Re: [PATCH v2 1/2] nvme: expose hostnqn via sysfs for fabrics controllers

[Christoph Hellwig <hch@lst.de>]

On Fri, Feb 07, 2020 at 05:13:53PM -0800, Sagi Grimberg wrote:
> We allow userspace to connect with a custom hostnqn which
> is useful for certain use-cases. however there is is no way
> to tell what is the hostnqn used to connect to a given controller.
> 
> Expose this so userspace can correlate controllers based on hostnqn.
> 
> Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
> ---
> Changes from v1:
> - fix changelog
>  drivers/nvme/host/core.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index 5dc32b72e7fa..29a4f14360fa 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -3242,6 +3242,16 @@ static ssize_t nvme_sysfs_show_subsysnqn(struct device *dev,
>  }
>  static DEVICE_ATTR(subsysnqn, S_IRUGO, nvme_sysfs_show_subsysnqn, NULL);
>  
> +static ssize_t nvme_sysfs_show_hostnqn(struct device *dev,
> +					struct device_attribute *attr,
> +					char *buf)
> +{
> +	struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
> +
> +	return snprintf(buf, PAGE_SIZE, "%s\n", ctrl->opts->host->nqn);
> +}
> +static DEVICE_ATTR(hostnqn, S_IRUGO, nvme_sysfs_show_hostnqn, NULL);
> +
>  static ssize_t nvme_sysfs_show_address(struct device *dev,
>  					 struct device_attribute *attr,
>  					 char *buf)
> @@ -3267,6 +3277,7 @@ static struct attribute *nvme_dev_attrs[] = {
>  	&dev_attr_numa_node.attr,
>  	&dev_attr_queue_count.attr,
>  	&dev_attr_sqsize.attr,
> +	&dev_attr_hostnqn.attr,
>  	NULL
>  };
>  
> @@ -3280,6 +3291,8 @@ static umode_t nvme_dev_attrs_are_visible(struct kobject *kobj,
>  		return 0;
>  	if (a == &dev_attr_address.attr && !ctrl->ops->get_address)
>  		return 0;
> +	if (a == &dev_attr_hostnqn.attr && (!ctrl->opts))

No nee for the inner braces here.

Otherwise looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

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