Re: [PATCH 1/1] drm/amdgpu: ignore -EPERM error from debugfs

["Christian König" <christian.koenig@amd.com>]

Am 05.10.21 um 15:11 schrieb Nirmoy Das:
> Debugfs core APIs will throw -EPERM when user disables debugfs
> using CONFIG_DEBUG_FS_ALLOW_NONE or with kernel param. We shouldn't
> see that as an error. Also validate drm root dentry before creating
> amdgpu debugfs files.
>
> Signed-off-by: Nirmoy Das <nirmoy.das@amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c | 10 ++++++++++
>   1 file changed, 10 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
> index 6611b3c7c149..d786072e918b 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
> @@ -1617,6 +1617,16 @@ int amdgpu_debugfs_init(struct amdgpu_device *adev)
>   	struct dentry *ent;
>   	int r, i;
>   
> +	if (IS_ERR(root)) {
> +		/* When debugfs is disabled we get -EPERM which is not an
> +		 * error as this is user controllable.
> +		 */

Well setting primary->debugfs_root to an error code is probably not a 
good idea to begin with.

When debugfs is disabled that should most likely be NULL.

Regards,
Christian.

> +		if (PTR_ERR(root) == -EPERM)
> +			return 0;
> +
> +		return PTR_ERR(ent);
> +	}
> +
>   	ent = debugfs_create_file("amdgpu_preempt_ib", 0600, root, adev,
>   				  &fops_ib_preempt);
>   	if (IS_ERR(ent)) {