From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ding Tianhong Subject: Re: [PATCH v4 net-next 01/12] bonding: remove bond->lock from bond_arp_rcv Date: Tue, 18 Feb 2014 12:02:41 +0800 Message-ID: <5302DB61.4070505@huawei.com> References: <1392648088-21336-1-git-send-email-vfalico@redhat.com> <1392648088-21336-2-git-send-email-vfalico@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Jay Vosburgh , Andy Gospodarek To: Veaceslav Falico , Return-path: Received: from szxga02-in.huawei.com ([119.145.14.65]:18304 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752209AbaBREDO (ORCPT ); Mon, 17 Feb 2014 23:03:14 -0500 In-Reply-To: <1392648088-21336-2-git-send-email-vfalico@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: On 2014/2/17 22:41, Veaceslav Falico wrote: > We're always called with rcu_read_lock() held (bond_arp_rcv() is only > called from bond_handle_frame(), which is rx_handler and always called > under rcu from __netif_receive_skb_core() ). > > The slave active/passive and/or bonding params can change in-flight, however > we don't really care about that - we only modify the last time packet was > received, which is harmless. > > CC: Jay Vosburgh > CC: Andy Gospodarek > Signed-off-by: Veaceslav Falico > --- > drivers/net/bonding/bond_main.c | 3 --- > 1 file changed, 3 deletions(-) > > diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c > index 3bce855..3c50bec 100644 > --- a/drivers/net/bonding/bond_main.c > +++ b/drivers/net/bonding/bond_main.c > @@ -2260,8 +2260,6 @@ int bond_arp_rcv(const struct sk_buff *skb, struct bonding *bond, > if (skb->protocol != __cpu_to_be16(ETH_P_ARP)) > return RX_HANDLER_ANOTHER; > > - read_lock(&bond->lock); > - > if (!slave_do_arp_validate(bond, slave)) > goto out_unlock; > > @@ -2318,7 +2316,6 @@ int bond_arp_rcv(const struct sk_buff *skb, struct bonding *bond, > bond_validate_arp(bond, slave, tip, sip); > > out_unlock: > - read_unlock(&bond->lock); > if (arp != (struct arphdr *)skb->data) > kfree(arp); > return RX_HANDLER_ANOTHER; > I think it is not enough, you should add rcu_dereference for bond->curr_active_slave, it may be changed during the recv processing. Regards Ding