Re: Kevent POSIX timers support.

Evgeniy Polyakov
2006-11-28T19:23:22Z

On Tue, Nov 28, 2006 at 11:13:00AM -0800, David Miller (davem@davemloft.net) wrote:
> From: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
> Date: Tue, 28 Nov 2006 12:16:02 +0300
>
> > Although ukevent has pointer embedded, it is unioned with u64, so there
> > should be no problems until 128 bit arch appeared, which likely will not
> > happen soon. There is also unused in kevent posix timers patch
> > 'u32 ret_val[2]' field, which can store segval's value too.
> >
> > But the fact that ukevent does not and will not in any way have variable
> > size is absolutely.
>
> I believe that in order to be %100 safe you will need to use the
> special aligned_u64 type, as that takes care of a crucial difference
> between x86 and x86_64 API, namely that u64 needs 8-byte alignment on
> x86_64 but not on x86.
>
> You probably know this already :-)

Yep :)
So I put it at the end, where structure is already correctly aligned, so
there is no need for special alignment.
And, btw, last time I checked, aligned_u64 was not exported to
userspace.

--
Evgeniy Polyakov