On Wed, 2018-02-07 at 16:57 -0700, Jason Gunthorpe wrote:
> On Wed, Feb 07, 2018 at 11:54:25PM +0000, Bart Van Assche wrote:
> > On Wed, 2018-02-07 at 16:41 -0700, Jason Gunthorpe wrote:
> > > diff --git a/include/uapi/rdma/rdma_user_rxe.h b/include/uapi/rdma/rdma_user_rxe.h
> > > index e3e6852b58eb45..b501deb18d8184 100644
> > > +++ b/include/uapi/rdma/rdma_user_rxe.h
> > > @@ -58,6 +58,8 @@ struct rxe_global_route {
> > > struct rxe_av {
> > > __u8 port_num;
> > > __u8 network_type;
> > > + __u16 reserved1;
> > > + __u32 reserved2;
> >
> > Hello Jason,
> >
> > Seeing two consecutive reserved members is a bit weird. Have you considered
> > to use something like __u8 reserved[6] instead?
>
> Ah, I had that originally but changed it to make pahole work properly..
> Can switch it back.
>
> Although, this does really firmly say what the alighment is, eg
> down the road someone might be tempted to do:
>
> - __u8 reserved[6];
> + __u32 new_value;
> + __u16 reserved;
>
> Which would be quite wrong..
Please consider to add BUILD_BUG_ON() statements into the rxe driver to verify
offsets of members of ABI structures. That approach is used in the rdma-core
library for e.g. the umad library and srp_daemon.
Thanks,
Bart.
��.n��������+%������w��{.n�����{���fk��ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
