Commit b637108a authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

blk-mq: fix filesystem I/O request allocation 



submit_bio_checks() may update bio->bi_opf, so we have to initialize
blk_mq_alloc_data.cmd_flags with bio->bi_opf after submit_bio_checks()
returns when allocating new request.

In case of using cached request, fallback to allocate new request if
cached rq isn't compatible with the incoming bio, otherwise change
rq->cmd_flags with incoming bio->bi_opf.

Fixes: 900e0807 ("block: move queue enter logic into blk_mq_submit_bio()")
Reported-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Tested-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent b781d8db

block/blk-mq.c

+30 −9
Original line number Diff line number Diff line
@@ -2521,12 +2521,8 @@ static struct request *blk_mq_get_new_requests(struct request_queue *q, 
	};

	struct request *rq;



	if (unlikely(bio_queue_enter(bio)))

		return NULL;

	if (unlikely(!submit_bio_checks(bio)))

		goto put_exit;

	if (blk_mq_attempt_bio_merge(q, bio, nsegs, same_queue_rq))

		goto put_exit;

		return NULL;



	rq_qos_throttle(q, bio);
@@ -2543,19 +2539,32 @@ static struct request *blk_mq_get_new_requests(struct request_queue *q, 
	rq_qos_cleanup(q, bio);

	if (bio->bi_opf & REQ_NOWAIT)

		bio_wouldblock_error(bio);

put_exit:

	blk_queue_exit(q);



	return NULL;

}



static inline bool blk_mq_can_use_cached_rq(struct request *rq,

		struct bio *bio)

{

	if (blk_mq_get_hctx_type(bio->bi_opf) != rq->mq_hctx->type)

		return false;



	if (op_is_flush(rq->cmd_flags) != op_is_flush(bio->bi_opf))

		return false;



	return true;

}



static inline struct request *blk_mq_get_request(struct request_queue *q,

						 struct blk_plug *plug,

						 struct bio *bio,

						 unsigned int nsegs,

						 bool *same_queue_rq)

{

	if (plug) {

	struct request *rq;

	bool checked = false;



	if (plug) {



		rq = rq_list_peek(&plug->cached_rq);

		if (rq && rq->q == q) {
@@ -2564,6 +2573,10 @@ static inline struct request *blk_mq_get_request(struct request_queue *q, 
			if (blk_mq_attempt_bio_merge(q, bio, nsegs,

						same_queue_rq))

				return NULL;

			checked = true;

			if (!blk_mq_can_use_cached_rq(rq, bio))

				goto fallback;

			rq->cmd_flags = bio->bi_opf;

			plug->cached_rq = rq_list_next(rq);

			INIT_LIST_HEAD(&rq->queuelist);

			rq_qos_throttle(q, bio);
@@ -2571,7 +2584,15 @@ static inline struct request *blk_mq_get_request(struct request_queue *q, 
		}

	}



	return blk_mq_get_new_requests(q, plug, bio, nsegs, same_queue_rq);

fallback:

	if (unlikely(bio_queue_enter(bio)))

		return NULL;

	if (!checked && !submit_bio_checks(bio))

		return NULL;

	rq = blk_mq_get_new_requests(q, plug, bio, nsegs, same_queue_rq);

	if (!rq)

		blk_queue_exit(q);

	return rq;

}



/**

block/blk-mq.h

+15 −11
Original line number Diff line number Diff line
@@ -89,15 +89,7 @@ static inline struct blk_mq_hw_ctx *blk_mq_map_queue_type(struct request_queue * 
	return q->queue_hw_ctx[q->tag_set->map[type].mq_map[cpu]];

}



/*

 * blk_mq_map_queue() - map (cmd_flags,type) to hardware queue

 * @q: request queue

 * @flags: request command flags

 * @ctx: software queue cpu ctx

 */

static inline struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *q,

						     unsigned int flags,

						     struct blk_mq_ctx *ctx)

static inline enum hctx_type blk_mq_get_hctx_type(unsigned int flags)

{

	enum hctx_type type = HCTX_TYPE_DEFAULT;
@@ -108,8 +100,20 @@ static inline struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *q, 
		type = HCTX_TYPE_POLL;

	else if ((flags & REQ_OP_MASK) == REQ_OP_READ)

		type = HCTX_TYPE_READ;

	return type;

}



	return ctx->hctxs[type];

/*

 * blk_mq_map_queue() - map (cmd_flags,type) to hardware queue

 * @q: request queue

 * @flags: request command flags

 * @ctx: software queue cpu ctx

 */

static inline struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *q,

						     unsigned int flags,

						     struct blk_mq_ctx *ctx)

{

	return ctx->hctxs[blk_mq_get_hctx_type(flags)];

}



/*