[PATCH] nvme: improve logging

[minwoo.im.dev@gmail.com (Minwoo Im)]

On 4/10/19 11:17 PM, Hannes Reinecke wrote:
> Currently nvme is very reluctant if it comes to logging anything,
> _unless_ it's an ANA AEN. So this patch tries to remedy this by
> decreasing the priority for the ANA AEN logging message, and improve
> the logging when calling nvme_reset_ctrl().
> 
> Signed-off-by: Hannes Reinecke <hare at suse.com>
> ---
>   drivers/nvme/host/core.c      | 44 +++++++++++++++++++++++++++++--------------
>   drivers/nvme/host/multipath.c |  5 ++++-
>   2 files changed, 34 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index 8d285bfcd352..98260b2c7a6f 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -94,6 +94,24 @@ static void nvme_put_subsystem(struct nvme_subsystem *subsys);
>   static void nvme_remove_invalid_namespaces(struct nvme_ctrl *ctrl,
>   					   unsigned nsid);
>   
> +static const char *nvme_ctrl_state_name(struct nvme_ctrl *ctrl)
> +{
> +	static const char *const state_name[] = {
> +		[NVME_CTRL_NEW]		= "new",
> +		[NVME_CTRL_LIVE]	= "live",
> +		[NVME_CTRL_ADMIN_ONLY]	= "only-admin",
> +		[NVME_CTRL_RESETTING]	= "resetting",
> +		[NVME_CTRL_CONNECTING]	= "connecting",
> +		[NVME_CTRL_DELETING]	= "deleting",
> +		[NVME_CTRL_DEAD]	= "dead",
> +	};
> +
> +	if ((unsigned)ctrl->state < ARRAY_SIZE(state_name) &&
> +	    state_name[ctrl->state])
> +		return state_name[ctrl->state];
> +	return NULL;

Hi, Hannes,

IMHO, If you want to print out "unknown" in the caller level, why don't 
we just
return "unknown" string itself to the caller to make caller don't need 
to print
out "unknown" OR "unknown state\n" just like below ?

I think this might make duplications for "unknown" string in callers.

Thanks,

> +}
> +
>   static void nvme_set_queue_dying(struct nvme_ns *ns)
>   {
>   	/*
> @@ -119,10 +137,17 @@ static void nvme_queue_scan(struct nvme_ctrl *ctrl)
>   
>   int nvme_reset_ctrl(struct nvme_ctrl *ctrl)
>   {
> -	if (!nvme_change_ctrl_state(ctrl, NVME_CTRL_RESETTING))
> +	if (!nvme_change_ctrl_state(ctrl, NVME_CTRL_RESETTING)) {
> +		const char *state_name = nvme_ctrl_state_name(ctrl);
> +
> +		dev_warn(ctrl->device, "cannot reset ctrl in state %s\n",
> +			 state_name ? state_name : "unknown");
>   		return -EBUSY;
> -	if (!queue_work(nvme_reset_wq, &ctrl->reset_work))
> +	}
> +	if (!queue_work(nvme_reset_wq, &ctrl->reset_work)) {
> +		dev_dbg(ctrl->device, "ctrl reset already queued\n");
>   		return -EBUSY;
> +	}
>   	return 0;
>   }
>   EXPORT_SYMBOL_GPL(nvme_reset_ctrl);
> @@ -2971,19 +2996,10 @@ static ssize_t nvme_sysfs_show_state(struct device *dev,
>   				     char *buf)
>   {
>   	struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
> -	static const char *const state_name[] = {
> -		[NVME_CTRL_NEW]		= "new",
> -		[NVME_CTRL_LIVE]	= "live",
> -		[NVME_CTRL_ADMIN_ONLY]	= "only-admin",
> -		[NVME_CTRL_RESETTING]	= "resetting",
> -		[NVME_CTRL_CONNECTING]	= "connecting",
> -		[NVME_CTRL_DELETING]	= "deleting",
> -		[NVME_CTRL_DEAD]	= "dead",
> -	};
> +	const char *state_name = nvme_ctrl_state_name(ctrl);
>   
> -	if ((unsigned)ctrl->state < ARRAY_SIZE(state_name) &&
> -	    state_name[ctrl->state])
> -		return sprintf(buf, "%s\n", state_name[ctrl->state]);
> +	if (state_name)
> +		return sprintf(buf, "%s\n", state_name);
>   
>   	return sprintf(buf, "unknown state\n");
>   }
> diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
> index 503539d4616a..cca60044163b 100644
> --- a/drivers/nvme/host/multipath.c
> +++ b/drivers/nvme/host/multipath.c
> @@ -81,6 +81,9 @@ void nvme_failover_req(struct request *req)
>   		 * Reset the controller for any non-ANA error as we don't know
>   		 * what caused the error.
>   		 */
> +		dev_info(ns->ctrl->device,
> +			"nvme status 0x%04x, resetting controller\n",
> +			status);
>   		nvme_reset_ctrl(ns->ctrl);
>   		break;
>   	}
> @@ -423,7 +426,7 @@ static int nvme_update_ana_state(struct nvme_ctrl *ctrl,
>   	unsigned *nr_change_groups = data;
>   	struct nvme_ns *ns;
>   
> -	dev_info(ctrl->device, "ANA group %d: %s.\n",
> +	dev_dbg(ctrl->device, "ANA group %d: %s.\n",
>   			le32_to_cpu(desc->grpid),
>   			nvme_ana_state_names[desc->state]);
>   
>