From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: [PATCH net-next 6/9] bonding: use RTNL instead of bond lock for bond_3ad_state_machine_handler() Date: Thu, 07 Nov 2013 02:50:20 +0300 Message-ID: <527AD5BC.7040907@cogentembedded.com> References: <5279E74C.8070403@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit To: Ding Tianhong , Jay Vosburgh , Andy Gospodarek , "David S. Miller" , Nikolay Aleksandrov , Veaceslav Falico , Netdev Return-path: Received: from mail-la0-f45.google.com ([209.85.215.45]:35136 "EHLO mail-la0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750909Ab3KFWu2 (ORCPT ); Wed, 6 Nov 2013 17:50:28 -0500 Received: by mail-la0-f45.google.com with SMTP id el20so143218lab.4 for ; Wed, 06 Nov 2013 14:50:26 -0800 (PST) In-Reply-To: <5279E74C.8070403@huawei.com> Sender: netdev-owner@vger.kernel.org List-ID: Hello. On 11/06/2013 09:53 AM, Ding Tianhong wrote: > The bond_3ad_state_machine_handler() is a slow path, it use the bond > lock to protect the bond slave list and slave port, the slave list > could not be protect by bond lock anymore, so I need to use RTNL or > RCU instead of bond lock, but if I remove the bond lock, the > bond_3ad_state_machine_handler() may use the slave port when bond > releasing the slave, it will occur problems. > As the bond_3ad_unbind_slave() only protected by bond lock or RTNL, > so add RCU is not a good solution as it could not protect the slave > port, so RTNL is fit here. > Signed-off-by: Ding Tianhong > --- > drivers/net/bonding/bond_3ad.c | 15 +++++++-------- > 1 file changed, 7 insertions(+), 8 deletions(-) > > diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c > index 187b1b7..a4d190e 100644 > --- a/drivers/net/bonding/bond_3ad.c > +++ b/drivers/net/bonding/bond_3ad.c > @@ -2068,18 +2068,19 @@ void bond_3ad_state_machine_handler(struct work_struct *work) [...] > - //check if there are any slaves > if (!bond_has_slaves(bond)) > goto re_arm; > > - // check if agg_select_timer timer after initialize is timed out > + /* check if agg_select_timer timer after initialize is timed out */ > if (BOND_AD_INFO(bond).agg_select_timer && !(--BOND_AD_INFO(bond).agg_select_timer)) { > slave = bond_first_slave(bond); > port = slave ? &(SLAVE_AD_INFO(slave).port) : NULL; > > - // select the active aggregator for the bond > if (port) { > if (!port->slave) { > pr_warning("%s: Warning: bond's first port is uninitialized\n", > @@ -2093,7 +2094,6 @@ void bond_3ad_state_machine_handler(struct work_struct *work) > bond_3ad_set_carrier(bond); > } > > - // for each port run the state machines > bond_for_each_slave(bond, slave, iter) { > port = &(SLAVE_AD_INFO(slave).port); > if (!port->slave) { > @@ -2114,7 +2114,7 @@ void bond_3ad_state_machine_handler(struct work_struct *work) > ad_mux_machine(port); > ad_tx_machine(port); > > - // turn off the BEGIN bit, since we already handled it > + /* turn off the BEGIN bit, since we already handled it */ > if (port->sm_vars & AD_PORT_BEGIN) > port->sm_vars &= ~AD_PORT_BEGIN; > These comment changes are not documented in the changelog and should most probably be in a separate patch. WBR, Sergei