Merge tag 'drm-intel-next-2014-04-16' of git://anongit.freedesktop.org/drm-intel...

[cascardo/linux.git] / drivers / gpu / drm / drm_cache.c

diff --git a/drivers/gpu/drm/drm_cache.c b/drivers/gpu/drm/drm_cache.c
index 4bfad5f..ae251b8 100644 (file)
--- 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(void *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;
        }