From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755400Ab3GCCpH (ORCPT ); Tue, 2 Jul 2013 22:45:07 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39535 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751691Ab3GCCpF (ORCPT ); Tue, 2 Jul 2013 22:45:05 -0400 Message-ID: <51D39010.5090902@redhat.com> Date: Wed, 03 Jul 2013 10:44:32 +0800 From: Jason Wang User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130623 Thunderbird/17.0.7 MIME-Version: 1.0 To: Thomas Zeitlhofer CC: Fabio Estevam , linux-kernel@vger.kernel.org, netdev@vger.kernel.org Subject: Re: tuntap regression in v3.9.8 and v3.10 References: <20130702195910.GA20271@toau.bambla> <20130702220651.GA23097@toau.bambla> In-Reply-To: <20130702220651.GA23097@toau.bambla> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/03/2013 06:06 AM, Thomas Zeitlhofer wrote: > On Tue, Jul 02, 2013 at 06:01:12PM -0300, Fabio Estevam wrote: >> On Tue, Jul 2, 2013 at 4:59 PM, Thomas Zeitlhofer >> wrote: >>> Commit "tuntap: set SOCK_ZEROCOPY flag during open" introduces a >>> regression which is observed with live migration of qemu/kvm based >>> virtual machines that are connected to an openvswitch bridge. >>> >>> Reverting this commit (b26c93c46a3dec25ed236d4ba6107eb4ed5d9401 in >>> v3.9.8 and accordingly 19a6afb23e5d323e1245baa4e62755492b2f1200 in >>> v3.10) fixes the following problem: >> Should the sock_set_flag stay in tun_set_iff as it was prior to 54f968d6efd? >> >> --- a/drivers/net/tun.c >> +++ b/drivers/net/tun.c >> @@ -1652,6 +1652,7 @@ static int tun_set_iff(struct net *net, struct >> file *file, struct ifreq *ifr) >> tun->txflt.count = 0; >> tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); >> >> + sock_set_flag(&tfile->sk, SOCK_ZEROCOPY); >> tun->filter_attached = false; >> tun->sndbuf = tfile->socket.sk->sk_sndbuf; >> >> @@ -2159,8 +2160,6 @@ static int tun_chr_open(struct inode *inode, >> struct file * file) >> set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags); >> INIT_LIST_HEAD(&tfile->next); >> >> - sock_set_flag(&tfile->sk, SOCK_ZEROCOPY); >> - >> return 0; >> } > I guess no, as this also leads to a kernel panic (tested against v3.10). Yes, commit "tuntap: set SOCK_ZEROCOPY flag during open" just re-enable the zerocopy capability of tuntap. I believe it just uncover other zerocopy bugs. Which regression did you see? Thanks