Looks good to me. One cosmetic comment inline. With that fixed this
patch is Reviewed-by: Felix Kuehling <Felix.Kuehling@xxxxxxx>
On 2019-06-14 12:51 p.m., StDenis, Tom wrote:
> On 32-bit hosts mem->num_pages is 32-bits and can overflow
> when shifted. Add a cast to avoid this.
>
> Signed-off-by: Tom St Denis <tom.stdenis@xxxxxxx>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 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..31895d3c33de 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> @@ -279,14 +279,16 @@ static int amdgpu_vram_mgr_new(struct ttm_mem_type_manager *man,
> uint64_t vis_usage = 0;
> unsigned i;
> int r;
> + uint64_t mem_bytes;
Christian likes the "upside-down christmas tree" to help readability of
local variable declarations.
>
> lpfn = place->lpfn;
> if (!lpfn)
> 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 +310,7 @@ 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;
> }
>
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