diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 132be08..704adad 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -374,7 +374,7 @@
 {
 	unsigned int mask;
 	struct sock *sk = sock->sk;
-	struct tcp_sock *tp = tcp_sk(sk);
+	const struct tcp_sock *tp = tcp_sk(sk);
 
 	sock_poll_wait(file, sk_sleep(sk), wait);
 	if (sk->sk_state == TCP_LISTEN)
@@ -528,7 +528,7 @@
 	tp->pushed_seq = tp->write_seq;
 }
 
-static inline int forced_push(struct tcp_sock *tp)
+static inline int forced_push(const struct tcp_sock *tp)
 {
 	return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
 }
@@ -891,9 +891,9 @@
 #define TCP_PAGE(sk)	(sk->sk_sndmsg_page)
 #define TCP_OFF(sk)	(sk->sk_sndmsg_off)
 
-static inline int select_size(struct sock *sk, int sg)
+static inline int select_size(const struct sock *sk, int sg)
 {
-	struct tcp_sock *tp = tcp_sk(sk);
+	const struct tcp_sock *tp = tcp_sk(sk);
 	int tmp = tp->mss_cache;
 
 	if (sg) {
@@ -2408,7 +2408,7 @@
 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
 		   unsigned int optlen)
 {
-	struct inet_connection_sock *icsk = inet_csk(sk);
+	const struct inet_connection_sock *icsk = inet_csk(sk);
 
 	if (level != SOL_TCP)
 		return icsk->icsk_af_ops->setsockopt(sk, level, optname,
@@ -2430,9 +2430,9 @@
 #endif
 
 /* Return information about state of tcp endpoint in API format. */
-void tcp_get_info(struct sock *sk, struct tcp_info *info)
+void tcp_get_info(const struct sock *sk, struct tcp_info *info)
 {
-	struct tcp_sock *tp = tcp_sk(sk);
+	const struct tcp_sock *tp = tcp_sk(sk);
 	const struct inet_connection_sock *icsk = inet_csk(sk);
 	u32 now = tcp_time_stamp;
 
@@ -3010,7 +3010,7 @@
 EXPORT_SYMBOL(tcp_md5_hash_header);
 
 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
-			  struct sk_buff *skb, unsigned header_len)
+			  const struct sk_buff *skb, unsigned int header_len)
 {
 	struct scatterlist sg;
 	const struct tcphdr *tp = tcp_hdr(skb);
@@ -3043,7 +3043,7 @@
 }
 EXPORT_SYMBOL(tcp_md5_hash_skb_data);
 
-int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, struct tcp_md5sig_key *key)
+int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key)
 {
 	struct scatterlist sg;