drm/amdgpu: Explicitly add a flexible array at the end of 'struct amdgpu_bo_list'

'struct amdgpu_bo_list' is really used as if it was ended by a flex array.
So make it more explicit and add a 'struct amdgpu_bo_list_entry entries[]'
field at the end of the structure.

This way, struct_size() can be used when it is allocated.
It is less verbose.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c

@@ -75,7 +75,6 @@ int amdgpu_bo_list_create(struct amdgpu_device *adev, struct drm_file *filp,
 	struct amdgpu_bo_list_entry *array;
 	struct amdgpu_bo_list *list;
 	uint64_t total_size = 0;
-	size_t size;
 	unsigned i;
 	int r;
 
@@ -83,9 +82,7 @@ int amdgpu_bo_list_create(struct amdgpu_device *adev, struct drm_file *filp,
 				/ sizeof(struct amdgpu_bo_list_entry))
 		return -EINVAL;
 
-	size = sizeof(struct amdgpu_bo_list);
-	size += num_entries * sizeof(struct amdgpu_bo_list_entry);
-	list = kvmalloc(size, GFP_KERNEL);
+	list = kvmalloc(struct_size(list, entries, num_entries), GFP_KERNEL);
 	if (!list)
 		return -ENOMEM;
 

drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h

@@ -55,6 +55,8 @@ struct amdgpu_bo_list {
 	/* Protect access during command submission.
 	 */
 	struct mutex bo_list_mutex;
+
+	struct amdgpu_bo_list_entry entries[];
 };
 
 int amdgpu_bo_list_get(struct amdgpu_fpriv *fpriv, int id,