net/ipv6: Move rcu locking to callers of fib6_get_cookie_safe

A later patch protects 'from' in rt6_info and this simplifies the
locking needed by it.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ip6_fib.h

@@ -234,7 +234,6 @@ static inline bool fib6_get_cookie_safe(const struct fib6_info *f6i,
 	struct fib6_node *fn;
 	bool status = false;
 
-	rcu_read_lock();
 	fn = rcu_dereference(f6i->fib6_node);
 
 	if (fn) {
@@ -244,7 +243,6 @@ static inline bool fib6_get_cookie_safe(const struct fib6_info *f6i,
 		status = true;
 	}
 
-	rcu_read_unlock();
 	return status;
 }
 
@@ -252,10 +250,14 @@ static inline u32 rt6_get_cookie(const struct rt6_info *rt)
 {
 	u32 cookie = 0;
 
+	rcu_read_lock();
+
 	if (rt->rt6i_flags & RTF_PCPU ||
 	    (unlikely(!list_empty(&rt->rt6i_uncached)) && rt->from))
 		fib6_get_cookie_safe(rt->from, &cookie);
 
+	rcu_read_unlock();
+
 	return cookie;
 }
 

net/ipv6/route.c

@@ -2159,9 +2159,12 @@ static struct dst_entry *rt6_dst_from_check(struct rt6_info *rt, u32 cookie)
 
 static struct dst_entry *ip6_dst_check(struct dst_entry *dst, u32 cookie)
 {
+	struct dst_entry *dst_ret;
 	struct rt6_info *rt;
 
-	rt = (struct rt6_info *) dst;
+	rt = container_of(dst, struct rt6_info, dst);
+
+	rcu_read_lock();
 
 	/* All IPV6 dsts are created with ->obsolete set to the value
 	 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
@@ -2170,9 +2173,13 @@ static struct dst_entry *ip6_dst_check(struct dst_entry *dst, u32 cookie)
 
 	if (rt->rt6i_flags & RTF_PCPU ||
 	    (unlikely(!list_empty(&rt->rt6i_uncached)) && rt->from))
-		return rt6_dst_from_check(rt, cookie);
+		dst_ret = rt6_dst_from_check(rt, cookie);
 	else
-		return rt6_check(rt, cookie);
+		dst_ret = rt6_check(rt, cookie);
+
+	rcu_read_unlock();
+
+	return dst_ret;
 }
 
 static struct dst_entry *ip6_negative_advice(struct dst_entry *dst)