From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: [RFC, VLAN]: Propagate selected feature bits to VLAN devices Date: Tue, 20 May 2008 17:20:12 +0100 Message-ID: <20080520162011.GT28241@solarflare.com> References: <4832E223.7020206@trash.net> <20080520144822.GR28241@solarflare.com> <4832E55E.2030009@trash.net> <4832F260.5000104@candelatech.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Patrick McHardy , Peter P Waskiewicz Jr , Linux Netdev List To: Ben Greear Return-path: Received: from 82-69-137-158.dsl.in-addr.zen.co.uk ([82.69.137.158]:35552 "EHLO uklogin.uk.level5networks.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755451AbYETQU2 (ORCPT ); Tue, 20 May 2008 12:20:28 -0400 Content-Disposition: inline In-Reply-To: <4832F260.5000104@candelatech.com> Sender: netdev-owner@vger.kernel.org List-ID: Ben Greear wrote: > Patrick McHardy wrote: > >Ben Hutchings wrote: > >>Patrick McHardy wrote: > >>>diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h > >>>index b11e6e1..3be4559 100644 > >>>--- a/include/linux/netdevice.h > >>>+++ b/include/linux/netdevice.h > >>>@@ -514,10 +514,11 @@ struct net_device > >>> #define NETIF_F_NETNS_LOCAL 8192 /* Does not change network > >>>namespaces */ > >>> #define NETIF_F_MULTI_QUEUE 16384 /* Has multiple TX/RX > >>>queues */ > >>> #define NETIF_F_LRO 32768 /* large receive offload */ > >>>+#define NETIF_F_VLAN_TSO 65536 /* Supports TSO for VLANs */ > >>> > >>> /* Segmentation offload features */ > >>>-#define NETIF_F_GSO_SHIFT 16 > >>>-#define NETIF_F_GSO_MASK 0xffff0000 > >>>+#define NETIF_F_GSO_SHIFT 20 > >>>+#define NETIF_F_GSO_MASK 0xfff00000 > >> > >>I really don't think it's a good idea to move around existing flags. > >>How > >>about stealing some of the unused high-order bits of NETIF_F_GSO_MASK > >>instead? > > > > > >Mhh it doesn't really belong there. Whats the problem with > >moving these bits? They are only used internally (and use > >up too much space anyway). > I've been running with it shifted to 24 on 2.6.25 with no problems. If > no one else objects, I'd prefer it shifted all the way > to 24 to make room for more flags w/out additional changes in the > shiftage later... I would certainly be happy to see NETIF_F_GSO_MASK narrowed. It's just a question of whether the low-order or high-order bits are removed. My instinct is not to change the existing assigned flags if it's not really necessary. They are exposed through /sys/class/net/ even if the flag names aren't part of the user-land headers. Ben. -- Ben Hutchings, Senior Software Engineer, Solarflare Communications Not speaking for my employer; that's the marketing department's job.