6.6-stable review patch. If anyone has any objections, please let me know.
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From: Ming Lei ming.lei@redhat.com
[ Upstream commit 0e4237ae8d159e3d28f3cd83146a46f576ffb586 ]
Request queue quiesce may interrupt flush sequence, and the original request may have been marked as COMPLETE, but can't get finished because of queue quiesce.
This way is fine from driver viewpoint, because flush sequence is block layer concept, and it isn't related with driver.
However, driver(such as dm-rq) can call blk_mq_queue_inflight() to count & drain inflight requests, then the wait & drain never gets done because the completed & not-finished flush request is counted as inflight.
Fix this issue by not counting completed flush data request as inflight in case of quiesce.
Cc: Mike Snitzer snitzer@kernel.org Cc: David Jeffery djeffery@redhat.com Cc: John Pittman jpittman@redhat.com Signed-off-by: Ming Lei ming.lei@redhat.com Link: https://lore.kernel.org/r/20231201085605.577730-1-ming.lei@redhat.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- block/blk-mq.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c index 6ab7f360ff2a..20ecd0ab616f 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1511,14 +1511,26 @@ void blk_mq_delay_kick_requeue_list(struct request_queue *q, } EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list);
+static bool blk_is_flush_data_rq(struct request *rq) +{ + return (rq->rq_flags & RQF_FLUSH_SEQ) && !is_flush_rq(rq); +} + static bool blk_mq_rq_inflight(struct request *rq, void *priv) { /* * If we find a request that isn't idle we know the queue is busy * as it's checked in the iter. * Return false to stop the iteration. + * + * In case of queue quiesce, if one flush data request is completed, + * don't count it as inflight given the flush sequence is suspended, + * and the original flush data request is invisible to driver, just + * like other pending requests because of quiesce */ - if (blk_mq_request_started(rq)) { + if (blk_mq_request_started(rq) && !(blk_queue_quiesced(rq->q) && + blk_is_flush_data_rq(rq) && + blk_mq_request_completed(rq))) { bool *busy = priv;
*busy = true;