From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH V6 0/3] handle polling errors in vhost/vhost_net Date: Thu, 24 Jan 2013 12:38:07 +0200 Message-ID: <20130124103807.GB9368@redhat.com> References: <1358351078-58915-1-git-send-email-jasowang@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Jason Wang Return-path: Received: from mx1.redhat.com ([209.132.183.28]:18075 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752980Ab3AXKd6 (ORCPT ); Thu, 24 Jan 2013 05:33:58 -0500 Content-Disposition: inline In-Reply-To: <1358351078-58915-1-git-send-email-jasowang@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, Jan 16, 2013 at 11:44:35PM +0800, Jason Wang wrote: > This is an update version of last version to fix the handling of polling errors > in vhost/vhost_net. > > Currently, vhost and vhost_net ignore polling errors which can lead kernel > crashing when it tries to remove itself from waitqueue after the polling > failure. Fix this by: > > - examing the POLLERR when setting backend and report erros to userspace > - let tun always add to waitqueue in .poll() after the queue is created even if > it was detached. > > Changes from V5: > - use rcu_dereference() instead of the wrong rtnl_dereference() in data path > - test with CONFIG_PROVE_RCU > > Changes from V4: > - check the detached state by tfile->detached and protect it by RCU > > Changes from V3: > - make a smaller patch that doesn't touch the whole polling state and only check > the polliner errors in backend setting. > - add a patch that allows tuntap to do polling/reading/writing when detached > which could simplify the work of its user. > > Changes from v2: > - check poll->wqh instead of the wrong assumption about POLLERR and waitqueue > - drop the whole tx polling state check since it was replaced by the wqh > checking > - drop the buggy tuntap patch > > Changes from v1: > - restore the state before the ioctl when vhost_init_used() fails > - log the error when meet polling errors in the data path > - don't put into waitqueue when tun_chr_poll() return POLLERR > > Jason Wang (3): > vhost_net: correct error handling in vhost_net_set_backend() > vhost_net: handle polling errors when setting backend > tuntap: allow polling/writing/reading when detached > > drivers/net/tun.c | 45 ++++++++++++++++++++++++++------------------- > drivers/vhost/net.c | 41 ++++++++++++++++++++++++++++------------- > drivers/vhost/vhost.c | 18 +++++++++++++++--- > drivers/vhost/vhost.h | 2 +- > 4 files changed, 70 insertions(+), 36 deletions(-) Acked-by: Michael S. Tsirkin