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

[Chris Wilson]

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 <arnd at arndb.de>
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre