drm/amd/amdgpu: cast mem->num_pages to 64-bits when shifting (v2)

On 32-bit hosts mem->num_pages is 32-bits and can overflow
when shifted.  Add a cast to avoid this.

(v2): Style fix.

Signed-off-by: Tom St Denis <tom.stdenis@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 5 insertions, 4 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
index c963ad86072e..1150e34bc28f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
@@ -276,7 +276,7 @@ static int amdgpu_vram_mgr_new(struct ttm_mem_type_manager *man,
         struct drm_mm_node *nodes;
         enum drm_mm_insert_mode mode;
         unsigned long lpfn, num_nodes, pages_per_node, pages_left;
-        uint64_t vis_usage = 0;
+        uint64_t vis_usage = 0, mem_bytes;
         unsigned i;
         int r;
 
@@ -285,8 +285,9 @@ static int amdgpu_vram_mgr_new(struct ttm_mem_type_manager *man,
                 lpfn = man->size;
 
         /* bail out quickly if there's likely not enough VRAM for this BO */
-        if (atomic64_add_return(mem->num_pages << PAGE_SHIFT, &mgr->usage) > adev->gmc.mc_vram_size) {
-                atomic64_sub(mem->num_pages << PAGE_SHIFT, &mgr->usage);
+        mem_bytes = (u64)mem->num_pages << PAGE_SHIFT;
+        if (atomic64_add_return(mem_bytes, &mgr->usage) > adev->gmc.mc_vram_size) {
+                atomic64_sub(mem_bytes, &mgr->usage);
                 mem->mm_node = NULL;
                 return 0;
         }
@@ -308,7 +309,7 @@ static int amdgpu_vram_mgr_new(struct ttm_mem_type_manager *man,
         nodes = kvmalloc_array((uint32_t)num_nodes, sizeof(*nodes),
                                GFP_KERNEL | __GFP_ZERO);
         if (!nodes) {
-                atomic64_sub(mem->num_pages << PAGE_SHIFT, &mgr->usage);
+                atomic64_sub(mem_bytes, &mgr->usage);
                 return -ENOMEM;
         }