[PATCH 1/2] nvme-auth: retry command if DNR bit is not set

[Hannes Reinecke]

If the cqe returns a status with the DNR bit not set we should
retry the command; otherwise we might incur spurious failures.

Reported-by: Martin George <marting at netapp.com>
Signed-off-by: Hannes Reinecke <hare at suse.de>
---
 drivers/nvme/host/auth.c |  2 +-
 drivers/nvme/host/core.c | 20 ++++++++++++++++++--
 include/linux/blk-mq.h   |  2 ++
 3 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/drivers/nvme/host/auth.c b/drivers/nvme/host/auth.c
index c8a6db7c4498..4ca3f7d042f1 100644
--- a/drivers/nvme/host/auth.c
+++ b/drivers/nvme/host/auth.c
@@ -69,7 +69,7 @@ static int nvme_auth_submit(struct nvme_ctrl *ctrl, int qid,
 
 	ret = __nvme_submit_sync_cmd(q, &cmd, NULL, data, data_len,
 				     qid == 0 ? NVME_QID_ANY : qid,
-				     0, flags);
+				     0, BLK_MQ_REQ_RETRY | flags);
 	if (ret > 0)
 		dev_warn(ctrl->device,
 			"qid %d auth_send failed with status %d\n", qid, ret);
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 66ae23e9cb0e..a77f406512eb 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -355,7 +355,8 @@ static inline enum nvme_disposition nvme_decide_disposition(struct request *req)
 	if (likely(nvme_req(req)->status == 0))
 		return COMPLETE;
 
-	if ((nvme_req(req)->status & 0x7ff) == NVME_SC_AUTH_REQUIRED)
+	if ((nvme_req(req)->status & 0x7ff) == NVME_SC_AUTH_REQUIRED &&
+	    !(nvme_req(req)->status & NVME_SC_DNR))
 		return AUTHENTICATE;
 
 	if (blk_noretry_request(req) ||
@@ -1037,15 +1038,30 @@ int __nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
 	if (IS_ERR(req))
 		return PTR_ERR(req);
 	nvme_init_request(req, cmd);
+	if (flags & BLK_MQ_REQ_RETRY)
+		nvme_req(req)->retries = nvme_max_retries;
 
 	if (buffer && bufflen) {
 		ret = blk_rq_map_kern(q, req, buffer, bufflen, GFP_KERNEL);
 		if (ret)
 			goto out;
 	}
-
+retry:
 	req->rq_flags |= RQF_QUIET;
 	ret = nvme_execute_rq(req, at_head);
+	if (ret > 0) {
+		struct nvme_ctrl *ctrl = nvme_req(req)->ctrl;
+
+		if (ctrl->kas)
+			ctrl->comp_seen = true;
+
+		switch (nvme_decide_disposition(req)) {
+		case COMPLETE:
+			break;
+		default:
+			goto retry;
+		}
+	}
 	if (result && ret >= 0)
 		*result = nvme_req(req)->result;
  out:
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index effee1dc715a..acd833f37cd4 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -713,6 +713,8 @@ enum {
 	BLK_MQ_REQ_RESERVED	= (__force blk_mq_req_flags_t)(1 << 1),
 	/* set RQF_PM */
 	BLK_MQ_REQ_PM		= (__force blk_mq_req_flags_t)(1 << 2),
+	/* Retry reserved commands */
+	BLK_MQ_REQ_RETRY	= (__force blk_mq_req_flags_t)(1 << 3),
 };
 
 struct request *blk_mq_alloc_request(struct request_queue *q, blk_opf_t opf,
-- 
2.35.3