From: Wei Wang <wei...@google.com>
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 <wei...@google.com>
Acked-by: Eric Dumazet <eduma...@google.com>
---
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 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct
rt6_info *rt,
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 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct
rt6_info *rt,
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 a9d3564caf49..33629f2a0f9d 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,
--
2.14.1.342.g6490525c54-goog
