Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752874Ab0LaKWA (ORCPT ); Fri, 31 Dec 2010 05:22:00 -0500 Received: from www84.your-server.de ([213.133.104.84]:51829 "EHLO www84.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750811Ab0LaKV6 convert rfc822-to-8bit (ORCPT ); Fri, 31 Dec 2010 05:21:58 -0500 Subject: Re: [PATCH] UDPCP Communication Protocol From: Stefani Seibold To: Eric Dumazet Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, davem@davemloft.net, netdev@vger.kernel.org In-Reply-To: <1293789629.2973.26.camel@edumazet-laptop> References: <1293787785-3834-1-git-send-email-stefani@seibold.net> <1293789629.2973.26.camel@edumazet-laptop> Content-Type: text/plain; charset="ISO-8859-15" Date: Fri, 31 Dec 2010 11:22:59 +0100 Message-ID: <1293790979.4787.10.camel@wall-e> Mime-Version: 1.0 X-Mailer: Evolution 2.32.1 Content-Transfer-Encoding: 8BIT X-Authenticated-Sender: stefani@seibold.net Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1750 Lines: 49 Am Freitag, den 31.12.2010, 11:00 +0100 schrieb Eric Dumazet: > Le vendredi 31 d?cembre 2010 ? 10:29 +0100, stefani@seibold.net a > ?crit : > > From: Stefani Seibold > > > > > > /* > > * Handle MSG_ERRQUEUE > > diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c > > index 2d3ded4..f9890a2 100644 > > --- a/net/ipv4/udp.c > > +++ b/net/ipv4/udp.c > > @@ -1310,7 +1310,7 @@ static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb) > > if (inet_sk(sk)->inet_daddr) > > sock_rps_save_rxhash(sk, skb->rxhash); > > > > - rc = ip_queue_rcv_skb(sk, skb); > > + rc = sock_queue_rcv_skb(sk, skb); > > Ouch... Care to explain why you changed this part ??? > > You just destroyed commit f84af32cbca70a intent, without any word in > your changelog. Making UDP slower, while others try to speed it must be > explained and advertised. > > In general, we prefer a preliminary patch introducing all the changes in > current stack, then another one with the new protocol. > I reverted this for two reasons: First ip_queue_rcv_skb drops the dst entry, which breaks the user land application which expect packet info after a setsockopt(handle, IPPROTO_IP, IP_PKTINFO, &const_int_1, sizeof(int)); But for packets already in the queue this information will be lost. So it is a potential race condition. Second it breaks my UDPCP communication protocol stack module, which works very well till 2.6.35. I need this information in the data_ready() function to generate an ACK. -- 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/