Re: [PATCH] drm/amdgpu: do not use amdgpu_bo_gpu_offset_no_check individually

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

On 11/3/25 16:24, Saleemkhan Jamadar wrote:
> This should not be used indiviually, use amdgpu_bo_gpu_offset
> with bo reserved.
> 
> Signed-off-by: Saleemkhan Jamadar <saleemkhan083@gmail.com>
> Suggested-by: Christian König <christian.koenig@amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c |  2 +-
>  drivers/gpu/drm/amd/amdgpu/mes_userqueue.c       | 10 +++++++++-
>  2 files changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c
> index 3040437d99c2..bc7858567321 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c
> @@ -129,7 +129,7 @@ uint32_t amdgpu_doorbell_index_on_bar(struct amdgpu_device *adev,
>  {
>  	int db_bo_offset;
>  
> -	db_bo_offset = amdgpu_bo_gpu_offset_no_check(db_bo);
> +	db_bo_offset = amdgpu_bo_gpu_offset(db_bo);
>  
>  	/* doorbell index is 32 bit but doorbell's size can be 32 bit
>  	 * or 64 bit, so *db_size(in byte)/4 for alignment.
> diff --git a/drivers/gpu/drm/amd/amdgpu/mes_userqueue.c b/drivers/gpu/drm/amd/amdgpu/mes_userqueue.c
> index b1ee9473d628..0a244f80426c 100644
> --- a/drivers/gpu/drm/amd/amdgpu/mes_userqueue.c
> +++ b/drivers/gpu/drm/amd/amdgpu/mes_userqueue.c
> @@ -93,7 +93,15 @@ mes_userq_create_wptr_mapping(struct amdgpu_userq_mgr *uq_mgr,
>  		return ret;
>  	}
>  
> -	queue->wptr_obj.gpu_addr = amdgpu_bo_gpu_offset_no_check(wptr_obj->obj);
> +	ret = amdgpu_bo_reserve(wptr_obj->obj, true);
> +	if (ret) {
> +		DRM_ERROR("Failed to reserve wptr bo\n");
> +		return ret;
> +	}
> +
> +	queue->wptr_obj.gpu_addr = amdgpu_bo_gpu_offset(wptr_obj->obj);
> +	amdgpu_bo_unreserve(wptr_obj->obj);

The problem here is that the return value of amdgpu_bo_gpu_offset() can change as soon as you unlock the BO.

So that wptr BO either need to be pinned or fenced for this to work.

Regards,
Christian.

> +
>  	return 0;
>  }
>