Re: [PATCH v1 1/2] drm/amdgpu: make non-NULL out fence mandatory

[Pierre-Eric Pelloux-Prayer]

Le 16/09/2025 à 11:25, Christian König a écrit :
On 16.09.25 09:08, Pierre-Eric Pelloux-Prayer wrote:
amdgpu_ttm_copy_mem_to_mem has a single caller, make sure the out
fence is non-NULL to simplify the code.
Since none of the pointers should be NULL, we can enable
__attribute__((nonnull))__.

While at it make the function static since it's only used from
amdgpuu_ttm.c.

Signed-off-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-pra...@amd.com>
---
  drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 17 ++++++++---------
  drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h |  6 ------
  2 files changed, 8 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 27ab4e754b2a..70b817b5578d 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -284,12 +284,13 @@ static int amdgpu_ttm_map_buffer(struct ttm_buffer_object 
*bo,
   * move and different for a BO to BO copy.
   *
   */
-int amdgpu_ttm_copy_mem_to_mem(struct amdgpu_device *adev,
-                              const struct amdgpu_copy_mem *src,
-                              const struct amdgpu_copy_mem *dst,
-                              uint64_t size, bool tmz,
-                              struct dma_resv *resv,
-                              struct dma_fence **f)
+__attribute__((nonnull))

That looks fishy.

+static int amdgpu_ttm_copy_mem_to_mem(struct amdgpu_device *adev,
+                                     const struct amdgpu_copy_mem *src,
+                                     const struct amdgpu_copy_mem *dst,
+                                     uint64_t size, bool tmz,
+                                     struct dma_resv *resv,
+                                     struct dma_fence **f)

I'm not an expert for those, but looking at other examples that should be here 
and look something like:

__attribute__((nonnull(7)))

Both syntax are valid. The GCC docs says:

   If no arg-index is given to the nonnull attribute, all pointer arguments are 
marked as non-null



But I think for this case here it is also not a must have to have that.

I can remove it if you prefer, but it doesn't hurt to have the compiler validate 
usage of the functions.

Pierre-Eric



Regards,
Christian.

  {
        struct amdgpu_ring *ring = adev->mman.buffer_funcs_ring;
        struct amdgpu_res_cursor src_mm, dst_mm;
@@ -363,9 +364,7 @@ int amdgpu_ttm_copy_mem_to_mem(struct amdgpu_device *adev,
        }
  error:
        mutex_unlock(&adev->mman.gtt_window_lock);
-       if (f)
-               *f = dma_fence_get(fence);
-       dma_fence_put(fence);
+       *f = fence;
        return r;
  }
  
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
index bb17987f0447..07ae2853c77c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
@@ -170,12 +170,6 @@ int amdgpu_copy_buffer(struct amdgpu_ring *ring, uint64_t 
src_offset,
                       struct dma_resv *resv,
                       struct dma_fence **fence, bool direct_submit,
                       bool vm_needs_flush, uint32_t copy_flags);
-int amdgpu_ttm_copy_mem_to_mem(struct amdgpu_device *adev,
-                              const struct amdgpu_copy_mem *src,
-                              const struct amdgpu_copy_mem *dst,
-                              uint64_t size, bool tmz,
-                              struct dma_resv *resv,
-                              struct dma_fence **f);
  int amdgpu_ttm_clear_buffer(struct amdgpu_bo *bo,
                            struct dma_resv *resv,
                            struct dma_fence **fence);