drm/gpu: Add comment for memory barrier

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

Signed-off-by: Bhanusree <bhanusreemahesh@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/1571891313-14341-1-git-send-email-bhanusreemahesh@gmail.com

diff --git a/drivers/gpu/drm/drm_cache.c b/drivers/gpu/drm/drm_cache.c
index 3bd76e918b5d29ab5e37a733960925d765c080c9..e574261f6bc3dbabbdd593da216630eb01271913 100644 (file)
--- 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