From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH v3 1/2] macvtap: include all checksum offloads in TUN_OFFLOAD mask Date: Thu, 15 Aug 2013 21:52:10 +0300 Message-ID: <20130815185210.GC11350@redhat.com> References: <1376586173-4242-1-git-send-email-vyasevic@redhat.com> <1376586173-4242-2-git-send-email-vyasevic@redhat.com> <20130815182430.GB10265@redhat.com> <520D21CA.4090400@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org To: Vlad Yasevich Return-path: Received: from mx1.redhat.com ([209.132.183.28]:18261 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759266Ab3HOSuZ (ORCPT ); Thu, 15 Aug 2013 14:50:25 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r7FIoPeb030521 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 15 Aug 2013 14:50:25 -0400 Content-Disposition: inline In-Reply-To: <520D21CA.4090400@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: On Thu, Aug 15, 2013 at 02:45:30PM -0400, Vlad Yasevich wrote: > On 08/15/2013 02:24 PM, Michael S. Tsirkin wrote: > >On Thu, Aug 15, 2013 at 01:02:52PM -0400, Vlad Yasevich wrote: > >>The features of the macvlan are based on the features of lower > >>device and thus can have checksum featurs other then IFF_F_HW_CSUM > > > >s/featurs/features/ > > > >:set spell spelllang=en_us > > > >or whatever's the equivalent in your editor of choice. > > > >>set. However, TUN_OFFLOAD mask only includes IFF_F_HW_CSUM. Thus > >>when performing gso segmentation during macvtap_forward(), > >>it is possbile to end up with skbs that have ip_summed set > >>to CHECKSUM_PARTIAL. This is incorrect when the user > >>turns off checksum offloading. > >> > >>Include all possible checksum offload values so that > >>we'll properly mask them off when performing GSO. > >> > >>Signed-off-by: Vlad Yasevich > >>--- > >> drivers/net/macvtap.c | 2 +- > >> 1 file changed, 1 insertion(+), 1 deletion(-) > >> > >>diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c > >>index b51db2a..8121358 100644 > >>--- a/drivers/net/macvtap.c > >>+++ b/drivers/net/macvtap.c > >>@@ -65,7 +65,7 @@ static struct cdev macvtap_cdev; > >> > >> static const struct proto_ops macvtap_socket_ops; > >> > >>-#define TUN_OFFLOADS (NETIF_F_HW_CSUM | NETIF_F_TSO_ECN | NETIF_F_TSO | \ > >>+#define TUN_OFFLOADS (NETIF_F_ALL_CSUM | NETIF_F_TSO_ECN | NETIF_F_TSO | \ > >> NETIF_F_TSO6 | NETIF_F_UFO) > >> #define RX_OFFLOADS (NETIF_F_GRO | NETIF_F_LRO) > >> /* > > > >Okay so you are talking about hardware that sets some other > >checksum bit besides HW_CSUM, e.g. IP_CSUM, so > > > > vlan->tap_features = vlan->dev->features & > > (feature_mask | ~TUN_OFFLOADS); > > > >will not clear IP_CSUM even if feature_mask is 0. > > > >Maybe mention this in the changelog, in case user > >will wonder whether his hardware is affected. > > > >So I agree, that's a bug, but if you make this change the reverse will hold > >(on this hardware): > >if user sets TUN_F_CSUM, we won't set NETIF_F_IP_CSUM > >so checksum offloading won't work. > > > >So I think you want s/NETIF_F_HW_CSUM/NETIF_F_ALL_CSUM/ everywhere > >and not just in this place. > > Yes. I thought about that, but forgot to do in this patch set. > > > > >Also - Cc stable? > > > > The offloads work went into 3.11, so I don't think there is a need > for stable. Right. Thanks for the correction. > -vlad > > > >>-- > >>1.8.1.4