Re: [PATCH net 1/2] socket: fix option SO_TIMESTAMPING_NEW

[Willem de Bruijn]

On Fri, Oct 9, 2020 at 8:30 PM Deepa Dinamani <deepa.kernel@xxxxxxxxx> wrote:
>
> On Fri, Oct 9, 2020 at 3:32 AM Christian Eggers <ceggers@xxxxxxx> wrote:
> >
> > The comparison of optname with SO_TIMESTAMPING_NEW is wrong way around,
> > so SOCK_TSTAMP_NEW will first be set and than reset again. Additionally
> > move it out of the test for SOF_TIMESTAMPING_RX_SOFTWARE as this seems
> > unrelated.
>
> The SOCK_TSTAMP_NEW is reset only in the case when
> SOF_TIMESTAMPING_RX_SOFTWARE is not set.
> Note that we only call sock_enable_timestamp() at that time.
>
> Why would SOCK_TSTAMP_NEW be relevant otherwise?

Other timestamps can be configured, such as hardware timestamps.

As the follow-on patch shows, there is also the issue of overlap
between SO_TIMESTAMP(NS) and SO_TIMESTAMPING.

Don't select OLD on timestamp disable, which may only disable
some of the ongoing timestamping.

Setting based on the syscall is simpler, too. __sock_set_timestamps
already uses for SO_TIMESTAMP(NS) the valbool approach I
suggest for SO_TIMESTAMPING.

The fallthrough can also be removed. My rough patch missed that.