Merge: blk-mq: don't count completed flush data request as inflight in case of quiesce

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/3451

JIRA: https://issues.redhat.com/browse/RHEL-18054

Signed-off-by: Ming Lei <[email protected]>

Approved-by: Jeff Moyer <[email protected]>
Approved-by: John Meneghini <[email protected]>

Signed-off-by: Scott Weaver <[email protected]>

Author: swvrrh

block/blk-mq.c

@@ -1514,14 +1514,26 @@ 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;