tcp: md5: constify tcp_md5_do_lookup() socket argument

When TCP new listener is done, these functions will be called
without socket lock being held. Make sure they don't change
anything.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 9d968ca..1c1009d 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -865,7 +865,7 @@
  */
 
 /* Find the Key structure for an address.  */
-struct tcp_md5sig_key *tcp_md5_do_lookup(struct sock *sk,
+struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
 					 const union tcp_md5_addr *addr,
 					 int family)
 {
@@ -877,7 +877,7 @@
 	/* caller either holds rcu_read_lock() or socket lock */
 	md5sig = rcu_dereference_check(tp->md5sig_info,
 				       sock_owned_by_user(sk) ||
-				       lockdep_is_held(&sk->sk_lock.slock));
+				       lockdep_is_held((spinlock_t *)&sk->sk_lock.slock));
 	if (!md5sig)
 		return NULL;
 #if IS_ENABLED(CONFIG_IPV6)
@@ -894,7 +894,7 @@
 }
 EXPORT_SYMBOL(tcp_md5_do_lookup);
 
-struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
+struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
 					 const struct sock *addr_sk)
 {
 	const union tcp_md5_addr *addr;
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 9016797..1071131 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -476,13 +476,13 @@
 }
 
 #ifdef CONFIG_TCP_MD5SIG
-static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(struct sock *sk,
+static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
 						   const struct in6_addr *addr)
 {
 	return tcp_md5_do_lookup(sk, (union tcp_md5_addr *)addr, AF_INET6);
 }
 
-static struct tcp_md5sig_key *tcp_v6_md5_lookup(struct sock *sk,
+static struct tcp_md5sig_key *tcp_v6_md5_lookup(const struct sock *sk,
 						const struct sock *addr_sk)
 {
 	return tcp_v6_md5_do_lookup(sk, &addr_sk->sk_v6_daddr);