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| author | Bart Van Assche <bart.vanassche@sandisk.com> | 2017-06-20 21:15:44 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2017-06-21 04:27:14 +0300 |
| commit | 9e0c829906b9aa1e7ad84689f2bcd56457bdb417 (patch) | |
| tree | d6fa3112daba8efadb06670737bca74f393319ff /include/linux/blkdev.h | |
| parent | c3a148d20affcc334348402865169a61000d3905 (diff) | |
| download | linux-9e0c829906b9aa1e7ad84689f2bcd56457bdb417.tar.xz | |
block: Add a comment above queue_lockdep_assert_held()
Add a comment above the queue_lockdep_assert_held() macro that
explains the purpose of the q->queue_lock test.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Omar Sandoval <osandov@fb.com>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include/linux/blkdev.h')
| -rw-r--r-- | include/linux/blkdev.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 9a36164487d0..3e60e7a654bd 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -635,6 +635,13 @@ struct request_queue { (1 << QUEUE_FLAG_SAME_COMP) | \ (1 << QUEUE_FLAG_POLL)) +/* + * @q->queue_lock is set while a queue is being initialized. Since we know + * that no other threads access the queue object before @q->queue_lock has + * been set, it is safe to manipulate queue flags without holding the + * queue_lock if @q->queue_lock == NULL. See also blk_alloc_queue_node() and + * blk_init_allocated_queue(). + */ static inline void queue_lockdep_assert_held(struct request_queue *q) { if (q->queue_lock) |