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: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/tcp.h

@@ -1372,16 +1372,16 @@ int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
 		   int family, const u8 *newkey, u8 newkeylen, gfp_t gfp);
 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr,
 		   int family);
-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);
 
 #ifdef CONFIG_TCP_MD5SIG
-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);
 #define tcp_twsk_md5_key(twsk)	((twsk)->tw_md5_key)
 #else
-static inline struct tcp_md5sig_key *tcp_md5_do_lookup(struct sock *sk,
+static inline struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
 					 const union tcp_md5_addr *addr,
 					 int family)
 {
@@ -1684,7 +1684,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
 /* TCP af-specific functions */
 struct tcp_sock_af_ops {
 #ifdef CONFIG_TCP_MD5SIG
-	struct tcp_md5sig_key	*(*md5_lookup) (struct sock *sk,
+	struct tcp_md5sig_key	*(*md5_lookup) (const struct sock *sk,
 						const struct sock *addr_sk);
 	int		(*calc_md5_hash)(char *location,
 					 const struct tcp_md5sig_key *md5,
@@ -1699,7 +1699,7 @@ struct tcp_sock_af_ops {
 struct tcp_request_sock_ops {
 	u16 mss_clamp;
 #ifdef CONFIG_TCP_MD5SIG
-	struct tcp_md5sig_key *(*req_md5_lookup)(struct sock *sk,
+	struct tcp_md5sig_key *(*req_md5_lookup)(const struct sock *sk,
 						 const struct sock *addr_sk);
 	int		(*calc_md5_hash) (char *location,
 					  const struct tcp_md5sig_key *md5,

net/ipv4/tcp_ipv4.c

@@ -865,7 +865,7 @@ static void tcp_v4_reqsk_destructor(struct request_sock *req)
  */
 
 /* 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 @@ struct tcp_md5sig_key *tcp_md5_do_lookup(struct sock *sk,
 	/* 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 @@ struct tcp_md5sig_key *tcp_md5_do_lookup(struct sock *sk,
 }
 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;

net/ipv6/tcp_ipv6.c

@@ -476,13 +476,13 @@ static void tcp_v6_reqsk_destructor(struct request_sock *req)
 }
 
 #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);