block: add QUEUE_FLAG_NOWAIT
Add QUEUE_FLAG_NOWAIT to allow a block device to advertise support for
REQ_NOWAIT. Bio-based devices may set QUEUE_FLAG_NOWAIT where
applicable.
Update QUEUE_FLAG_MQ_DEFAULT to include QUEUE_FLAG_NOWAIT. Also
update submit_bio_checks() to verify it is set for REQ_NOWAIT bios.
Reported-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/blk-core.c b/block/blk-core.c
index 1cc4fa6..4884f1e 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -814,9 +814,9 @@ static noinline_for_stack bool submit_bio_checks(struct bio *bio)
/*
* For a REQ_NOWAIT based request, return -EOPNOTSUPP
- * if queue is not a request based queue.
+ * if queue does not support NOWAIT.
*/
- if ((bio->bi_opf & REQ_NOWAIT) && !queue_is_mq(q))
+ if ((bio->bi_opf & REQ_NOWAIT) && !blk_queue_nowait(q))
goto not_supported;
if (should_fail_bio(bio))
