Re: [RFC v3 1/1] nvme: add passthrough error logging opt-in

Sagi Grimberg
2023-04-03T10:17:34Z

On 4/1/23 01:18, Alan Adamson wrote:
> 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 error logging.
>
> To enable passthrough error logging:
> echo 1 > /sys/class/nvme/nvme0/passthrough_logging
>
> To disable passthrough error logging:
> echo 0 > /sys/class/nvme/nvme0/passthrough_logging
>
> By default, passthrough error logging will remain disabled.
>
> Signed-off-by: Alan Adamson <alan.adamson@oracle.com>
> ---
> drivers/nvme/host/core.c | 93 ++++++++++++++++++++++++++++++++++++++--
> drivers/nvme/host/nvme.h | 1 +
> 2 files changed, 90 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index 53ef028596c6..82d4f8235a8f 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -337,6 +337,49 @@ static void nvme_log_error(struct request *req)
> nr->status & NVME_SC_DNR ? "DNR " : "");
> }
>
> +static void nvme_log_error_passthrough(struct request *req)
> +{
> + struct nvme_ns *ns = req->q->queuedata;
> + struct nvme_request *nr = nvme_req(req);
> +
> + if (ns) {
> + 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->disk ? ns->disk->disk_name : "?",
> + nvme_get_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);
> + return;
> + }
> +
> + 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",
> + dev_name(nr->ctrl->device),
> + 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 +424,12 @@ 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_error_passthrough(req);
> + else
> + nvme_log_error(req);
> + }
> nvme_end_req_zoned(req);
> nvme_trace_bio_complete(req);
> if (req->cmd_flags & REQ_NVME_MPATH)
> @@ -666,6 +713,8 @@ 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 */
> @@ -678,8 +727,10 @@ 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));
> + if (!nr->ctrl->error_logging)
> + req->rq_flags |= RQF_QUIET;
> +
> + memcpy(nr->cmd, cmd, sizeof(*cmd));

Question, if we already introduce granularity to this setting, why
not per-ns? why only per controller? I'd think it makes more
sense to do this per ns. Will also remove access to ctrl in the hot
path...

> }
> EXPORT_SYMBOL_GPL(nvme_init_request);
>
> @@ -3418,6 +3469,38 @@ static ssize_t nvme_sysfs_rescan(struct device *dev,
> }
> static DEVICE_ATTR(rescan_controller, S_IWUSR, NULL, nvme_sysfs_rescan);
>
> +static ssize_t nvme_passthrough_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
> +
> + if (ctrl->error_logging)
> + return sysfs_emit(buf, "on\n");
> + else
> + return sysfs_emit(buf, "off\n");
> +}
> +
> +static ssize_t nvme_passthrough_store(struct device *dev,
> + struct device_attribute *attr, const char *buf, size_t count)
> +{
> + struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
> + int passthrough_enable, err;
> +
> + err = kstrtoint(buf, 10, &passthrough_enable);
> + if (err)
> + return -EINVAL;
> +
> + if (passthrough_enable)
> + ctrl->error_logging = true;
> + else
> + ctrl->error_logging = false;
> +
> + return count;
> +}
> +
> +static DEVICE_ATTR(passthrough_logging, S_IRUGO | S_IWUSR,
> + nvme_passthrough_show, nvme_passthrough_store);
> +
> static inline struct nvme_ns_head *dev_to_ns_head(struct device *dev)
> {
> struct gendisk *disk = dev_to_disk(dev);
> @@ -3926,6 +4009,7 @@ static struct attribute *nvme_dev_attrs[] = {
> &dev_attr_dhchap_secret.attr,
> &dev_attr_dhchap_ctrl_secret.attr,
> #endif
> + &dev_attr_passthrough_logging.attr,
> NULL
> };
>
> @@ -5125,6 +5209,7 @@ int nvme_init_ctrl(struct nvme_ctrl *ctrl, struct device *dev,
> int ret;
>
> ctrl->state = NVME_CTRL_NEW;
> + ctrl->error_logging = 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..dce5e6f7260c 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 error_logging;
> spinlock_t lock;
> struct mutex scan_lock;
> const struct nvme_ctrl_ops *ops;