linux-kernel - Re: [PATCH] checkpatch: Warn on unnecessary void function return statements

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Message-ID: <1402975557.2797.8.camel@joe-AO725>
Date:	Mon, 16 Jun 2014 20:25:57 -0700
From:	Joe Perches <joe@...ches.com>
To:	Sachin Kamat <spk.linux@...il.com>
Cc:	Anish Bhatt <anish@...lsio.com>, linux-kernel@...r.kernel.org,
	akpm@...ux-foundation.org
Subject: Re: [PATCH] checkpatch: Warn on unnecessary void function return
 statements

On Tue, 2014-06-17 at 08:46 +0530, Sachin Kamat wrote:
> On Tue, Jun 17, 2014 at 7:30 AM, Joe Perches <joe@...ches.com> wrote:
> > On Mon, 2014-06-16 at 17:44 -0700, Anish Bhatt wrote:
> >> My code has multiple exit lables:
> >> void function(void)
> >> {
> >>       ...
> >>
> >>       if (err1)
> >>               goto exit1;
> >>       ...
> >>       if (err2)
> >>               goto exit2;
> >>
> >>       ...
> >>       return; /* Good return, no errors */
> >> exit1:
> >>       printk(err1);
> >>       return;
> >> exit2:
> >>       printk(err2);
> >> }
> >>
> >> The single tabbed return was required to prevent the good return & err1
> >> messages cascading down. The extra exit label with a noop looks weird,
> >> but is passing checkpatch.pl --strict, so I will go with that, thanks.
> >> -Anish
> >>
> >
> > Hmm, those return uses seem reasonable
> > to me.
> >
> > Perhaps the test should warn only on
> > this specific 3 line sequence:
> >
> > [any line but a label]
> >         return;
> > }
> >
> > Andrew?  Anyone else?  Opinions?
> 
> It should warn only if the return is followed by a value like
> return 0; or return -EERROR_CODE; etc. and not just 'return;'

No.  The compiler gets to warn on those.
checkpatch isn't a compiler.

It's a code style verifying and sometimes an
API misuse checking tool.

In this case, using return at the bottom of a
void function like

void function(void)
{
	[code...]

	return;
}

is undesired and would generally be written as

void function(void)
{
	[code...]
}


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