Index: ip_vs_sync.c
===================================================================
RCS file: /home/wensong/cvsroot/ipvs/ip_vs_sync.c,v
retrieving revision 1.6
diff -u -r1.6 ip_vs_sync.c
--- ip_vs_sync.c	11 Jul 2002 14:26:41 -0000	1.6
+++ ip_vs_sync.c	25 Jul 2002 10:07:32 -0000
@@ -132,7 +132,7 @@
 {
 	struct ip_vs_sync_buff *sb;
 
-	spin_lock(&ip_vs_sync_lock);
+	spin_lock_bh(&ip_vs_sync_lock);
 	if (list_empty(&ip_vs_sync_queue)) {
 		sb = NULL;
 	} else {
@@ -141,7 +141,7 @@
 				list);
 		list_del(&sb->list);
 	}
-	spin_unlock(&ip_vs_sync_lock);
+	spin_unlock_bh(&ip_vs_sync_lock);
 
 	return sb;
 }
@@ -180,13 +180,13 @@
 {
 	struct ip_vs_sync_buff *sb;
 
-	spin_lock(&curr_sb_lock);
+	spin_lock_bh(&curr_sb_lock);
 	if (curr_sb && (jiffies - curr_sb->firstuse > time)) {
 		sb = curr_sb;
 		curr_sb = NULL;
 	} else
 		sb = NULL;
-	spin_unlock(&curr_sb_lock);
+	spin_unlock_bh(&curr_sb_lock);
 	return sb;
 }
 
@@ -561,7 +561,7 @@
 static int errno;
 
 static DECLARE_WAIT_QUEUE_HEAD(sync_wait);
-static int sync_pid = 0;
+static pid_t sync_pid = 0;
 
 static DECLARE_WAIT_QUEUE_HEAD(stop_sync_wait);
 static int stop_sync = 0;
@@ -586,7 +586,7 @@
 			ip_vs_sync_buff_release(sb);
 		}
 
-		/* check if entries stay in curr_sb for a while */
+		/* check if entries stay in curr_sb for 2 seconds */
 		if ((sb = get_curr_sync_buff(2*HZ))) {
 			m = sb->mesg;
 			if (ip_vs_send_async(sock, (char *)m,
@@ -607,12 +607,12 @@
 	while ((sb=sb_dequeue())) {
 		ip_vs_sync_buff_release(sb);
 	}
-	spin_lock(&curr_sb_lock);
+	spin_lock_bh(&curr_sb_lock);
 	if (curr_sb) {
 		ip_vs_sync_buff_release(curr_sb);
 		curr_sb = NULL;
 	}
-	spin_unlock(&curr_sb_lock);
+	spin_unlock_bh(&curr_sb_lock);
 
 	/* release the sending multicast socket */
 	sock_release(sock);
@@ -667,15 +667,11 @@
 	DECLARE_WAITQUEUE(wait, current);
 	mm_segment_t oldmm;
 
-	MOD_INC_USE_COUNT;
 	daemonize();
 
 	oldmm = get_fs();
 	set_fs(KERNEL_DS);
 
-	sync_pid = current->pid;
-	IP_VS_INFO("sync thread started.\n");
-
 	if (ip_vs_sync_state == IP_VS_STATE_MASTER)
 		sprintf(current->comm, "ipvs syncmaster");
 	else if (ip_vs_sync_state == IP_VS_STATE_BACKUP)
@@ -704,14 +700,10 @@
 	remove_wait_queue(&sync_wait, &wait);
 
 	/* thread exits */
-	sync_pid = 0;
-	IP_VS_INFO("sync thread stopped!\n");
-
 	stop_sync = 0;
 	wake_up(&stop_sync_wait);
 
 	set_fs(oldmm);
-	MOD_DEC_USE_COUNT;
 
 	return 0;
 }
@@ -721,13 +713,18 @@
 	if (sync_pid)
 		return -EEXIST;
 
+	MOD_INC_USE_COUNT;
+	IP_VS_DBG(7, "%s: pid %d\n", __FUNCTION__, current->pid);
 	IP_VS_DBG(7, "Each ip_vs_sync_conn entry need %d bytes\n",
 		  sizeof(struct ip_vs_sync_conn));
+
 	ip_vs_sync_state = state;
 	strcpy(ip_vs_mcast_ifn, mcast_ifn);
 
-	if (kernel_thread(sync_thread, NULL, 0) < 0)
+	if ((sync_pid = kernel_thread(sync_thread, NULL, 0)) < 0)
 		IP_VS_BUG();
+
+	IP_VS_INFO("sync thread started.\n");
 	return 0;
 }
 
@@ -735,10 +732,12 @@
 int stop_sync_thread(void)
 {
 	DECLARE_WAITQUEUE(wait, current);
+	pid_t pid;
 
 	if (!sync_pid)
 		return -ESRCH;
 
+	IP_VS_DBG(7, "%s: pid %d\n", __FUNCTION__, current->pid);
 	IP_VS_INFO("stopping sync thread %d ...\n", sync_pid);
 
 	__set_current_state(TASK_UNINTERRUPTIBLE);
@@ -750,13 +749,19 @@
 	__set_current_state(TASK_RUNNING);
 	remove_wait_queue(&stop_sync_wait, &wait);
 
-	/* it is probably not correct here. we need use sys_wait4, but need
-	to patch the kernel to export sys_wait4, check it later...
-	sys_wait4(sync_pid, NULL, __WCLONE, NULL); */
-	waitpid(sync_pid, NULL, __WCLONE);
+	/* When the same process start/stop the sync thread (in this case
+	   the parent process of the sync thread is this process, instead
+	   of the init process), must reap the sync thread here. */
+	pid = waitpid(sync_pid, NULL, __WCLONE|WNOHANG);
+	if (pid > 0 && pid != sync_pid)
+		IP_VS_ERR("waitpid bug!\n");
 
 	if (stop_sync)
 		IP_VS_BUG();
+
+	IP_VS_INFO("sync thread stopped!\n");
+	sync_pid = 0;
+	MOD_DEC_USE_COUNT;
 
 	return 0;
 }