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From:   Jason Wang <jasowang@redhat.com>
Date:   Wed, 22 Nov 2023 14:23:18 +0800
Message-ID: <CACGkMEsC-8tW30pDR4NcqP1gfK8dWpbVwE5KV4Q9nkQuXFYhdA@mail.gmail.com>
Subject: Re: [PATCH v2 1/5] vduse: Add function to get/free the pages for reconnection
To:     Cindy Lu <lulu@redhat.com>
Cc:     mst@redhat.com, xieyongji@bytedance.com,
        linux-kernel@vger.kernel.org, maxime.coquelin@redhat.com
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On Tue, Nov 21, 2023 at 3:31=E2=80=AFPM Cindy Lu <lulu@redhat.com> wrote:
>
> Add the function vduse_alloc_reconnnect_info_mem
> and vduse_alloc_reconnnect_info_mem
> In this 2 function, vduse will get/free (vq_num + 1)*page
> Page 0 will be used to save the reconnection information, The
> Userspace App will maintain this. Page 1 ~ vq_num + 1 will save
> the reconnection information for vqs.
>
> Signed-off-by: Cindy Lu <lulu@redhat.com>
> ---
>  drivers/vdpa/vdpa_user/vduse_dev.c | 80 ++++++++++++++++++++++++++++++
>  1 file changed, 80 insertions(+)
>
> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/=
vduse_dev.c
> index 26b7e29cb900..6209e2f00278 100644
> --- a/drivers/vdpa/vdpa_user/vduse_dev.c
> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> @@ -41,6 +41,16 @@
>  #define VDUSE_IOVA_SIZE (128 * 1024 * 1024)
>  #define VDUSE_MSG_DEFAULT_TIMEOUT 30
>
> +/* struct vdpa_reconnect_info saved the alloc pages info
> + * these pages will mmaped to userspace for reconnection
> + */
> +struct vdpa_reconnect_info {
> +       /* Offset (within vm_file) in PAGE_SIZE */
> +       u32 index;

Is index ever used in this series?

> +       /* virtual address for this page*/
> +       unsigned long vaddr;
> +};
> +
>  struct vduse_virtqueue {
>         u16 index;
>         u16 num_max;
> @@ -57,6 +67,7 @@ struct vduse_virtqueue {
>         struct vdpa_callback cb;
>         struct work_struct inject;
>         struct work_struct kick;
> +       struct vdpa_reconnect_info reconnect_info;
>  };
>
>  struct vduse_dev;
> @@ -106,6 +117,7 @@ struct vduse_dev {
>         u32 vq_align;
>         struct vduse_umem *umem;
>         struct mutex mem_lock;
> +       struct vdpa_reconnect_info reconnect_info;
>  };
>
>  struct vduse_dev_msg {
> @@ -1030,6 +1042,64 @@ static int vduse_dev_reg_umem(struct vduse_dev *de=
v,
>         return ret;
>  }
>
> +static int vduse_alloc_reconnnect_info_mem(struct vduse_dev *dev)
> +{
> +       struct vdpa_reconnect_info *info;
> +       struct vduse_virtqueue *vq;
> +
> +       for (int i =3D 0; i < dev->vq_num + 1; i++) {
> +               if (i =3D=3D 0) {
> +                       /*page 0 is use to save status,Userland APP will =
use this to
> +                        *save the information needed in reconnection,
> +                        *kernel don't need to maintain this

Please tweak the case here and to make sure the series can pass checkpatch.

> +                        */
> +                       info =3D &dev->reconnect_info;
> +                       info->vaddr =3D get_zeroed_page(GFP_KERNEL);
> +                       if (info->vaddr =3D=3D 0)
> +                               return -ENOMEM;
> +                       /* index is vm Offset in PAGE_SIZE */

The case seems odd but anyhow this has been explained in the uAPI file?

Thanks