Commit 653a5b0b authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
Browse files

locking/ww_mutex: Abstract out internal lock accesses 



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

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211304.734635961@linutronix.de
parent bdb18914

include/linux/ww_mutex.h

+9 −4
Original line number Diff line number Diff line
@@ -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_mutex *lock); 
 */

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(struct ww_mutex *lock) 
 */

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

kernel/locking/ww_mutex.h

+19 −4
Original line number Diff line number Diff line
@@ -68,6 +68,21 @@ __ww_mutex_has_waiters(struct mutex *lock) 
	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 MUTEX *lock, 
{

	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 @@ __ww_mutex_check_waiters(struct MUTEX *lock, struct ww_acquire_ctx *ww_ctx) 
{

	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_mutex *lock, struct ww_acquire_ctx *ctx) 
	 * 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