Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763930Ab3ECXf7 (ORCPT ); Fri, 3 May 2013 19:35:59 -0400 Received: from mx4-phx2.redhat.com ([209.132.183.25]:43826 "EHLO mx4-phx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759772Ab3ECXf5 convert rfc822-to-8bit (ORCPT ); Fri, 3 May 2013 19:35:57 -0400 Date: Fri, 3 May 2013 19:35:35 -0400 (EDT) From: Pavel Simerda To: =?utf-8?Q?Micha=C5=82_Miros=C5=82aw?= Cc: =?utf-8?Q?Bj=C3=B8rn?= Mork , Ben Hutchings , David Miller , kaber@trash.net, torvalds@linux-foundation.org, hayeswang@realtek.com, akpm@linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Dan Williams , Jiri Pirko Message-ID: <1925922763.4087858.1367624135286.JavaMail.root@redhat.com> In-Reply-To: References: <20130502.041625.412316202038784117.davem@davemloft.net> <20130502083619.GA22010@macbook.localnet> <87d2t9bvj1.fsf@nemi.mork.no> <20130502.051727.949429506738234701.davem@davemloft.net> <1367490491.5106.137.camel@deadeye.wl.decadent.org.uk> <87zjwda9bl.fsf@nemi.mork.no> Subject: Re: [GIT] Networking MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT X-Originating-IP: [10.5.82.12] X-Mailer: Zimbra 8.0.3_GA_5664 (ZimbraWebClient - FF19 (Linux)/8.0.3_GA_5664) Thread-Topic: Networking Thread-Index: pHD2SyZ8vi2jX+Tiv36y73SK9F5RhQ== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3711 Lines: 88 ----- Original Message ----- > From: "Michał Mirosław" > To: "Bjørn Mork" , "Pavel Šimerda" > Cc: "Ben Hutchings" , "David Miller" , kaber@trash.net, > torvalds@linux-foundation.org, hayeswang@realtek.com, akpm@linux-foundation.org, netdev@vger.kernel.org, > linux-kernel@vger.kernel.org > Sent: Thursday, May 2, 2013 6:22:47 PM > Subject: Re: [GIT] Networking > > 2013/5/2 Bjørn Mork : > > Ben Hutchings writes: > >> On Thu, 2013-05-02 at 05:17 -0400, David Miller wrote: > >>> From: Bjørn Mork > >>> Date: Thu, 02 May 2013 11:06:42 +0200 > >>> > >>> > Adding the new netdev features will make it go from 1 to 2: > >>> > >>> We already had more than 31 feature bits before Patrick's > >>> changes, and I'm pretty sure this was the case when we added > >>> that ethtool API. > >> > >> It wasn't, but this should be OK. Userland is supposed to query the > >> number of features using ETHTOOL_GSSET_INFO and then work out the number > >> of words/blocks using FEATURE_BITS_TO_BLOCKS(). > > > > > > Looking at > > http://cgit.freedesktop.org/NetworkManager/NetworkManager/tree/src/platform/nm-linux-platform.c#n1025 > > there seems to be a couple of bugs in this area. This is certainly > > abusing the exported API, but it does mean that NM breaks if you ever > > move NETIF_F_VLAN_CHALLENGED (like the 802.1ad patch did): > > > > ---- > > #define NETIF_F_VLAN_CHALLENGED (1 << 10) > > > > static gboolean > > link_supports_vlans (NMPlatform *platform, int ifindex) > > { > > auto_nl_object struct rtnl_link *rtnllink = link_get (platform, > > ifindex); > > const char *name = nm_platform_link_get_name (ifindex); > > struct { > > struct ethtool_gfeatures features; > > struct ethtool_get_features_block features_block; > > } edata = { .features = { .cmd = ETHTOOL_GFEATURES, .size = 1 } }; > > > > /* Only ARPHRD_ETHER links can possibly support VLANs. */ > > if (!rtnllink || rtnl_link_get_arptype (rtnllink) != ARPHRD_ETHER) > > return FALSE; > > > > if (!name || !ethtool_get (name, &edata)) > > return FALSE; > > > > return !(edata.features.features[0].active & > > NETIF_F_VLAN_CHALLENGED); > > } > > ---- > > > > > > Not that I see how this particular bug matters unless you need VLAN > > support in NM. But there could be similar issues around. I guess > > avoiding unnecessary renumbering of the NETIF_F bits can save us some > > trouble. Although you can certainly argue that those bits never were > > intended to be part of the API, and that using them like this is a user > > application bug. > > This is certainly a bug in NM, and a fresh one: commit > b636ea86b1c0a28b77eda311c84d3b2417cad22e from 2013-04-10 14:40:58 > (GMT). Userspace is expected to use ETHTOOL_GSTRINGS for > ETH_SS_FEATURES and find a corresponding bit position by feature name > ("vlan-challenged" in this case). > > Cc: commit's author. Recorded the bug with NetworkManager bugzilla blocking the upcoming release: https://bugzilla.gnome.org/show_bug.cgi?id=699649 The code is experimental and is not used by NetworkManager even in the 'master' branch except by nm-platform's automated tests. Once we fix it, you don't need to worry about it. Thanks! Pavel -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/