patch-2.2.11 linux/net/ipv4/tcp.c

• Lines: 91
• Date: Mon Aug 9 12:05:45 1999
• Orig file: v2.2.10/linux/net/ipv4/tcp.c
• Orig date: Wed Jun 2 09:55:22 1999

diff -u --recursive --new-file v2.2.10/linux/net/ipv4/tcp.c linux/net/ipv4/tcp.c
@@ -5,7 +5,7 @@
  *
  *		Implementation of the Transmission Control Protocol(TCP).
  *
- * Version:	$Id: tcp.c,v 1.140.2.1 1999/05/29 04:16:48 davem Exp $
+ * Version:	$Id: tcp.c,v 1.140.2.4 1999/08/09 03:13:12 davem Exp $
  *
  * Authors:	Ross Biro, <bir7@leland.Stanford.Edu>
  *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
@@ -725,6 +725,23 @@
 	lock_sock(sk);
 }
 
+/*
+ * Wait for a buffer.
+ */ 
+static int wait_for_buffer(struct sock *sk) 
+{ 
+	struct wait_queue wait = { current, NULL }; 
+
+	release_sock(sk); 
+	add_wait_queue(sk->sleep, &wait); 
+	current->state = TASK_INTERRUPTIBLE; 
+	schedule(); 
+	current->state = TASK_RUNNING; 
+	remove_wait_queue(sk->sleep, &wait);
+	lock_sock(sk); 
+	return 0; 
+} 
+
 /* When all user supplied data has been queued set the PSH bit */
 #define PSH_NEEDED (seglen == 0 && iovlen == 0)
 
@@ -802,11 +819,21 @@
 				    tp->snd_nxt < TCP_SKB_CB(skb)->end_seq) {
 					int last_byte_was_odd = (copy % 4);
 
+					/* 
+					 * Check for parallel writers sleeping in user access.
+					 */ 
+					if (tp->partial_writers++ > 0) { 
+						wait_for_buffer(sk);
+						tp->partial_writers--;
+						continue; 
+					}
+				
 					copy = mss_now - copy;
 					if(copy > skb_tailroom(skb))
 						copy = skb_tailroom(skb);
 					if(copy > seglen)
 						copy = seglen;
+		
 					if(last_byte_was_odd) {
 						if(copy_from_user(skb_put(skb, copy),
 								  from, copy))
@@ -819,6 +846,7 @@
 							from, skb_put(skb, copy),
 							copy, skb->csum, &err);
 					}
+		
 					/*
 					 * FIXME: the *_user functions should
 					 *	  return how much data was
@@ -838,6 +866,10 @@
 					seglen -= copy;
 					if (PSH_NEEDED)
 						TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
+
+					if (--tp->partial_writers > 0) 
+						wake_up_interruptible(sk->sleep); 
+
 					continue;
 				}
 			}
@@ -1332,12 +1364,12 @@
 		break;
 	}
 
-	if(copied > 0 && msg->msg_name)
+	if(copied >= 0 && msg->msg_name) {
 		tp->af_specific->addr2sockaddr(sk, (struct sockaddr *)
 					       msg->msg_name);       
-
-	if(addr_len)
-		*addr_len = tp->af_specific->sockaddr_len;
+		if(addr_len)
+			*addr_len = tp->af_specific->sockaddr_len;
+	}
 
 	remove_wait_queue(sk->sleep, &wait);
 	current->state = TASK_RUNNING;