[PATCH 4.4 50/93] blk-mq: actually hook up defer list when running requests

From: Greg Kroah-Hartman
Date: Thu Oct 06 2016 - 04:56:34 EST

4.4-stable review patch. If anyone has any objections, please let me know.


From: Omar Sandoval <osandov@xxxxxx>

commit 52b9c330c6a8a4b5a1819bdaddf4ec76ab571e81 upstream.

If ->queue_rq() returns BLK_MQ_RQ_QUEUE_OK, we use continue and skip
over the rest of the loop body. However, dptr is assigned later in the
loop body, and the BLK_MQ_RQ_QUEUE_OK case is exactly the case that we'd
want it for.

NVMe isn't actually using BLK_MQ_F_DEFER_ISSUE yet, nor is any other
in-tree driver, but if the code's going to be there, it might as well

Fixes: 74c450521dd8 ("blk-mq: add a 'list' parameter to ->queue_rq()")
Signed-off-by: Omar Sandoval <osandov@xxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

block/blk-mq.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -780,7 +780,7 @@ static void __blk_mq_run_hw_queue(struct
switch (ret) {
- continue;
+ break;
list_add(&rq->queuelist, &rq_list);