drm/i915: Move whole object to CPU domain for coherent shmem access

If the object is coherent, we can simply update the cache domain on the
whole object rather than calculate the before/after clflushes. The
advantage is that we then get correct tracking of ellided flushes when
changing coherency later.

Testcase: igt/gem_pwrite_snooped
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170310000942.11661-1-chris@chris-wilson.co.uk
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 6a1c431..d11c964 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -3353,9 +3353,9 @@ int i915_gem_obj_prepare_shmem_read(struct drm_i915_gem_object *obj,
 				    unsigned int *needs_clflush);
 int i915_gem_obj_prepare_shmem_write(struct drm_i915_gem_object *obj,
 				     unsigned int *needs_clflush);
-#define CLFLUSH_BEFORE 0x1
-#define CLFLUSH_AFTER 0x2
-#define CLFLUSH_FLAGS (CLFLUSH_BEFORE | CLFLUSH_AFTER)
+#define CLFLUSH_BEFORE	BIT(0)
+#define CLFLUSH_AFTER	BIT(1)
+#define CLFLUSH_FLAGS	(CLFLUSH_BEFORE | CLFLUSH_AFTER)
 
 static inline void
 i915_gem_obj_finish_shmem_access(struct drm_i915_gem_object *obj)