(sem);
-}
-
-static inline int __down_write_trylock(struct rw_semaphore *sem)
-{
- int tmp;
-
- tmp = cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE,
- RWSEM_ACTIVE_WRITE_BIAS);
- smp_wmb();
- return tmp == RWSEM_UNLOCKED_VALUE;
-}
-
-/*
- * unlock after reading
- */
-static inline void __up_read(struct rw_semaphore *sem)
-{
- int tmp;
-
- smp_wmb();
- tmp = atomic_sub_return(1,(atomic_t *)(&sem->count));
- if (tmp < -1 && (tmp & RWSEM_ACTIVE_MASK) == 0)
- rwsem_wake(sem);
-}
-
-/*
- * unlock after writing
- */
-static inline void __up_write(struct rw_semaphore *sem)
-{
- smp_wmb();
- if (atomic_sub_return(RWSEM_ACTIVE_WRITE_BIAS,
- (atomic_t *)(&sem->count)) < 0)
- rwsem_wake(sem);
-}
-
-/*
- * implement atomic add functionality
- */
-static inline void rwsem_atomic_add(int delta, struct rw_semaphore *sem)
-{
- atomic_add(delta, (atomic_t *)(&sem->count));
-}
-
-/*
- * downgrade write lock to read lock
- */
-static inline void __downgrade_write(struct rw_semaphore *sem)
-{
- int tmp;
-
- smp_wmb();
- tmp = atomic_add_return(-RWSEM_WAITING_BIAS, (atomic_t *)(&sem->count));
- if (tmp < 0)
- rwsem_downgrade_wake(sem);
-}
-
-/*
- * implement exchange and add functionality
- */
-static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem)
-{
- smp_mb();
- return atomic_add_return(delta, (atomic_t *)(&sem->count));
-}
-
-static inline int rwsem_is_locked(struct rw_semaphore *sem)
-{
- return (sem->count != 0);
-}
-
-#endif /* _XTENSA_RWSEM_H */
Index: linux-2.6/kernel/rwsem.c
===================================================================
--- linux-2.6.orig/kernel/rwsem.c
+++ linux-2.6/kernel/rwsem.c
@@ -8,11 +8,282 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/rwsem.h>
+#include <linux/sched.h>

#include <asm/system.h>
#include <asm/atomic.h>

/*
+ * The MSW of the count is the negated number of active writers and waiting
+ * lockers, and the LSW is the total number of active locks
+ *
+ * The lock count is initialized to 0 (no active and no waiting lockers).
+ *
+ * When a writer subtracts WRITE_BIAS, it'll get 0xffff0001 for the case of an
+ * uncontended lock. This can be determined because atomic_add_return returns
+ * the old value. Readers increment by 1 and see a positive value when
+ * uncontended, negative if there are writers (and maybe) readers waiting (in
+ * which case it goes to sleep).
+ *
+ * On 32-bit architectures, the value of WAITING_BIAS supports up to 32766
+ * waiting processes. The value of ACTIVE_BIAS supports up to 65535 active
+ * processes. On 64-bit, these are much larger.
+ */
+#define RWSEM_ACTIVE_BIAS 0x00000001L
+#if BITS_PER_LONG == 32
+#define RWSEM_ACTIVE_MASK 0x0000ffffL
+#define RWSEM_WAITING_BIAS 0xffff0000L
+#elif BITS_PER_LONG == 64
+#define RWSEM_ACTIVE_MASK 0x00000000ffffffffL
+#define RWSEM_WAITING_BIAS 0xffffffff00000000L
+#endif
+#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS
+#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)
+
+/*
+ * Initialize an rwsem:
+ */
+void __init_rwsem(struct rw_semaphore *sem, const char *name,
+ struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ /*
+ * Make sure we are not reinitializing a held semaphore:
+ */
+ debug_check_no_locks_freed((void *)sem, sizeof(*sem));
+ lockdep_init_map(&sem->dep_map, name, key, 0);
+#endif
+ atomic_long_set(&sem->count, RWSEM_UNLOCKED_VALUE);
+ spin_lock_init(&sem->wait_lock);
+ INIT_LIST_HEAD(&sem->wait_list);
+}
+
+EXPORT_SYMBOL(__init_rwsem);
+
+struct rwsem_waiter {
+ struct list_head list;
+ struct task_struct *task;
+ unsigned int flags;
+#define RWSEM_WAITING_FOR_READ 0x00000001
+#define RWSEM_WAITING_FOR_WRITE 0x00000002
+};
+
+/*
+ * handle the lock release when processes blocked on it that can now run
+ * - if we come here from up_xxxx(), then:
+ * - the 'active part' of count (&0x0000ffff) reached 0 (but may have changed)
+ * - the 'waiting part' of count (&0xffff0000) is -ve (and will still be so)
+ * - there must be someone on the queue
+ * - the spinlock must be held by the caller
+ * - woken process blocks are discarded from the list after having task zeroed
+ * - writers are only woken if downgrading is false
+ */
+static struct rw_semaphore *__rwsem_do_wake(struct rw_semaphore *sem,
+ int downgrading)
+{
+ struct rwsem_waiter *waiter;
+ struct task_struct *tsk;
+ struct list_head *next;
+ long oldcount, woken, loop;
+
+ if (downgrading)
+ goto dont_wake_writers;
+
+ /* if we came through an up_xxxx() call, we only only wake someone up
+ * if we can transition the active part of the count from 0 -> 1
+ */
+ try_again:
+ oldcount = atomic_long_add_return(RWSEM_ACTIVE_BIAS, &sem->count)
+ - RWSEM_ACTIVE_BIAS;
+ if (oldcount & RWSEM_ACTIVE_MASK)
+ goto undo;
+
+ waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list);
+
+ /* try to grant a single write lock if there's a writer at the front
+ * of the queue - note we leave the 'active part' of the count
+ * incremented by 1 and the waiting part incremented by 0x00010000
+ */
+ if (!(waiter->flags & RWSEM_WAITING_FOR_WRITE))
+ goto readers_only;
+
+ /* We must be careful not to touch 'waiter' after we set ->task = NULL.
+ * It is an allocated on the waiter's stack and may become invalid at
+ * any time after that point (due to a wakeup from another source).
+ */
+ list_del(&waiter->list);
+ tsk = waiter->task;
+ smp_mb();
+ waiter->task = NULL;
+ wake_up_process(tsk);
+ put_task_struct(tsk);
+ goto out;
+
+ /* don't want to wake any writers */
+ dont_wake_writers:
+ waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list);
+ if (waiter->flags & RWSEM_WAITING_FOR_WRITE)
+ goto out;
+
+ /* grant an infinite number of read locks to the readers at the front
+ * of the queue
+ * - note we increment the 'active part' of the count by the number of
+ * readers before waking any processes up
+ */
+ readers_only:
+ woken = 0;
+ do {
+ woken++;
+
+ if (waiter->list.next == &sem->wait_list)
+ break;
+
+ waiter = list_entry(waiter->list.next,
+ struct rwsem_waiter, list);
+
+ } while (waiter->flags & RWSEM_WAITING_FOR_READ);
+
+ loop = woken;
+ woken *= RWSEM_ACTIVE_BIAS - RWSEM_WAITING_BIAS;
+ if (!downgrading)
+ /* we'd already done one increment earlier */
+ woken -= RWSEM_ACTIVE_BIAS;
+
+ atomic_long_add(woken, &sem->count);
+
+ next = sem->wait_list.next;
+ for (; loop > 0; loop--) {
+ waiter = list_entry(next, struct rwsem_waiter, list);
+ next = waiter->list.next;
+ tsk = waiter->task;
+ smp_mb();
+ waiter->task = NULL;
+ wake_up_process(tsk);
+ put_task_struct(tsk);
+ }
+
+ sem->wait_list.next = next;
+ next->prev = &sem->wait_list;
+
+ out:
+ return sem;
+
+ /* undo the change to count, but check for a transition 1->0 */
+ undo:
+ if (atomic_long_add_return(-RWSEM_ACTIVE_BIAS, &sem->count) != 0)
+ goto out;
+ goto try_again;
+}
+
+/*
+ * wait for a lock to be granted
+ */
+static struct rw_semaphore *rwsem_down_failed_common(struct rw_semaphore *sem,
+ struct rwsem_waiter *waiter, signed long adjustment)
+{
+ struct task_struct *tsk = current;
+ long count;
+
+ set_task_state(tsk, TASK_UNINTERRUPTIBLE);
+
+ /* set up my own style of waitqueue */
+ spin_lock_irq(&sem->wait_lock);
+ waiter->task = tsk;
+ get_task_struct(tsk);
+
+ list_add_tail(&waiter->list, &sem->wait_list);
+
+ /* we're now waiting on the lock, but no longer actively read-locking */
+ count = atomic_long_add_return(adjustment, &sem->count);
+
+ /* if there are no active locks, wake the front queued process(es) up */
+ if (!(count & RWSEM_ACTIVE_MASK))
+ sem = __rwsem_do_wake(sem, 0);
+
+ spin_unlock_irq(&sem->wait_lock);
+
+ /* wait to be given the lock */
+ for (;;) {
+ if (!waiter->task)
+ break;
+ schedule();
+ set_task_state(tsk, TASK_UNINTERRUPTIBLE);
+ }
+
+ tsk->state = TASK_RUNNING;
+
+ return sem;
+}
+
+/*
+ * wait for the read lock to be granted
+ */
+static struct rw_semaphore __sched *rwsem_down_read_failed(
+ struct rw_semaphore *sem)
+{
+ struct rwsem_waiter waiter;
+
+ waiter.flags = RWSEM_WAITING_FOR_READ;
+ rwsem_down_failed_common(sem, &waiter,
+ RWSEM_WAITING_BIAS - RWSEM_ACTIVE_BIAS);
+ return sem;
+}
+
+/*
+ * wait for the write lock to be granted
+ */
+static struct rw_semaphore __sched *rwsem_down_write_failed(
+ struct rw_semaphore *sem)
+{
+ struct rwsem_waiter waiter;
+
+ waiter.flags = RWSEM_WAITING_FOR_WRITE;
+ rwsem_down_failed_common(sem, &waiter, -RWSEM_ACTIVE_BIAS);
+
+ return sem;
+}
+
+/*
+ * handle waking up a waiter on the semaphore
+ * - up_read/up_write has decremented the active part of count if we come here
+ */
+static struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&sem->wait_lock, flags);
+
+ /* do nothing if list empty */
+ if (!list_empty(&sem->wait_list))
+ sem = __rwsem_do_wake(sem, 0);
+
+ spin_unlock_irqrestore(&sem->wait_lock, flags);
+
+ return sem;
+}
+
+/*
+ * downgrade a write lock into a read lock
+ * - caller incremented waiting part of count and discovered it still negative
+ * - just wake up any readers at the front of the queue
+ */
+static struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&sem->wait_lock, flags);
+
+ /* do nothing if list empty */
+ if (!list_empty(&sem->wait_list))
+ sem = __rwsem_do_wake(sem, 1);
+
+ spin_unlock_irqrestore(&sem->wait_lock, flags);
+
+ return sem;
+}
+
+
+/*
* lock for reading
*/
void down_read(struct rw_semaphore *sem)
@@ -20,7 +291,8 @@ void down_read(struct rw_semaphore *sem)
might_sleep();
rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_);

- __down_read(sem);
+ if (unlikely(atomic_long_inc_return(&sem->count) <= 0))
+ rwsem_down_read_failed(sem);
}

EXPORT_SYMBOL(down_read);
@@ -30,11 +302,16 @@ EXPORT_SYMBOL(down_read);
*/
int down_read_trylock(struct rw_semaphore *sem)
{
- int ret = __down_read_trylock(sem);
+ long tmp;

- if (ret == 1)
- rwsem_acquire_read(&sem->dep_map, 0, 1, _RET_IP_);
- return ret;
+ while ((tmp = atomic_long_read(&sem->count)) >= 0) {
+ if (tmp == atomic_long_cmpxchg(&sem->count, tmp,
+ tmp + RWSEM_ACTIVE_READ_BIAS)) {
+ rwsem_acquire_read(&sem->dep_map, 0, 1, _RET_IP_);
+ return 1;
+ }
+ }
+ return 0;
}

EXPORT_SYMBOL(down_read_trylock);
@@ -44,10 +321,14 @@ EXPORT_SYMBOL(down_read_trylock);
*/
void down_write(struct rw_semaphore *sem)
{
+ long tmp;
+
might_sleep();
rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);

- __down_write(sem);
+ tmp = atomic_long_add_return(RWSEM_ACTIVE_WRITE_BIAS, &sem->count);
+ if (unlikely(tmp != RWSEM_ACTIVE_WRITE_BIAS))
+ rwsem_down_write_failed(sem);
}

EXPORT_SYMBOL(down_write);
@@ -57,11 +338,15 @@ EXPORT_SYMBOL(down_write);
*/
int down_write_trylock(struct rw_semaphore *sem)
{
- int ret = __down_write_trylock(sem);
+ long tmp;

- if (ret == 1)
+ tmp = atomic_long_cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE,
+ RWSEM_ACTIVE_WRITE_BIAS);
+ if (tmp == RWSEM_UNLOCKED_VALUE) {
rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);
- return ret;
+ return 1;
+ }
+ return 0;
}

EXPORT_SYMBOL(down_write_trylock);
@@ -71,9 +356,13 @@ EXPORT_SYMBOL(down_write_trylock);
*/
void up_read(struct rw_semaphore *sem)
{
+ long tmp;
+
rwsem_release(&sem->dep_map, 1, _RET_IP_);

- __up_read(sem);
+ tmp = atomic_long_dec_return(&sem->count);
+ if (unlikely(tmp < -1 && (tmp & RWSEM_ACTIVE_MASK) == 0))
+ rwsem_wake(sem);
}

EXPORT_SYMBOL(up_read);
@@ -85,7 +374,9 @@ void up_write(struct rw_semaphore *sem)
{
rwsem_release(&sem->dep_map, 1, _RET_IP_);

- __up_write(sem);
+ if (unlikely(atomic_long_sub_return(RWSEM_ACTIVE_WRITE_BIAS,
+ &sem->count) < 0))
+ rwsem_wake(sem);
}

EXPORT_SYMBOL(up_write);
@@ -95,11 +386,16 @@ EXPORT_SYMBOL(up_write);
*/
void downgrade_write(struct rw_semaphore *sem)
{
+ long tmp;
+
/*
* lockdep: a downgraded write will live on as a write
* dependency.
*/
- __downgrade_write(sem);
+
+ tmp = atomic_long_add_return(-RWSEM_WAITING_BIAS, &sem->count);
+ if (tmp < 0)
+ rwsem_downgrade_wake(sem);
}

EXPORT_SYMBOL(downgrade_write);
Index: linux-2.6/lib/rwsem.c
===================================================================
--- linux-2.6.orig/lib/rwsem.c
+++ /dev/null
@@ -1,257 +0,0 @@
-/* rwsem.c: R/W semaphores: contention handling functions
- *
- * Written by David Howells (dhowells@redhat.com).
- * Derived from arch/i386/kernel/semaphore.c
- */
-#include <linux/rwsem.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/module.h>
-
-/*
- * Initialize an rwsem:
- */
-void __init_rwsem(struct rw_semaphore *sem, const char *name,
- struct lock_class_key *key)
-{
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
- /*
- * Make sure we are not reinitializing a held semaphore:
- */
- debug_check_no_locks_freed((void *)sem, sizeof(*sem));
- lockdep_init_map(&sem->dep_map, name, key, 0);
-#endif
- sem->count = RWSEM_UNLOCKED_VALUE;
- spin_lock_init(&sem->wait_lock);
- INIT_LIST_HEAD(&sem->wait_list);
-}
-
-EXPORT_SYMBOL(__init_rwsem);
-
-struct rwsem_waiter {
- struct list_head list;
- struct task_struct *task;
- unsigned int flags;
-#define RWSEM_WAITING_FOR_READ 0x00000001
-#define RWSEM_WAITING_FOR_WRITE 0x00000002
-};
-
-/*
- * handle the lock release when processes blocked on it that can now run
- * - if we come here from up_xxxx(), then:
- * - the 'active part' of count (&0x0000ffff) reached 0 (but may have changed)
- * - the 'waiting part' of count (&0xffff0000) is -ve (and will still be so)
- * - there must be someone on the queue
- * - the spinlock must be held by the caller
- * - woken process blocks are discarded from the list after having task zeroed
- * - writers are only woken if downgrading is false
- */
-static inline struct rw_semaphore *
-__rwsem_do_wake(struct rw_semaphore *sem, int downgrading)
-{
- struct rwsem_waiter *waiter;
- struct task_struct *tsk;
- struct list_head *next;
- signed long oldcount, woken, loop;
-
- if (downgrading)
- goto dont_wake_writers;
-
- /* if we came through an up_xxxx() call, we only only wake someone up
- * if we can transition the active part of the count from 0 -> 1
- */
- try_again:
- oldcount = rwsem_atomic_update(RWSEM_ACTIVE_BIAS, sem)
- - RWSEM_ACTIVE_BIAS;
- if (oldcount & RWSEM_ACTIVE_MASK)
- goto undo;
-
- waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list);
-
- /* try to grant a single write lock if there's a writer at the front
- * of the queue - note we leave the 'active part' of the count
- * incremented by 1 and the waiting part incremented by 0x00010000
- */
- if (!(waiter->flags & RWSEM_WAITING_FOR_WRITE))
- goto readers_only;
-
- /* We must be careful not to touch 'waiter' after we set ->task = NULL.
- * It is an allocated on the waiter's stack and may become invalid at
- * any time after that point (due to a wakeup from another source).
- */
- list_del(&waiter->list);
- tsk = waiter->task;
- smp_mb();
- waiter->task = NULL;
- wake_up_process(tsk);
- put_task_struct(tsk);
- goto out;
-
- /* don't want to wake any writers */
- dont_wake_writers:
- waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list);
- if (waiter->flags & RWSEM_WAITING_FOR_WRITE)
- goto out;
-
- /* grant an infinite number of read locks to the readers at the front
- * of the queue
- * - note we increment the 'active part' of the count by the number of
- * readers before waking any processes up
- */
- readers_only:
- woken = 0;
- do {
- woken++;
-
- if (waiter->list.next == &sem->wait_list)
- break;
-
- waiter = list_entry(waiter->list.next,
- struct rwsem_waiter, list);
-
- } while (waiter->flags & RWSEM_WAITING_FOR_READ);
-
- loop = woken;
- woken *= RWSEM_ACTIVE_BIAS - RWSEM_WAITING_BIAS;
- if (!downgrading)
- /* we'd already done one increment earlier */
- woken -= RWSEM_ACTIVE_BIAS;
-
- rwsem_atomic_add(woken, sem);
-
- next = sem->wait_list.next;
- for (; loop > 0; loop--) {
- waiter = list_entry(next, struct rwsem_waiter, list);
- next = waiter->list.next;
- tsk = waiter->task;
- smp_mb();
- waiter->task = NULL;
- wake_up_process(tsk);
- put_task_struct(tsk);
- }
-
- sem->wait_list.next = next;
- next->prev = &sem->wait_list;
-
- out:
- return sem;
-
- /* undo the change to count, but check for a transition 1->0 */
- undo:
- if (rwsem_atomic_update(-RWSEM_ACTIVE_BIAS, sem) != 0)
- goto out;
- goto try_again;
-}
-
-/*
- * wait for a lock to be granted
- */
-static struct rw_semaphore *
-rwsem_down_failed_common(struct rw_semaphore *sem,
- struct rwsem_waiter *waiter, signed long adjustment)
-{
- struct task_struct *tsk = current;
- signed long count;
-
- set_task_state(tsk, TASK_UNINTERRUPTIBLE);
-
- /* set up my own style of waitqueue */
- spin_lock_irq(&sem->wait_lock);
- waiter->task = tsk;
- get_task_struct(tsk);
-
- list_add_tail(&waiter->list, &sem->wait_list);
-
- /* we're now waiting on the lock, but no longer actively read-locking */
- count = rwsem_atomic_update(adjustment, sem);
-
- /* if there are no active locks, wake the front queued process(es) up */
- if (!(count & RWSEM_ACTIVE_MASK))
- sem = __rwsem_do_wake(sem, 0);
-
- spin_unlock_irq(&sem->wait_lock);
-
- /* wait to be given the lock */
- for (;;) {
- if (!waiter->task)
- break;
- schedule();
- set_task_state(tsk, TASK_UNINTERRUPTIBLE);
- }
-
- tsk->state = TASK_RUNNING;
-
- return sem;
-}
-
-/*
- * wait for the read lock to be granted
- */
-struct rw_semaphore fastcall __sched *
-rwsem_down_read_failed(struct rw_semaphore *sem)
-{
- struct rwsem_waiter waiter;
-
- waiter.flags = RWSEM_WAITING_FOR_READ;
- rwsem_down_failed_common(sem, &waiter,
- RWSEM_WAITING_BIAS - RWSEM_ACTIVE_BIAS);
- return sem;
-}
-
-/*
- * wait for the write lock to be granted
- */
-struct rw_semaphore fastcall __sched *
-rwsem_down_write_failed(struct rw_semaphore *sem)
-{
- struct rwsem_waiter waiter;
-
- waiter.flags = RWSEM_WAITING_FOR_WRITE;
- rwsem_down_failed_common(sem, &waiter, -RWSEM_ACTIVE_BIAS);
-
- return sem;
-}
-
-/*
- * handle waking up a waiter on the semaphore
- * - up_read/up_write has decremented the active part of count if we come here
- */
-struct rw_semaphore fastcall *rwsem_wake(struct rw_semaphore *sem)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&sem->wait_lock, flags);
-
- /* do nothing if list empty */
- if (!list_empty(&sem->wait_list))
- sem = __rwsem_do_wake(sem, 0);
-
- spin_unlock_irqrestore(&sem->wait_lock, flags);
-
- return sem;
-}
-
-/*
- * downgrade a write lock into a read lock
- * - caller incremented waiting part of count and discovered it still negative
- * - just wake up any readers at the front of the queue
- */
-struct rw_semaphore fastcall *rwsem_downgrade_wake(struct rw_semaphore *sem)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&sem->wait_lock, flags);
-
- /* do nothing if list empty */
- if (!list_empty(&sem->wait_list))
- sem = __rwsem_do_wake(sem, 1);
-
- spin_unlock_irqrestore(&sem->wait_lock, flags);
-
- return sem;
-}
-
-EXPORT_SYMBOL(rwsem_down_read_failed);
-EXPORT_SYMBOL(rwsem_down_write_failed);
-EXPORT_SYMBOL(rwsem_wake);
-EXPORT_SYMBOL(rwsem_downgrade_wake);
Index: linux-2.6/arch/alpha/Kconfig
===================================================================
--- linux-2.6.orig/arch/alpha/Kconfig
+++ linux-2.6/arch/alpha/Kconfig
@@ -18,13 +18,6 @@ config MMU
bool
default y

-config RWSEM_GENERIC_SPINLOCK
- bool
-
-config RWSEM_XCHGADD_ALGORITHM
- bool
- default y
-
config ARCH_HAS_ILOG2_U32
bool
default n
Index: linux-2.6/arch/arm/Kconfig
===================================================================
--- linux-2.6.orig/arch/arm/Kconfig
+++ linux-2.6/arch/arm/Kconfig
@@ -79,13 +79,6 @@ config GENERIC_IRQ_PROBE
bool
default y

-config RWSEM_GENERIC_SPINLOCK
- bool
- default y
-
-config RWSEM_XCHGADD_ALGORITHM
- bool
-
config ARCH_HAS_ILOG2_U32
bool
default n
Index: linux-2.6/arch/arm26/Kconfig
===================================================================
--- linux-2.6.orig/arch/arm26/Kconfig
+++ linux-2.6/arch/arm26/Kconfig
@@ -34,13 +34,6 @@ config FORCE_MAX_ZONEORDER
int
default 9

-config RWSEM_GENERIC_SPINLOCK
- bool
- default y
-
-config RWSEM_XCHGADD_ALGORITHM
- bool
-
config ARCH_HAS_ILOG2_U32
bool
default n
Index: linux-2.6/arch/cris/Kconfig
===================================================================
--- linux-2.6.orig/arch/cris/Kconfig
+++ linux-2.6/arch/cris/Kconfig
@@ -13,13 +13,6 @@ config ZONE_DMA
bool
default y

-config RWSEM_GENERIC_SPINLOCK
- bool
- default y
-
-config RWSEM_XCHGADD_ALGORITHM
- bool
-
config ARCH_HAS_ILOG2_U32
bool
default n
Index: linux-2.6/arch/frv/Kconfig
===================================================================
--- linux-2.6.orig/arch/frv/Kconfig
+++ linux-2.6/arch/frv/Kconfig
@@ -10,13 +10,6 @@ config ZONE_DMA
bool
default y

-config RWSEM_GENERIC_SPINLOCK
- bool
- default y
-
-config RWSEM_XCHGADD_ALGORITHM
- bool
-
config GENERIC_FIND_NEXT_BIT
bool
default y
Index: linux-2.6/arch/h8300/Kconfig
===================================================================
--- linux-2.6.orig/arch/h8300/Kconfig
+++ linux-2.6/arch/h8300/Kconfig
@@ -25,14 +25,6 @@ config FPU
bool
default n

-config RWSEM_GENERIC_SPINLOCK
- bool
- default y
-
-config RWSEM_XCHGADD_ALGORITHM
- bool
- default n
-
config ARCH_HAS_ILOG2_U32
bool
default n
Index: linux-2.6/arch/ia64/Kconfig
===================================================================
--- linux-2.6.orig/arch/ia64/Kconfig
+++ linux-2.6/arch/ia64/Kconfig
@@ -37,10 +37,6 @@ config MMU
config SWIOTLB
bool

-config RWSEM_XCHGADD_ALGORITHM
- bool
- default y
-
config ARCH_HAS_ILOG2_U32
bool
default n
Index: linux-2.6/arch/m32r/Kconfig
===================================================================
--- linux-2.6.orig/arch/m32r/Kconfig
+++ linux-2.6/arch/m32r/Kconfig
@@ -212,15 +212,6 @@ config IRAM_SIZE
# Define implied options from the CPU selection here
#

-config RWSEM_GENERIC_SPINLOCK
- bool
- depends on M32R
- default y
-
-config RWSEM_XCHGADD_ALGORITHM
- bool
- default n
-
config ARCH_HAS_ILOG2_U32
bool
default n
Index: linux-2.6/arch/m68k/Kconfig
===================================================================
--- linux-2.6.orig/arch/m68k/Kconfig
+++ linux-2.6/arch/m68k/Kconfig
@@ -10,13 +10,6 @@ config MMU
bool
default y

-config RWSEM_GENERIC_SPINLOCK
- bool
- default y
-
-config RWSEM_XCHGADD_ALGORITHM
- bool
-
config ARCH_HAS_ILOG2_U32
bool
default n
Index: linux-2.6/arch/m68knommu/Kconfig
===================================================================
--- linux-2.6.orig/arch/m68knommu/Kconfig
+++ linux-2.6/arch/m68knommu/Kconfig
@@ -21,14 +21,6 @@ config ZONE_DMA
bool
default y

-config RWSEM_GENERIC_SPINLOCK
- bool
- default y
-
-config RWSEM_XCHGADD_ALGORITHM
- bool
- default n
-
config ARCH_HAS_ILOG2_U32
bool
default n
Index: linux-2.6/arch/mips/Kconfig
===================================================================
--- linux-2.6.orig/arch/mips/Kconfig
+++ linux-2.6/arch/mips/Kconfig
@@ -838,13 +838,6 @@ source "arch/mips/philips/pnx8550/common

endmenu

-config RWSEM_GENERIC_SPINLOCK
- bool
- default y
-
-config RWSEM_XCHGADD_ALGORITHM
- bool
-
config ARCH_HAS_ILOG2_U32
bool
default n
@@ -1970,10 +1963,6 @@ config SECCOMP

endmenu

-config RWSEM_GENERIC_SPINLOCK
- bool
- default y
-
config LOCKDEP_SUPPORT
bool
default y
Index: linux-2.6/arch/parisc/Kconfig
===================================================================
--- linux-2.6.orig/arch/parisc/Kconfig
+++ linux-2.6/arch/parisc/Kconfig
@@ -19,12 +19,6 @@ config MMU
config STACK_GROWSUP
def_bool y

-config RWSEM_GENERIC_SPINLOCK
- def_bool y
-
-config RWSEM_XCHGADD_ALGORITHM
- bool
-
config ARCH_HAS_ILOG2_U32
bool
default n
Index: linux-2.6/arch/powerpc/Kconfig
===================================================================
--- linux-2.6.orig/arch/powerpc/Kconfig
+++ linux-2.6/arch/powerpc/Kconfig
@@ -34,13 +34,6 @@ config IRQ_PER_CPU
bool
default y

-config RWSEM_GENERIC_SPINLOCK
- bool
-
-config RWSEM_XCHGADD_ALGORITHM
- bool
- default y
-
config ARCH_HAS_ILOG2_U32
bool
default y
Index: linux-2.6/arch/ppc/Kconfig
===================================================================
--- linux-2.6.orig/arch/ppc/Kconfig
+++ linux-2.6/arch/ppc/Kconfig
@@ -12,13 +12,6 @@ config GENERIC_HARDIRQS
bool
default y

-config RWSEM_GENERIC_SPINLOCK
- bool
-
-config RWSEM_XCHGADD_ALGORITHM
- bool
- default y
-
config ARCH_HAS_ILOG2_U32
bool
default y
Index: linux-2.6/arch/s390/Kconfig
===================================================================
--- linux-2.6.orig/arch/s390/Kconfig
+++ linux-2.6/arch/s390/Kconfig
@@ -19,13 +19,6 @@ config STACKTRACE_SUPPORT
bool
default y

-config RWSEM_GENERIC_SPINLOCK
- bool
-
-config RWSEM_XCHGADD_ALGORITHM
- bool
- default y
-
config ARCH_HAS_ILOG2_U32
bool
default n
Index: linux-2.6/arch/sh/Kconfig
===================================================================
--- linux-2.6.orig/arch/sh/Kconfig
+++ linux-2.6/arch/sh/Kconfig
@@ -15,13 +15,6 @@ config SUPERH
gaming console. The SuperH port has a home page at
<http://www.linux-sh.org/>.

-config RWSEM_GENERIC_SPINLOCK
- bool
- default y
-
-config RWSEM_XCHGADD_ALGORITHM
- bool
-
config GENERIC_FIND_NEXT_BIT
bool
default y
Index: linux-2.6/arch/sh64/Kconfig
===================================================================
--- linux-2.6.orig/arch/sh64/Kconfig
+++ linux-2.6/arch/sh64/Kconfig
@@ -17,10 +17,6 @@ config MMU
bool
default y

-config RWSEM_GENERIC_SPINLOCK
- bool
- default y
-
config GENERIC_FIND_NEXT_BIT
bool
default y
@@ -33,9 +29,6 @@ config GENERIC_CALIBRATE_DELAY
bool
default y

-config RWSEM_XCHGADD_ALGORITHM
- bool
-
config ARCH_HAS_ILOG2_U32
bool
default n
Index: linux-2.6/arch/sparc/Kconfig
===================================================================
--- linux-2.6.orig/arch/sparc/Kconfig
+++ linux-2.6/arch/sparc/Kconfig
@@ -147,13 +147,6 @@ config SUN_IO
bool
default y

-config RWSEM_GENERIC_SPINLOCK
- bool
- default y
-
-config RWSEM_XCHGADD_ALGORITHM
- bool
-
config GENERIC_FIND_NEXT_BIT
bool
default y
Index: linux-2.6/arch/sparc64/Kconfig
===================================================================
--- linux-2.6.orig/arch/sparc64/Kconfig
+++ linux-2.6/arch/sparc64/Kconfig
@@ -167,13 +167,6 @@ config US2E_FREQ
If in doubt, say N.

# Global things across all Sun machines.
-config RWSEM_GENERIC_SPINLOCK
- bool
-
-config RWSEM_XCHGADD_ALGORITHM
- bool
- default y
-
config GENERIC_FIND_NEXT_BIT
bool
default y
Index: linux-2.6/arch/v850/Kconfig
===================================================================
--- linux-2.6.orig/arch/v850/Kconfig
+++ linux-2.6/arch/v850/Kconfig
@@ -13,12 +13,6 @@ config MMU
config ZONE_DMA
bool
default y
-config RWSEM_GENERIC_SPINLOCK
- bool
- default y
-config RWSEM_XCHGADD_ALGORITHM
- bool
- default n
config GENERIC_FIND_NEXT_BIT
bool
default y
Index: linux-2.6/arch/x86_64/Kconfig
===================================================================
--- linux-2.6.orig/arch/x86_64/Kconfig
+++ linux-2.6/arch/x86_64/Kconfig
@@ -62,13 +62,6 @@ config ISA
config SBUS
bool

-config RWSEM_GENERIC_SPINLOCK
- bool
- default y
-
-config RWSEM_XCHGADD_ALGORITHM
- bool
-
config GENERIC_HWEIGHT
bool
default y
Index: linux-2.6/arch/xtensa/Kconfig
===================================================================
--- linux-2.6.orig/arch/xtensa/Kconfig
+++ linux-2.6/arch/xtensa/Kconfig
@@ -22,10 +22,6 @@ config XTENSA
with reasonable minimum requirements. The Xtensa Linux project has
a home page at <http://xtensa.sourceforge.net/>.

-config RWSEM_XCHGADD_ALGORITHM
- bool
- default y
-
config GENERIC_FIND_NEXT_BIT
bool
default y
Index: linux-2.6/arch/i386/Kconfig.cpu
===================================================================
--- linux-2.6.orig/arch/i386/Kconfig.cpu
+++ linux-2.6/arch/i386/Kconfig.cpu
@@ -233,16 +233,6 @@ config X86_L1_CACHE_SHIFT
default "5" if MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCRUSOE || MEFFICEON || MCYRIXIII || MK6 || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || M586 || MVIAC3_2 || MGEODE_LX
default "6" if MK7 || MK8 || MPENTIUMM || MCORE2

-config RWSEM_GENERIC_SPINLOCK
- bool
- depends on M386
- default y
-
-config RWSEM_XCHGADD_ALGORITHM
- bool
- depends on !M386
- default y
-
config ARCH_HAS_ILOG2_U32
bool
default n
Index: linux-2.6/arch/um/Kconfig.x86_64
===================================================================
--- linux-2.6.orig/arch/um/Kconfig.x86_64
+++ linux-2.6/arch/um/Kconfig.x86_64
@@ -7,10 +7,6 @@ config 64BIT
default y

#XXX: this is so in the underlying arch, but it's wrong!!!
-config RWSEM_GENERIC_SPINLOCK
- bool
- default y
-
config SEMAPHORE_SLEEPERS
bool
default y
Index: linux-2.6/lib/Makefile
===================================================================
--- linux-2.6.orig/lib/Makefile
+++ linux-2.6/lib/Makefile
@@ -23,8 +23,6 @@ obj-$(CONFIG_GENERIC_IOMAP) += iomap.o
obj-$(CONFIG_HAS_IOMEM) += iomap_copy.o devres.o
obj-$(CONFIG_DEBUG_LOCKING_API_SELFTESTS) += locking-selftest.o
obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
-lib-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
-lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
lib-$(CONFIG_SEMAPHORE_SLEEPERS) += semaphore-sleepers.o
lib-$(CONFIG_GENERIC_FIND_NEXT_BIT) += find_next_bit.o
obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o
Index: linux-2.6/include/linux/rwsem-spinlock.h
===================================================================
--- linux-2.6.orig/include/linux/rwsem-spinlock.h
+++ /dev/null
@@ -1,78 +0,0 @@
-/* rwsem-spinlock.h: fallback C implementation
- *
- * Copyright (c) 2001 David Howells (dhowells@redhat.com).
- * - Derived partially from ideas by Andrea Arcangeli <andrea@suse.de>
- * - Derived also from comments by Linus
- */
-
-#ifndef _LINUX_RWSEM_SPINLOCK_H
-#define _LINUX_RWSEM_SPINLOCK_H
-
-#ifndef _LINUX_RWSEM_H
-#error "please don't include linux/rwsem-spinlock.h directly, use linux/rwsem.h instead"
-#endif
-
-#include <linux/spinlock.h>
-#include <linux/list.h>
-
-#ifdef __KERNEL__
-
-#include <linux/types.h>
-
-struct rwsem_waiter;
-
-/*
- * the rw-semaphore definition
- * - if activity is 0 then there are no active readers or writers
- * - if activity is +ve then that is the number of active readers
- * - if activity is -1 then there is one active writer
- * - if wait_list is not empty, then there are processes waiting for the semaphore
- */
-struct rw_semaphore {
- __s32 activity;
- spinlock_t wait_lock;
- struct list_head wait_list;
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
- struct lockdep_map dep_map;
-#endif
-};
-
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-# define __RWSEM_DEP_MAP_INIT(lockname) , .dep_map = { .name = #lockname }
-#else
-# define __RWSEM_DEP_MAP_INIT(lockname)
-#endif
-
-#define __RWSEM_INITIALIZER(name) \
-{ 0, __SPIN_LOCK_UNLOCKED(name.wait_lock), LIST_HEAD_INIT((name).wait_list) \
- __RWSEM_DEP_MAP_INIT(name) }
-
-#define DECLARE_RWSEM(name) \
- struct rw_semaphore name = __RWSEM_INITIALIZER(name)
-
-extern void __init_rwsem(struct rw_semaphore *sem, const char *name,
- struct lock_class_key *key);
-
-#define init_rwsem(sem) \
-do { \
- static struct lock_class_key __key; \
- \
- __init_rwsem((sem), #sem, &__key); \
-} while (0)
-
-extern void FASTCALL(__down_read(struct rw_semaphore *sem));
-extern int FASTCALL(__down_read_trylock(struct rw_semaphore *sem));
-extern void FASTCALL(__down_write(struct rw_semaphore *sem));
-extern void FASTCALL(__down_write_nested(struct rw_semaphore *sem, int subclass));
-extern int FASTCALL(__down_write_trylock(struct rw_semaphore *sem));
-extern void FASTCALL(__up_read(struct rw_semaphore *sem));
-extern void FASTCALL(__up_write(struct rw_semaphore *sem));
-extern void FASTCALL(__downgrade_write(struct rw_semaphore *sem));
-
-static inline int rwsem_is_locked(struct rw_semaphore *sem)
-{
- return (sem->activity != 0);
-}
-
-#endif /* __KERNEL__ */
-#endif /* _LINUX_RWSEM_SPINLOCK_H */
Index: linux-2.6/arch/sparc/lib/rwsem.S
===================================================================
--- linux-2.6.orig/arch/sparc/lib/rwsem.S
+++ /dev/null
@@ -1,204 +0,0 @@
-/* $Id: rwsem.S,v 1.5 2000/05/09 17:40:13 davem Exp $
- * Assembly part of rw semaphores.
- *
- * Copyright (C) 1999 Jakub Jelinek (jakub@redhat.com)
- */
-
-#include <asm/ptrace.h>
-#include <asm/psr.h>
-
- .section .sched.text
- .align 4
-
- .globl ___down_read
-___down_read:
- rd %psr, %g3
- nop
- nop
- nop
- or %g3, PSR_PIL, %g7
- wr %g7, 0, %psr
- nop
- nop
- nop
-#ifdef CONFIG_SMP
-1: ldstub [%g1 + 4], %g7
- tst %g7
- bne 1b
- ld [%g1], %g7
- sub %g7, 1, %g7
- st %g7, [%g1]
- stb %g0, [%g1 + 4]
-#else
- ld [%g1], %g7
- sub %g7, 1, %g7
- st %g7, [%g1]
-#endif
- wr %g3, 0, %psr
- add %g7, 1, %g7
- nop
- nop
- subcc %g7, 1, %g7
- bneg 3f
- nop
-2: jmpl %o7, %g0
- mov %g4, %o7
-3: save %sp, -64, %sp
- mov %g1, %l1
- mov %g4, %l4
- bcs 4f
- mov %g5, %l5
- call down_read_failed
- mov %l1, %o0
- mov %l1, %g1
- mov %l4, %g4
- ba ___down_read
- restore %l5, %g0, %g5
-4: call down_read_failed_biased
- mov %l1, %o0
- mov %l1, %g1
- mov %l4, %g4
- ba 2b
- restore %l5, %g0, %g5
-
- .globl ___down_write
-___down_write:
- rd %psr, %g3
- nop
- nop
- nop
- or %g3, PSR_PIL, %g7
- wr %g7, 0, %psr
- sethi %hi(0x01000000), %g2
- nop
- nop
-#ifdef CONFIG_SMP
-1: ldstub [%g1 + 4], %g7
- tst %g7
- bne 1b
- ld [%g1], %g7
- sub %g7, %g2, %g7
- st %g7, [%g1]
- stb %g0, [%g1 + 4]
-#else
- ld [%g1], %g7
- sub %g7, %g2, %g7
- st %g7, [%g1]
-#endif
- wr %g3, 0, %psr
- add %g7, %g2, %g7
- nop
- nop
- subcc %g7, %g2, %g7
- bne 3f
- nop
-2: jmpl %o7, %g0
- mov %g4, %o7
-3: save %sp, -64, %sp
- mov %g1, %l1
- mov %g4, %l4
- bcs 4f
- mov %g5, %l5
- call down_write_failed
- mov %l1, %o0
- mov %l1, %g1
- mov %l4, %g4
- ba ___down_write
- restore %l5, %g0, %g5
-4: call down_write_failed_biased
- mov %l1, %o0
- mov %l1, %g1
- mov %l4, %g4
- ba 2b
- restore %l5, %g0, %g5
-
- .text
- .globl ___up_read
-___up_read:
- rd %psr, %g3
- nop
- nop
- nop
- or %g3, PSR_PIL, %g7
- wr %g7, 0, %psr
- nop
- nop
- nop
-#ifdef CONFIG_SMP
-1: ldstub [%g1 + 4], %g7
- tst %g7
- bne 1b
- ld [%g1], %g7
- add %g7, 1, %g7
- st %g7, [%g1]
- stb %g0, [%g1 + 4]
-#else
- ld [%g1], %g7
- add %g7, 1, %g7
- st %g7, [%g1]
-#endif
- wr %g3, 0, %psr
- nop
- nop
- nop
- cmp %g7, 0
- be 3f
- nop
-2: jmpl %o7, %g0
- mov %g4, %o7
-3: save %sp, -64, %sp
- mov %g1, %l1
- mov %g4, %l4
- mov %g5, %l5
- clr %o1
- call __rwsem_wake
- mov %l1, %o0
- mov %l1, %g1
- mov %l4, %g4
- ba 2b
- restore %l5, %g0, %g5
-
- .globl ___up_write
-___up_write:
- rd %psr, %g3
- nop
- nop
- nop
- or %g3, PSR_PIL, %g7
- wr %g7, 0, %psr
- sethi %hi(0x01000000), %g2
- nop
- nop
-#ifdef CONFIG_SMP
-1: ldstub [%g1 + 4], %g7
- tst %g7
- bne 1b
- ld [%g1], %g7
- add %g7, %g2, %g7
- st %g7, [%g1]
- stb %g0, [%g1 + 4]
-#else
- ld [%g1], %g7
- add %g7, %g2, %g7
- st %g7, [%g1]
-#endif
- wr %g3, 0, %psr
- sub %g7, %g2, %g7
- nop
- nop
- addcc %g7, %g2, %g7
- bcs 3f
- nop
-2: jmpl %o7, %g0
- mov %g4, %o7
-3: save %sp, -64, %sp
- mov %g1, %l1
- mov %g4, %l4
- mov %g5, %l5
- mov %g7, %o1
- call __rwsem_wake
- mov %l1, %o0
- mov %l1, %g1
- mov %l4, %g4
- ba 2b
- restore %l5, %g0, %g5
Index: linux-2.6/arch/sparc64/lib/rwsem.S
===================================================================
--- linux-2.6.orig/arch/sparc64/lib/rwsem.S
+++ /dev/null
@@ -1,170 +0,0 @@
-/* rwsem.S: RW semaphore assembler.
- *
- * Written by David S. Miller (davem@redhat.com), 2001.
- * Derived from asm-i386/rwsem.h
- */
-
-#include <asm/rwsem-const.h>
-
- .section .sched.text
-
- .globl __down_read
-__down_read:
-1: lduw [%o0], %g1
- add %g1, 1, %g7
- cas [%o0], %g1, %g7
- cmp %g1, %g7
- bne,pn %icc, 1b
- add %g7, 1, %g7
- cmp %g7, 0
- membar #StoreLoad | #StoreStore
- bl,pn %icc, 3f
- nop
-2:
- retl
- nop
-3:
- save %sp, -192, %sp
- call rwsem_down_read_failed
- mov %i0, %o0
- ret
- restore
- .size __down_read, .-__down_read
-
- .globl __down_read_trylock
-__down_read_trylock:
-1: lduw [%o0], %g1
- add %g1, 1, %g7
- cmp %g7, 0
- bl,pn %icc, 2f
- mov 0, %o1
- cas [%o0], %g1, %g7
- cmp %g1, %g7
- bne,pn %icc, 1b
- mov 1, %o1
- membar #StoreLoad | #StoreStore
-2: retl
- mov %o1, %o0
- .size __down_read_trylock, .-__down_read_trylock
-
- .globl __down_write
-__down_write:
- sethi %hi(RWSEM_ACTIVE_WRITE_BIAS), %g1
- or %g1, %lo(RWSEM_ACTIVE_WRITE_BIAS), %g1
-1:
- lduw [%o0], %g3
- add %g3, %g1, %g7
- cas [%o0], %g3, %g7
- cmp %g3, %g7
- bne,pn %icc, 1b
- cmp %g7, 0
- membar #StoreLoad | #StoreStore
- bne,pn %icc, 3f
- nop
-2: retl
- nop
-3:
- save %sp, -192, %sp
- call rwsem_down_write_failed
- mov %i0, %o0
- ret
- restore
- .size __down_write, .-__down_write
-
- .globl __down_write_trylock
-__down_write_trylock:
- sethi %hi(RWSEM_ACTIVE_WRITE_BIAS), %g1
- or %g1, %lo(RWSEM_ACTIVE_WRITE_BIAS), %g1
-1:
- lduw [%o0], %g3
- cmp %g3, 0
- bne,pn %icc, 2f
- mov 0, %o1
- add %g3, %g1, %g7
- cas [%o0], %g3, %g7
- cmp %g3, %g7
- bne,pn %icc, 1b
- mov 1, %o1
- membar #StoreLoad | #StoreStore
-2: retl
- mov %o1, %o0
- .size __down_write_trylock, .-__down_write_trylock
-
- .globl __up_read
-__up_read:
-1:
- lduw [%o0], %g1
- sub %g1, 1, %g7
- cas [%o0], %g1, %g7
- cmp %g1, %g7
- bne,pn %icc, 1b
- cmp %g7, 0
- membar #StoreLoad | #StoreStore
- bl,pn %icc, 3f
- nop
-2: retl
- nop
-3: sethi %hi(RWSEM_ACTIVE_MASK), %g1
- sub %g7, 1, %g7
- or %g1, %lo(RWSEM_ACTIVE_MASK), %g1
- andcc %g7, %g1, %g0
- bne,pn %icc, 2b
- nop
- save %sp, -192, %sp
- call rwsem_wake
- mov %i0, %o0
- ret
- restore
- .size __up_read, .-__up_read
-
- .globl __up_write
-__up_write:
- sethi %hi(RWSEM_ACTIVE_WRITE_BIAS), %g1
- or %g1, %lo(RWSEM_ACTIVE_WRITE_BIAS), %g1
-1:
- lduw [%o0], %g3
- sub %g3, %g1, %g7
- cas [%o0], %g3, %g7
- cmp %g3, %g7
- bne,pn %icc, 1b
- sub %g7, %g1, %g7
- cmp %g7, 0
- membar #StoreLoad | #StoreStore
- bl,pn %icc, 3f
- nop
-2:
- retl
- nop
-3:
- save %sp, -192, %sp
- call rwsem_wake
- mov %i0, %o0
- ret
- restore
- .size __up_write, .-__up_write
-
- .globl __downgrade_write
-__downgrade_write:
- sethi %hi(RWSEM_WAITING_BIAS), %g1
- or %g1, %lo(RWSEM_WAITING_BIAS), %g1
-1:
- lduw [%o0], %g3
- sub %g3, %g1, %g7
- cas [%o0], %g3, %g7
- cmp %g3, %g7
- bne,pn %icc, 1b
- sub %g7, %g1, %g7
- cmp %g7, 0
- membar #StoreLoad | #StoreStore
- bl,pn %icc, 3f
- nop
-2:
- retl
- nop
-3:
- save %sp, -192, %sp
- call rwsem_downgrade_wake
- mov %i0, %o0
- ret
- restore
- .size __downgrade_write, .-__downgrade_write