[PATCH v2] drm/gpu: Add comment for memory barrier

[Bhanusree]

-Add comment for memory barrier
-Issue found using checkpatch.pl

Signed-off-by: Bhanusree <bhanusreemahesh at gmail.com>
---

v2:modified memory barrier comments appropriately

 drivers/gpu/drm/drm_cache.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_cache.c b/drivers/gpu/drm/drm_cache.c
index 3bd76e9..e574261 100644
--- a/drivers/gpu/drm/drm_cache.c
+++ b/drivers/gpu/drm/drm_cache.c
@@ -62,10 +62,10 @@ static void drm_cache_flush_clflush(struct page *pages[],
 {
 	unsigned long i;
 
-	mb();
+	mb(); /*Full memory barrier used before so that CLFLUSH is ordered*/
 	for (i = 0; i < num_pages; i++)
 		drm_clflush_page(*pages++);
-	mb();
+	mb(); /*Also used after CLFLUSH so that all cache is flushed*/
 }
 #endif
 
-- 
2.7.4