Parav Pandit
2022-Jul-24 15:23 UTC
[PATCH V3 3/6] vDPA: allow userspace to query features of a vDPA device
> From: Zhu, Lingshan <lingshan.zhu at 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.zhu at 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.