[PATCH] nvme-tcp: print correct opcode on timeout and error handling

[Akinobu Mita]

In timeout and error handling, various information is reported about the
command in error, but the printed opcode may not be correct

The opcode is obtained from the nvme_command structure referenced by the
'cmd' member in the nvme_request structure.
(i.e. nvme_req(req)->cmd->common.opcode)

For the nvme-tcp driver, the 'cmd' member in the nvme_request structure
points to a structure within the page fragment allocated by
nvme_tcp_init_request().  This page fragment is used as a command capsule
PDU, and then may be reused as a h2c data PDU, so the nvme_command
referenced by the 'cmd' member has already been overwritten.

To fix this problem, when setting up the nvme_command, keep the opcode in
a newly added member in the nvme_tcp_request and use that instead.

Signed-off-by: Akinobu Mita <akinobu.mita at gmail.com>
Cc: Sagi Grimberg <sagi at grimberg.me>
Cc: Chaitanya Kulkarni <kch at nvidia.com>
Cc: Christoph Hellwig <hch at lst.de>
Cc: Keith Busch <kbusch at kernel.org>
Cc: Jens Axboe <axboe at fb.com>
Cc: Hannes Reinecke <hare at suse.de>
---
 drivers/nvme/host/core.c | 10 ++++++----
 drivers/nvme/host/nvme.h | 11 +++++++++++
 drivers/nvme/host/tcp.c  | 15 ++++++++++++++-
 3 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index c2730b116dc6..a86f787ba3bd 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -310,12 +310,14 @@ static void nvme_log_error(struct request *req)
 {
 	struct nvme_ns *ns = req->q->queuedata;
 	struct nvme_request *nr = nvme_req(req);
+	u8 opcode;
 
+	nvme_get_request_info(req, &opcode);
 	if (ns) {
 		pr_err_ratelimited("%s: %s(0x%x) @ LBA %llu, %llu blocks, %s (sct 0x%x / sc 0x%x) %s%s\n",
 		       ns->disk ? ns->disk->disk_name : "?",
-		       nvme_get_opcode_str(nr->cmd->common.opcode),
-		       nr->cmd->common.opcode,
+		       nvme_get_opcode_str(opcode),
+		       opcode,
 		       (unsigned long long)nvme_sect_to_lba(ns, blk_rq_pos(req)),
 		       (unsigned long long)blk_rq_bytes(req) >> ns->lba_shift,
 		       nvme_get_error_status_str(nr->status),
@@ -328,8 +330,8 @@ static void nvme_log_error(struct request *req)
 
 	pr_err_ratelimited("%s: %s(0x%x), %s (sct 0x%x / sc 0x%x) %s%s\n",
 			   dev_name(nr->ctrl->device),
-			   nvme_get_admin_opcode_str(nr->cmd->common.opcode),
-			   nr->cmd->common.opcode,
+			   nvme_get_admin_opcode_str(opcode),
+			   opcode,
 			   nvme_get_error_status_str(nr->status),
 			   nr->status >> 8 & 7,	/* Status Code Type */
 			   nr->status & 0xff,	/* Status Code */
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index bf46f122e9e1..bbb458323e91 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -525,6 +525,7 @@ struct nvme_ctrl_ops {
 	int (*get_address)(struct nvme_ctrl *ctrl, char *buf, int size);
 	void (*print_device_info)(struct nvme_ctrl *ctrl);
 	bool (*supports_pci_p2pdma)(struct nvme_ctrl *ctrl);
+	void (*get_request_info)(struct request *req, u8 *opcode);
 };
 
 /*
@@ -597,6 +598,16 @@ static inline void nvme_print_device_info(struct nvme_ctrl *ctrl)
 		subsys->firmware_rev);
 }
 
+static inline void nvme_get_request_info(struct request *rq, u8 *opcode)
+{
+	struct nvme_request *req = nvme_req(rq);
+
+	if (req->ctrl->ops->get_request_info)
+		req->ctrl->ops->get_request_info(rq, opcode);
+	else
+		*opcode = req->cmd->common.opcode;
+}
+
 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
 void nvme_fault_inject_init(struct nvme_fault_inject *fault_inj,
 			    const char *dev_name);
diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 7723a4989524..a6c0ae51d830 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -90,6 +90,8 @@ struct nvme_tcp_request {
 	struct list_head	entry;
 	struct llist_node	lentry;
 	__le32			ddgst;
+	u8			opcode;
+	u8			fctype;
 
 	struct bio		*curr_bio;
 	struct iov_iter		iter;
@@ -2285,7 +2287,7 @@ static enum blk_eh_timer_return nvme_tcp_timeout(struct request *rq)
 	struct nvme_tcp_request *req = blk_mq_rq_to_pdu(rq);
 	struct nvme_ctrl *ctrl = &req->queue->ctrl->ctrl;
 	struct nvme_tcp_cmd_pdu *pdu = req->pdu;
-	u8 opc = pdu->cmd.common.opcode, fctype = pdu->cmd.fabrics.fctype;
+	u8 opc = req->opcode, fctype = req->fctype;
 	int qid = nvme_tcp_queue_id(req->queue);
 
 	dev_warn(ctrl->device,
@@ -2354,6 +2356,9 @@ static blk_status_t nvme_tcp_setup_cmd_pdu(struct nvme_ns *ns,
 
 	req->state = NVME_TCP_SEND_CMD_PDU;
 	req->status = cpu_to_le16(NVME_SC_SUCCESS);
+	req->opcode = pdu->cmd.common.opcode;
+	if (req->opcode == nvme_fabrics_command)
+		req->fctype = pdu->cmd.fabrics.fctype;
 	req->offset = 0;
 	req->data_sent = 0;
 	req->pdu_len = 0;
@@ -2509,6 +2514,13 @@ static int nvme_tcp_get_address(struct nvme_ctrl *ctrl, char *buf, int size)
 	return len;
 }
 
+static void nvme_tcp_get_request_info(struct request *rq, u8 *opcode)
+{
+	struct nvme_tcp_request *req = blk_mq_rq_to_pdu(rq);
+
+	*opcode = req->opcode;
+}
+
 static const struct blk_mq_ops nvme_tcp_mq_ops = {
 	.queue_rq	= nvme_tcp_queue_rq,
 	.commit_rqs	= nvme_tcp_commit_rqs,
@@ -2542,6 +2554,7 @@ static const struct nvme_ctrl_ops nvme_tcp_ctrl_ops = {
 	.delete_ctrl		= nvme_tcp_delete_ctrl,
 	.get_address		= nvme_tcp_get_address,
 	.stop_ctrl		= nvme_tcp_stop_ctrl,
+	.get_request_info	= nvme_tcp_get_request_info,
 };
 
 static bool
-- 
2.34.1