Since blk_cleanup_queue() waits until q->q_usage_counter drops to zero
before setting the "dead" flag, it is guaranteed that all requests that
were in progress when blk_cleanup_queue() was called have finished before
the "dead" flag is set. This means it is not possible that any .queue_rq()
call is ongoing while the "dead" flag is set. Hence remove the code that
waits for ongoing .queue_rq() calls to finish after the "dead" flag has
been set. See also commit c2856ae2f315 ("blk-mq: quiesce queue before
freeing queue") # v4.16.

Cc: Christoph Hellwig <[email protected]>
Cc: Hannes Reinecke <[email protected]>
Cc: James Smart <[email protected]>
Cc: Ming Lei <[email protected]>
Cc: Jianchao Wang <[email protected]>
Cc: Dongli Zhang <[email protected]>
Cc: <[email protected]>
Signed-off-by: Bart Van Assche <[email protected]>
---
 block/blk-core.c | 12 ------------
 1 file changed, 12 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index bfdbdbb8ec65..2921af6f8d33 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -348,18 +348,6 @@ void blk_cleanup_queue(struct request_queue *q)
 
        blk_queue_flag_set(QUEUE_FLAG_DEAD, q);
 
-       /*
-        * make sure all in-progress dispatch are completed because
-        * blk_freeze_queue() can only complete all requests, and
-        * dispatch may still be in-progress since we dispatch requests
-        * from more than one contexts.
-        *
-        * We rely on driver to deal with the race in case that queue
-        * initialization isn't done.
-        */
-       if (queue_is_mq(q) && blk_queue_init_done(q))
-               blk_mq_quiesce_queue(q);
-
        /* for synchronous bio-based driver finish in-flight integrity i/o */
        blk_flush_integrity();
 
-- 
2.21.0.196.g041f5ea1cf98

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