Re: [PATCH v2 2/3] vdpa: Add a device object for vdpa management device

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, May 16, 2022 at 05:31:27PM +0800, Yongji Xie wrote:
> On Mon, May 16, 2022 at 5:14 PM Jason Wang <jasowang@redhat.com> wrote:
> >
> >
> > 在 2022/5/16 14:03, Xie Yongji 写道:
> > > Introduce a device object for vdpa management device to control
> > > its lifecycle. And the device name will be used to match
> > > VDPA_ATTR_MGMTDEV_DEV_NAME field of netlink message rather than
> > > using parent device name.
> > >
> > > With this patch applied, drivers should use vdpa_mgmtdev_alloc()
> > > or _vdpa_mgmtdev_alloc() to allocate a vDPA management device
> > > before calling vdpa_mgmtdev_register(). And some buggy empty
> > > release function can also be removed from the driver codes.
> > >
> > > Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
> > > ---
> > >   drivers/vdpa/ifcvf/ifcvf_main.c      | 11 ++--
> > >   drivers/vdpa/mlx5/net/mlx5_vnet.c    | 11 ++--
> > >   drivers/vdpa/vdpa.c                  | 92 ++++++++++++++++++++++++----
> > >   drivers/vdpa/vdpa_sim/vdpa_sim_blk.c | 39 ++++--------
> > >   drivers/vdpa/vdpa_sim/vdpa_sim_net.c | 46 +++++---------
> > >   drivers/vdpa/vdpa_user/vduse_dev.c   | 38 ++++--------
> > >   include/linux/vdpa.h                 | 38 +++++++++++-
> > >   7 files changed, 168 insertions(+), 107 deletions(-)
> > >
> > > diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
> > > index 4366320fb68d..d4087c37cfdf 100644
> > > --- a/drivers/vdpa/ifcvf/ifcvf_main.c
> > > +++ b/drivers/vdpa/ifcvf/ifcvf_main.c
> > > @@ -821,10 +821,11 @@ static int ifcvf_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> > >       u32 dev_type;
> > >       int ret;
> > >
> > > -     ifcvf_mgmt_dev = kzalloc(sizeof(struct ifcvf_vdpa_mgmt_dev), GFP_KERNEL);
> > > -     if (!ifcvf_mgmt_dev) {
> > > +     ifcvf_mgmt_dev = vdpa_mgmtdev_alloc(struct ifcvf_vdpa_mgmt_dev,
> > > +                                         mdev, dev_name(dev), dev);
> >
> >
> > Just wonder if it's better to make vDPA device a child of the mgmt
> > device instead of the PCI device?
> >
> > (Currently we use PCI device as the parent of the vDPA device, or at
> > least we can do this for the simulator which doesn't have a parent?)
> >
> 
> Make sense. I think we can do it for all vDPA drivers. Make sure the
> parent of the vDPA device is the vDPA management device.
> 
> Thanks,
> Yongji


that's an ABI change though isn't it? parent is exposed in sysfs,
right?

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