From 4e587ea71bf924f7dac621f1351653bd41e446cb Mon Sep 17 00:00:00 2001 From: Wei Wang Date: Fri, 25 Aug 2017 15:03:10 -0700 Subject: [PATCH] ipv6: fix sparse warning on rt6i_node 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 Acked-by: Eric Dumazet Acked-by: Martin KaFai Lau Signed-off-by: David S. Miller --- include/net/ip6_fib.h | 2 +- net/ipv6/addrconf.c | 2 +- net/ipv6/ip6_fib.c | 11 +++++++---- net/ipv6/route.c | 3 ++- 4 files changed, 11 insertions(+), 7 deletions(-) diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h index e9c59db92942..af509f801084 100644 --- a/include/net/ip6_fib.h +++ b/include/net/ip6_fib.h @@ -105,7 +105,7 @@ 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; diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 3c46e9513a31..936e9ab4dda5 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -5556,7 +5556,7 @@ static void __ipv6_ifa_notify(int event, struct inet6_ifaddr *ifp) * 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); diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index a5ebf86f6be8..10b4b1f8b838 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -889,7 +889,7 @@ add: rt->dst.rt6_next = iter; *ins = rt; - rt->rt6i_node = fn; + rcu_assign_pointer(rt->rt6i_node, fn); atomic_inc(&rt->rt6i_ref); if (!info->skip_notify) inet6_rt_notify(RTM_NEWROUTE, rt, info, nlflags); @@ -915,7 +915,7 @@ add: return err; *ins = rt; - rt->rt6i_node = fn; + rcu_assign_pointer(rt->rt6i_node, fn); rt->dst.rt6_next = iter->dst.rt6_next; atomic_inc(&rt->rt6i_ref); if (!info->skip_notify) @@ -1480,8 +1480,9 @@ static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp, 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 @@ -1670,7 +1671,9 @@ static int fib6_clean_node(struct fib6_walker *w) if (res) { #if RT6_DEBUG >= 2 pr_debug("%s: del failed: rt=%p@%p err=%d\n", - __func__, rt, rt->rt6i_node, res); + __func__, rt, + rcu_access_pointer(rt->rt6i_node), + res); #endif continue; } diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 48c8c92dcbd3..86fb2411e2bd 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -1383,7 +1383,8 @@ static void rt6_do_update_pmtu(struct rt6_info *rt, u32 mtu) static bool rt6_cache_allowed_for_pmtu(const struct rt6_info *rt) { return !(rt->rt6i_flags & RTF_CACHE) && - (rt->rt6i_flags & RTF_PCPU || rt->rt6i_node); + (rt->rt6i_flags & RTF_PCPU || + rcu_access_pointer(rt->rt6i_node)); } static void __ip6_rt_update_pmtu(struct dst_entry *dst, const struct sock *sk, -- 2.20.1