From: Arnd Bergmann <arnd@arndb.de>
To: Daniel Vetter <daniel.vetter@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
        Jani Nikula <jani.nikula@linux.intel.com>,
        David Airlie <airlied@linux.ie>,
        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        Chris Wilson <chris@chris-wilson.co.uk>,
        intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH] drm/i915: avoid harmless empty-body warning
Date: Tue,  8 Nov 2016 14:58:17 +0100
Message-Id: <20161108135834.2166677-1-arnd@arndb.de>
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Sender: linux-kernel-owner@vger.kernel.org
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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@arndb.de>
---
 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