Commit e4fdb2b1 authored Dec 13, 2021 by Keith Busch Committed by Christoph Hellwig Dec 23, 2021

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 <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

parent f18ee3d9

drivers/nvme/host/core.c

+0 −2

Original line number	Diff line number	Diff line
		@@ -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;

drivers/nvme/host/nvme.h

+4 −0

Original line number	Diff line number	Diff line
		@@ -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;