drm/ttm: swap consecutive allocated cached pages v3

When we detect consecutive allocation of pages swap them to avoid
accidentally freeing them as huge page.

v2: use swap
v3: check if it's really the first allocated page

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Roger He <Hongbo.He@amd.com>
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc.c b/drivers/gpu/drm/ttm/ttm_page_alloc.c
index 116897a20514..b6f7ce286fb1 100644
--- a/drivers/gpu/drm/ttm/ttm_page_alloc.c
+++ b/drivers/gpu/drm/ttm/ttm_page_alloc.c
@@ -877,7 +877,7 @@ static int ttm_get_pages(struct page **pages, unsigned npages, int flags,
 #endif
         struct list_head plist;
         struct page *p = NULL;
-        unsigned count;
+        unsigned count, first;
         int r;
 
         /* No pool for cached pages */
@@ -918,6 +918,7 @@ static int ttm_get_pages(struct page **pages, unsigned npages, int flags,
                 }
 #endif
 
+                first = i;
                 while (npages) {
                         p = alloc_page(gfp_flags);
                         if (!p) {
@@ -925,6 +926,10 @@ static int ttm_get_pages(struct page **pages, unsigned npages, int flags,
                                 return -ENOMEM;
                         }
 
+                        /* Swap the pages if we detect consecutive order */
+                        if (i > first && pages[i - 1] == p - 1)
+                                swap(p, pages[i - 1]);
+
                         pages[i++] = p;
                         --npages;
                 }