RE: [PATCH V3 3/6] vDPA: allow userspace to query features of a vDPA device

[Parav Pandit via Virtualization]

> From: Zhu, Lingshan <lingshan....@intel.com>
> Sent: Saturday, July 23, 2022 7:27 AM
> 
> On 7/6/2022 10:25 AM, Zhu, Lingshan wrote:
> >
> >
> > On 7/6/2022 1:01 AM, Parav Pandit wrote:
> >>> From: Zhu, Lingshan <lingshan....@intel.com>
> >>> Sent: Tuesday, July 5, 2022 12:56 PM
> >>>> Both can be queried simultaneously. Each will return their own
> >>>> feature bits
> >>> using same attribute.
> >>>> It wont lead to the race.
> >>> How? It is just a piece of memory, xxxx[attr], do you see locks in
> >>> nla_put_u64_64bit()? It is a typical race condition, data accessed
> >>> by multiple producers / consumers.
> >> No. There is no race condition in here.
> >> And new attribute enum by no means avoid any race.
> >>
> >> Data put using nla_put cannot be accessed until they are transferred.
> > How this is guaranteed? Do you see errors when calling nla_put_xxx()
> > twice?
> Parav, did you miss this?
It is not called twice and reading attribute and packing in nla message is not 
race condition.
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