diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index df8c99c99df9..dfeb7174219e 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1174,6 +1174,51 @@ enum { BTRFS_ROOT_RESET_LOCKDEP_CLASS, }; +/* + * Lockdep annotation for wait events. + * + * @owner: The struct where the lockdep map is defined + * @lock: The lockdep map corresponding to a wait event + * + * This macro is used to annotate a wait event. In this case a thread acquires + * the lockdep map as writer (exclusive lock) because it has to block until all + * the threads that hold the lock as readers signal the condition for the wait + * event and release their locks. + */ +#define btrfs_might_wait_for_event(owner, lock) \ + do { \ + rwsem_acquire(&owner->lock##_map, 0, 0, _THIS_IP_); \ + rwsem_release(&owner->lock##_map, _THIS_IP_); \ + } while (0) + +/* + * Protection for the resource/condition of a wait event. + * + * @owner: The struct where the lockdep map is defined + * @lock: The lockdep map corresponding to a wait event + * + * Many threads can modify the condition for the wait event at the same time + * and signal the threads that block on the wait event. The threads that modify + * the condition and do the signaling acquire the lock as readers (shared + * lock). + */ +#define btrfs_lockdep_acquire(owner, lock) \ + rwsem_acquire_read(&owner->lock##_map, 0, 0, _THIS_IP_) + +/* + * Used after signaling the condition for a wait event to release the lockdep + * map held by a reader thread. + */ +#define btrfs_lockdep_release(owner, lock) \ + rwsem_release(&owner->lock##_map, _THIS_IP_) + +/* Initialization of the lockdep map */ +#define btrfs_lockdep_init_map(owner, lock) \ + do { \ + static struct lock_class_key lock##_key; \ + lockdep_init_map(&owner->lock##_map, #lock, &lock##_key, 0); \ + } while (0) + static inline void btrfs_wake_unfinished_drop(struct btrfs_fs_info *fs_info) { clear_and_wake_up_bit(BTRFS_FS_UNFINISHED_DROPS, &fs_info->flags);