Make sock_writeable (used mostly by datagram

protocols) more reasonable.  Kill all references
to SOCK_MIN_WRITE_SPACE and kill its definition.
Replace with appropriate sock_writeable calls.

include/net/sock.h

@@ -750,16 +750,13 @@ static inline void sk_wake_async(struct sock *sk, int how, int band)
 
 #define SOCK_MIN_SNDBUF 2048
 #define SOCK_MIN_RCVBUF 256
-/* Must be less or equal SOCK_MIN_SNDBUF */
-#define SOCK_MIN_WRITE_SPACE	SOCK_MIN_SNDBUF
 
 /*
  *	Default write policy as shown to user space via poll/select/SIGIO
- *	Kernel internally doesn't use the MIN_WRITE_SPACE threshold.
  */
 static inline int sock_writeable(struct sock *sk) 
 {
-	return sock_wspace(sk) >= SOCK_MIN_WRITE_SPACE;
+	return atomic_read(&sk->wmem_alloc) < (sk->sndbuf / 2);
 }
 
 static inline int gfp_any(void)

net/irda/af_irda.c

@@ -1700,7 +1700,7 @@ static unsigned int irda_poll(struct file * file, struct socket *sock,
 
 		if (sk->state == TCP_ESTABLISHED) {
 			if ((self->tx_flow == FLOW_START) && 
-			    (sk->sndbuf - (int)atomic_read(&sk->wmem_alloc) >= SOCK_MIN_WRITE_SPACE))
+			    sock_writeable(sk))
 			{
 				mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
 			}
@@ -1708,13 +1708,13 @@ static unsigned int irda_poll(struct file * file, struct socket *sock,
 		break;
 	case SOCK_SEQPACKET:
 		if ((self->tx_flow == FLOW_START) && 
-		    (sk->sndbuf - (int)atomic_read(&sk->wmem_alloc) >= SOCK_MIN_WRITE_SPACE))
+		    sock_writeable(sk))
 		{	
 			mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
 		}
 		break;
 	case SOCK_DGRAM:
-		if (sk->sndbuf - (int)atomic_read(&sk->wmem_alloc) >= SOCK_MIN_WRITE_SPACE)
+		if (sock_writeable(sk))
 			mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
 		break;
 	default:

net/sunrpc/xprt.c

@@ -67,9 +67,6 @@
 
 #include <asm/uaccess.h>
 
-/* Following value should be > 32k + RPC overhead */
-#define XPRT_MIN_WRITE_SPACE (35000 + SOCK_MIN_WRITE_SPACE)
-
 extern spinlock_t rpc_queue_lock;
 
 /*
@@ -1099,9 +1096,8 @@ udp_write_space(struct sock *sk)
 	if (xprt->shutdown)
 		return;
 
-
-	/* Wait until we have enough socket memory */
-	if (sock_wspace(sk) < min_t(int, sk->sndbuf,XPRT_MIN_WRITE_SPACE))
+	/* Wait until we have enough socket memory. */
+	if (sock_writeable(sk))
 		return;
 
 	if (!xprt_test_and_set_wspace(xprt)) {