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authorMing Lei <ming.lei@redhat.com>2020-07-07 11:04:33 -0400
committerJens Axboe <axboe@kernel.dk>2020-07-07 09:06:25 -0600
commit05a4fed69ff00a8bd83538684cb602a4636b07a7 (patch)
tree17db1d5a04efd784ca07e743b205b2012cd13232 /block
parent65752aef0a407e1ef17ec78a7fc31ba4e0b360f9 (diff)
downloadlwn-05a4fed69ff00a8bd83538684cb602a4636b07a7.tar.gz
lwn-05a4fed69ff00a8bd83538684cb602a4636b07a7.zip
blk-mq: consider non-idle request as "inflight" in blk_mq_rq_inflight()
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>
Diffstat (limited to 'block')
-rw-r--r--block/blk-mq.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index a9aa6d1e44cf..4e0d173beaa3 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -828,10 +828,10 @@ static bool blk_mq_rq_inflight(struct blk_mq_hw_ctx *hctx, struct request *rq,
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;