1 files changed, 8 insertions, 2 deletions

diff --git a/drivers/gpu/drm/drm_cache.c b/drivers/gpu/drm/drm_cache.c
index bb8f58012189..534cb89b160d 100644
--- a/drivers/gpu/drm/drm_cache.c
+++ b/drivers/gpu/drm/drm_cache.c
@@ -32,6 +32,12 @@
 #include <drm/drmP.h>
 
 #if defined(CONFIG_X86)
+
+/*
+ * clflushopt is an unordered instruction which needs fencing with mfence or
+ * sfence to avoid ordering issues.  For drm_clflush_page this fencing happens
+ * in the caller.
+ */
 static void
 drm_clflush_page(struct page *page)
 {
@@ -44,7 +50,7 @@ drm_clflush_page(struct page *page)
 
         page_virtual = kmap_atomic(page);
         for (i = 0; i < PAGE_SIZE; i += size)
-                clflush(page_virtual + i);
+                clflushopt(page_virtual + i);
         kunmap_atomic(page_virtual);
 }
 
@@ -133,7 +139,7 @@ drm_clflush_virt_range(char *addr, unsigned long length)
                 mb();
                 for (; addr < end; addr += boot_cpu_data.x86_clflush_size)
                         clflush(addr);
-                clflush(end - 1);
+                clflushopt(end - 1);
                 mb();
                 return;
         }