diff options
| -rw-r--r-- | include/linux/percpu-rwsem.h | 6 | ||||
| -rw-r--r-- | include/linux/rwsem.h | 6 | ||||
| -rw-r--r-- | kernel/locking/rwsem-xadd.c | 2 |
3 files changed, 13 insertions, 1 deletions
diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h index b1f37a89e368..79b99d653e03 100644 --- a/include/linux/percpu-rwsem.h +++ b/include/linux/percpu-rwsem.h @@ -133,7 +133,7 @@ static inline void percpu_rwsem_release(struct percpu_rw_semaphore *sem, lock_release(&sem->rw_sem.dep_map, 1, ip); #ifdef CONFIG_RWSEM_SPIN_ON_OWNER if (!read) - sem->rw_sem.owner = NULL; + sem->rw_sem.owner = RWSEM_OWNER_UNKNOWN; #endif } @@ -141,6 +141,10 @@ static inline void percpu_rwsem_acquire(struct percpu_rw_semaphore *sem, bool read, unsigned long ip) { lock_acquire(&sem->rw_sem.dep_map, 0, 1, read, 1, NULL, ip); +#ifdef CONFIG_RWSEM_SPIN_ON_OWNER + if (!read) + sem->rw_sem.owner = current; +#endif } #endif diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h index 56707d5ff6ad..ab93b6eae696 100644 --- a/include/linux/rwsem.h +++ b/include/linux/rwsem.h @@ -44,6 +44,12 @@ struct rw_semaphore { #endif }; +/* + * Setting bit 0 of the owner field with other non-zero bits will indicate + * that the rwsem is writer-owned with an unknown owner. + */ +#define RWSEM_OWNER_UNKNOWN ((struct task_struct *)-1L) + extern struct rw_semaphore *rwsem_down_read_failed(struct rw_semaphore *sem); extern struct rw_semaphore *rwsem_down_read_failed_killable(struct rw_semaphore *sem); extern struct rw_semaphore *rwsem_down_write_failed(struct rw_semaphore *sem); diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c index 604d247ea8c3..a90336779375 100644 --- a/kernel/locking/rwsem-xadd.c +++ b/kernel/locking/rwsem-xadd.c @@ -352,6 +352,8 @@ static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem) struct task_struct *owner; bool ret = true; + BUILD_BUG_ON(!rwsem_has_anonymous_owner(RWSEM_OWNER_UNKNOWN)); + if (need_resched()) return false; |