From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net-next] gro: introduce gro_mac_header_len Date: Mon, 06 Feb 2012 12:00:15 -0500 (EST) Message-ID: <20120206.120015.1104308784569339801.davem@davemloft.net> References: <1328545627.2220.72.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <20120206.113145.1284864994961472499.davem@davemloft.net> <4F300353.2080705@mellanox.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: eric.dumazet-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, sean.hefty-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, herbert-F6s6mLieUQo7FNHlEwC/lvQIK84fMopw@public.gmane.org, linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, shlomop-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org, roland-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: ogerlitz-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org Return-path: In-Reply-To: <4F300353.2080705-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: netdev.vger.kernel.org From: Or Gerlitz Date: Mon, 6 Feb 2012 18:44:03 +0200 > As I wrote earlier on this thread, the reason is that in order to be > able to xmit skb's for which the stack doesn't provide a neighbour, > IPoIB makes sure to have extra INFINIBAND_ALEN bytes headroom on > skbs. Such that the ipoib hard_header functions writes a > "ipoib_pseudoheader" (= hw address) on the skb and the xmit function > grabs it from there and use that pseudoheader to search for the actual > IB L2 address handle kept for that dest. Example such skbs are unicast > ARP replies and multicast. see below some relevant code sections from > ipoib_main.c Then IPoIB is broken and must be fixed, see my other reply. We're not adding a bogus member to the netdevice just because IPoIB tries to do path resolution and neighbour validation behind the neighbour cache's back. -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html