[PATCH 1/1] nvme-pci: do not call nvme_write_sq_db() if the commands list is empty

[Maurizio Lombardi]

nvme_submit_cmds() should check the rqlist
before calling nvme_write_sq_db();
if the list is empty, it must return immediately.

Fixes: beadf0088501 ("nvme-pci: reverse request order in nvme_queue_rqs")
Signed-off-by: Maurizio Lombardi <mlombard at redhat.com>
---
 drivers/nvme/host/pci.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 2883d17ee1eb..b178d52eac1b 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -986,6 +986,9 @@ static void nvme_submit_cmds(struct nvme_queue *nvmeq, struct rq_list *rqlist)
 {
 	struct request *req;
 
+	if (rq_list_empty(rqlist))
+		return;
+
 	spin_lock(&nvmeq->sq_lock);
 	while ((req = rq_list_pop(rqlist))) {
 		struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
-- 
2.43.5