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 21:24:31 +0300 Message-ID: <20130815182430.GB10265@redhat.com> References: <1376586173-4242-1-git-send-email-vyasevic@redhat.com> <1376586173-4242-2-git-send-email-vyasevic@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]:41587 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751903Ab3HOSWp (ORCPT ); Thu, 15 Aug 2013 14:22:45 -0400 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r7FIMjrw015806 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 15 Aug 2013 14:22:45 -0400 Content-Disposition: inline In-Reply-To: <1376586173-4242-2-git-send-email-vyasevic@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: 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. Also - Cc stable? > -- > 1.8.1.4