# Re: \[RFC v4 02/11\] vhost-vdpa: protect concurrent access to vhost device iotlb

- From: Jason Wang \<hidden\>
- Date: 2021-03-02 12:06:24 
- List: netdev
- Page: https://ratatoskr.run/netdev/2021/03/200893
- Thread: https://ratatoskr.run/netdev/2021/02/200438/t.md

```text

On 2021/2/23 7:50 下午, Xie Yongji wrote:
> Use vhost_dev->mutex to protect vhost device iotlb from
> concurrent access.
>
> Fixes: 4c8cf318("vhost: introduce vDPA-based backend")
> Signed-off-by: Xie Yongji <redacted>
> ---
>   drivers/vhost/vdpa.c | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> index c50079dfb281..5500e3bf05c1 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -723,6 +723,7 @@ static int vhost_vdpa_process_iotlb_msg(struct vhost_dev *dev,
>   	if (r)
>   		return r;
>   
> +	mutex_lock(&dev->mutex);


I think this should be done before the vhost_dev_check_owner() above.

Thanks


>   	switch (msg->type) {
>   	case VHOST_IOTLB_UPDATE:
>   		r = vhost_vdpa_process_iotlb_update(v, msg);
> @@ -742,6 +743,7 @@ static int vhost_vdpa_process_iotlb_msg(struct vhost_dev *dev,
>   		r = -EINVAL;
>   		break;
>   	}
> +	mutex_unlock(&dev->mutex);
>   
>   	return r;
>   }

```