diff options
| author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2015-12-21 03:14:03 +0100 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2015-12-21 03:14:03 +0100 |
| commit | e219aafe50fd546b8686582ddbafd24c3c2eda04 (patch) | |
| tree | a665e08ca8d42f20ac8e5dcc8565d666cffb26bd /kernel/locking/osq_lock.c | |
| parent | ffe12855a5f7f195589130197558e6a5c276caa4 (diff) | |
| parent | 24c96dc79c5e76d3cff7a33f955a4d3244644766 (diff) | |
Merge back earlier 'pm-domains' material for v4.5.
Diffstat (limited to 'kernel/locking/osq_lock.c')
| -rw-r--r-- | kernel/locking/osq_lock.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/kernel/locking/osq_lock.c b/kernel/locking/osq_lock.c index dc85ee23a26f..d092a0c9c2d4 100644 --- a/kernel/locking/osq_lock.c +++ b/kernel/locking/osq_lock.c @@ -50,7 +50,7 @@ osq_wait_next(struct optimistic_spin_queue *lock, for (;;) { if (atomic_read(&lock->tail) == curr && - atomic_cmpxchg(&lock->tail, curr, old) == curr) { + atomic_cmpxchg_acquire(&lock->tail, curr, old) == curr) { /* * We were the last queued, we moved @lock back. @prev * will now observe @lock and will complete its @@ -92,7 +92,11 @@ bool osq_lock(struct optimistic_spin_queue *lock) node->next = NULL; node->cpu = curr; - old = atomic_xchg(&lock->tail, curr); + /* + * ACQUIRE semantics, pairs with corresponding RELEASE + * in unlock() uncontended, or fastpath. + */ + old = atomic_xchg_acquire(&lock->tail, curr); if (old == OSQ_UNLOCKED_VAL) return true; @@ -184,7 +188,8 @@ void osq_unlock(struct optimistic_spin_queue *lock) /* * Fast path for the uncontended case. */ - if (likely(atomic_cmpxchg(&lock->tail, curr, OSQ_UNLOCKED_VAL) == curr)) + if (likely(atomic_cmpxchg_release(&lock->tail, curr, + OSQ_UNLOCKED_VAL) == curr)) return; /* |