Re: [PATCH] Don't test for NULL firmware before releasing

[Mikko Perttunen]

On 2/16/23 15:19, Stanislaw Gruszka wrote:
> Hi
>
> On Thu, Feb 16, 2023 at 02:37:15AM +0100, Jesper Juhl wrote:
> >  From 4fe34831e2e7677b1c9616356f0a2e0a36ec092f Mon Sep 17 00:00:00 2001
> > From: Jesper Juhl <jesperjuhl76@xxxxxxxxx>
> > Date: Thu, 16 Feb 2023 02:33:05 +0100
> > Subject: [PATCH] Don't test for NULL firmware before releasing
> >
> > release_firmware() tests for a NULL pointer itself, no need to do it up-front.
> >
> > Signed-off-by: Jesper Juhl <jesperjuhl76@xxxxxxxxx>
> >
> > ---
> >   drivers/gpu/drm/tegra/falcon.c | 3 +--
> >   1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/tegra/falcon.c b/drivers/gpu/drm/tegra/falcon.c
> > index c0d85463eb1a..ae599441f031 100644
> > --- a/drivers/gpu/drm/tegra/falcon.c
> > +++ b/drivers/gpu/drm/tegra/falcon.c
> > @@ -153,8 +153,7 @@ int falcon_init(struct falcon *falcon)
> >
> >   void falcon_exit(struct falcon *falcon)
> >   {
> > -	if (falcon->firmware.firmware)
> > -		release_firmware(falcon->firmware.firmware);
> > +       	release_firmware(falcon->firmware.firmware);
>
> Please check patches with checkpatch.pl before posting.
>
> Regards
> Stanislaw

Aside the formatting deficiencies, I'm also not in favor of relying on 
NULL checks inside callees since doing so removes contextual information 
from the programmer; just looking at the code, it is easy to assume the 
pointer cannot be NULL if there is no NULL check. Recently had a longer 
thread about this in the context of kfree in TegraDRM.

Thanks
Mikko