[patch V4 47/68] locking/ww_mutex: Abstract internal lock access

Thomas Gleixner
2021-08-11T12:27:01Z

Accessing the internal wait_lock of mutex and rtmutex is slightly
different. Provide helper functions for that.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
include/linux/ww_mutex.h | 13 +++++++++----
kernel/locking/ww_mutex.h | 23 +++++++++++++++++++----
2 files changed, 28 insertions(+), 8 deletions(-)

--- a/include/linux/ww_mutex.h
+++ b/include/linux/ww_mutex.h
@@ -19,6 +19,11 @@

#include <linux/mutex.h>

+#define WW_MUTEX_BASE mutex
+#define ww_mutex_base_init(l,n,k) __mutex_init(l,n,k)
+#define ww_mutex_base_trylock(l) mutex_trylock(l)
+#define ww_mutex_base_is_locked(b) mutex_is_locked((b))
+
struct ww_class {
atomic_long_t stamp;
struct lock_class_key acquire_key;
@@ -29,7 +34,7 @@ struct ww_class {
};

struct ww_mutex {
- struct mutex base;
+ struct WW_MUTEX_BASE base;
struct ww_acquire_ctx *ctx;
#ifdef CONFIG_DEBUG_MUTEXES
struct ww_class *ww_class;
@@ -82,7 +87,7 @@ struct ww_acquire_ctx {
static inline void ww_mutex_init(struct ww_mutex *lock,
struct ww_class *ww_class)
{
- __mutex_init(&lock->base, ww_class->mutex_name, &ww_class->mutex_key);
+ ww_mutex_base_init(&lock->base, ww_class->mutex_name, &ww_class->mutex_key);
lock->ctx = NULL;
#ifdef CONFIG_DEBUG_MUTEXES
lock->ww_class = ww_class;
@@ -330,7 +335,7 @@ extern void ww_mutex_unlock(struct ww_mu
*/
static inline int __must_check ww_mutex_trylock(struct ww_mutex *lock)
{
- return mutex_trylock(&lock->base);
+ return ww_mutex_base_trylock(&lock->base);
}

/***
@@ -354,7 +359,7 @@ static inline void ww_mutex_destroy(stru
*/
static inline bool ww_mutex_is_locked(struct ww_mutex *lock)
{
- return mutex_is_locked(&lock->base);
+ return ww_mutex_base_is_locked(&lock->base);
}

#endif
--- a/kernel/locking/ww_mutex.h
+++ b/kernel/locking/ww_mutex.h
@@ -68,6 +68,21 @@ static inline bool
return atomic_long_read(&lock->owner) & MUTEX_FLAG_WAITERS;
}

+static inline void lock_wait_lock(struct mutex *lock)
+{
+ raw_spin_lock(&lock->wait_lock);
+}
+
+static inline void unlock_wait_lock(struct mutex *lock)
+{
+ raw_spin_unlock(&lock->wait_lock);
+}
+
+static inline void lockdep_assert_wait_lock_held(struct mutex *lock)
+{
+ lockdep_assert_held(&lock->wait_lock);
+}
+
/*
* Wait-Die:
* The newer transactions are killed when:
@@ -174,7 +189,7 @@ static bool __ww_mutex_wound(struct MUTE
{
struct task_struct *owner = __ww_mutex_owner(lock);

- lockdep_assert_held(&lock->wait_lock);
+ lockdep_assert_wait_lock_held(lock);

/*
* Possible through __ww_mutex_add_waiter() when we race with
@@ -227,7 +242,7 @@ static void
{
struct MUTEX_WAITER *cur;

- lockdep_assert_held(&lock->wait_lock);
+ lockdep_assert_wait_lock_held(lock);

for (cur = __ww_waiter_first(lock); cur;
cur = __ww_waiter_next(lock, cur)) {
@@ -275,9 +290,9 @@ ww_mutex_set_context_fastpath(struct ww_
* Uh oh, we raced in fastpath, check if any of the waiters need to
* die or wound us.
*/
- raw_spin_lock(&lock->base.wait_lock);
+ lock_wait_lock(&lock->base);
__ww_mutex_check_waiters(&lock->base, ctx);
- raw_spin_unlock(&lock->base.wait_lock);
+ unlock_wait_lock(&lock->base);
}

static __always_inline int