RE: [PATCH v5 3/3] vdpa/mlx5: Add support for reading descriptor statistics

[Eli Cohen]

> From: Si-Wei Liu <si-wei.liu@xxxxxxxxxx>
> Sent: Friday, May 13, 2022 12:15 AM
> To: Eli Cohen <elic@xxxxxxxxxx>; mst@xxxxxxxxxx; jasowang@xxxxxxxxxx
> Cc: virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v5 3/3] vdpa/mlx5: Add support for reading descriptor statistics
> 
> 
> On 5/11/2022 10:25 AM, Si-Wei Liu wrote:
> >>
> >> +
> >> +static int mlx5_vdpa_get_vendor_vq_stats(struct vdpa_device *vdev,
> >> u16 idx,
> >> +                     struct sk_buff *msg,
> >> +                     struct netlink_ext_ack *extack)
> >> +{
> >> +    struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
> >> +    struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
> >> +    struct mlx5_vdpa_virtqueue *mvq;
> >> +    struct mlx5_control_vq *cvq;
> >> +    u64 received_desc;
> >> +    u64 completed_desc;
> >> +    int err = 0;
> >> +    u16 max_vqp;
> >> +
> >> +    mutex_lock(&ndev->reslock);
> > I wonder if we can change this lock to r/w semaphore too, otherwise it
> > almost defeats the merit of converting vdpa_dev_mutex to the same.
> > This change would benefit multiple parallel readers.
> It looks like the lately posted v6 series missed this change somehow?

Yes, I missed that. I will add it as an additional patch.


> 
> -Siwei