drm/amdgpu: Fix error codes if copy_to_user() fails

The copy_to_user() function returns the number of bytes that it wasn't
able to copy, but we should return -EFAULT to the user.

Fixes: 4d82724 ("drm/amdgpu: Add mapping info option for GEM_OP ioctl")
Fixes: f9db1fc ("drm/amdgpu: Add ioctl to get all gem handles for a process")
Reviewed-By: David Francis <David.Francis@amd.com>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Author: Dan Carpenter

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

@@ -1066,7 +1066,8 @@ int amdgpu_gem_op_ioctl(struct drm_device *dev, void *data,
 		drm_exec_fini(&exec);
 
 		if (num_mappings > 0 && num_mappings <= args->num_entries)
-			r = copy_to_user(u64_to_user_ptr(args->value), vm_entries, num_mappings * sizeof(*vm_entries));
+			if (copy_to_user(u64_to_user_ptr(args->value), vm_entries, num_mappings * sizeof(*vm_entries)))
+				r = -EFAULT;
 
 		args->num_entries = num_mappings;
 
@@ -1158,7 +1159,8 @@ int amdgpu_gem_list_handles_ioctl(struct drm_device *dev, void *data,
 	args->num_entries = bo_index;
 
 	if (!ret)
-		ret = copy_to_user(u64_to_user_ptr(args->entries), bo_entries, num_bos * sizeof(*bo_entries));
+		if (copy_to_user(u64_to_user_ptr(args->entries), bo_entries, num_bos * sizeof(*bo_entries)))
+			ret = -EFAULT;
 
 	kvfree(bo_entries);