nvme: increment request genctr on completion

The nvme request generation counter is intended to catch duplicate completions. Incrementing the counter on submission means duplicates can only be caught if the request tag is reallocated and dispatched prior to the driver observing the corrupted CQE. Incrementing on completion removes this window, making it possible to detect duplicate completions in consecutive entries. Signed-off-by: Keith Busch <[email protected]> Reviewed-by: Sagi Grimberg <[email protected]> Signed-off-by: Christoph Hellwig <[email protected]>
bignaux · Dec 23, 2021 · e4fdb2b · e4fdb2b
1 parent f18ee3d
commit e4fdb2b
Show file tree

Hide file tree

Showing 2 changed files with 4 additions and 2 deletions.
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
@@ -1037,8 +1037,6 @@ blk_status_t nvme_setup_cmd(struct nvme_ns *ns, struct request *req)
 		return BLK_STS_IOERR;
 	}
 
-	if (!(ctrl->quirks & NVME_QUIRK_SKIP_CID_GEN))
-		nvme_req(req)->genctr++;
 	cmd->common.command_id = nvme_cid(req);
 	trace_nvme_setup_cmd(req, cmd);
 	return ret;

diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
@@ -614,6 +614,10 @@ static inline bool nvme_try_complete_req(struct request *req, __le16 status,
 		union nvme_result result)
 {
 	struct nvme_request *rq = nvme_req(req);
+	struct nvme_ctrl *ctrl = rq->ctrl;
+
+	if (!(ctrl->quirks & NVME_QUIRK_SKIP_CID_GEN))
+		rq->genctr++;
 
 	rq->status = le16_to_cpu(status) >> 1;
 	rq->result = result;