2016-11-08 13:59:37

by Arnd Bergmann

Subject: [PATCH] drm/i915: avoid harmless empty-body warning

The newly added assert_kernel_context_is_current introduces a warning
when built with W=1:

drivers/gpu/drm/i915/i915_gem.c: In function ‘assert_kernel_context_is_current’:
drivers/gpu/drm/i915/i915_gem.c:4417:63: error: suggest braces around empty body in an ‘else’ statement [-Werror=empty-body]

Changing the GEM_BUG_ON() macro from an empty definition to "do { } while (0)"
makes the macro more robust to use and avoids the warning.

Fixes: 3033acab07f9 ("drm/i915: Queue the idling context switch after all other timelines")
Signed-off-by: Arnd Bergmann <[email protected]>
---
drivers/gpu/drm/i915/i915_gem.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.h b/drivers/gpu/drm/i915/i915_gem.h
index 735580d72eb1..51ec793f2e20 100644
--- a/drivers/gpu/drm/i915/i915_gem.h
+++ b/drivers/gpu/drm/i915/i915_gem.h
@@ -28,7 +28,7 @@
#ifdef CONFIG_DRM_I915_DEBUG_GEM
#define GEM_BUG_ON(expr) BUG_ON(expr)
#else
-#define GEM_BUG_ON(expr)
+#define GEM_BUG_ON(expr) do { } while (0)
#endif

#define I915_NUM_ENGINES 5
--
2.9.0

2016-11-08 15:06:46

by Chris Wilson

Subject: Re: [PATCH] drm/i915: avoid harmless empty-body warning

On Tue, Nov 08, 2016 at 02:58:17PM +0100, Arnd Bergmann wrote:
> The newly added assert_kernel_context_is_current introduces a warning
> when built with W=1:
>
> drivers/gpu/drm/i915/i915_gem.c: In function ‘assert_kernel_context_is_current’:
> drivers/gpu/drm/i915/i915_gem.c:4417:63: error: suggest braces around empty body in an ‘else’ statement [-Werror=empty-body]
>
> Changing the GEM_BUG_ON() macro from an empty definition to "do { } while (0)"
> makes the macro more robust to use and avoids the warning.
>
> Fixes: 3033acab07f9 ("drm/i915: Queue the idling context switch after all other timelines")
> Signed-off-by: Arnd Bergmann <[email protected]>
Reviewed-by: Chris Wilson <[email protected]>
-Chris

--
Chris Wilson, Intel Open Source Technology Centre

2016-11-08 16:35:54

by Daniel Vetter

Subject: Re: [Intel-gfx] [PATCH] drm/i915: avoid harmless empty-body warning

On Tue, Nov 08, 2016 at 02:49:05PM +0000, Chris Wilson wrote:
> On Tue, Nov 08, 2016 at 02:58:17PM +0100, Arnd Bergmann wrote:
> > The newly added assert_kernel_context_is_current introduces a warning
> > when built with W=1:
> >
> > drivers/gpu/drm/i915/i915_gem.c: In function ‘assert_kernel_context_is_current’:
> > drivers/gpu/drm/i915/i915_gem.c:4417:63: error: suggest braces around empty body in an ‘else’ statement [-Werror=empty-body]
> >
> > Changing the GEM_BUG_ON() macro from an empty definition to "do { } while (0)"
> > makes the macro more robust to use and avoids the warning.
> >
> > Fixes: 3033acab07f9 ("drm/i915: Queue the idling context switch after all other timelines")
> > Signed-off-by: Arnd Bergmann <[email protected]>
> Reviewed-by: Chris Wilson <[email protected]>

Queued for -next, thanks for the patch.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch