From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: [PATCH net-next-2.6] ipv4: avoid two atomic ops in ip_rt_redirect() Date: Mon, 07 Jun 2010 15:23:03 +0200 Message-ID: <1275916983.2545.73.camel@edumazet-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: netdev To: David Miller Return-path: Received: from mail-ww0-f46.google.com ([74.125.82.46]:45257 "EHLO mail-ww0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751004Ab0FGNXH (ORCPT ); Mon, 7 Jun 2010 09:23:07 -0400 Received: by wwe15 with SMTP id 15so385093wwe.19 for ; Mon, 07 Jun 2010 06:23:05 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: in_dev_get() -> __in_dev_get_rcu() in a rcu protected function. Signed-off-by: Eric Dumazet --- net/ipv4/route.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 7b8eacd..0c30534 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -1343,11 +1343,12 @@ static void rt_del(unsigned hash, struct rtable *rt) spin_unlock_bh(rt_hash_lock_addr(hash)); } +/* called in rcu_read_lock() section */ void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw, __be32 saddr, struct net_device *dev) { int i, k; - struct in_device *in_dev = in_dev_get(dev); + struct in_device *in_dev = __in_dev_get_rcu(dev); struct rtable *rth, **rthp; __be32 skeys[2] = { saddr, 0 }; int ikeys[2] = { dev->ifindex, 0 }; @@ -1383,7 +1384,6 @@ void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw, rthp=&rt_hash_table[hash].chain; - rcu_read_lock(); while ((rth = rcu_dereference(*rthp)) != NULL) { struct rtable *rt; @@ -1405,12 +1405,10 @@ void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw, break; dst_hold(&rth->u.dst); - rcu_read_unlock(); rt = dst_alloc(&ipv4_dst_ops); if (rt == NULL) { ip_rt_put(rth); - in_dev_put(in_dev); return; } @@ -1463,12 +1461,10 @@ void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw, ip_rt_put(rt); goto do_next; } - rcu_read_unlock(); do_next: ; } } - in_dev_put(in_dev); return; reject_redirect: @@ -1479,7 +1475,6 @@ reject_redirect: &old_gw, dev->name, &new_gw, &saddr, &daddr); #endif - in_dev_put(in_dev); } static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)