nvme: use return value from blk_execute_rq()

We don't have an nvme status to report if the driver's .queue_rq()
returns an error without dispatching the requested nvme command. Check
the return value from blk_execute_rq() for all passthrough commands so
the caller may know their command was not successful.

If the command is from the target passthrough interface and fails to
dispatch, synthesize the response back to the host as a internal target
error.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210610214437.641245-5-kbusch@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 27 insertions, 8 deletions

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index e0d3f0aa25da..11779be42186 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -609,6 +609,7 @@ EXPORT_SYMBOL_NS_GPL(nvme_put_ns, NVME_TARGET_PASSTHRU);
 
 static inline void nvme_clear_nvme_request(struct request *req)
 {
+	nvme_req(req)->status = 0;
 	nvme_req(req)->retries = 0;
 	nvme_req(req)->flags = 0;
 	req->rq_flags |= RQF_DONTPREP;
@@ -1032,6 +1033,25 @@ blk_status_t nvme_setup_cmd(struct nvme_ns *ns, struct request *req)
 EXPORT_SYMBOL_GPL(nvme_setup_cmd);
 
 /*
+ * Return values:
+ * 0:  success
+ * >0: nvme controller's cqe status response
+ * <0: kernel error in lieu of controller response
+ */
+static int nvme_execute_rq(struct gendisk *disk, struct request *rq,
+		bool at_head)
+{
+	blk_status_t status;
+
+	status = blk_execute_rq(disk, rq, at_head);
+	if (nvme_req(rq)->flags & NVME_REQ_CANCELLED)
+		return -EINTR;
+	if (nvme_req(rq)->status)
+		return nvme_req(rq)->status;
+	return blk_status_to_errno(status);
+}
+
+/*
  * Returns 0 on success.  If the result is negative, it's a Linux error code;
  * if the result is positive, it's an NVM Express status code
  */
@@ -1059,13 +1079,9 @@ int __nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
 			goto out;
 	}
 
-	blk_execute_rq(NULL, req, at_head);
-	if (result)
+	ret = nvme_execute_rq(NULL, req, at_head);
+	if (result && ret >= 0)
 		*result = nvme_req(req)->result;
-	if (nvme_req(req)->flags & NVME_REQ_CANCELLED)
-		ret = -EINTR;
-	else
-		ret = nvme_req(req)->status;
  out:
 	blk_mq_free_request(req);
 	return ret;
@@ -1153,18 +1169,21 @@ static void nvme_passthru_end(struct nvme_ctrl *ctrl, u32 effects)
 	}
 }
 
-void nvme_execute_passthru_rq(struct request *rq)
+int nvme_execute_passthru_rq(struct request *rq)
 {
 	struct nvme_command *cmd = nvme_req(rq)->cmd;
 	struct nvme_ctrl *ctrl = nvme_req(rq)->ctrl;
 	struct nvme_ns *ns = rq->q->queuedata;
 	struct gendisk *disk = ns ? ns->disk : NULL;
 	u32 effects;
+	int  ret;
 
 	effects = nvme_passthru_start(ctrl, ns, cmd->common.opcode);
-	blk_execute_rq(disk, rq, 0);
+	ret = nvme_execute_rq(disk, rq, false);
 	if (effects) /* nothing to be done for zero cmd effects */
 		nvme_passthru_end(ctrl, effects);
+
+	return ret;
 }
 EXPORT_SYMBOL_NS_GPL(nvme_execute_passthru_rq, NVME_TARGET_PASSTHRU);