From: Keith Busch <kbusch@kernel.org>
Date: Mon, 13 Dec 2021 09:08:47 -0800
Subject: nvme: increment request genctr on completion
Patch-mainline: v5.17-rc1
Git-commit: e4fdb2b167ed225a3793a249c4342da915940b6b
References: jsc#PED-1183

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 <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Daniel Wagner <dwagner@suse.de>
---
 drivers/nvme/host/core.c |    2 --
 drivers/nvme/host/nvme.h |    4 ++++
 2 files changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1038,8 +1038,6 @@ blk_status_t nvme_setup_cmd(struct nvme_
 		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;
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -614,6 +614,10 @@ static inline bool nvme_try_complete_req
 		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;