[PATCH] drm/ttm: fix ttm tt init fail when size exceeds kmalloc limit

[Yang Wang <KevinYang.Wang@xxxxxxx>]

if the __GFP_ZERO is set, the kvmalloc() can't fallback to use vmalloc()
to allocate memory, when request size is exceeds kmalloc limit, it will
cause allocate memory fail.

e.g: when ttm want to create a BO with 1TB size, it maybe fail.

Signed-off-by: Yang Wang <KevinYang.Wang@xxxxxxx>
---
 drivers/gpu/drm/ttm/ttm_tt.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c
index 79c870a3bef8..9f2f3e576b8d 100644
--- a/drivers/gpu/drm/ttm/ttm_tt.c
+++ b/drivers/gpu/drm/ttm/ttm_tt.c
@@ -97,9 +97,12 @@ int ttm_tt_create(struct ttm_buffer_object *bo, bool zero_alloc)
 static int ttm_tt_alloc_page_directory(struct ttm_tt *ttm)
 {
 	ttm->pages = kvmalloc_array(ttm->num_pages, sizeof(void*),
-			GFP_KERNEL | __GFP_ZERO);
+				    GFP_KERNEL);
 	if (!ttm->pages)
 		return -ENOMEM;
+
+	memset(ttm->pages, 0, ttm->num_pages * sizeof(void *));
+
 	return 0;
 }
 
@@ -108,10 +111,12 @@ static int ttm_dma_tt_alloc_page_directory(struct ttm_tt *ttm)
 	ttm->pages = kvmalloc_array(ttm->num_pages,
 				    sizeof(*ttm->pages) +
 				    sizeof(*ttm->dma_address),
-				    GFP_KERNEL | __GFP_ZERO);
+				    GFP_KERNEL);
 	if (!ttm->pages)
 		return -ENOMEM;
 
+	memset(ttm->pages, 0, ttm->num_pages * (sizeof(*ttm->pages) + sizeof(*ttm->dma_address)));
+
 	ttm->dma_address = (void *)(ttm->pages + ttm->num_pages);
 	return 0;
 }
@@ -120,9 +125,12 @@ static int ttm_sg_tt_alloc_page_directory(struct ttm_tt *ttm)
 {
 	ttm->dma_address = kvmalloc_array(ttm->num_pages,
 					  sizeof(*ttm->dma_address),
-					  GFP_KERNEL | __GFP_ZERO);
+					  GFP_KERNEL);
 	if (!ttm->dma_address)
 		return -ENOMEM;
+
+	memset(ttm->dma_address, 0, ttm->num_pages * sizeof(*ttm->dma_address));
+
 	return 0;
 }
 
-- 
2.25.1