linux-kernel - Re: [Nouveau] [PATCH] drm/nouveau/mmu: fix odd_ptr_err.cocci warnings (fwd)

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Date:   Tue, 28 Nov 2017 15:52:38 +0100 (CET)
From:   Julia Lawall <julia.lawall@...6.fr>
To:     Karol Herbst <kherbst@...hat.com>
cc:     Ben Skeggs <bskeggs@...hat.com>, David Airlie <airlied@...ux.ie>,
        nouveau <nouveau@...ts.freedesktop.org>,
        linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        kbuild-all@...org
Subject: Re: [Nouveau] [PATCH] drm/nouveau/mmu: fix odd_ptr_err.cocci warnings
 (fwd)

On Tue, 28 Nov 2017, Karol Herbst wrote:

> Hi julia,
>
> I think it would be better to extract the assignment out of the if
> clause. Then you'll get something like this:
>
> memory = ...;
> if (IS_ERR(memory)) {
> ....
> }
>
> so, to answer your question: no, it isn't necessary.

Will someone take care of it?  I'm just the 0-day proxy :)

julia

> On Tue, Nov 28, 2017 at 1:56 PM, Julia Lawall <julia.lawall@...6.fr> wrote:
> > This is a false positive, but I wonder if it is really necessary to put
> > the assignment in the conditional test expression.
> >
> > julia
> >
> > ---------- Forwarded message ----------
> > Date: Tue, 28 Nov 2017 13:23:36 +0800
> > From: kbuild test robot <fengguang.wu@...el.com>
> > To: kbuild@...org
> > Cc: Julia Lawall <julia.lawall@...6.fr>
> > Subject: [PATCH] drm/nouveau/mmu: fix odd_ptr_err.cocci warnings
> >
> > CC: kbuild-all@...org
> > CC: linux-kernel@...r.kernel.org
> > TO: Ben Skeggs <bskeggs@...hat.com>
> > CC: David Airlie <airlied@...ux.ie>
> > CC: dri-devel@...ts.freedesktop.org
> > CC: nouveau@...ts.freedesktop.org
> > CC: linux-kernel@...r.kernel.org
> >
> > drivers/gpu/drm/nouveau/nvkm/subdev/mmu/uvmm.c:109:5-11: inconsistent IS_ERR and PTR_ERR on line 110.
> > drivers/gpu/drm/nouveau/nvkm/subdev/mmu/uvmm.c:109:5-11: inconsistent IS_ERR and PTR_ERR on line 111.
> >
> >  PTR_ERR should access the value just tested by IS_ERR
> >
> > Semantic patch information:
> >  There can be false positives in the patch case, where it is the call to
> >  IS_ERR that is wrong.
> >
> > Generated by: scripts/coccinelle/tests/odd_ptr_err.cocci
> >
> > Fixes: 920d2b5ef215 ("drm/nouveau/mmu: define user interfaces to mmu vmm opertaions")
> > Signed-off-by: Fengguang Wu <fengguang.wu@...el.com>
> > ---
> >
> > Please take the patch only if it's a positive warning. Thanks!
> >
> >  uvmm.c |    5 +++--
> >  1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > --- a/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/uvmm.c
> > +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/uvmm.c
> > @@ -107,8 +107,9 @@ nvkm_uvmm_mthd_map(struct nvkm_uvmm *uvm
> >                 return ret;
> >
> >         if (IS_ERR((memory = nvkm_umem_search(client, handle)))) {
> > -               VMM_DEBUG(vmm, "memory %016llx %ld\n", handle, PTR_ERR(memory));
> > -               return PTR_ERR(memory);
> > +               VMM_DEBUG(vmm, "memory %016llx %ld\n", handle,
> > +                         PTR_ERR((memory = nvkm_umem_search(client, handle))));
> > +               return PTR_ERR((memory = nvkm_umem_search(client, handle)));
> >         }
> >
> >         mutex_lock(&vmm->mutex);
> > _______________________________________________
> > Nouveau mailing list
> > Nouveau@...ts.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/nouveau
>

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