Re: [PATCH v3] eeepc-laptop: simplify parse_arg()

Frans Klaver
2014-09-17T20:36:50Z

On Wed, Sep 17, 2014 at 01:35:10PM -0700, Darren Hart wrote:
> On Wed, Sep 17, 2014 at 09:02:51PM +0200, Paul Bolle wrote:
> > parse_arg() has three possible return values:
> > -EINVAL if sscanf(), in short, fails;
> > zero if "count" is zero; and
> > "count" in all other cases
> >
> > But "count" will never be zero. See, parse_arg() is called by the
> > various store functions. And the callchain of these functions starts
> > with sysfs_kf_write(). And that function checks for a zero "count". So
> > we can stop checking for a zero "count", drop the "count" argument
> > entirely, and transform parse_arg() into a function that returns zero on
> > success or a negative error. That, in turn, allows to make those store
> > functions just return "count" on success. The net effect is that the
> > code becomes a bit easier to understand.
> >
> > A nice side effect is that this GCC warning is silenced too:
> > drivers/platform/x86/eeepc-laptop.c: In function ‘store_sys_acpi’:
> > drivers/platform/x86/eeepc-laptop.c:279:10: warning: ‘value’ may be used uninitialized in this function [-Wmaybe-uninitialized]
> > int rv, value;
> >
> > Which is, of course, the reason to have a look at parse_arg().
> >
> > Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
> > ---
> > Still build tested only, but now on top of v3.17-rc5. Has Frans tested
> > writing zero length values to these sysfs files?
>
> Frans, can you confirm testing when you get a chance please?

Will do.

Frans