From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Petazzoni Subject: Re: [patch 4/4] Configure out IGMP support Date: Mon, 4 Aug 2008 14:48:07 +0200 Message-ID: <20080804144807.6b2374d9@surf> References: <20080731092703.661994657@free-electrons.com> <20080731093221.565015353@free-electrons.com> <1217619715.3454.488.camel@pmac.infradead.org> Mime-Version: 1.0 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <1217619715.3454.488.camel@pmac.infradead.org> Sender: linux-embedded-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="iso-8859-1" To: David Woodhouse Cc: linux-kernel@vger.kernel.org, linux-embedded@vger.kernel.org, michael@free-electrons.com, Matt Mackall , netdev@vger.kernel.org, davem@davemloft.net, akpm@linux-foundation.org Le Fri, 01 Aug 2008 20:41:55 +0100, David Woodhouse a =C3=A9crit : > The config option probably lives in net/Kconfig, not init/Kconfig. Yes, it could. But AFAIK, until now, all CONFIG_EMBEDDED-related options have been put in init/Kconfig. But if it's preferred, I can of course change the patch to move the config option to net/Kconfig. > And please could you make it clear how this interacts with > IP_MULTICAST? >=20 > We already have a CONFIG_IP_MULTICAST option, for which the help text > says "For more people, it's safe to say N'. And I think it defaults t= o > that too. What more does CONFIG_IGMP remove? It's not made clear by > the help text. The interaction of IGMP support with CONFIG_IP_MULTICAST is fairly unclear to me. A large portion of igmp.c is already under #ifdef CONFIG_IP_MULTICAST: all the igmp_*() functions, amongst which is igmp_rcv(), referenced in igmp_protocol in net/ipv4/af_inet.c, which is compiled-out when !CONFIG_IP_MULTICAST. All the proc-related code at the end of the file is only conditionnaly compiled on CONFIG_PROC_FS, but seems to in fact be only used if both CONFIG_IP_MULTICAST and CONFIG_PROC_FS are selected: igmp_mc_proc_init() in net/ipv4/ip_output.c is only called when CONFIG_IP_MULTICAST and CONFIG_PROC_FS are selected. Besides that, it's unclear to me why the ip_mc_*() functions are useful when !CONFIG_IP_MULTICAST, but I'm probably missing something. They are used to implement setsockopt-operations related to multicast, hooks for the routing code to handle multicast-related traffic, etc. Sincerly, Thomas --=20 Thomas Petazzoni, Free Electrons Kernel, drivers and embedded Linux development, consulting, training and support. http://free-electrons.com