From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-eopbgr30113.outbound.protection.outlook.com ([40.107.3.113]:62150 "EHLO EUR03-AM5-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932735AbeCSJOy (ORCPT ); Mon, 19 Mar 2018 05:14:54 -0400 Subject: [PATCH net-next v2 1/5] net: Revert "ipv4: get rid of ip_ra_lock" From: Kirill Tkhai To: davem@davemloft.net, yoshfuji@linux-ipv6.org, edumazet@google.com, yanhaishuang@cmss.chinamobile.com, nikolay@cumulusnetworks.com, yotamg@mellanox.com, soheil@google.com, avagin@virtuozzo.com, nicolas.dichtel@6wind.com, ebiederm@xmission.com, fw@strlen.de, roman.kapl@sysgo.com, netdev@vger.kernel.org, xiyou.wangcong@gmail.com, dvyukov@google.com, andreyknvl@google.com, lkp@intel.com, ktkhai@virtuozzo.com Date: Mon, 19 Mar 2018 12:14:43 +0300 Message-ID: <152145088368.7718.3918627726636433625.stgit@localhost.localdomain> In-Reply-To: <152145065475.7718.16297762717744383072.stgit@localhost.localdomain> References: <152145065475.7718.16297762717744383072.stgit@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org List-ID: This reverts commit ba3f571d5dde. The commit was made after 1215e51edad1 "ipv4: fix a deadlock in ip_ra_control", and killed ip_ra_lock, which became useless after rtnl_lock() made used to destroy every raw ipv4 socket. This scales very bad, and next patch in series reverts 1215e51edad1. ip_ra_lock will be used again. Signed-off-by: Kirill Tkhai --- net/ipv4/ip_sockglue.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index 74c962b9b09c..be7c3b71914d 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -334,6 +334,7 @@ int ip_cmsg_send(struct sock *sk, struct msghdr *msg, struct ipcm_cookie *ipc, sent to multicast group to reach destination designated router. */ struct ip_ra_chain __rcu *ip_ra_chain; +static DEFINE_SPINLOCK(ip_ra_lock); static void ip_ra_destroy_rcu(struct rcu_head *head) @@ -355,17 +356,21 @@ int ip_ra_control(struct sock *sk, unsigned char on, new_ra = on ? kmalloc(sizeof(*new_ra), GFP_KERNEL) : NULL; + spin_lock_bh(&ip_ra_lock); for (rap = &ip_ra_chain; - (ra = rtnl_dereference(*rap)) != NULL; + (ra = rcu_dereference_protected(*rap, + lockdep_is_held(&ip_ra_lock))) != NULL; rap = &ra->next) { if (ra->sk == sk) { if (on) { + spin_unlock_bh(&ip_ra_lock); kfree(new_ra); return -EADDRINUSE; } /* dont let ip_call_ra_chain() use sk again */ ra->sk = NULL; RCU_INIT_POINTER(*rap, ra->next); + spin_unlock_bh(&ip_ra_lock); if (ra->destructor) ra->destructor(sk); @@ -379,14 +384,17 @@ int ip_ra_control(struct sock *sk, unsigned char on, return 0; } } - if (!new_ra) + if (!new_ra) { + spin_unlock_bh(&ip_ra_lock); return -ENOBUFS; + } new_ra->sk = sk; new_ra->destructor = destructor; RCU_INIT_POINTER(new_ra->next, ra); rcu_assign_pointer(*rap, new_ra); sock_hold(sk); + spin_unlock_bh(&ip_ra_lock); return 0; }