lkml.org 
[lkml]   [2018]   [Nov]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH 6/8] socket: Add struct sock_timeval
On Sun, Nov 25, 2018 at 5:52 AM Deepa Dinamani <deepa.kernel@gmail.com> wrote:
> On Sat, Nov 24, 2018 at 11:38 AM Willem de Bruijn <willemdebruijn.kernel@gmail.com> wrote:
> > On Sat, Nov 24, 2018 at 4:00 AM Deepa Dinamani <deepa.kernel@gmail.com> wrote:
> > >
> > > The new type is meant to be used as a y2038 safe structure
> > > to be used as part of cmsg data.
> > > Presently the SO_TIMESTAMP socket option uses struct timeval
> > > for timestamps. This is not y2038 safe.
> > > Subsequent patches in the series add new y2038 safe socket
> > > option to be used in the place of SO_TIMESTAMP_OLD.
> > > struct sock_timeval will be used as the timestamp format
> > > at that time.
> > >
> > > struct sock_timeval also maintains the same layout across
> > > 32 bit and 64 bit ABIs.
> > >
> > > Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
> > > ---
> > > include/uapi/linux/time.h | 5 +++++
> > > 1 file changed, 5 insertions(+)
> > >
> > > diff --git a/include/uapi/linux/time.h b/include/uapi/linux/time.h
> > > index 04d5587f30d3..106f9398c285 100644
> > > --- a/include/uapi/linux/time.h
> > > +++ b/include/uapi/linux/time.h
> > > @@ -70,6 +70,11 @@ struct __kernel_old_timeval {
> > > };
> > > #endif
> > >
> > > +struct sock_timeval {
> > > + long long tv_sec;
> > > + long long tv_usec;
> >
> > should these use fixed-width type __u64?
>
> We have avoided using __u64/__s64 types for time types in uapi.
> I think we did this for portability reasons.
> Although this new type might not be required to be interpreted in
> libc, I would prefer for this to be long long.
> If there is a strong preference then I can change it.

I think we want signed types to keep it closer to what we
have today with 'timeval'. as long as linux/types.h is included
first (it is).

Between __s64 or long long, I don't think it makes a difference,
so let's just go with Willem's suggestion. We already rely on
'long long' being exactly 64 bit wide in 'struct __kernel_timespec'
as well.

We could however debate whether 'sock_timeval' should
be visible to user space in linux/tme.h like this, or if it
should be put in a namespace like '__kernel_sock_timeval'
to ensure it won't conflict with user space headers defining
a type of the same name.

Arnd

\
 
 \ /
  Last update: 2018-11-25 21:51    [W:0.076 / U:13.520 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site