Commit bfd343aa authored by Keith Busch's avatar Keith Busch Committed by Jens Axboe
Browse files

blk-mq: don't wait in blk_mq_queue_enter() if __GFP_WAIT isn't set 



Return -EBUSY if we're unable to enter a queue immediately when
allocating a blk-mq request without __GFP_WAIT.

Signed-off-by: default avatarKeith Busch <keith.busch@intel.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent b94ec296

block/blk-mq.c

+6 −3
Original line number Diff line number Diff line
@@ -77,7 +77,7 @@ static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx, 
	clear_bit(CTX_TO_BIT(hctx, ctx), &bm->word);

}



static int blk_mq_queue_enter(struct request_queue *q)

static int blk_mq_queue_enter(struct request_queue *q, gfp_t gfp)

{

	while (true) {

		int ret;
@@ -85,6 +85,9 @@ static int blk_mq_queue_enter(struct request_queue *q) 
		if (percpu_ref_tryget_live(&q->mq_usage_counter))

			return 0;



		if (!(gfp & __GFP_WAIT))

			return -EBUSY;



		ret = wait_event_interruptible(q->mq_freeze_wq,

				!q->mq_freeze_depth || blk_queue_dying(q));

		if (blk_queue_dying(q))
@@ -256,7 +259,7 @@ struct request *blk_mq_alloc_request(struct request_queue *q, int rw, gfp_t gfp, 
	struct blk_mq_alloc_data alloc_data;

	int ret;



	ret = blk_mq_queue_enter(q);

	ret = blk_mq_queue_enter(q, gfp);

	if (ret)

		return ERR_PTR(ret);
@@ -1186,7 +1189,7 @@ static struct request *blk_mq_map_request(struct request_queue *q, 
	int rw = bio_data_dir(bio);

	struct blk_mq_alloc_data alloc_data;



	if (unlikely(blk_mq_queue_enter(q))) {

	if (unlikely(blk_mq_queue_enter(q, GFP_KERNEL))) {

		bio_endio(bio, -EIO);

		return NULL;

	}