[NET] generalise tcp_moderate_sndbuf

Renaming it to sk_stream_moderate_sndbuf, further patches will move
all the tcp memory pressure handling support into net/core/stream.c
to make them usable by the poor cousins, starting with LLC.
Signed-off-by: Arnaldo Carvalho de Melo <acme@conectiva.com.br>

include/net/sock.h

@@ -1095,6 +1095,14 @@ static inline void sk_wake_async(struct sock *sk, int how, int band)
 #define SOCK_MIN_SNDBUF 2048
 #define SOCK_MIN_RCVBUF 256
 
+static inline void sk_stream_moderate_sndbuf(struct sock *sk)
+{
+	if (!(sk->sk_userlocks & SOCK_SNDBUF_LOCK)) {
+		sk->sk_sndbuf = min(sk->sk_sndbuf, sk->sk_wmem_queued / 2);
+		sk->sk_sndbuf = max(sk->sk_sndbuf, SOCK_MIN_SNDBUF);
+	}
+}
+
 /*
  *	Default write policy as shown to user space via poll/select/SIGIO
  */

include/net/tcp.h

@@ -1893,14 +1893,6 @@ static inline void tcp_enter_memory_pressure(void)
 	}
 }
 
-static inline void tcp_moderate_sndbuf(struct sock *sk)
-{
-	if (!(sk->sk_userlocks & SOCK_SNDBUF_LOCK)) {
-		sk->sk_sndbuf = min(sk->sk_sndbuf, sk->sk_wmem_queued / 2);
-		sk->sk_sndbuf = max(sk->sk_sndbuf, SOCK_MIN_SNDBUF);
-	}
-}
-
 static inline struct sk_buff *tcp_alloc_pskb(struct sock *sk, int size, int mem, int gfp)
 {
 	struct sk_buff *skb = alloc_skb(size+MAX_TCP_HEADER, gfp);
@@ -1915,7 +1907,7 @@ static inline struct sk_buff *tcp_alloc_pskb(struct sock *sk, int size, int mem,
 		__kfree_skb(skb);
 	} else {
 		tcp_enter_memory_pressure();
-		tcp_moderate_sndbuf(sk);
+		sk_stream_moderate_sndbuf(sk);
 	}
 	return NULL;
 }
@@ -1934,7 +1926,7 @@ static inline struct page * tcp_alloc_page(struct sock *sk)
 			return page;
 	}
 	tcp_enter_memory_pressure();
-	tcp_moderate_sndbuf(sk);
+	sk_stream_moderate_sndbuf(sk);
 	return NULL;
 }
 

net/ipv4/tcp.c

@@ -333,7 +333,7 @@ int tcp_mem_schedule(struct sock *sk, int size, int kind)
 suppress_allocation:
 
 	if (!kind) {
-		tcp_moderate_sndbuf(sk);
+		sk_stream_moderate_sndbuf(sk);
 
 		/* Fail only if socket is _under_ its sndbuf.
 		 * In this case we cannot block, so that we have to fail.