From mboxrd@z Thu Jan 1 00:00:00 1970 From: Simon Horman Subject: Re: [ovs-dev] [PATCH v3 net-next] MPLS: Use mpls_features to activate software MPLS GSO segmentation Date: Mon, 2 Jun 2014 13:39:50 +0900 Message-ID: <20140602043947.GA28083@verge.net.au> References: <1401669515-24142-1-git-send-email-horms@verge.net.au> <20140602035153.E5721710BF@kuma.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: davem@davemloft.net, netdev@vger.kernel.org, dev@openvswitch.org To: YAMAMOTO Takashi Return-path: Received: from kirsty.vergenet.net ([202.4.237.240]:56572 "EHLO kirsty.vergenet.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750724AbaFBEjy (ORCPT ); Mon, 2 Jun 2014 00:39:54 -0400 Content-Disposition: inline In-Reply-To: <20140602035153.E5721710BF@kuma.localdomain> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, Jun 02, 2014 at 12:51:53PM +0900, YAMAMOTO Takashi wrote: > > If an MPLS packet requires segmentation then use mpls_features > > to determine if the software implementation should be used. > > > > As no driver advertises MPLS GSO segmentation this will always be > > the case. > > > > I had not noticed that this was necessary before as software MPLS GSO > > segmentation was already being used in my test environment. I believe that > > the reason for that is the skbs in question always had fragments and the > > driver I used does not advertise NETIF_F_FRAGLIST (which seems to be the > > case for most drivers). Thus software segmentation was activated by > > skb_gso_ok(). > > > > Thanks to Jesse Gross for prompting me to investigate this. > > > > Acked-by: Jesse Gross > > Signed-off-by: Simon Horman > > > > --- > > v3 > > * As requested by David Miller > > - Do not mark net_mpls_features as inline > > - Correct alignment of parameters > > > > v2 > > * Added Ack from Jesse Gross > > * Removed duplicate 'Thus' from changelog > > --- > > net/core/dev.c | 38 ++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 38 insertions(+) > > > > diff --git a/net/core/dev.c b/net/core/dev.c > > index 0355ca5..1aa7004 100644 > > --- a/net/core/dev.c > > +++ b/net/core/dev.c > > @@ -2540,6 +2540,42 @@ netdev_features_t netif_skb_features(struct sk_buff *skb) > > } > > EXPORT_SYMBOL(netif_skb_features); > > > > +/* If MPLS offload request, verify we are testing hardware MPLS features > > + * instead of standard features for the netdev. > > + */ > > +#ifdef CONFIG_NET_MPLS_GSO > > +static netdev_features_t net_mpls_features(struct sk_buff *skb, > > + struct net_device *dev, > > + netdev_features_t features) > > +{ > > + /* There is no support for MPLS LRO. So the only way that > > + * an MPLS skb could require GSO segmentation is if it > > + * was received as a non-MPLS skb and then became an MPLS skb. > > + * This may be effected by Open vSwitch in which case the > > + * mac_len will non-zero and not equal to skb_network_offset > > + * as the former indicates the end of L2 the latter indicates > > s/L2/& and/ > > > + * the beginning of L3 and there is a gap between them occupied > > + * by the MPLS label stack. > > + * > > + * Thus it is possible to avoid traversing any VLAN tags that are > > + * present to determine if the ethtype is MPLS. Instead the > > + * inequality of mac_llen and skb_network_offset are used to > > s/mac_llen/mac_len/ > > Acked-by: YAMAMOTO Takashi Thanks, I will fix that and post v4.