Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 9a7a67af authored by Jens Axboe's avatar Jens Axboe Committed by Linus Torvalds
Browse files

[PATCH] fix ordering on requeued request drainage 



Previously, if a fs request which was being drained failed and got
requeued, blk_do_ordered() didn't allow it to be reissued, which causes
queue stall.  This patch makes blk_do_ordered() use the sequence of each
request to determine whether a request can be issued or not.  This fixes
the bug and simplifies code.

Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
Acked-by: default avatarJens Axboe <axboe@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 88a2a4ac

block/ll_rw_blk.c

+16 −22
Original line number Diff line number Diff line
@@ -508,7 +508,7 @@ static inline struct request *start_ordered(request_queue_t *q, 


int blk_do_ordered(request_queue_t *q, struct request **rqp)

{

	struct request *rq = *rqp, *allowed_rq;

	struct request *rq = *rqp;

	int is_barrier = blk_fs_request(rq) && blk_barrier_rq(rq);



	if (!q->ordseq) {
@@ -532,31 +532,25 @@ int blk_do_ordered(request_queue_t *q, struct request **rqp) 
		}

	}



	/*

	 * Ordered sequence in progress

	 */



	/* Special requests are not subject to ordering rules. */

	if (!blk_fs_request(rq) &&

	    rq != &q->pre_flush_rq && rq != &q->post_flush_rq)

		return 1;



	if (q->ordered & QUEUE_ORDERED_TAG) {

		/* Ordered by tag.  Blocking the next barrier is enough. */

		if (is_barrier && rq != &q->bar_rq)

			*rqp = NULL;

		return 1;

	}



	switch (blk_ordered_cur_seq(q)) {

	case QUEUE_ORDSEQ_PREFLUSH:

		allowed_rq = &q->pre_flush_rq;

		break;

	case QUEUE_ORDSEQ_BAR:

		allowed_rq = &q->bar_rq;

		break;

	case QUEUE_ORDSEQ_POSTFLUSH:

		allowed_rq = &q->post_flush_rq;

		break;

	default:

		allowed_rq = NULL;

		break;

	}



	if (rq != allowed_rq &&

	    (blk_fs_request(rq) || rq == &q->pre_flush_rq ||

	     rq == &q->post_flush_rq))

	} else {

		/* Ordered by draining.  Wait for turn. */

		WARN_ON(blk_ordered_req_seq(rq) < blk_ordered_cur_seq(q));

		if (blk_ordered_req_seq(rq) > blk_ordered_cur_seq(q))

			*rqp = NULL;

	}



	return 1;

}