From: Hannes Frederic Sowa <hannes@stressinduktion.org>
To: Alexander Duyck <alexander.duyck@gmail.com>, netdev@vger.kernel.org
Subject: Re: [PATCH net-next] ipv6: recreate ipv6 link-local addresses when increasing MTU over IPV6_MIN_MTU
Date: Mon, 26 Oct 2015 17:05:01 +0100 [thread overview]
Message-ID: <1445875501.168420.420547673.4BB6C209@webmail.messagingengine.com> (raw)
In-Reply-To: <562E4C26.3030501@gmail.com>
Hi Alex,
On Mon, Oct 26, 2015, at 16:52, Alexander Duyck wrote:
> On 10/26/2015 07:36 AM, Hannes Frederic Sowa wrote:
> > Take into consideration that the interface might be disabled for IPv6,
> > thus switch event type.
> >
> > Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
> > ---
> > net/ipv6/addrconf.c | 7 +++++--
> > 1 file changed, 5 insertions(+), 2 deletions(-)
> >
> > diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
> > index d0c685c..c2dcebe 100644
> > --- a/net/ipv6/addrconf.c
> > +++ b/net/ipv6/addrconf.c
> > @@ -3149,6 +3149,7 @@ static int addrconf_notify(struct notifier_block *this, unsigned long event,
> >
> > case NETDEV_UP:
> > case NETDEV_CHANGE:
> > +netdev_change:
> > if (dev->flags & IFF_SLAVE)
> > break;
> >
> > @@ -3244,8 +3245,10 @@ static int addrconf_notify(struct notifier_block *this, unsigned long event,
> >
> > if (!idev && dev->mtu >= IPV6_MIN_MTU) {
> > idev = ipv6_add_dev(dev);
> > - if (!IS_ERR(idev))
> > - break;
> > + if (!IS_ERR(idev)) {
> > + event = NETDEV_UP;
> > + goto netdev_change;
> > + }
> > }
> >
> > /*
>
> Seems like this code isn't quite correct. You are calling ipv6_add_dev
> for slave devices, and if I understand things correctly I don't believe
> that was happening before and may be an unintended side effect.
Hmm, could you quickly help me where I get into this situation? I made
sure I enter the NETDEV_UP part before the IFF_SLAVE test and
disable_ipv6 test.
> You might want to instead just make it so that you only do the jump, and
> perhaps change the code in the NETDEV_UP/NETDEV_CHANGE section so that
> you test for NETDEV_CHANGE instead of NETDEV_UP. That should be enough
> to get the effect you are looking for and I believe there would be no
> change to behaviour other than adding IPv6 link-local addresses when the
> MTU is increased.
>
> Give me a bit and I can submit an alternative that may actually work out
> a bit better I think.
If you go the NETDEV_CHANGE route instead of NETDEV_UP, you end up with
the IF_READY flag already set from ipv6_add_dev and thus won't do any
initialization of the device.
Sure, I wait.
Bye,
Hannes
next prev parent reply other threads:[~2015-10-26 16:05 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-26 14:36 [PATCH net-next] ipv6: recreate ipv6 link-local addresses when increasing MTU over IPV6_MIN_MTU Hannes Frederic Sowa
2015-10-26 15:52 ` Alexander Duyck
2015-10-26 16:05 ` Hannes Frederic Sowa [this message]
2015-10-26 17:07 ` Alexander Duyck
2015-10-26 17:21 ` Hannes Frederic Sowa
2015-10-26 19:05 ` Hannes Frederic Sowa
2015-10-26 16:33 ` Hannes Frederic Sowa
2015-10-26 19:16 ` Jay Vosburgh
2015-10-26 20:45 ` Hannes Frederic Sowa
2015-10-26 20:52 ` Alexander Duyck
2015-10-26 18:06 ` [net-next PATCH v2] " Alexander Duyck
2015-10-30 9:11 ` David Miller
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