Re: [PATCH v4 4/6] blk-wbt: don't show valid wbt_lat_usec in sysfs while wbt is disabled

[Christoph Hellwig]

>  static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)
>  {
> +	u64 lat;
> +
>  	if (!wbt_rq_qos(q))
>  		return -EINVAL;
>  
> -	return sprintf(page, "%llu\n", div_u64(wbt_get_min_lat(q), 1000));
> +	lat = wbt_disabled(q) ? 0 : div_u64(wbt_get_min_lat(q), 1000);
> +
> +	return sprintf(page, "%llu\n", lat);

	if (wbt_disabled(q))
		return sprintf(page, "0\n");
	return sprintf(page, "%llu\n", div_u64(wbt_get_min_lat(q), 1000));

but otherwise the patch looks fine:

Reviewed-by: Christoph Hellwig <hch@xxxxxx>