linux-kernel - Re: [PATCH] ALSA: usb-audio: Fix missing return assignment

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Date:   Thu, 25 Mar 2021 10:07:51 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Muhammad Usama Anjum <musamaanjum@...il.com>
Cc:     Jaroslav Kysela <perex@...ex.cz>, Takashi Iwai <tiwai@...e.com>,
        alsa-devel@...a-project.org, linux-kernel@...r.kernel.org,
        kernel-janitors@...r.kernel.org, colin.king@...onical.com
Subject: Re: [PATCH] ALSA: usb-audio: Fix missing return assignment

On Thu, Mar 25, 2021 at 01:24:23AM +0500, Muhammad Usama Anjum wrote:
> On Wed, 2021-03-24 at 21:50 +0300, Dan Carpenter wrote:
> > > -			usb_driver_claim_interface(driver, iface, (void *)-1L);
> > > +			err = usb_driver_claim_interface(driver, iface, (void *)-1L);
> > 
> > This is in a loop so only the last return value is used.  Which seems
> > sort of weird and pointless that the last value would matter more than
> > the others.
> > 
> Correct. Lets not store the return value. To stop the static analyzers
> to report the missing return assignment, can we add (void) in start of
> this function call? I've not seen use of (void) this way in the
> kernel. Is there any other way used in the kernel?

Don't add (void).  Don't add any code just to help static checkers, only
do it if it helps humans.  The (void) stuff is ugly.  We have a
__must_check annotation for functions where it's a bug not to check the
return and the usb_driver_claim_interface() is not a __must_check
function.  Just ignore the static checker when it's wrong.

When I'm reviewing static checker warnings, I only look at the new ones.
Then after I've looked at them, I mark them as old.  I currently have
65k old ignored warnings.

regards,
dan carpenter