From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roopa Prabhu Subject: Re: [PATCH 2/3] bridge: offload bridge port attributes to switch asic if feature flag set Date: Sun, 07 Dec 2014 12:24:19 -0800 Message-ID: <5484B773.7000809@cumulusnetworks.com> References: <1417746401-8140-3-git-send-email-roopa@cumulusnetworks.com> <54815883.80909@cumulusnetworks.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: "Arad, Ronen" , Netdev , =?UTF-8?B?Smlyw60gUMOtcmtv?= , Jamal Hadi Salim , Benjamin LaHaise , Thomas Graf , john fastabend , "stephen@networkplumber.org" , John Linville , "nhorman@tuxdriver.com" , Nicolas Dichtel , "vyasevic@redhat.com" , Florian Fainelli , "buytenh@wantstofly.org" , Aviad Raveh , "David S. Miller" , "shm@cumulusnetworks.com" , Andy Gospodarek To: Scott Feldman Return-path: Received: from ext3.cumulusnetworks.com ([198.211.106.187]:45854 "EHLO ext3.cumulusnetworks.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751255AbaLGUY0 convert rfc822-to-8bit (ORCPT ); Sun, 7 Dec 2014 15:24:26 -0500 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On 12/5/14, 10:54 PM, Scott Feldman wrote: > On Fri, Dec 5, 2014 at 3:21 PM, Arad, Ronen wr= ote: >> >>> -----Original Message----- >>> From: netdev-owner@vger.kernel.org [mailto:netdev- >>> owner@vger.kernel.org] On Behalf Of Roopa Prabhu >>> Sent: Thursday, December 04, 2014 11:02 PM >>> To: Scott Feldman >>> Cc: Ji=C5=99=C3=AD P=C3=ADrko; Jamal Hadi Salim; Benjamin LaHaise; = Thomas Graf; john >>> fastabend; stephen@networkplumber.org; John Linville; >>> nhorman@tuxdriver.com; Nicolas Dichtel; vyasevic@redhat.com; Floria= n >>> Fainelli; buytenh@wantstofly.org; Aviad Raveh; Netdev; David S. Mil= ler; >>> shm@cumulusnetworks.com; Andy Gospodarek >>> Subject: Re: [PATCH 2/3] bridge: offload bridge port attributes to = switch asic >>> if feature flag set >>> >>> On 12/4/14, 10:41 PM, Scott Feldman wrote: >>>> On Thu, Dec 4, 2014 at 6:26 PM, wrote= : >>>>> From: Roopa Prabhu >>>>> >>>>> This allows offloading to switch asic without having the user to = set >>>>> any flag. And this is done in the bridge driver to rollback kerne= l >>>>> settings on hw offload failure if required in the future. >>>>> >>>>> With this, it also makes sure a notification goes out only after = the >>>>> attributes are set both in the kernel and hw. >>>> I like this approach as it streamlines the steps for the user in >>>> setting port flags. There is one case for FLOODING where you'll h= ave >>>> to turn off flooding for both, and then turn on flooding in hw. Y= ou >>>> don't want flooding turned on on kernel and hw. >>> ok, maybe using the higher bits as in >>> https://patchwork.ozlabs.org/patch/413211/ >>> >>> might help with that. Let me think some more. >>>>> --- >>>>> net/bridge/br_netlink.c | 27 ++++++++++++++++++++++++++- >>>>> 1 file changed, 26 insertions(+), 1 deletion(-) >>>>> >>>>> diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c in= dex >>>>> 9f5eb55..ce173f0 100644 >>>>> --- a/net/bridge/br_netlink.c >>>>> +++ b/net/bridge/br_netlink.c >>>>> @@ -407,9 +407,21 @@ int br_setlink(struct net_device *dev, struc= t >>> nlmsghdr *nlh) >>>>> afspec, RTM_SETLINK); >>>>> } >>>>> >>>>> + if ((dev->features & NETIF_F_HW_SWITCH_OFFLOAD) && >>>>> + dev->netdev_ops->ndo_bridge_setlink) { >>>>> + int ret =3D dev->netdev_ops->ndo_bridge_setlink(d= ev, >>>>> + nlh); >>>> I think you want to up-level this to net/core/rtnetlink.c because >>>> you're only enabling the feature for one instance of a driver that >>>> implements ndo_bridge_setlink: the bridge driver. If another driv= er >>>> was MASTER and implemented ndo_bridge_setlink, you'd want same che= ck >>>> to push setting down to SELF port driver. >>> yeah, i thought about that. But i moved it here so that rollback wo= uld be >>> easier. >> There is a need for propagating setlink/dellink requests down multip= le levels. >> The use-case I have in mind is a bridge at the top, team/bond in the= middle, and port devices at the bottom. >> A setlink for VLAN filtering attributes would come with MASTER flag = set, and either port or bond/team netdev. >> How would this be handled? >> >> The propagation rules between bridge and enslaved port device could = be different from those between bond/team and enslaved devices. >> The current bridge driver does not propagate VLAN filtering from bri= dge to its ports as each port could have different configuration. In a = case of a bond/team all members need to have the same configuration suc= h that the a bond/team would be indistinguishable from a simple port. >> >> Therefore rtnetlink.c might not have the knowledge for propagation a= cross multiple levels. >> It seems that each device which implements ndo_bridge_setlink/ndo_br= idge_dellink and could have master role, need to take care of propagat= ion to its slaves. > Thanks Ronen for bringing up this use-case of stacked masters. I > think for VLAN filtering, the stacked master case is handled, not by > ndo_setlink/dellink at each level, but with ndo_vlan_rx_kill_vid and > ndo_vlan_rx_add_vid. So the switch port driver can know VLAN > membership for port even if port is under bond which is under bridge, > by using ndo_vlan_rx_xxx and setting NETIF_F_HW_VLAN_CTAG_FILTER. Th= e > bonding driver's ndo_vlan_rx_xxx handlers seem to keep ports in bond > VLAN membership consistent across bond. > > But in general, ndo_setlink/dellink don't work for the stack use-case > for other non-VLAN attributes. Maybe the answer is to use the VLAN > propogation model for other attributes. ndo_setlink/dellink/getlink > have enough weird-isms it might be time to define cleaner ndo ops to > propagate the other attrs down. And, only the switch asic driver is interested in these attrs. So, seem= s=20 like for these cases, we need to send these attrs to the switchdriver=20 directly instead of going through the stack of netdevs ?. see my=20 response to ronen's other email. Thanks, Roopa