tcp: convert tcp_md5_needed to static_branch API

We prefer static_branch_unlikely() over static_key_false() these days.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/tcp.h

@@ -1558,7 +1558,7 @@ struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
 
 #ifdef CONFIG_TCP_MD5SIG
 #include <linux/jump_label.h>
-extern struct static_key tcp_md5_needed;
+extern struct static_key_false tcp_md5_needed;
 struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk,
 					   const union tcp_md5_addr *addr,
 					   int family);
@@ -1567,7 +1567,7 @@ tcp_md5_do_lookup(const struct sock *sk,
 		  const union tcp_md5_addr *addr,
 		  int family)
 {
-	if (!static_key_false(&tcp_md5_needed))
+	if (!static_branch_unlikely(&tcp_md5_needed))
 		return NULL;
 	return __tcp_md5_do_lookup(sk, addr, family);
 }

net/ipv4/tcp.c

@@ -3699,7 +3699,7 @@ bool tcp_alloc_md5sig_pool(void)
 		if (!tcp_md5sig_pool_populated) {
 			__tcp_alloc_md5sig_pool();
 			if (tcp_md5sig_pool_populated)
-				static_key_slow_inc(&tcp_md5_needed);
+				static_branch_inc(&tcp_md5_needed);
 		}
 
 		mutex_unlock(&tcp_md5sig_mutex);

net/ipv4/tcp_ipv4.c

@@ -973,7 +973,7 @@ static void tcp_v4_reqsk_destructor(struct request_sock *req)
  * We need to maintain these in the sk structure.
  */
 
-struct static_key tcp_md5_needed __read_mostly;
+DEFINE_STATIC_KEY_FALSE(tcp_md5_needed);
 EXPORT_SYMBOL(tcp_md5_needed);
 
 /* Find the Key structure for an address.  */

net/ipv4/tcp_output.c

@@ -597,7 +597,7 @@ static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb,
 
 	*md5 = NULL;
 #ifdef CONFIG_TCP_MD5SIG
-	if (static_key_false(&tcp_md5_needed) &&
+	if (static_branch_unlikely(&tcp_md5_needed) &&
 	    rcu_access_pointer(tp->md5sig_info)) {
 		*md5 = tp->af_specific->md5_lookup(sk, sk);
 		if (*md5) {
@@ -734,7 +734,7 @@ static unsigned int tcp_established_options(struct sock *sk, struct sk_buff *skb
 
 	*md5 = NULL;
 #ifdef CONFIG_TCP_MD5SIG
-	if (static_key_false(&tcp_md5_needed) &&
+	if (static_branch_unlikely(&tcp_md5_needed) &&
 	    rcu_access_pointer(tp->md5sig_info)) {
 		*md5 = tp->af_specific->md5_lookup(sk, sk);
 		if (*md5) {