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From:   Jason Wang <jasowang@redhat.com>
Date:   Mon, 25 Oct 2021 10:23:51 +0800
Message-ID: <CACGkMEvyiJk+o9DNxoUGSUcytu9a56XQje-HZncYNDc9_eJGHA@mail.gmail.com>
Subject: Re: [PATCH v6 7/8] vdpa: add new attribute VDPA_ATTR_DEV_MIN_VQ_SIZE
To:     Wu Zongyong <wuzongyong@linux.alibaba.com>
Cc:     virtualization <virtualization@lists.linux-foundation.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        mst <mst@redhat.com>, wei.yang1@linux.alibaba.com
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On Fri, Oct 22, 2021 at 10:45 AM Wu Zongyong
<wuzongyong@linux.alibaba.com> wrote:
>
> This attribute advertises the min value of virtqueue size. The value is
> 0 by default.

As discussed previously, 0 seems an invalid value. We should use 1 at least.

Thanks

>
> Signed-off-by: Wu Zongyong <wuzongyong@linux.alibaba.com>
> ---
>  drivers/vdpa/vdpa.c       | 5 +++++
>  include/uapi/linux/vdpa.h | 1 +
>  2 files changed, 6 insertions(+)
>
> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
> index fd014ecec711..4aeb1458b924 100644
> --- a/drivers/vdpa/vdpa.c
> +++ b/drivers/vdpa/vdpa.c
> @@ -500,6 +500,7 @@ vdpa_dev_fill(struct vdpa_device *vdev, struct sk_buff *msg, u32 portid, u32 seq
>               int flags, struct netlink_ext_ack *extack)
>  {
>         u16 max_vq_size;
> +       u16 min_vq_size = 0;
>         u32 device_id;
>         u32 vendor_id;
>         void *hdr;
> @@ -516,6 +517,8 @@ vdpa_dev_fill(struct vdpa_device *vdev, struct sk_buff *msg, u32 portid, u32 seq
>         device_id = vdev->config->get_device_id(vdev);
>         vendor_id = vdev->config->get_vendor_id(vdev);
>         max_vq_size = vdev->config->get_vq_num_max(vdev);
> +       if (vdev->config->get_vq_num_min)
> +               min_vq_size = vdev->config->get_vq_num_min(vdev);
>
>         err = -EMSGSIZE;
>         if (nla_put_string(msg, VDPA_ATTR_DEV_NAME, dev_name(&vdev->dev)))
> @@ -528,6 +531,8 @@ vdpa_dev_fill(struct vdpa_device *vdev, struct sk_buff *msg, u32 portid, u32 seq
>                 goto msg_err;
>         if (nla_put_u16(msg, VDPA_ATTR_DEV_MAX_VQ_SIZE, max_vq_size))
>                 goto msg_err;
> +       if (nla_put_u16(msg, VDPA_ATTR_DEV_MIN_VQ_SIZE, min_vq_size))
> +               goto msg_err;
>
>         genlmsg_end(msg, hdr);
>         return 0;
> diff --git a/include/uapi/linux/vdpa.h b/include/uapi/linux/vdpa.h
> index 66a41e4ec163..e3b87879514c 100644
> --- a/include/uapi/linux/vdpa.h
> +++ b/include/uapi/linux/vdpa.h
> @@ -32,6 +32,7 @@ enum vdpa_attr {
>         VDPA_ATTR_DEV_VENDOR_ID,                /* u32 */
>         VDPA_ATTR_DEV_MAX_VQS,                  /* u32 */
>         VDPA_ATTR_DEV_MAX_VQ_SIZE,              /* u16 */
> +       VDPA_ATTR_DEV_MIN_VQ_SIZE,              /* u16 */
>
>         /* new attributes must be added above here */
>         VDPA_ATTR_MAX,
> --
> 2.31.1
>