From mboxrd@z Thu Jan 1 00:00:00 1970 From: Martin KaFai Lau Subject: [PATCH RFC v4 net 3/3] ipv6: Avoid redo-ing fib6_lookup() with reachable = 0 by saving fn Date: Fri, 10 Oct 2014 11:48:08 -0700 Message-ID: <1412966888-31384-4-git-send-email-kafai@fb.com> References: <1412966888-31384-1-git-send-email-kafai@fb.com> Mime-Version: 1.0 Content-Type: text/plain Cc: David Miller , Hannes Frederic Sowa To: Return-path: Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:39515 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751406AbaJJSsQ (ORCPT ); Fri, 10 Oct 2014 14:48:16 -0400 Received: from pps.filterd (m0004060 [127.0.0.1]) by mx0b-00082601.pphosted.com (8.14.5/8.14.5) with SMTP id s9AIkIi6026445 for ; Fri, 10 Oct 2014 11:48:15 -0700 Received: from mail.thefacebook.com (mailwest.thefacebook.com [173.252.71.148]) by mx0b-00082601.pphosted.com with ESMTP id 1pxahr288p-2 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=OK) for ; Fri, 10 Oct 2014 11:48:15 -0700 Received: from facebook.com (2401:db00:20:7029:face:0:33:0) by mx-out.facebook.com (10.102.107.99) with ESMTP id fd9e13b250ad11e48f4a0002c99293a0-84bfd3e0 for ; Fri, 10 Oct 2014 11:48:14 -0700 In-Reply-To: <1412966888-31384-1-git-send-email-kafai@fb.com> Sender: netdev-owner@vger.kernel.org List-ID: This patch saves the fn before doing rt6_backtrack. Hence, without redo-ing the fib6_lookup(), saved_fn can be used to redo rt6_select() with RT6_LOOKUP_F_REACHABLE off. Some minor changes I think make sense to review as a single patch: * Remove the 'out:' goto label. * Remove the 'reachable' variable. After this patch, "failing ip6_ins_rt()" is the only case that requires a redo of fib6_lookup(). Cc: David Miller Cc: Hannes Frederic Sowa Signed-off-by: Martin KaFai Lau --- net/ipv6/route.c | 30 ++++++++++++++++-------------- 1 file changed, 16 insertions(+), 14 deletions(-) diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 5469ecf..a8ecb9f 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -900,31 +900,40 @@ static struct rt6_info *rt6_alloc_clone(struct rt6_info *ort, static struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table, int oif, struct flowi6 *fl6, int flags) { - struct fib6_node *fn; + struct fib6_node *fn, *saved_fn; struct rt6_info *rt, *nrt; int strict = 0; int attempts = 3; int err; - int reachable = net->ipv6.devconf_all->forwarding ? 0 : RT6_LOOKUP_F_REACHABLE; strict |= flags & RT6_LOOKUP_F_IFACE; + if (net->ipv6.devconf_all->forwarding == 0) + strict |= RT6_LOOKUP_F_REACHABLE; redo_fib6_lookup_lock: read_lock_bh(&table->tb6_lock); -redo_fib6_lookup: fn = fib6_lookup(&table->tb6_root, &fl6->daddr, &fl6->saddr); + saved_fn = fn; redo_rt6_select: - rt = rt6_select(fn, oif, strict | reachable); + rt = rt6_select(fn, oif, strict); if (rt->rt6i_nsiblings) - rt = rt6_multipath_select(rt, fl6, oif, strict | reachable); + rt = rt6_multipath_select(rt, fl6, oif, strict); if (rt == net->ipv6.ip6_null_entry) { fn = fib6_backtrack(fn, &fl6->saddr); if (fn) goto redo_rt6_select; - else - goto out; + else if (strict & RT6_LOOKUP_F_REACHABLE) { + /* also consider unreachable route */ + strict &= ~RT6_LOOKUP_F_REACHABLE; + fn = saved_fn; + goto redo_rt6_select; + } else { + dst_hold(&rt->dst); + read_unlock_bh(&table->tb6_lock); + goto out2; + } } dst_hold(&rt->dst); @@ -960,13 +969,6 @@ redo_rt6_select: ip6_rt_put(rt); goto redo_fib6_lookup_lock; -out: - if (reachable) { - reachable = 0; - goto redo_fib6_lookup; - } - dst_hold(&rt->dst); - read_unlock_bh(&table->tb6_lock); out2: rt->dst.lastuse = jiffies; rt->dst.__use++; -- 1.8.1