| From 05a4fed69ff00a8bd83538684cb602a4636b07a7 Mon Sep 17 00:00:00 2001 |
| From: Ming Lei <ming.lei@redhat.com> |
| Date: Tue, 7 Jul 2020 11:04:33 -0400 |
| Subject: blk-mq: consider non-idle request as "inflight" in blk_mq_rq_inflight() |
| |
| From: Ming Lei <ming.lei@redhat.com> |
| |
| commit 05a4fed69ff00a8bd83538684cb602a4636b07a7 upstream. |
| |
| dm-multipath is the only user of blk_mq_queue_inflight(). When |
| dm-multipath calls blk_mq_queue_inflight() to check if it has |
| outstanding IO it can get a false negative. The reason for this is |
| blk_mq_rq_inflight() doesn't consider requests that are no longer |
| MQ_RQ_IN_FLIGHT but that are now MQ_RQ_COMPLETE (->complete isn't |
| called or finished yet) as "inflight". |
| |
| This causes request-based dm-multipath's dm_wait_for_completion() to |
| return before all outstanding dm-multipath requests have actually |
| completed. This breaks DM multipath's suspend functionality because |
| blk-mq requests complete after DM's suspend has finished -- which |
| shouldn't happen. |
| |
| Fix this by considering any request not in the MQ_RQ_IDLE state |
| (so either MQ_RQ_COMPLETE or MQ_RQ_IN_FLIGHT) as "inflight" in |
| blk_mq_rq_inflight(). |
| |
| Fixes: 3c94d83cb3526 ("blk-mq: change blk_mq_queue_busy() to blk_mq_queue_inflight()") |
| Signed-off-by: Ming Lei <ming.lei@redhat.com> |
| Signed-off-by: Mike Snitzer <snitzer@redhat.com> |
| Cc: stable@vger.kernel.org |
| Signed-off-by: Jens Axboe <axboe@kernel.dk> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| block/blk-mq.c | 4 ++-- |
| 1 file changed, 2 insertions(+), 2 deletions(-) |
| |
| --- a/block/blk-mq.c |
| +++ b/block/blk-mq.c |
| @@ -829,10 +829,10 @@ static bool blk_mq_rq_inflight(struct bl |
| void *priv, bool reserved) |
| { |
| /* |
| - * If we find a request that is inflight and the queue matches, |
| + * If we find a request that isn't idle and the queue matches, |
| * we know the queue is busy. Return false to stop the iteration. |
| */ |
| - if (rq->state == MQ_RQ_IN_FLIGHT && rq->q == hctx->queue) { |
| + if (blk_mq_request_started(rq) && rq->q == hctx->queue) { |
| bool *busy = priv; |
| |
| *busy = true; |