Linux Virtualization - Jan 2021 - [RFC v3 04/11] vhost-vdpa: protect concurrent access to vhost device iotlb

On 2021/1/19 ??12:59, Xie Yongji wrote:
> Introduce a mutex to protect vhost device iotlb from
> concurrent access.
>
> Fixes: 4c8cf318("vhost: introduce vDPA-based backend")
> Signed-off-by: Xie Yongji <xieyongji at bytedance.com>
> ---
>   drivers/vhost/vdpa.c | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> index 448be7875b6d..4a241d380c40 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -49,6 +49,7 @@ struct vhost_vdpa {
>   	struct eventfd_ctx *config_ctx;
>   	int in_batch;
>   	struct vdpa_iova_range range;
> +	struct mutex mutex;

Let's use the device mutex like what vhost_process_iotlb_msg() did.

Thanks

>   };
>   
>   static DEFINE_IDA(vhost_vdpa_ida);
> @@ -728,6 +729,7 @@ static int vhost_vdpa_process_iotlb_msg(struct
vhost_dev *dev,
>   	if (r)
>   		return r;
>   
> +	mutex_lock(&v->mutex);
>   	switch (msg->type) {
>   	case VHOST_IOTLB_UPDATE:
>   		r = vhost_vdpa_process_iotlb_update(v, msg);
> @@ -747,6 +749,7 @@ static int vhost_vdpa_process_iotlb_msg(struct
vhost_dev *dev,
>   		r = -EINVAL;
>   		break;
>   	}
> +	mutex_unlock(&v->mutex);
>   
>   	return r;
>   }
> @@ -1017,6 +1020,7 @@ static int vhost_vdpa_probe(struct vdpa_device *vdpa)
>   		return minor;
>   	}
>   
> +	mutex_init(&v->mutex);
>   	atomic_set(&v->opened, 0);
>   	v->minor = minor;
>   	v->vdpa = vdpa;