diff options
Diffstat (limited to 'block/blk.h')
| -rw-r--r-- | block/blk.h | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/block/blk.h b/block/blk.h index a6b1de509733..f6053e9dd2aa 100644 --- a/block/blk.h +++ b/block/blk.h @@ -729,4 +729,35 @@ static inline void blk_unfreeze_release_lock(struct request_queue *q) } #endif +/* + * debugfs directory and file creation can trigger fs reclaim, which can enter + * back into the block layer request_queue. This can cause deadlock if the + * queue is frozen. Use NOIO context together with debugfs_mutex to prevent fs + * reclaim from triggering block I/O. + */ +static inline void blk_debugfs_lock_nomemsave(struct request_queue *q) +{ + mutex_lock(&q->debugfs_mutex); +} + +static inline void blk_debugfs_unlock_nomemrestore(struct request_queue *q) +{ + mutex_unlock(&q->debugfs_mutex); +} + +static inline unsigned int __must_check blk_debugfs_lock(struct request_queue *q) +{ + unsigned int memflags = memalloc_noio_save(); + + blk_debugfs_lock_nomemsave(q); + return memflags; +} + +static inline void blk_debugfs_unlock(struct request_queue *q, + unsigned int memflags) +{ + blk_debugfs_unlock_nomemrestore(q); + memalloc_noio_restore(memflags); +} + #endif /* BLK_INTERNAL_H */ |