RE: [PATCH 003/117] Staging: hv: Add struct hv_vmbus_device_id tomod_devicetable.h

From: KY Srinivasan
Date: Tue Aug 23 2011 - 20:44:48 EST




> -----Original Message-----
> From: Greg KH [mailto:greg@xxxxxxxxx]
> Sent: Tuesday, August 23, 2011 6:42 PM
> To: KY Srinivasan
> Cc: gregkh@xxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> devel@xxxxxxxxxxxxxxxxxxxxxx; virtualization@xxxxxxxxxxxxxx; Haiyang Zhang
> Subject: Re: [PATCH 003/117] Staging: hv: Add struct hv_vmbus_device_id to
> mod_devicetable.h
>
> On Fri, Jul 15, 2011 at 10:45:51AM -0700, K. Y. Srinivasan wrote:
> > In preparation for implementing vmbus aliases for auto-loading
> > Hyper-V drivers, define vmbus specific device ID.
> >
> > Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
> > Signed-off-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
> > ---
> > include/linux/mod_devicetable.h | 7 +++++++
> > 1 files changed, 7 insertions(+), 0 deletions(-)
> >
> > diff --git a/include/linux/mod_devicetable.h
> b/include/linux/mod_devicetable.h
> > index ae28e93..5a12377 100644
> > --- a/include/linux/mod_devicetable.h
> > +++ b/include/linux/mod_devicetable.h
> > @@ -405,6 +405,13 @@ struct virtio_device_id {
> > };
> > #define VIRTIO_DEV_ANY_ID 0xffffffff
> >
> > +/*
> > + * For Hyper-V devices we use the device guid as the id.
> > + */
> > +struct hv_vmbus_device_id {
> > + __u8 guid[16];
> > +};
>
> Why do you not need a driver_data pointer here? Are you sure you aren't
> ever going to need it in the future? Hint, I think you will...

I am not sure I am following you here; the guid is the device ID and it is
guaranteed to remain the same. What is the driver _data pointer here
you are referring to here. While some device id have the _data pointer,
there are others that don't - for instance struct virtio_device_id. In
our case, I am not sure how I would use this private pointer.

Regards,

K. Y
>
> greg k-h

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