Merge branch 'tcp-cleanups'

Eric Dumazet says:

====================
tcp: cleanups for linux-5.1

This small patch series cleanups few things, and add a small
timewait optimization for hosts not using md5.
====================

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);
 }
@@ -1716,20 +1716,9 @@ static inline bool tcp_rtx_and_write_queues_empty(const struct sock *sk)
 	return tcp_rtx_queue_empty(sk) && tcp_write_queue_empty(sk);
 }
 
-static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked)
-{
-	if (tcp_write_queue_empty(sk))
-		tcp_chrono_stop(sk, TCP_CHRONO_BUSY);
-}
-
-static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
-{
-	__skb_queue_tail(&sk->sk_write_queue, skb);
-}
-
 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
 {
-	__tcp_add_write_queue_tail(sk, skb);
+	__skb_queue_tail(&sk->sk_write_queue, skb);
 
 	/* Queue it, remembering where we must start sending. */
 	if (sk->sk_write_queue.next == skb)

net/ipv4/tcp.c

@@ -1412,7 +1412,8 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
 		/* It is the one place in all of TCP, except connection
 		 * reset, where we can be unlinking the send_head.
 		 */
-		tcp_check_send_head(sk, skb);
+		if (tcp_write_queue_empty(sk))
+			tcp_chrono_stop(sk, TCP_CHRONO_BUSY);
 		sk_wmem_free_skb(sk, skb);
 	}
 
@@ -3698,7 +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_minisocks.c

@@ -294,12 +294,15 @@ void tcp_time_wait(struct sock *sk, int state, int timeo)
 		 * so the timewait ack generating code has the key.
 		 */
 		do {
-			struct tcp_md5sig_key *key;
 			tcptw->tw_md5_key = NULL;
-			key = tp->af_specific->md5_lookup(sk, sk);
-			if (key) {
-				tcptw->tw_md5_key = kmemdup(key, sizeof(*key), GFP_ATOMIC);
-				BUG_ON(tcptw->tw_md5_key && !tcp_alloc_md5sig_pool());
+			if (static_branch_unlikely(&tcp_md5_needed)) {
+				struct tcp_md5sig_key *key;
+
+				key = tp->af_specific->md5_lookup(sk, sk);
+				if (key) {
+					tcptw->tw_md5_key = kmemdup(key, sizeof(*key), GFP_ATOMIC);
+					BUG_ON(tcptw->tw_md5_key && !tcp_alloc_md5sig_pool());
+				}
 			}
 		} while (0);
 #endif
@@ -338,10 +341,12 @@ EXPORT_SYMBOL(tcp_time_wait);
 void tcp_twsk_destructor(struct sock *sk)
 {
 #ifdef CONFIG_TCP_MD5SIG
-	struct tcp_timewait_sock *twsk = tcp_twsk(sk);
+	if (static_branch_unlikely(&tcp_md5_needed)) {
+		struct tcp_timewait_sock *twsk = tcp_twsk(sk);
 
-	if (twsk->tw_md5_key)
-		kfree_rcu(twsk->tw_md5_key, rcu);
+		if (twsk->tw_md5_key)
+			kfree_rcu(twsk->tw_md5_key, rcu);
+	}
 #endif
 }
 EXPORT_SYMBOL_GPL(tcp_twsk_destructor);

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) {
@@ -1846,17 +1846,17 @@ static bool tcp_snd_wnd_test(const struct tcp_sock *tp,
  * know that all the data is in scatter-gather pages, and that the
  * packet has never been sent out before (and thus is not cloned).
  */
-static int tso_fragment(struct sock *sk, enum tcp_queue tcp_queue,
-			struct sk_buff *skb, unsigned int len,
+static int tso_fragment(struct sock *sk, struct sk_buff *skb, unsigned int len,
 			unsigned int mss_now, gfp_t gfp)
 {
-	struct sk_buff *buff;
 	int nlen = skb->len - len;
+	struct sk_buff *buff;
 	u8 flags;
 
 	/* All of a TSO frame must be composed of paged data.  */
 	if (skb->len != skb->data_len)
-		return tcp_fragment(sk, tcp_queue, skb, len, mss_now, gfp);
+		return tcp_fragment(sk, TCP_FRAG_IN_WRITE_QUEUE,
+				    skb, len, mss_now, gfp);
 
 	buff = sk_stream_alloc_skb(sk, 0, gfp, true);
 	if (unlikely(!buff))
@@ -1892,7 +1892,7 @@ static int tso_fragment(struct sock *sk, enum tcp_queue tcp_queue,
 
 	/* Link BUFF into the send queue. */
 	__skb_header_release(buff);
-	tcp_insert_write_queue_after(skb, buff, sk, tcp_queue);
+	tcp_insert_write_queue_after(skb, buff, sk, TCP_FRAG_IN_WRITE_QUEUE);
 
 	return 0;
 }
@@ -2391,8 +2391,7 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle,
 						    nonagle);
 
 		if (skb->len > limit &&
-		    unlikely(tso_fragment(sk, TCP_FRAG_IN_WRITE_QUEUE,
-					  skb, limit, mss_now, gfp)))
+		    unlikely(tso_fragment(sk, skb, limit, mss_now, gfp)))
 			break;
 
 		if (tcp_small_queue_check(sk, skb, 0))