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Date:   Mon, 31 Jul 2023 18:00:20 +0200
From:   Boris Brezillon <boris.brezillon@collabora.com>
To:     Nathan Chancellor <nathan@kernel.org>
Cc:     Christian =?UTF-8?B?S8O2bmln?= <ckoenig.leichtzumerken@gmail.com>,
        ndesaulniers@google.com, maarten.lankhorst@linux.intel.com,
        mripard@kernel.org, tzimmermann@suse.de, airlied@gmail.com,
        daniel@ffwll.ch, trix@redhat.com, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
        naresh.kamboju@linaro.org, dakr@redhat.com
Subject: Re: [PATCH 1/2] drm/exec: use unique instead of local label
Message-ID: <20230731180020.4c47e0e3@collabora.com>
In-Reply-To: <20230731153119.GA773004@dev-arch.thelio-3990X>
References: <20230731123625.3766-1-christian.koenig@amd.com>
        <20230731153119.GA773004@dev-arch.thelio-3990X>
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On Mon, 31 Jul 2023 08:31:19 -0700
Nathan Chancellor <nathan@kernel.org> wrote:

> On Mon, Jul 31, 2023 at 02:36:24PM +0200, Christian K=C3=B6nig wrote:
> > GCC forbids to jump to labels in loop conditions and a new clang
> > check stumbled over this.
> >=20
> > So instead using a local label inside the loop condition use an
> > unique label outside of it.
> >=20
> > Fixes: commit 09593216bff1 ("drm: execution context for GEM buffers v7")
> > Link: https://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html
> > Link: https://github.com/ClangBuiltLinux/linux/issues/1890
> > Link: https://github.com/llvm/llvm-project/commit/20219106060208f0c2f5d=
096eb3aed7b712f5067
> > Reported-by: Nathan Chancellor <nathan@kernel.org>
> > Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
> > CC: Boris Brezillon <boris.brezillon@collabora.com>

Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>

> > Signed-off-by: Christian K=C3=B6nig <christian.koenig@amd.com> =20
>=20
> Passes my build tests and I inspected the preprocessed output to make
> sure it should work. I ran the KUnit tests, which all pass (although [1]
> is needed to fix a tangential issue):
>=20
> Tested-by: Nathan Chancellor <nathan@kernel.org>
>=20
> Thanks for fixing this!
>=20
> [1]: https://lore.kernel.org/20230728183400.306193-1-arthurgrillo@riseup.=
net/
>=20
> > ---
> >  include/drm/drm_exec.h | 14 +++++++-------
> >  1 file changed, 7 insertions(+), 7 deletions(-)
> >=20
> > diff --git a/include/drm/drm_exec.h b/include/drm/drm_exec.h
> > index 73205afec162..e0462361adf9 100644
> > --- a/include/drm/drm_exec.h
> > +++ b/include/drm/drm_exec.h
> > @@ -3,6 +3,7 @@
> >  #ifndef __DRM_EXEC_H__
> >  #define __DRM_EXEC_H__
> > =20
> > +#include <linux/compiler.h>
> >  #include <linux/ww_mutex.h>
> > =20
> >  #define DRM_EXEC_INTERRUPTIBLE_WAIT	BIT(0)
> > @@ -74,13 +75,12 @@ struct drm_exec {
> >   * Since labels can't be defined local to the loops body we use a jump=
 pointer
> >   * to make sure that the retry is only used from within the loops body.
> >   */
> > -#define drm_exec_until_all_locked(exec)				\
> > -	for (void *__drm_exec_retry_ptr; ({			\
> > -		__label__ __drm_exec_retry;			\
> > -__drm_exec_retry:						\
> > -		__drm_exec_retry_ptr =3D &&__drm_exec_retry;	\
> > -		(void)__drm_exec_retry_ptr;			\
> > -		drm_exec_cleanup(exec);				\
> > +#define drm_exec_until_all_locked(exec)					\
> > +__PASTE(__drm_exec_, __LINE__):						\
> > +	for (void *__drm_exec_retry_ptr; ({				\
> > +		__drm_exec_retry_ptr =3D &&__PASTE(__drm_exec_, __LINE__);\
> > +		(void)__drm_exec_retry_ptr;				\
> > +		drm_exec_cleanup(exec);					\
> >  	});)
> > =20
> >  /**
> > --=20
> > 2.34.1
> >=20
> >  =20