diff options
| -rw-r--r-- | kernel/locking/mutex.c | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index 4dd6e4c219de..fbbd2eda867e 100644 --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -136,9 +136,12 @@ void mspin_lock(struct mspin_node **lock, struct mspin_node *node) return; } ACCESS_ONCE(prev->next) = node; - smp_wmb(); - /* Wait until the lock holder passes the lock down */ - while (!ACCESS_ONCE(node->locked)) + /* + * Wait until the lock holder passes the lock down. + * Using smp_load_acquire() provides a memory barrier that + * ensures subsequent operations happen after the lock is acquired. + */ + while (!(smp_load_acquire(&node->locked))) arch_mutex_cpu_relax(); } @@ -156,8 +159,13 @@ static void mspin_unlock(struct mspin_node **lock, struct mspin_node *node) while (!(next = ACCESS_ONCE(node->next))) arch_mutex_cpu_relax(); } - ACCESS_ONCE(next->locked) = 1; - smp_wmb(); + /* + * Pass lock to next waiter. + * smp_store_release() provides a memory barrier to ensure + * all operations in the critical section has been completed + * before unlocking. + */ + smp_store_release(&next->locked, 1); } /* |