Merge branch 'stealer/ipvs/sync-daemon-cleanup-for-next' of git://git.stealer.net/linux-2.6

net/ipv4/ipvs/ip_vs_sync.c

@@ -27,10 +27,12 @@
 #include <linux/in.h>
 #include <linux/igmp.h>                 /* for ip_mc_join_group */
 #include <linux/udp.h>
+#include <linux/err.h>
+#include <linux/kthread.h>
+#include <linux/wait.h>
 
 #include <net/ip.h>
 #include <net/sock.h>
-#include <asm/uaccess.h>                /* for get_fs and set_fs */
 
 #include <net/ip_vs.h>
 
@@ -66,8 +68,8 @@ struct ip_vs_sync_conn_options {
 };
 
 struct ip_vs_sync_thread_data {
-	struct completion *startup;
-	int state;
+	struct socket *sock;
+	char *buf;
 };
 
 #define SIMPLE_CONN_SIZE  (sizeof(struct ip_vs_sync_conn))
@@ -138,18 +140,19 @@ volatile int ip_vs_backup_syncid = 0;
 char ip_vs_master_mcast_ifn[IP_VS_IFNAME_MAXLEN];
 char ip_vs_backup_mcast_ifn[IP_VS_IFNAME_MAXLEN];
 
-/* multicast addr */
-static struct sockaddr_in mcast_addr;
+/* sync daemon tasks */
+static struct task_struct *sync_master_thread;
+static struct task_struct *sync_backup_thread;
 
+/* multicast addr */
+static struct sockaddr_in mcast_addr = {
+	.sin_family		= AF_INET,
+	.sin_port		= __constant_htons(IP_VS_SYNC_PORT),
+	.sin_addr.s_addr	= __constant_htonl(IP_VS_SYNC_GROUP),
+};
 
-static inline void sb_queue_tail(struct ip_vs_sync_buff *sb)
-{
-	spin_lock(&ip_vs_sync_lock);
-	list_add_tail(&sb->list, &ip_vs_sync_queue);
-	spin_unlock(&ip_vs_sync_lock);
-}
 
-static inline struct ip_vs_sync_buff * sb_dequeue(void)
+static inline struct ip_vs_sync_buff *sb_dequeue(void)
 {
 	struct ip_vs_sync_buff *sb;
 
@@ -193,6 +196,16 @@ static inline void ip_vs_sync_buff_release(struct ip_vs_sync_buff *sb)
 	kfree(sb);
 }
 
+static inline void sb_queue_tail(struct ip_vs_sync_buff *sb)
+{
+	spin_lock(&ip_vs_sync_lock);
+	if (ip_vs_sync_state & IP_VS_STATE_MASTER)
+		list_add_tail(&sb->list, &ip_vs_sync_queue);
+	else
+		ip_vs_sync_buff_release(sb);
+	spin_unlock(&ip_vs_sync_lock);
+}
+
 /*
  *	Get the current sync buffer if it has been created for more
  *	than the specified time or the specified time is zero.
@@ -572,14 +585,17 @@ static int bind_mcastif_addr(struct socket *sock, char *ifname)
 static struct socket * make_send_sock(void)
 {
 	struct socket *sock;
+	int result;
 
 	/* First create a socket */
-	if (sock_create_kern(PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock) < 0) {
+	result = sock_create_kern(PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock);
+	if (result < 0) {
 		IP_VS_ERR("Error during creation of socket; terminating\n");
-		return NULL;
+		return ERR_PTR(result);
 	}
 
-	if (set_mcast_if(sock->sk, ip_vs_master_mcast_ifn) < 0) {
+	result = set_mcast_if(sock->sk, ip_vs_master_mcast_ifn);
+	if (result < 0) {
 		IP_VS_ERR("Error setting outbound mcast interface\n");
 		goto error;
 	}
@@ -587,14 +603,15 @@ static struct socket * make_send_sock(void)
 	set_mcast_loop(sock->sk, 0);
 	set_mcast_ttl(sock->sk, 1);
 
-	if (bind_mcastif_addr(sock, ip_vs_master_mcast_ifn) < 0) {
+	result = bind_mcastif_addr(sock, ip_vs_master_mcast_ifn);
+	if (result < 0) {
 		IP_VS_ERR("Error binding address of the mcast interface\n");
 		goto error;
 	}
 
-	if (sock->ops->connect(sock,
-			       (struct sockaddr*)&mcast_addr,
-			       sizeof(struct sockaddr), 0) < 0) {
+	result = sock->ops->connect(sock, (struct sockaddr *) &mcast_addr,
+			sizeof(struct sockaddr), 0);
+	if (result < 0) {
 		IP_VS_ERR("Error connecting to the multicast addr\n");
 		goto error;
 	}
@@ -603,7 +620,7 @@ static struct socket * make_send_sock(void)
 
   error:
 	sock_release(sock);
-	return NULL;
+	return ERR_PTR(result);
 }
 
 
@@ -613,27 +630,30 @@ static struct socket * make_send_sock(void)
 static struct socket * make_receive_sock(void)
 {
 	struct socket *sock;
+	int result;
 
 	/* First create a socket */
-	if (sock_create_kern(PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock) < 0) {
+	result = sock_create_kern(PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock);
+	if (result < 0) {
 		IP_VS_ERR("Error during creation of socket; terminating\n");
-		return NULL;
+		return ERR_PTR(result);
 	}
 
 	/* it is equivalent to the REUSEADDR option in user-space */
 	sock->sk->sk_reuse = 1;
 
-	if (sock->ops->bind(sock,
-			    (struct sockaddr*)&mcast_addr,
-			    sizeof(struct sockaddr)) < 0) {
+	result = sock->ops->bind(sock, (struct sockaddr *) &mcast_addr,
+			sizeof(struct sockaddr));
+	if (result < 0) {
 		IP_VS_ERR("Error binding to the multicast addr\n");
 		goto error;
 	}
 
 	/* join the multicast group */
-	if (join_mcast_group(sock->sk,
-			     (struct in_addr*)&mcast_addr.sin_addr,
-			     ip_vs_backup_mcast_ifn) < 0) {
+	result = join_mcast_group(sock->sk,
+			(struct in_addr *) &mcast_addr.sin_addr,
+			ip_vs_backup_mcast_ifn);
+	if (result < 0) {
 		IP_VS_ERR("Error joining to the multicast group\n");
 		goto error;
 	}
@@ -642,7 +662,7 @@ static struct socket * make_receive_sock(void)
 
   error:
 	sock_release(sock);
-	return NULL;
+	return ERR_PTR(result);
 }
 
 
@@ -700,44 +720,29 @@ ip_vs_receive(struct socket *sock, char *buffer, const size_t buflen)
 }
 
 
-static DECLARE_WAIT_QUEUE_HEAD(sync_wait);
-static pid_t sync_master_pid = 0;
-static pid_t sync_backup_pid = 0;
-
-static DECLARE_WAIT_QUEUE_HEAD(stop_sync_wait);
-static int stop_master_sync = 0;
-static int stop_backup_sync = 0;
-
-static void sync_master_loop(void)
+static int sync_thread_master(void *data)
 {
-	struct socket *sock;
+	struct ip_vs_sync_thread_data *tinfo = data;
 	struct ip_vs_sync_buff *sb;
 
-	/* create the sending multicast socket */
-	sock = make_send_sock();
-	if (!sock)
-		return;
-
 	IP_VS_INFO("sync thread started: state = MASTER, mcast_ifn = %s, "
 		   "syncid = %d\n",
 		   ip_vs_master_mcast_ifn, ip_vs_master_syncid);
 
-	for (;;) {
-		while ((sb=sb_dequeue())) {
-			ip_vs_send_sync_msg(sock, sb->mesg);
+	while (!kthread_should_stop()) {
+		while ((sb = sb_dequeue())) {
+			ip_vs_send_sync_msg(tinfo->sock, sb->mesg);
 			ip_vs_sync_buff_release(sb);
 		}
 
 		/* check if entries stay in curr_sb for 2 seconds */
-		if ((sb = get_curr_sync_buff(2*HZ))) {
-			ip_vs_send_sync_msg(sock, sb->mesg);
+		sb = get_curr_sync_buff(2 * HZ);
+		if (sb) {
+			ip_vs_send_sync_msg(tinfo->sock, sb->mesg);
 			ip_vs_sync_buff_release(sb);
 		}
 
-		if (stop_master_sync)
-			break;
-
-		msleep_interruptible(1000);
+		schedule_timeout_interruptible(HZ);
 	}
 
 	/* clean up the sync_buff queue */
@@ -751,267 +756,175 @@ static void sync_master_loop(void)
 	}
 
 	/* release the sending multicast socket */
-	sock_release(sock);
+	sock_release(tinfo->sock);
+	kfree(tinfo);
+
+	return 0;
 }
 
 
-static void sync_backup_loop(void)
+static int sync_thread_backup(void *data)
 {
-	struct socket *sock;
-	char *buf;
+	struct ip_vs_sync_thread_data *tinfo = data;
 	int len;
 
-	if (!(buf = kmalloc(sync_recv_mesg_maxlen, GFP_ATOMIC))) {
-		IP_VS_ERR("sync_backup_loop: kmalloc error\n");
-		return;
-	}
-
-	/* create the receiving multicast socket */
-	sock = make_receive_sock();
-	if (!sock)
-		goto out;
-
 	IP_VS_INFO("sync thread started: state = BACKUP, mcast_ifn = %s, "
 		   "syncid = %d\n",
 		   ip_vs_backup_mcast_ifn, ip_vs_backup_syncid);
 
-	for (;;) {
-		/* do you have data now? */
-		while (!skb_queue_empty(&(sock->sk->sk_receive_queue))) {
-			if ((len =
-			     ip_vs_receive(sock, buf,
-					   sync_recv_mesg_maxlen)) <= 0) {
+	while (!kthread_should_stop()) {
+		wait_event_interruptible(*tinfo->sock->sk->sk_sleep,
+			 !skb_queue_empty(&tinfo->sock->sk->sk_receive_queue)
+			 || kthread_should_stop());
+
+		/* do we have data now? */
+		while (!skb_queue_empty(&(tinfo->sock->sk->sk_receive_queue))) {
+			len = ip_vs_receive(tinfo->sock, tinfo->buf,
+					sync_recv_mesg_maxlen);
+			if (len <= 0) {
 				IP_VS_ERR("receiving message error\n");
 				break;
 			}
-			/* disable bottom half, because it accessed the data
+
+			/* disable bottom half, because it accesses the data
 			   shared by softirq while getting/creating conns */
 			local_bh_disable();
-			ip_vs_process_message(buf, len);
+			ip_vs_process_message(tinfo->buf, len);
 			local_bh_enable();
 		}
-
-		if (stop_backup_sync)
-			break;
-
-		msleep_interruptible(1000);
 	}
 
 	/* release the sending multicast socket */
-	sock_release(sock);
+	sock_release(tinfo->sock);
+	kfree(tinfo->buf);
+	kfree(tinfo);
 
-  out:
-	kfree(buf);
+	return 0;
 }
 
 
-static void set_sync_pid(int sync_state, pid_t sync_pid)
-{
-	if (sync_state == IP_VS_STATE_MASTER)
-		sync_master_pid = sync_pid;
-	else if (sync_state == IP_VS_STATE_BACKUP)
-		sync_backup_pid = sync_pid;
-}
-
-static void set_stop_sync(int sync_state, int set)
+int start_sync_thread(int state, char *mcast_ifn, __u8 syncid)
 {
-	if (sync_state == IP_VS_STATE_MASTER)
-		stop_master_sync = set;
-	else if (sync_state == IP_VS_STATE_BACKUP)
-		stop_backup_sync = set;
-	else {
-		stop_master_sync = set;
-		stop_backup_sync = set;
-	}
-}
+	struct ip_vs_sync_thread_data *tinfo;
+	struct task_struct **realtask, *task;
+	struct socket *sock;
+	char *name, *buf = NULL;
+	int (*threadfn)(void *data);
+	int result = -ENOMEM;
 
-static int sync_thread(void *startup)
-{
-	DECLARE_WAITQUEUE(wait, current);
-	mm_segment_t oldmm;
-	int state;
-	const char *name;
-	struct ip_vs_sync_thread_data *tinfo = startup;
+	IP_VS_DBG(7, "%s: pid %d\n", __func__, task_pid_nr(current));
+	IP_VS_DBG(7, "Each ip_vs_sync_conn entry needs %Zd bytes\n",
+		  sizeof(struct ip_vs_sync_conn));
 
-	/* increase the module use count */
-	ip_vs_use_count_inc();
+	if (state == IP_VS_STATE_MASTER) {
+		if (sync_master_thread)
+			return -EEXIST;
 
-	if (ip_vs_sync_state & IP_VS_STATE_MASTER && !sync_master_pid) {
-		state = IP_VS_STATE_MASTER;
+		strlcpy(ip_vs_master_mcast_ifn, mcast_ifn,
+			sizeof(ip_vs_master_mcast_ifn));
+		ip_vs_master_syncid = syncid;
+		realtask = &sync_master_thread;
 		name = "ipvs_syncmaster";
-	} else if (ip_vs_sync_state & IP_VS_STATE_BACKUP && !sync_backup_pid) {
-		state = IP_VS_STATE_BACKUP;
+		threadfn = sync_thread_master;
+		sock = make_send_sock();
+	} else if (state == IP_VS_STATE_BACKUP) {
+		if (sync_backup_thread)
+			return -EEXIST;
+
+		strlcpy(ip_vs_backup_mcast_ifn, mcast_ifn,
+			sizeof(ip_vs_backup_mcast_ifn));
+		ip_vs_backup_syncid = syncid;
+		realtask = &sync_backup_thread;
 		name = "ipvs_syncbackup";
+		threadfn = sync_thread_backup;
+		sock = make_receive_sock();
 	} else {
-		IP_VS_BUG();
-		ip_vs_use_count_dec();
 		return -EINVAL;
 	}
 
-	daemonize(name);
-
-	oldmm = get_fs();
-	set_fs(KERNEL_DS);
-
-	/* Block all signals */
-	spin_lock_irq(&current->sighand->siglock);
-	siginitsetinv(&current->blocked, 0);
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
+	if (IS_ERR(sock)) {
+		result = PTR_ERR(sock);
+		goto out;
+	}
 
-	/* set the maximum length of sync message */
 	set_sync_mesg_maxlen(state);
+	if (state == IP_VS_STATE_BACKUP) {
+		buf = kmalloc(sync_recv_mesg_maxlen, GFP_KERNEL);
+		if (!buf)
+			goto outsocket;
+	}
 
-	/* set up multicast address */
-	mcast_addr.sin_family = AF_INET;
-	mcast_addr.sin_port = htons(IP_VS_SYNC_PORT);
-	mcast_addr.sin_addr.s_addr = htonl(IP_VS_SYNC_GROUP);
-
-	add_wait_queue(&sync_wait, &wait);
-
-	set_sync_pid(state, task_pid_nr(current));
-	complete(tinfo->startup);
-
-	/*
-	 * once we call the completion queue above, we should
-	 * null out that reference, since its allocated on the
-	 * stack of the creating kernel thread
-	 */
-	tinfo->startup = NULL;
-
-	/* processing master/backup loop here */
-	if (state == IP_VS_STATE_MASTER)
-		sync_master_loop();
-	else if (state == IP_VS_STATE_BACKUP)
-		sync_backup_loop();
-	else IP_VS_BUG();
-
-	remove_wait_queue(&sync_wait, &wait);
-
-	/* thread exits */
+	tinfo = kmalloc(sizeof(*tinfo), GFP_KERNEL);
+	if (!tinfo)
+		goto outbuf;
 
-	/*
-	 * If we weren't explicitly stopped, then we
-	 * exited in error, and should undo our state
-	 */
-	if ((!stop_master_sync) && (!stop_backup_sync))
-		ip_vs_sync_state -= tinfo->state;
+	tinfo->sock = sock;
+	tinfo->buf = buf;
 
-	set_sync_pid(state, 0);
-	IP_VS_INFO("sync thread stopped!\n");
+	task = kthread_run(threadfn, tinfo, name);
+	if (IS_ERR(task)) {
+		result = PTR_ERR(task);
+		goto outtinfo;
+	}
 
-	set_fs(oldmm);
+	/* mark as active */
+	*realtask = task;
+	ip_vs_sync_state |= state;
 
-	/* decrease the module use count */
-	ip_vs_use_count_dec();
+	/* increase the module use count */
+	ip_vs_use_count_inc();
 
-	set_stop_sync(state, 0);
-	wake_up(&stop_sync_wait);
+	return 0;
 
-	/*
-	 * we need to free the structure that was allocated
-	 * for us in start_sync_thread
-	 */
+outtinfo:
 	kfree(tinfo);
-	return 0;
+outbuf:
+	kfree(buf);
+outsocket:
+	sock_release(sock);
+out:
+	return result;
 }
 
 
-static int fork_sync_thread(void *startup)
+int stop_sync_thread(int state)
 {
-	pid_t pid;
-
-	/* fork the sync thread here, then the parent process of the
-	   sync thread is the init process after this thread exits. */
-  repeat:
-	if ((pid = kernel_thread(sync_thread, startup, 0)) < 0) {
-		IP_VS_ERR("could not create sync_thread due to %d... "
-			  "retrying.\n", pid);
-		msleep_interruptible(1000);
-		goto repeat;
-	}
-
-	return 0;
-}
-
+	IP_VS_DBG(7, "%s: pid %d\n", __func__, task_pid_nr(current));
 
-int start_sync_thread(int state, char *mcast_ifn, __u8 syncid)
-{
-	DECLARE_COMPLETION_ONSTACK(startup);
-	pid_t pid;
-	struct ip_vs_sync_thread_data *tinfo;
+	if (state == IP_VS_STATE_MASTER) {
+		if (!sync_master_thread)
+			return -ESRCH;
 
-	if ((state == IP_VS_STATE_MASTER && sync_master_pid) ||
-	    (state == IP_VS_STATE_BACKUP && sync_backup_pid))
-		return -EEXIST;
+		IP_VS_INFO("stopping master sync thread %d ...\n",
+			   task_pid_nr(sync_master_thread));
 
 		/*
-	 * Note that tinfo will be freed in sync_thread on exit
+		 * The lock synchronizes with sb_queue_tail(), so that we don't
+		 * add sync buffers to the queue, when we are already in
+		 * progress of stopping the master sync daemon.
 		 */
-	tinfo = kmalloc(sizeof(struct ip_vs_sync_thread_data), GFP_KERNEL);
-	if (!tinfo)
-		return -ENOMEM;
-
-	IP_VS_DBG(7, "%s: pid %d\n", __func__, task_pid_nr(current));
-	IP_VS_DBG(7, "Each ip_vs_sync_conn entry need %Zd bytes\n",
-		  sizeof(struct ip_vs_sync_conn));
 
-	ip_vs_sync_state |= state;
-	if (state == IP_VS_STATE_MASTER) {
-		strlcpy(ip_vs_master_mcast_ifn, mcast_ifn,
-			sizeof(ip_vs_master_mcast_ifn));
-		ip_vs_master_syncid = syncid;
-	} else {
-		strlcpy(ip_vs_backup_mcast_ifn, mcast_ifn,
-			sizeof(ip_vs_backup_mcast_ifn));
-		ip_vs_backup_syncid = syncid;
-	}
+		spin_lock(&ip_vs_sync_lock);
+		ip_vs_sync_state &= ~IP_VS_STATE_MASTER;
+		spin_unlock(&ip_vs_sync_lock);
+		kthread_stop(sync_master_thread);
+		sync_master_thread = NULL;
+	} else if (state == IP_VS_STATE_BACKUP) {
+		if (!sync_backup_thread)
+			return -ESRCH;
 
-	tinfo->state = state;
-	tinfo->startup = &startup;
+		IP_VS_INFO("stopping backup sync thread %d ...\n",
+			   task_pid_nr(sync_backup_thread));
 
-  repeat:
-	if ((pid = kernel_thread(fork_sync_thread, tinfo, 0)) < 0) {
-		IP_VS_ERR("could not create fork_sync_thread due to %d... "
-			  "retrying.\n", pid);
-		msleep_interruptible(1000);
-		goto repeat;
+		ip_vs_sync_state &= ~IP_VS_STATE_BACKUP;
+		kthread_stop(sync_backup_thread);
+		sync_backup_thread = NULL;
+	} else {
+		return -EINVAL;
 	}
 
-	wait_for_completion(&startup);
-
-	return 0;
-}
-
-
-int stop_sync_thread(int state)
-{
-	DECLARE_WAITQUEUE(wait, current);
-
-	if ((state == IP_VS_STATE_MASTER && !sync_master_pid) ||
-	    (state == IP_VS_STATE_BACKUP && !sync_backup_pid))
-		return -ESRCH;
-
-	IP_VS_DBG(7, "%s: pid %d\n", __func__, task_pid_nr(current));
-	IP_VS_INFO("stopping sync thread %d ...\n",
-		   (state == IP_VS_STATE_MASTER) ?
-		   sync_master_pid : sync_backup_pid);
-
-	__set_current_state(TASK_UNINTERRUPTIBLE);
-	add_wait_queue(&stop_sync_wait, &wait);
-	set_stop_sync(state, 1);
-	ip_vs_sync_state -= state;
-	wake_up(&sync_wait);
-	schedule();
-	__set_current_state(TASK_RUNNING);
-	remove_wait_queue(&stop_sync_wait, &wait);
-
-	/* Note: no need to reap the sync thread, because its parent
-	   process is the init process */
-
-	if ((state == IP_VS_STATE_MASTER && stop_master_sync) ||
-	    (state == IP_VS_STATE_BACKUP && stop_backup_sync))
-		IP_VS_BUG();
+	/* decrease the module use count */
+	ip_vs_use_count_dec();
 
 	return 0;
 }