Re: [PATCH net-next 4/7] netconsole: add configfs controls for taskname sysdata feature

[Paolo Abeni]

On 2/21/25 2:52 PM, Breno Leitao wrote:
> Add configfs interface to enable/disable the taskname sysdata feature.
> This adds the following functionality:
> 
> The implementation follows the same pattern as the existing CPU number
> feature, ensuring consistent behavior and error handling across sysdata
> features.
> 
> Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx>
> ---
>  drivers/net/netconsole.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 50 insertions(+)
> 
> diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
> index 1b109f46512ffb7628c6b34c6efdfc301376dd53..5a29144ae37ee7b487b1a252b0f2ce8574f9cefa 100644
> --- a/drivers/net/netconsole.c
> +++ b/drivers/net/netconsole.c
> @@ -426,6 +426,20 @@ static ssize_t sysdata_cpu_nr_enabled_show(struct config_item *item, char *buf)
>  	return sysfs_emit(buf, "%d\n", cpu_nr_enabled);
>  }
>  
> +/* configfs helper to display if taskname sysdata feature is enabled */
> +static ssize_t sysdata_taskname_enabled_show(struct config_item *item,
> +					     char *buf)
> +{
> +	struct netconsole_target *nt = to_target(item->ci_parent);
> +	bool taskname_enabled;
> +
> +	mutex_lock(&dynamic_netconsole_mutex);
> +	taskname_enabled = !!(nt->sysdata_fields & SYSDATA_TASKNAME);
> +	mutex_unlock(&dynamic_netconsole_mutex);
> +
> +	return sysfs_emit(buf, "%d\n", taskname_enabled);
> +}
> +
>  /*
>   * This one is special -- targets created through the configfs interface
>   * are not enabled (and the corresponding netpoll activated) by default.
> @@ -841,6 +855,40 @@ static void disable_sysdata_feature(struct netconsole_target *nt,
>  	nt->extradata_complete[nt->userdata_length] = 0;
>  }
>  
> +static ssize_t sysdata_taskname_enabled_store(struct config_item *item,
> +					      const char *buf, size_t count)
> +{
> +	struct netconsole_target *nt = to_target(item->ci_parent);
> +	bool taskname_enabled, curr;
> +	ssize_t ret;
> +
> +	ret = kstrtobool(buf, &taskname_enabled);
> +	if (ret)
> +		return ret;
> +
> +	mutex_lock(&dynamic_netconsole_mutex);
> +	curr = nt->sysdata_fields & SYSDATA_TASKNAME;

Minor nit:
	curr = !!(nt->sysdata_fields & SYSDATA_TASKNAME);

would be preferable, and more robust if later on other SYSDATA_ bits are
added, 'moving down' SYSDATA_TASKNAME definition.

Also it would be more consistent with previous usage in
`sysdata_taskname_enabled_show()`

Cheers,

Paolo