From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net] netlink: fix netlink_ack with large messages Date: Sat, 09 Nov 2013 00:00:12 -0500 (EST) Message-ID: <20131109.000012.1393414533296613338.davem@davemloft.net> References: <9333f540a9b87adbdd15e274d12a9d60994fdb34.1383850578.git.jbenc@redhat.com> <20131108.150741.966018155704146843.davem@davemloft.net> <20131109000434.GD28793@casper.infradead.org> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: jbenc@redhat.com, netdev@vger.kernel.org, pablo@netfilter.org To: tgraf@suug.ch Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:39387 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750753Ab3KIFAP (ORCPT ); Sat, 9 Nov 2013 00:00:15 -0500 In-Reply-To: <20131109000434.GD28793@casper.infradead.org> Sender: netdev-owner@vger.kernel.org List-ID: From: Thomas Graf Date: Sat, 9 Nov 2013 00:04:34 +0000 > I agree it seems over the top for pure ACKs but we also use > netlink_ack() to report errors where it makes sense to quote > the full message. The user has the message, they gave it to us in the sendmsg() we are responding to. We absolutely do not need to give it to them again. If they care about referring to the contents of that message, they can refer to it in their own copy and make sure they are really looking at the same thing by comparing the sequence number in the netlink ACK to the one they used in the netlink header they gave to the kernel in the sendmsg() call. What happens now is pure duplication, and for such huge netlink messages it's really not smart at all.