diff options
Diffstat (limited to 'kernel/locking/rwsem.c')
| -rw-r--r-- | kernel/locking/rwsem.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index 65f0262f635e..44873594de03 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -133,14 +133,19 @@ * the owner value concurrently without lock. Read from owner, however, * may not need READ_ONCE() as long as the pointer value is only used * for comparison and isn't being dereferenced. + * + * Both rwsem_{set,clear}_owner() functions should be in the same + * preempt disable section as the atomic op that changes sem->count. */ static inline void rwsem_set_owner(struct rw_semaphore *sem) { + lockdep_assert_preemption_disabled(); atomic_long_set(&sem->owner, (long)current); } static inline void rwsem_clear_owner(struct rw_semaphore *sem) { + lockdep_assert_preemption_disabled(); atomic_long_set(&sem->owner, 0); } @@ -251,13 +256,16 @@ static inline bool rwsem_read_trylock(struct rw_semaphore *sem, long *cntp) static inline bool rwsem_write_trylock(struct rw_semaphore *sem) { long tmp = RWSEM_UNLOCKED_VALUE; + bool ret = false; + preempt_disable(); if (atomic_long_try_cmpxchg_acquire(&sem->count, &tmp, RWSEM_WRITER_LOCKED)) { rwsem_set_owner(sem); - return true; + ret = true; } - return false; + preempt_enable(); + return ret; } /* @@ -1352,8 +1360,10 @@ static inline void __up_write(struct rw_semaphore *sem) DEBUG_RWSEMS_WARN_ON((rwsem_owner(sem) != current) && !rwsem_test_oflags(sem, RWSEM_NONSPINNABLE), sem); + preempt_disable(); rwsem_clear_owner(sem); tmp = atomic_long_fetch_add_release(-RWSEM_WRITER_LOCKED, &sem->count); + preempt_enable(); if (unlikely(tmp & RWSEM_FLAG_WAITERS)) rwsem_wake(sem); } |