[PATCH 2/5] memstick: mspro_block: wait for running dispatches in mspro_block_stop()

[Ho Jie Feng <hjf3108@gmail.com>]

mspro_block_stop() only calls blk_mq_stop_hw_queues() once it sees that
msb->block_req is NULL. That marks the queues stopped so that no new
dispatch starts, but does not wait for dispatches that are already
running. In this case, a request can start just after
mspro_block_stop() has returned, causing a race condition.

Stop the queues before checking msb->block_req, and use
blk_mq_wait_quiesce_done() to wait for running ->queue_rq() calls to
return. The existing loop then waits for the current request to finish
before mspro_block_stop() returns.

Fixes: d0be12274dad ("mspro_block: convert to blk-mq")
Signed-off-by: Ho Jie Feng <hjf3108@gmail.com>
---
 drivers/memstick/core/mspro_block.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/memstick/core/mspro_block.c b/drivers/memstick/core/mspro_block.c
index fe38b42431219..215f4c3759c41 100644
--- a/drivers/memstick/core/mspro_block.c
+++ b/drivers/memstick/core/mspro_block.c
@@ -727,12 +727,13 @@ static void mspro_block_stop(struct memstick_dev *card)
 	int rc = 0;
 	unsigned long flags;
 
+	blk_mq_stop_hw_queues(msb->queue);
+	blk_mq_wait_quiesce_done(&msb->tag_set);
+
 	while (1) {
 		spin_lock_irqsave(&msb->q_lock, flags);
-		if (!msb->block_req) {
-			blk_mq_stop_hw_queues(msb->queue);
+		if (!msb->block_req)
 			rc = 1;
-		}
 		spin_unlock_irqrestore(&msb->q_lock, flags);
 
 		if (rc)
-- 
2.56.0