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-rw-r--r--kernel/mutex.c41
1 files changed, 18 insertions, 23 deletions
diff --git a/kernel/mutex.c b/kernel/mutex.c
index 7ff48c55a98b..386ad5da47a5 100644
--- a/kernel/mutex.c
+++ b/kernel/mutex.c
@@ -463,7 +463,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
* performed the optimistic spinning cannot be done.
*/
if (ACCESS_ONCE(ww->ctx))
- break;
+ goto slowpath;
}
/*
@@ -474,7 +474,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
owner = ACCESS_ONCE(lock->owner);
if (owner && !mutex_spin_on_owner(lock, owner)) {
mspin_unlock(MLOCK(lock), &node);
- break;
+ goto slowpath;
}
if ((atomic_read(&lock->count) == 1) &&
@@ -489,8 +489,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
mutex_set_owner(lock);
mspin_unlock(MLOCK(lock), &node);
- preempt_enable();
- return 0;
+ goto done;
}
mspin_unlock(MLOCK(lock), &node);
@@ -501,7 +500,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
* the owner complete.
*/
if (!owner && (need_resched() || rt_task(task)))
- break;
+ goto slowpath;
/*
* The cpu_relax() call is a compiler barrier which forces
@@ -515,6 +514,10 @@ slowpath:
#endif
spin_lock_mutex(&lock->wait_lock, flags);
+ /* once more, can we acquire the lock? */
+ if (MUTEX_SHOW_NO_WAITER(lock) && (atomic_xchg(&lock->count, 0) == 1))
+ goto skip_wait;
+
debug_mutex_lock_common(lock, &waiter);
debug_mutex_add_waiter(lock, &waiter, task_thread_info(task));
@@ -522,9 +525,6 @@ slowpath:
list_add_tail(&waiter.list, &lock->wait_list);
waiter.task = task;
- if (MUTEX_SHOW_NO_WAITER(lock) && (atomic_xchg(&lock->count, -1) == 1))
- goto done;
-
lock_contended(&lock->dep_map, ip);
for (;;) {
@@ -538,7 +538,7 @@ slowpath:
* other waiters:
*/
if (MUTEX_SHOW_NO_WAITER(lock) &&
- (atomic_xchg(&lock->count, -1) == 1))
+ (atomic_xchg(&lock->count, -1) == 1))
break;
/*
@@ -563,24 +563,25 @@ slowpath:
schedule_preempt_disabled();
spin_lock_mutex(&lock->wait_lock, flags);
}
+ mutex_remove_waiter(lock, &waiter, current_thread_info());
+ /* set it to 0 if there are no waiters left: */
+ if (likely(list_empty(&lock->wait_list)))
+ atomic_set(&lock->count, 0);
+ debug_mutex_free_waiter(&waiter);
-done:
+skip_wait:
+ /* got the lock - cleanup and rejoice! */
lock_acquired(&lock->dep_map, ip);
- /* got the lock - rejoice! */
- mutex_remove_waiter(lock, &waiter, current_thread_info());
mutex_set_owner(lock);
if (!__builtin_constant_p(ww_ctx == NULL)) {
- struct ww_mutex *ww = container_of(lock,
- struct ww_mutex,
- base);
+ struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
struct mutex_waiter *cur;
/*
* This branch gets optimized out for the common case,
* and is only important for ww_mutex_lock.
*/
-
ww_mutex_lock_acquired(ww, ww_ctx);
ww->ctx = ww_ctx;
@@ -594,15 +595,9 @@ done:
}
}
- /* set it to 0 if there are no waiters left: */
- if (likely(list_empty(&lock->wait_list)))
- atomic_set(&lock->count, 0);
-
spin_unlock_mutex(&lock->wait_lock, flags);
-
- debug_mutex_free_waiter(&waiter);
+done:
preempt_enable();
-
return 0;
err: