Re: [PATCH] led: try to get LED's label from the 'label' property

[Antony Pavlov <antonynpavlov@gmail.com>]

On Mon, 28 Jul 2014 08:29:13 +0200
Sascha Hauer <s.hauer@pengutronix.de> wrote:

> On Mon, Jul 28, 2014 at 10:22:43AM +0400, Antony Pavlov wrote:
> > On Mon, 28 Jul 2014 07:49:17 +0200
> > Sascha Hauer <s.hauer@pengutronix.de> wrote:
> > 
> > > On Sun, Jul 27, 2014 at 12:35:52PM +0400, Antony Pavlov wrote:
> > > > Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
> > > > ---
> > > >  drivers/led/led-gpio.c | 4 +++-
> > > >  1 file changed, 3 insertions(+), 1 deletion(-)
> > > > 
> > > > diff --git a/drivers/led/led-gpio.c b/drivers/led/led-gpio.c
> > > > index 7bb3b49..cddac08 100644
> > > > --- a/drivers/led/led-gpio.c
> > > > +++ b/drivers/led/led-gpio.c
> > > > @@ -212,7 +212,9 @@ static int led_gpio_of_probe(struct device_d *dev)
> > > >  			continue;
> > > >  
> > > >  		gled = xzalloc(sizeof(*gled));
> > > > -		gled->led.name = xstrdup(child->name);
> > > > +		gled->led.name = xstrdup(of_get_property(child, "label", NULL));
> > > 
> > > When the property doesn't exist you pass NULL to xstrdup. This will
> > > crash.
> > 
> > My bad. I have seen barebox strdup() realization but missed xstrdup() realization.
> > 
> > Barebox' strdup() can handle NULL argument:
> > 
> > char * strdup(const char *s)
> > {
> >         char *new;
> > 
> >         if ((s == NULL) ||
> >             ((new = malloc (strlen(s) + 1)) == NULL) ) {                         
> >                 return NULL;                                                     
> >         }
> > 
> >         strcpy (new, s);
> >         return new;
> > }
> > 
> > But xstrdup() can't do so:
> > 
> > char *xstrdup(const char *s)
> > {
> >         char *p = strdup(s);
> > 
> >         if (!p)
> >                 panic("ERROR: out of memory\n");
> >         return p;
> > }               
> > 
> > Can I just change first xstrdup() to strdup() in my patch?
> 
> Why not add a NULL pointer check to xstrdup?

This will be duplication of code. strdup() inside xstrdup() check it too.

> > 
> > E.g.
> > 
> > -               gled->led.name = xstrdup(of_get_property(child, "label", NULL));
> > +               gled->led.name = strdup(of_get_property(child, "label", NULL));
> >                 if (!gled->led.name)
> >                         gled->led.name = xstrdup(child->name);
> 
> I think this code will raise questions. When reading this code one could
> easily ask why stdrup is used in the first place and xstrdup in the
> second. A year ahead even we may not know the answer without thinking
> about it ;)
> 
> Sascha
> 
> 
> -- 
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-- 
-- 
Best regards,
  Antony Pavlov

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