[NETFILTER]: Avoid nesting readlocks in conntrack code.

include/linux/netfilter_ipv4/ip_conntrack_core.h

@@ -17,7 +17,7 @@ extern void ip_conntrack_cleanup(void);
 struct ip_conntrack_protocol;
 extern struct ip_conntrack_protocol *ip_ct_find_proto(u_int8_t protocol);
 /* Like above, but you already have conntrack read lock. */
-extern struct ip_conntrack_protocol *__find_proto(u_int8_t protocol);
+extern struct ip_conntrack_protocol *__ip_ct_find_proto(u_int8_t protocol);
 extern struct list_head protocol_list;
 
 /* Returns conntrack if it dealt with ICMP, and filled in skb->nfct */

net/ipv4/netfilter/ip_conntrack_core.c

@@ -75,7 +75,7 @@ static inline int proto_cmpfn(const struct ip_conntrack_protocol *curr,
 	return protocol == curr->proto;
 }
 
-struct ip_conntrack_protocol *__find_proto(u_int8_t protocol)
+struct ip_conntrack_protocol *__ip_ct_find_proto(u_int8_t protocol)
 {
 	struct ip_conntrack_protocol *p;
 
@@ -93,7 +93,7 @@ struct ip_conntrack_protocol *ip_ct_find_proto(u_int8_t protocol)
 	struct ip_conntrack_protocol *p;
 
 	READ_LOCK(&ip_conntrack_lock);
-	p = __find_proto(protocol);
+	p = __ip_ct_find_proto(protocol);
 	READ_UNLOCK(&ip_conntrack_lock);
 	return p;
 }

net/ipv4/netfilter/ip_conntrack_standalone.c

@@ -71,7 +71,7 @@ print_expect(char *buffer, const struct ip_conntrack_expect *expect)
 	len += sprintf(buffer + len, "use=%u proto=%u ",
 		      atomic_read(&expect->use), expect->tuple.dst.protonum);
 	len += print_tuple(buffer + len, &expect->tuple,
-			   __find_proto(expect->tuple.dst.protonum));
+			   __ip_ct_find_proto(expect->tuple.dst.protonum));
 	len += sprintf(buffer + len, "\n");
 	return len;
 }
@@ -81,7 +81,7 @@ print_conntrack(char *buffer, const struct ip_conntrack *conntrack)
 {
 	unsigned int len;
 	struct ip_conntrack_protocol *proto
-		= __find_proto(conntrack->tuplehash[IP_CT_DIR_ORIGINAL]
+		= __ip_ct_find_proto(conntrack->tuplehash[IP_CT_DIR_ORIGINAL]
 			       .tuple.dst.protonum);
 
 	len = sprintf(buffer, "%-8s %u %lu ",
@@ -361,6 +361,7 @@ EXPORT_SYMBOL(ip_conntrack_helper_unregister);
 EXPORT_SYMBOL(ip_ct_selective_cleanup);
 EXPORT_SYMBOL(ip_ct_refresh);
 EXPORT_SYMBOL(ip_ct_find_proto);
+EXPORT_SYMBOL(__ip_ct_find_proto);
 EXPORT_SYMBOL(ip_ct_find_helper);
 EXPORT_SYMBOL(ip_conntrack_expect_related);
 EXPORT_SYMBOL(ip_conntrack_change_expect);

net/ipv4/netfilter/ip_nat_core.c

@@ -740,7 +740,7 @@ static inline int exp_for_packet(struct ip_conntrack_expect *exp,
 	int ret = 1;
 
 	MUST_BE_READ_LOCKED(&ip_conntrack_lock);
-	proto = ip_ct_find_proto((*pskb)->nh.iph->protocol);
+	proto = __ip_ct_find_proto((*pskb)->nh.iph->protocol);
 	if (proto->exp_matches_pkt)
 		ret = proto->exp_matches_pkt(exp, pskb);