From mboxrd@z Thu Jan 1 00:00:00 1970 From: Cong Wang Subject: [Patch net-next v2] ipv4: get rid of ip_ra_lock Date: Fri, 28 Apr 2017 10:04:29 -0700 Message-ID: <1493399069-31743-1-git-send-email-xiyou.wangcong@gmail.com> Cc: Cong Wang To: netdev@vger.kernel.org Return-path: Received: from mail-pg0-f67.google.com ([74.125.83.67]:34099 "EHLO mail-pg0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1424651AbdD1REi (ORCPT ); Fri, 28 Apr 2017 13:04:38 -0400 Received: by mail-pg0-f67.google.com with SMTP id t7so6266096pgt.1 for ; Fri, 28 Apr 2017 10:04:38 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: After commit 1215e51edad1 ("ipv4: fix a deadlock in ip_ra_control") we always take RTNL lock for ip_ra_control() which is the only place we update the list ip_ra_chain, so the ip_ra_lock is no longer needed. As Eric points out, BH does not need to disable either, RCU readers don't care. Signed-off-by: Cong Wang --- net/ipv4/ip_sockglue.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index 1d46d05..4c25458 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -330,7 +330,6 @@ 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) @@ -352,21 +351,17 @@ 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 = rcu_dereference_protected(*rap, - lockdep_is_held(&ip_ra_lock))) != NULL; + (ra = rtnl_dereference(*rap)) != 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); @@ -381,7 +376,6 @@ int ip_ra_control(struct sock *sk, unsigned char on, } } if (!new_ra) { - spin_unlock_bh(&ip_ra_lock); return -ENOBUFS; } new_ra->sk = sk; @@ -390,7 +384,6 @@ int ip_ra_control(struct sock *sk, unsigned char on, RCU_INIT_POINTER(new_ra->next, ra); rcu_assign_pointer(*rap, new_ra); sock_hold(sk); - spin_unlock_bh(&ip_ra_lock); return 0; } -- 2.5.5