Re: [PATCH net-next 4/9] netconsole: move netpoll_local_ip_unset() as netcons_local_ip_unset()

[Gustavo Luiz Duarte]

On Wed, Jul 29, 2026 at 11:23 AM Breno Leitao <leitao@xxxxxxxxxx> wrote:
>
> On Tue, Jul 28, 2026 at 12:49:46AM +0100, Gustavo Luiz Duarte wrote:
> > On Fri, Jul 24, 2026 at 4:05 PM Breno Leitao <leitao@xxxxxxxxxx> wrote:
> > >
> > > Move netpoll_local_ip_unset() from netpoll to netconsole and rename it
> > > to netcons_local_ip_unset();
> > >
> > > The body is otherwise unchanged, only the comment's setup-function
> > > reference is updated.
> > >
> > > Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx>
> > > ---
> > >  drivers/net/netconsole.c | 19 ++++++++++++++++++-
> > >  include/linux/netpoll.h  |  1 -
> > >  net/core/netpoll.c       | 18 ------------------
> > >  3 files changed, 18 insertions(+), 20 deletions(-)
> > >
> > > diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
> > > index 3a7a2cafc6276..70f9c5bfb3720 100644
> > > --- a/drivers/net/netconsole.c
> > > +++ b/drivers/net/netconsole.c
> > > @@ -351,6 +351,23 @@ static void netconsole_skb_pool_flush(struct netconsole_target *nt)
> > >         skb_queue_purge_reason(&nt->skb_pool, SKB_CONSUMED);
> > >  }
> > >
> > > +/*
> > > + * Test whether the caller left np->local_ip unset, so that
> > > + * netcons_netpoll_setup() should auto-populate it from the egress device.
> > > + *
> > > + * np->local_ip is a union of __be32 (IPv4) and struct in6_addr (IPv6),
> > > + * so an IPv6 address whose first 4 bytes are zero (e.g. ::1, ::2,
> > > + * IPv4-mapped ::ffff:a.b.c.d) must not be tested via the IPv4 arm —
> > > + * doing so would misclassify a caller-supplied address as unset and
> > > + * silently overwrite it with whatever address the device exposes.
> > > + */
> > > +static bool netcons_local_ip_unset(const struct netpoll *np)
> > > +{
> > > +       if (np->ipv6)
> > > +               return ipv6_addr_any(&np->local_ip.in6);
> > > +       return !np->local_ip.ip;
> > > +}
> >
> >
> > This whole checking if it is all zeroes in netcons_local_ip_unset()
> > looks very cumbersome.
> > Perhaps instead of storing 'bool ipv6' we could have something like
> > 'u8 family', which would contain AF_INET for ipv4, AF_INET6 for ipv6,
> > or AF_UNSPEC if unset.
>
> Agree, an explicit state machine would clarify the three cases: IPv4,
> IPv6, or unspecified (with netconsole deriving it from the device).
>
> Now that the helper lives in netconsole, the awkwardness is more visible.
>
> > But that would be another patch separate from this refactoring, so for
> > this patch:
>
> Thanks for the review. Would you be interested in pursuing that change
> once this lands?

Sure, I will send a patch once this series is merged.