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From:   Cindy Lu <lulu@redhat.com>
Date:   Sat, 25 Nov 2023 23:54:34 +0800
Message-ID: <CACLfguXSdYgrb=A9kb_C_91y6DTbMpmv1eN2vUmZp49+B_h7uw@mail.gmail.com>
Subject: Re: [PATCH v2 1/5] vduse: Add function to get/free the pages for reconnection
To:     Jason Wang <jasowang@redhat.com>
Cc:     mst@redhat.com, xieyongji@bytedance.com,
        linux-kernel@vger.kernel.org, maxime.coquelin@redhat.com
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On Wed, Nov 22, 2023 at 2:23=E2=80=AFPM Jason Wang <jasowang@redhat.com> wr=
ote:
>
> 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_use=
r/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?
>
this index was use for sanity check in mmap function

> > +       /* 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 *=
dev,
> >         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 wil=
l 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 checkpatc=
h.
>
sure will do
> > +                        */
> > +                       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?
>
sure will fix this
thanks
Cindy
> Thanks
>