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

[Breno Leitao]

On Tue, Feb 25, 2025 at 12:41:50PM +0100, Paolo Abeni wrote:
> 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()`

Good point, in fact. I will update!

Thanks for the review,
--breno