Commit 2b504bd4 authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

blk-mq: don't insert FUA request with data into scheduler queue 

We never insert flush request into scheduler queue before.

Recently commit d92ca9d8 ("blk-mq: don't handle non-flush requests in
blk_insert_flush") tries to handle FUA data request as normal request.
This way has caused warning[1] in mq-deadline dd_exit_sched() or io hang in
case of kyber since RQF_ELVPRIV isn't set for flush request, then
->finish_request won't be called.

Fix the issue by inserting FUA data request with blk_mq_request_bypass_insert()
when the device supports FUA, just like what we did before.

[1] https://lore.kernel.org/linux-block/CAHj4cs-_vkTW=dAzbZYGxpEWSpzpcmaNeY1R=vH311+9vMUSdg@mail.gmail.com/



Reported-by: default avatarYi Zhang <yi.zhang@redhat.com>
Fixes: d92ca9d8 ("blk-mq: don't handle non-flush requests in blk_insert_flush")
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Reviewed-by: default avatarBart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20211118153041.2163228-1-ming.lei@redhat.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 15c30104

block/blk-flush.c

+6 −6
Original line number Diff line number Diff line
@@ -379,7 +379,7 @@ static void mq_flush_data_end_io(struct request *rq, blk_status_t error) 
 * @rq is being submitted.  Analyze what needs to be done and put it on the

 * right queue.

 */

bool blk_insert_flush(struct request *rq)

void blk_insert_flush(struct request *rq)

{

	struct request_queue *q = rq->q;

	unsigned long fflags = q->queue_flags;	/* may change, cache */
@@ -409,7 +409,7 @@ bool blk_insert_flush(struct request *rq) 
	 */

	if (!policy) {

		blk_mq_end_request(rq, 0);

		return true;

		return;

	}



	BUG_ON(rq->bio != rq->biotail); /*assumes zero or single bio rq */
@@ -420,8 +420,10 @@ bool blk_insert_flush(struct request *rq) 
	 * for normal execution.

	 */

	if ((policy & REQ_FSEQ_DATA) &&

	    !(policy & (REQ_FSEQ_PREFLUSH | REQ_FSEQ_POSTFLUSH)))

		return false;

	    !(policy & (REQ_FSEQ_PREFLUSH | REQ_FSEQ_POSTFLUSH))) {

		blk_mq_request_bypass_insert(rq, false, true);

		return;

	}



	/*

	 * @rq should go through flush machinery.  Mark it part of flush
@@ -437,8 +439,6 @@ bool blk_insert_flush(struct request *rq) 
	spin_lock_irq(&fq->mq_flush_lock);

	blk_flush_complete_seq(rq, fq, REQ_FSEQ_ACTIONS & ~policy, 0);

	spin_unlock_irq(&fq->mq_flush_lock);



	return true;

}



/**

block/blk-mq.c

+3 −1
Original line number Diff line number Diff line
@@ -2647,8 +2647,10 @@ void blk_mq_submit_bio(struct bio *bio) 
		return;

	}



	if (op_is_flush(bio->bi_opf) && blk_insert_flush(rq))

	if (op_is_flush(bio->bi_opf)) {

		blk_insert_flush(rq);

		return;

	}



	if (plug && (q->nr_hw_queues == 1 ||

	    blk_mq_is_shared_tags(rq->mq_hctx->flags) ||

block/blk.h

+1 −1
Original line number Diff line number Diff line
@@ -271,7 +271,7 @@ void __blk_account_io_done(struct request *req, u64 now); 
 */

#define ELV_ON_HASH(rq) ((rq)->rq_flags & RQF_HASHED)



bool blk_insert_flush(struct request *rq);

void blk_insert_flush(struct request *rq);



int elevator_switch_mq(struct request_queue *q,

			      struct elevator_type *new_e);