From mboxrd@z Thu Jan 1 00:00:00 1970 From: Scott Feldman Subject: Re: [PATCH net-next] switchdev: enforce no pvid flag in vlan ranges Date: Wed, 14 Oct 2015 10:14:24 -0700 Message-ID: References: <1444651299-2813-1-git-send-email-razor@blackwall.org> <20151012173625.GA17983@ketchup.lan> <20151013083111.GA1432@colbert.mtl.com> <20151013143225.GA9636@ketchup.mtl.sfl> <20151014061446.GA29908@colbert.mtl.com> <20151014152515.GA6681@ketchup.mtl.sfl> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: Ido Schimmel , Nikolay Aleksandrov , Netdev , =?UTF-8?B?SmnFmcOtIFDDrXJrbw==?= , "David S. Miller" , Nikolay Aleksandrov , Elad Raz To: Vivien Didelot Return-path: Received: from mail-oi0-f54.google.com ([209.85.218.54]:33198 "EHLO mail-oi0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752325AbbJNROo (ORCPT ); Wed, 14 Oct 2015 13:14:44 -0400 Received: by oiar126 with SMTP id r126so31599515oia.0 for ; Wed, 14 Oct 2015 10:14:44 -0700 (PDT) In-Reply-To: <20151014152515.GA6681@ketchup.mtl.sfl> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, Oct 14, 2015 at 8:25 AM, Vivien Didelot wrote: > On Oct. Wednesday 14 (42) 09:14 AM, Ido Schimmel wrote: >> Tue, Oct 13, 2015 at 05:32:26PM IDT, vivien.didelot@savoirfairelinux.com wrote: >> >On Oct. Tuesday 13 (42) 11:31 AM, Ido Schimmel wrote: >> >> Mon, Oct 12, 2015 at 08:36:25PM IDT, vivien.didelot@savoirfairelinux.com wrote: >> >> >Hi guys, >> >> > >> >> >On Oct. Monday 12 (42) 02:01 PM, Nikolay Aleksandrov wrote: >> >> >> From: Nikolay Aleksandrov >> >> >> >> >> >> We shouldn't allow BRIDGE_VLAN_INFO_PVID flag in VLAN ranges. >> >> >> >> >> >> Signed-off-by: Nikolay Aleksandrov >> >> >> --- >> >> >> net/switchdev/switchdev.c | 3 +++ >> >> >> 1 file changed, 3 insertions(+) >> >> >> >> >> >> diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c >> >> >> index 6e4a4f9ad927..256c596de896 100644 >> >> >> --- a/net/switchdev/switchdev.c >> >> >> +++ b/net/switchdev/switchdev.c >> >> >> @@ -720,6 +720,9 @@ static int switchdev_port_br_afspec(struct net_device *dev, >> >> >> if (vlan.vid_begin) >> >> >> return -EINVAL; >> >> >> vlan.vid_begin = vinfo->vid; >> >> >> + /* don't allow range of pvids */ >> >> >> + if (vlan.flags & BRIDGE_VLAN_INFO_PVID) >> >> >> + return -EINVAL; >> >> >> } else if (vinfo->flags & BRIDGE_VLAN_INFO_RANGE_END) { >> >> >> if (!vlan.vid_begin) >> >> >> return -EINVAL; >> >> >> -- >> >> >> 2.4.3 >> >> >> >> >> > >> >> >Yes the patch looks good, but it is a minor check though. I hope the >> >> >subject of this thread is making sense. >> >> > >> >> >VLAN ranges seem to have been included for an UX purpose (so commands >> >> >look like Cisco IOS). We don't want to change any existing interface, so >> >> >we pushed that down to drivers, with the only valid reason that, maybe >> >> >one day, an hardware can be capable of programming a range on a per-port >> >> >basis. >> >> Hi, >> >> >> >> That's actually what we are doing in mlxsw. We can do up to 256 entries in >> >> one go. We've yet to submit this part. >> > >> >Perfect Ido, thanks for pointing this out! I'm OK with the range then. >> > >> >So there is now a very last question in my head for this, which is more >> >a matter of kernel design. Should the user be aware of such underlying >> >support? In other words, would it make sense to do this in a driver: >> > >> > foo_port_vlan_add(struct net_device *dev, >> > struct switchdev_obj_port_vlan *vlan) >> > { >> > if (vlan->vid_begin != vlan->vid_end) >> > return -ENOTSUPP; /* or something more relevant for user */ >> > >> > return foo_port_single_vlan_add(dev, vlan->vid_begin); >> > } >> > >> >So drivers keep being simple, and we can easily propagate the fact that >> >one-or-all VLAN is not supportable, vs. the VLAN feature itself is not >> >implemented and must be done in software. >> I think that if you want to keep it simple, then Scott's advice from the >> previous thread is the most appropriate one. I believe the hardware you >> are using is simply not meant to support multiple 802.1Q bridges. > > You mean allowing only one Linux bridge over an hardware switch? > > It would for sure simplify how, as developers and users, we represent a > physical switch. But I am not sure how to achieve that and I don't have > strong opinions on this TBH. Hi Vivien, I think it's possible to keep switch ports on just one bridge if we do a little bit of work on the NETDEV_CHANGEUPPER notifier. This will give you the driver-level control you want. Do you have time to investigate? The idea is: 1) In your driver's handler for NETDEV_CHANGEUPPER, if switch port is being added to a second bridge,then return NOTIFY_BAD. Your driver needs to track the bridge count. 2) In __netdev_upper_dev_link(), check the return code from the call_netdevice_notifiers_info(NETDEV_CHANGEUPPER, ...) call, and if NOTIFY_BAD, abort the linking operation (goto rollback_xxx). -scott