Re: [PATCH v2 net] tcp/udp: Make early_demux back namespacified.

[Kuniyuki Iwashima <kuniyu@amazon.com>]

From:   Eric Dumazet <edumazet@google.com>
Date:   Tue, 12 Jul 2022 19:51:02 +0200
> On Tue, Jul 12, 2022 at 7:38 PM Kuniyuki Iwashima <kuniyu@amazon.com> wrote:
> >
> > Commit e21145a9871a ("ipv4: namespacify ip_early_demux sysctl knob") made
> > it possible to enable/disable early_demux on a per-netns basis.  Then, we
> > introduced two knobs, tcp_early_demux and udp_early_demux, to switch it for
> > TCP/UDP in commit dddb64bcb346 ("net: Add sysctl to toggle early demux for
> > tcp and udp").  However, the .proc_handler() was wrong and actually
> > disabled us from changing the behaviour in each netns.
> >
> 
> >  static int proc_tfo_blackhole_detect_timeout(struct ctl_table *table,
> >                                              int write, void *buffer,
> >                                              size_t *lenp, loff_t *ppos)
> > @@ -695,14 +640,18 @@ static struct ctl_table ipv4_net_table[] = {
> >                 .data           = &init_net.ipv4.sysctl_udp_early_demux,
> >                 .maxlen         = sizeof(u8),
> >                 .mode           = 0644,
> > -               .proc_handler   = proc_udp_early_demux
> > +               .proc_handler   = proc_dou8vec_minmax,
> > +               .extra1         = SYSCTL_ZERO,
> > +               .extra2         = SYSCTL_ONE,
> 
> This does not belong to this patch.
> 
> It is IMO too late, some users might use:
> 
> echo 2 >/proc/sys/net/ipv4/udp_early_demux

Ok, I will drop these.


> >         },
> >         {
> >                 .procname       = "tcp_early_demux",
> >                 .data           = &init_net.ipv4.sysctl_tcp_early_demux,
> >                 .maxlen         = sizeof(u8),
> >                 .mode           = 0644,
> > -               .proc_handler   = proc_tcp_early_demux
> > +               .proc_handler   = proc_dou8vec_minmax,
> > +               .extra1         = SYSCTL_ZERO,
> > +               .extra2         = SYSCTL_ONE,
> 
> Same here.
> 
> Again, fix the bug, and only the bug. Do not hide 'fixes' in an innocent patch.
> 
> There is a reason for that, we want each commit to have a clear description,
> and we want to be able to revert a patch without having to think about
> what needs
> to be re-written.

Sorry for bothering you.
But this makes my criteria explicit, thank you!