3.2.95-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Wei Wang <weiwan@xxxxxxxxxx> commit 4e587ea71bf924f7dac621f1351653bd41e446cb upstream. Commit c5cff8561d2d adds rcu grace period before freeing fib6_node. This generates a new sparse warning on rt->rt6i_node related code: net/ipv6/route.c:1394:30: error: incompatible types in comparison expression (different address spaces) ./include/net/ip6_fib.h:187:14: error: incompatible types in comparison expression (different address spaces) This commit adds "__rcu" tag for rt6i_node and makes sure corresponding rcu API is used for it. After this fix, sparse no longer generates the above warning. Fixes: c5cff8561d2d ("ipv6: add rcu grace period before freeing fib6_node") Signed-off-by: Wei Wang <weiwan@xxxxxxxxxx> Acked-by: Eric Dumazet <edumazet@xxxxxxxxxx> Acked-by: Martin KaFai Lau <kafai@xxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> [bwh: Backported to 3.2: - fib6_add_rt2node() has only one assignment to update - Drop changes in rt6_cache_allowed_for_pmtu() - Adjust context] Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> --- --- a/include/net/ip6_fib.h +++ b/include/net/ip6_fib.h @@ -96,7 +96,7 @@ struct rt6_info { * the same cache line. */ struct fib6_table *rt6i_table; - struct fib6_node *rt6i_node; + struct fib6_node __rcu *rt6i_node; struct in6_addr rt6i_gateway; --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -4284,7 +4284,7 @@ static void __ipv6_ifa_notify(int event, * our DAD process, so we don't need * to do it again */ - if (!(ifp->rt->rt6i_node)) + if (!rcu_access_pointer(ifp->rt->rt6i_node)) ip6_ins_rt(ifp->rt); if (ifp->idev->cnf.forwarding) addrconf_join_anycast(ifp); --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -670,7 +670,7 @@ static int fib6_add_rt2node(struct fib6_ rt->dst.rt6_next = iter; *ins = rt; - rt->rt6i_node = fn; + rcu_assign_pointer(rt->rt6i_node, fn); atomic_inc(&rt->rt6i_ref); inet6_rt_notify(RTM_NEWROUTE, rt, info); info->nl_net->ipv6.rt6_stats->fib_rt_entries++; @@ -1181,8 +1181,9 @@ static void fib6_del_route(struct fib6_n int fib6_del(struct rt6_info *rt, struct nl_info *info) { + struct fib6_node *fn = rcu_dereference_protected(rt->rt6i_node, + lockdep_is_held(&rt->rt6i_table->tb6_lock)); struct net *net = info->nl_net; - struct fib6_node *fn = rt->rt6i_node; struct rt6_info **rtp; #if RT6_DEBUG >= 2 @@ -1360,7 +1361,10 @@ static int fib6_clean_node(struct fib6_w res = fib6_del(rt, &info); if (res) { #if RT6_DEBUG >= 2 - printk(KERN_DEBUG "fib6_clean_node: del failed: rt=%p@%p err=%d\n", rt, rt->rt6i_node, res); + pr_debug("%s: del failed: rt=%p@%p err=%d\n", + __func__, rt, + rcu_access_pointer(rt->rt6i_node), + res); #endif continue; }