linux-kernel - Re: [PATCH] drm: remove redundant assignment to variable 'ret'

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Message-ID: <20200716100202.GO3278063@phenom.ffwll.local>
Date:   Thu, 16 Jul 2020 12:02:19 +0200
From:   Daniel Vetter <daniel@...ll.ch>
To:     Jing Xiangfeng <jingxiangfeng@...wei.com>
Cc:     maarten.lankhorst@...ux.intel.com, mripard@...nel.org,
        tzimmermann@...e.de, airlied@...ux.ie, ajax@...hat.com,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm: remove redundant assignment to variable 'ret'

On Thu, Jul 16, 2020 at 09:59:38AM +0800, Jing Xiangfeng wrote:
> 
> 
> On 2020/7/15 20:05, Daniel Vetter wrote:
> > On Wed, Jul 15, 2020 at 03:05:59PM +0800, Jing Xiangfeng wrote:
> > > The variable ret has been assigned the value '-EINVAL'. The assignment
> > > in the if() is redundant. We can remove it.
> > 
> > Nope, that's not correct. Before this assignement ret is guaranteed to be
> > 0.
> 
> Before this assignment ret is '-EINVAL'(see commit 45bc3d26c95a: "drm:
> rework SET_MASTER and DROP_MASTER perm handling"). It is set to 0 above
> around the drm_drop_master() calls.

Ah indeed, but it got fixed already in 

commit 264ddd077c72092178153fc32d510dcecff32eeb
Author: Emil Velikov <emil.l.velikov@...il.com>
Date:   Sat May 30 13:46:40 2020 +0100

    drm/auth: make drm_{set,drop}master_ioctl symmetrical

That's why your patch didn't make any sense to me.
-Daniel

> 
> Thanks
> > -Daniel
> > 
> > > 
> > > Signed-off-by: Jing Xiangfeng <jingxiangfeng@...wei.com>
> > > ---
> > >   drivers/gpu/drm/drm_auth.c | 1 -
> > >   1 file changed, 1 deletion(-)
> > > 
> > > diff --git a/drivers/gpu/drm/drm_auth.c b/drivers/gpu/drm/drm_auth.c
> > > index 800ac39f3213..6e1b502f2797 100644
> > > --- a/drivers/gpu/drm/drm_auth.c
> > > +++ b/drivers/gpu/drm/drm_auth.c
> > > @@ -299,7 +299,6 @@ int drm_dropmaster_ioctl(struct drm_device *dev, void *data,
> > > 
> > >   	if (file_priv->master->lessor != NULL) {
> > >   		DRM_DEBUG_LEASE("Attempt to drop lessee %d as master\n", file_priv->master->lessee_id);
> > > -		ret = -EINVAL;
> > >   		goto out_unlock;
> > >   	}
> > > 
> > > --
> > > 2.17.1
> > > 
> > 
> _______________________________________________
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> dri-devel@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

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