[PATCH 2/4] drm/amdgpu: Optimization of critical section

[Christian König]

Am 12.06.2017 um 22:31 schrieb Alex Xie:
> Make the critical section smaller. There is no
> need to protect the bo_list, because there is
> no other task can access the newly created BO
> list yet.

NAK, a task can guess the next id number so could get the kernel to use 
the structure before it is initialized.

Christian.

>
> Signed-off-by: Alex Xie <AlexBin.Xie at amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
> index 02c138f..c994a04 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
> @@ -48,8 +48,9 @@ static int amdgpu_bo_list_create(struct amdgpu_fpriv *fpriv,
>   	mutex_lock(&fpriv->bo_list_lock);
>   	r = idr_alloc(&fpriv->bo_list_handles, *result,
>   		      1, 0, GFP_KERNEL);
> +	mutex_unlock(&fpriv->bo_list_lock);
> +
>   	if (r < 0) {
> -		mutex_unlock(&fpriv->bo_list_lock);
>   		kfree(*result);
>   		return r;
>   	}
> @@ -60,7 +61,6 @@ static int amdgpu_bo_list_create(struct amdgpu_fpriv *fpriv,
>   	(*result)->array = NULL;
>   
>   	mutex_lock(&(*result)->lock);
> -	mutex_unlock(&fpriv->bo_list_lock);
>   
>   	return 0;
>   }