[PATCH V5 1/1] nvme: allow passthru cmd error logging

[Chaitanya Kulkarni <kch@nvidia.com>]

From: Alan Adamson <alan.adamson@oracle.com>

Commit d7ac8dca938c ("nvme: quiet user passthrough command errors")
disabled error logging for user passthrough commands.  This commit
adds the ability to opt-in to passthrough admin error logging. IO
commands initiated as passthrough will always be logged.

The logging output for passthrough commands (Admin and IO) has been
changed to include CDWXX fields.

nvme0n1: Read(0x2), LBA Out of Range (sct 0x0 / sc 0x80) DNR cdw10=0x0 cdw11=0x1
        cdw12=0x70000 cdw13=0x0 cdw14=0x0 cdw15=0x0

Add a helper function nvme_log_err_passthru() which allows us to log
error for passthru commands by decoding cdw10-cdw15 values of nvme
command.

Add a new sysfs attr passthru_err_log that allows user to conditionally
enable passthru command logging, by default it is disabled.

To enable passthrough admin error logging:
        echo 1 > /sys/class/nvme/nvme0/passthru_err_log

To disable passthrough admin error logging:
        echo 0 > /sys/class/nvme/nvme0/passthru_err_log

Signed-off-by: Alan Adamson <alan.adamson@oracle.com>
[kch] fix sevaral nits and trim down code, details in cover-letter.
Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
---
 drivers/nvme/host/core.c | 83 +++++++++++++++++++++++++++++++++++++---
 drivers/nvme/host/nvme.h |  1 +
 2 files changed, 79 insertions(+), 5 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 954641a45e55..e32265adc034 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -337,6 +337,30 @@ static void nvme_log_error(struct request *req)
 			   nr->status & NVME_SC_DNR  ? "DNR "  : "");
 }
 
+static void nvme_log_err_passthru(struct request *req)
+{
+	struct nvme_ns *ns = req->q->queuedata;
+	struct nvme_request *nr = nvme_req(req);
+
+	pr_err_ratelimited("%s: %s(0x%x), %s (sct 0x%x / sc 0x%x) %s%s"
+		"cdw10=0x%x cdw11=0x%x cdw12=0x%x cdw13=0x%x cdw14=0x%x cdw15=0x%x\n",
+		ns ? ns->disk->disk_name : dev_name(nr->ctrl->device),
+		ns ? nvme_get_opcode_str(nr->cmd->common.opcode) :
+		     nvme_get_admin_opcode_str(nr->cmd->common.opcode),
+		nr->cmd->common.opcode,
+		nvme_get_error_status_str(nr->status),
+		nr->status >> 8 & 7,	/* Status Code Type */
+		nr->status & 0xff,	/* Status Code */
+		nr->status & NVME_SC_MORE ? "MORE " : "",
+		nr->status & NVME_SC_DNR  ? "DNR "  : "",
+		nr->cmd->common.cdw10,
+		nr->cmd->common.cdw11,
+		nr->cmd->common.cdw12,
+		nr->cmd->common.cdw13,
+		nr->cmd->common.cdw14,
+		nr->cmd->common.cdw14);
+}
+
 enum nvme_disposition {
 	COMPLETE,
 	RETRY,
@@ -381,8 +405,12 @@ static inline void nvme_end_req(struct request *req)
 {
 	blk_status_t status = nvme_error_status(nvme_req(req)->status);
 
-	if (unlikely(nvme_req(req)->status && !(req->rq_flags & RQF_QUIET)))
-		nvme_log_error(req);
+	if (unlikely(nvme_req(req)->status && !(req->rq_flags & RQF_QUIET))) {
+		if (blk_rq_is_passthrough(req))
+			nvme_log_err_passthru(req);
+		else
+			nvme_log_error(req);
+	}
 	nvme_end_req_zoned(req);
 	nvme_trace_bio_complete(req);
 	if (req->cmd_flags & REQ_NVME_MPATH)
@@ -666,10 +694,15 @@ static inline void nvme_clear_nvme_request(struct request *req)
 /* initialize a passthrough request */
 void nvme_init_request(struct request *req, struct nvme_command *cmd)
 {
+	struct nvme_request *nr = nvme_req(req);
+
 	if (req->q->queuedata)
 		req->timeout = NVME_IO_TIMEOUT;
-	else /* no queuedata implies admin queue */
+	else { /* no queuedata implies admin queue */
 		req->timeout = NVME_ADMIN_TIMEOUT;
+		if (!nr->ctrl->passthru_log_err)
+			req->rq_flags |= RQF_QUIET;
+	}
 
 	/* passthru commands should let the driver set the SGL flags */
 	cmd->common.flags &= ~NVME_CMD_SGL_ALL;
@@ -678,8 +711,8 @@ void nvme_init_request(struct request *req, struct nvme_command *cmd)
 	if (req->mq_hctx->type == HCTX_TYPE_POLL)
 		req->cmd_flags |= REQ_POLLED;
 	nvme_clear_nvme_request(req);
-	req->rq_flags |= RQF_QUIET;
-	memcpy(nvme_req(req)->cmd, cmd, sizeof(*cmd));
+
+	memcpy(nr->cmd, cmd, sizeof(*cmd));
 }
 EXPORT_SYMBOL_GPL(nvme_init_request);
 
@@ -3417,6 +3450,44 @@ static ssize_t nvme_sysfs_rescan(struct device *dev,
 }
 static DEVICE_ATTR(rescan_controller, S_IWUSR, NULL, nvme_sysfs_rescan);
 
+static ssize_t nvme_passthru_err_log_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
+
+	if (ctrl->passthru_log_err)
+		return sysfs_emit(buf, "on\n");
+
+	return sysfs_emit(buf, "off\n");
+}
+
+static ssize_t nvme_passthru_err_log_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
+	int passthru_enable, err;
+
+	err = kstrtoint(buf, 10, &passthru_enable);
+	if (err)
+		return -EINVAL;
+
+	switch (passthru_enable) {
+	case true:
+	case false:
+		ctrl->passthru_log_err = passthru_enable;
+		break;
+	default:
+		pr_err("invlid value %d for admin error logging [on:1 off:0]\n",
+			passthru_enable);
+		break;
+	}
+	return count;
+}
+
+static DEVICE_ATTR(passthru_err_log, S_IRUGO | S_IWUSR,
+	nvme_passthru_err_log_show,
+	nvme_passthru_err_log_store);
+
 static inline struct nvme_ns_head *dev_to_ns_head(struct device *dev)
 {
 	struct gendisk *disk = dev_to_disk(dev);
@@ -3925,6 +3996,7 @@ static struct attribute *nvme_dev_attrs[] = {
 	&dev_attr_dhchap_secret.attr,
 	&dev_attr_dhchap_ctrl_secret.attr,
 #endif
+	&dev_attr_passthru_err_log.attr,
 	NULL
 };
 
@@ -5124,6 +5196,7 @@ int nvme_init_ctrl(struct nvme_ctrl *ctrl, struct device *dev,
 	int ret;
 
 	ctrl->state = NVME_CTRL_NEW;
+	ctrl->passthru_log_err = false;
 	clear_bit(NVME_CTRL_FAILFAST_EXPIRED, &ctrl->flags);
 	spin_lock_init(&ctrl->lock);
 	mutex_init(&ctrl->scan_lock);
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index bf46f122e9e1..f5721ad8264c 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -248,6 +248,7 @@ struct nvme_ctrl {
 	bool comp_seen;
 	enum nvme_ctrl_state state;
 	bool identified;
+	bool passthru_log_err;
 	spinlock_t lock;
 	struct mutex scan_lock;
 	const struct nvme_ctrl_ops *ops;
-- 
2.29.0