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

[Arnd Bergmann]

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 âassert_kernel_context_is_currentâ:
drivers/gpu/drm/i915/i915_gem.c:4417:63: error: suggest braces around empty body in an âelseâ 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@xxxxxxxx>
---
 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