From: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>

Date: Wed, 26 Feb 2020 18:53:43 -0800

Subject: [PATCH] nvme-pci: Hold cq_poll_lock while completing CQEs

Git-commit: 9515743bfb39c61aaf3d4f3219a645c8d1fe9a0e

Patch-mainline: v5.6-rc4

References: bsc#1169045

Completions need to consumed in the same order the controller submitted

them, otherwise future completion entries may overwrite ones we haven't

handled yet. Hold the nvme queue's poll lock while completing new CQEs to

prevent another thread from freeing command tags for reuse out-of-order.

Fixes: dabcefab45d3 ("nvme: provide optimized poll function for separate poll queues")

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>

Reviewed-by: Sagi Grimberg <sagi@grimberg.me>

Reviewed-by: Jens Axboe <axboe@kernel.dk>

Signed-off-by: Keith Busch <kbusch@kernel.org>

Acked-by: Hannes Reinecke <hare@suse.com>

---

 drivers/nvme/host/pci.c | 2 +-

 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c

index ace4dd9e953c..d3f23d6254e4 100644

--- a/drivers/nvme/host/pci.c

+++ b/drivers/nvme/host/pci.c

@@ -1078,9 +1078,9 @@ static int nvme_poll(struct blk_mq_hw_ctx *hctx)

 	spin_lock(&nvmeq->cq_poll_lock);

 	found = nvme_process_cq(nvmeq, &start, &end, -1);

+	nvme_complete_cqes(nvmeq, start, end);

 	spin_unlock(&nvmeq->cq_poll_lock);

-	nvme_complete_cqes(nvmeq, start, end);

 	return found;

 }

-- 

2.16.4