Re: [PATCH 1/2] blk-mq: fixup request re-insert in blk_mq_try_issue_list_directly()

[Guoqing Jiang]

On 9/19/19 11:45 AM, Hannes Reinecke wrote:

From: Hannes Reinecke <h...@suse.com>

When blk_mq_request_issue_directly() returns BLK_STS_RESOURCE we
need to requeue the I/O, but adding it to the global request list
will mess up with the passed-in request list. So re-add the request
to the original list and leave it to the caller to handle situations
where the list wasn't completely emptied.

Signed-off-by: Hannes Reinecke <h...@suse.com>
---
  block/blk-mq.c | 3 +--
  1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index b038ec680e84..44ff3c1442a4 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1899,8 +1899,7 @@ void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx 
*hctx,
                if (ret != BLK_STS_OK) {
                        if (ret == BLK_STS_RESOURCE ||
                                        ret == BLK_STS_DEV_RESOURCE) {
-                               blk_mq_request_bypass_insert(rq,
-                                                       list_empty(list));
+                               list_add(list, &rq->queuelist);

Just curious, maybe the above should be "list_add(&rq->queuelist, list)".

Thanks,
Guoqing