[PATCHv2] ipvs: Cleanup sync daemon code

[PATCHv2] ipvs: Cleanup sync daemon code

[Sven Wegener]

It's been a while since my last post of this patch series, but here we go gain.

Changes since last post:
- Dropped the master daemon sleep change for now, that needs some more work.
- Splitted up the patch into a couple of logical chunks.

The patches are

Sven Wegener (5):
      ipvs: Initialize mcast addr at compile time
      ipvs: Use ERR_PTR for returning errors from make_receive_sock() and make_send_sock()
      ipvs: Use kthread_run() instead of doing a double-fork via kernel_thread()
      ipvs: Put backup thread on mcast socket wait queue
      ipvs: Use schedule_timeout_interruptible() instead of msleep_interruptible()

The overall difstat looks like

 ip_vs_sync.c |  431 +++++++++++++++++++++++------------------------------------
  1 file changed, 172 insertions(+), 259 deletions(-)

The patches are based on v2.6.26-rc8. If someone wants to pull them, that can
be done from

git://git.stealer.net/linux-2.6.git stealer/ipvs/sync-daemon-cleanup

Sven

[PATCH 1/5] ipvs: Initialize mcast addr at compile time

[Sven Wegener]

There's no need to do it at runtime, the values are constant.

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
---
 net/ipv4/ipvs/ip_vs_sync.c |   11 +++++------
 1 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/net/ipv4/ipvs/ip_vs_sync.c b/net/ipv4/ipvs/ip_vs_sync.c
index eff54ef..6a84c41 100644
--- a/net/ipv4/ipvs/ip_vs_sync.c
+++ b/net/ipv4/ipvs/ip_vs_sync.c
@@ -141,7 +141,11 @@ 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;
+static struct sockaddr_in mcast_addr = {
+	.sin_family		= AF_INET,
+	.sin_port		= htons(IP_VS_SYNC_PORT),
+	.sin_addr.s_addr	= htonl(IP_VS_SYNC_GROUP),
+};
 
 
 static inline void sb_queue_tail(struct ip_vs_sync_buff *sb)
@@ -864,11 +868,6 @@ static int sync_thread(void *startup)
 	/* set the maximum length of sync message */
 	set_sync_mesg_maxlen(state);
 
-	/* 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));
-- 
1.5.6.1

[PATCH 1/5] ipvs: Initialize mcast addr at compile time

[Sven Wegener]

There's no need to do it at runtime, the values are constant.

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
---
 net/ipv4/ipvs/ip_vs_sync.c |   11 +++++------
 1 files changed, 5 insertions(+), 6 deletions(-)

The hton* in the last version should be __constant_hton*. hton* normally 
works for initialization in global scope, but the check for constant 
values seems to be hidden in some ifdef and is not available in all cases.

diff --git a/net/ipv4/ipvs/ip_vs_sync.c b/net/ipv4/ipvs/ip_vs_sync.c
index eff54ef..b889276 100644
--- a/net/ipv4/ipvs/ip_vs_sync.c
+++ b/net/ipv4/ipvs/ip_vs_sync.c
@@ -141,7 +141,11 @@ 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;
+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)
@@ -864,11 +868,6 @@ static int sync_thread(void *startup)
 	/* set the maximum length of sync message */
 	set_sync_mesg_maxlen(state);
 
-	/* 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));

[PATCH 2/5] ipvs: Use ERR_PTR for returning errors from make_receive_sock() and make_send_sock()

[Sven Wegener]

The additional information we now return to the caller is currently not used,
but will be used to return errors to user space.

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
---
 net/ipv4/ipvs/ip_vs_sync.c |   46 +++++++++++++++++++++++++------------------
 1 files changed, 27 insertions(+), 19 deletions(-)

diff --git a/net/ipv4/ipvs/ip_vs_sync.c b/net/ipv4/ipvs/ip_vs_sync.c
index 6a84c41..035ddf5 100644
--- a/net/ipv4/ipvs/ip_vs_sync.c
+++ b/net/ipv4/ipvs/ip_vs_sync.c
@@ -29,6 +29,7 @@
 #include <linux/in.h>
 #include <linux/igmp.h>                 /* for ip_mc_join_group */
 #include <linux/udp.h>
+#include <linux/err.h>
 
 #include <net/ip.h>
 #include <net/sock.h>
@@ -578,14 +579,17 @@ 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;
 	}
@@ -593,14 +597,15 @@ 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;
 	}
@@ -609,7 +614,7 @@ static struct socket * make_send_sock(void)
 
   error:
 	sock_release(sock);
-	return NULL;
+	return ERR_PTR(result);
 }
 
 
@@ -619,27 +624,30 @@ 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;
 	}
@@ -648,7 +656,7 @@ static struct socket * make_receive_sock(void)
 
   error:
 	sock_release(sock);
-	return NULL;
+	return ERR_PTR(result);
 }
 
 
@@ -721,7 +729,7 @@ static void sync_master_loop(void)
 
 	/* create the sending multicast socket */
 	sock = make_send_sock();
-	if (!sock)
+	if (IS_ERR(sock))
 		return;
 
 	IP_VS_INFO("sync thread started: state = MASTER, mcast_ifn = %s, "
@@ -774,7 +782,7 @@ static void sync_backup_loop(void)
 
 	/* create the receiving multicast socket */
 	sock = make_receive_sock();
-	if (!sock)
+	if (IS_ERR(sock))
 		goto out;
 
 	IP_VS_INFO("sync thread started: state = BACKUP, mcast_ifn = %s, "
-- 
1.5.6.1

[PATCH 3/5] ipvs: Use kthread_run() instead of doing a double-fork via kernel_thread()

[Sven Wegener]

This also moves the setup code out of the daemons, so that we're able to
return proper error codes to user space. The current code will return success
to user space when the daemon is started with an invald mcast interface. With
these changes we get an appropriate "No such device" error.

We longer need our own completion to be sure the daemons are actually running,
because they no longer contain code that can fail and kthread_run() takes care
of the rest.

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
---
 net/ipv4/ipvs/ip_vs_sync.c |  369 ++++++++++++++++----------------------------
 1 files changed, 136 insertions(+), 233 deletions(-)

diff --git a/net/ipv4/ipvs/ip_vs_sync.c b/net/ipv4/ipvs/ip_vs_sync.c
index 035ddf5..26d58a6 100644
--- a/net/ipv4/ipvs/ip_vs_sync.c
+++ b/net/ipv4/ipvs/ip_vs_sync.c
@@ -30,10 +30,10 @@
 #include <linux/igmp.h>                 /* for ip_mc_join_group */
 #include <linux/udp.h>
 #include <linux/err.h>
+#include <linux/kthread.h>
 
 #include <net/ip.h>
 #include <net/sock.h>
-#include <asm/uaccess.h>                /* for get_fs and set_fs */
 
 #include <net/ip_vs.h>
 
@@ -69,8 +69,8 @@ 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))
@@ -141,6 +141,10 @@ 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];
 
+/* 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,
@@ -149,14 +153,7 @@ static struct sockaddr_in mcast_addr = {
 };
 
 
-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;
 
@@ -200,6 +197,16 @@ 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.
@@ -714,43 +721,28 @@ 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 (IS_ERR(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);
 	}
 
@@ -765,262 +757,173 @@ 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 (IS_ERR(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()) {
+		/* 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;
+	}
 
-	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 */
-
-	/*
-	 * 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 = kmalloc(sizeof(*tinfo), GFP_KERNEL);
+	if (!tinfo)
+		goto outbuf;
 
-	set_sync_pid(state, 0);
-	IP_VS_INFO("sync thread stopped!\n");
+	tinfo->sock = sock;
+	tinfo->buf = buf;
 
-	set_fs(oldmm);
+	task = kthread_run(threadfn, tinfo, name);
+	if (IS_ERR(task)) {
+		result = PTR_ERR(task);
+		goto outtinfo;
+	}
 
-	/* decrease the module use count */
-	ip_vs_use_count_dec();
+	/* mark as active */
+	*realtask = task;
+	ip_vs_sync_state |= state;
 
-	set_stop_sync(state, 0);
-	wake_up(&stop_sync_wait);
+	/* increase the module use count */
+	ip_vs_use_count_inc();
 
-	/*
-	 * we need to free the structure that was allocated
-	 * for us in start_sync_thread
-	 */
-	kfree(tinfo);
 	return 0;
-}
-
-
-static int fork_sync_thread(void *startup)
-{
-	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;
+outtinfo:
+	kfree(tinfo);
+outbuf:
+	kfree(buf);
+outsocket:
+	sock_release(sock);
+out:
+	return result;
 }
 
 
-int start_sync_thread(int state, char *mcast_ifn, __u8 syncid)
+int stop_sync_thread(int state)
 {
-	DECLARE_COMPLETION_ONSTACK(startup);
-	pid_t pid;
-	struct ip_vs_sync_thread_data *tinfo;
-
-	if ((state == IP_VS_STATE_MASTER && sync_master_pid) ||
-	    (state == IP_VS_STATE_BACKUP && sync_backup_pid))
-		return -EEXIST;
-
-	/*
-	 * Note that tinfo will be freed in sync_thread on exit
-	 */
-	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;
-	}
-
-	tinfo->state = state;
-	tinfo->startup = &startup;
+		if (!sync_master_thread)
+			return -ESRCH;
 
-  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_INFO("stopping master sync thread %d ...\n",
+			   task_pid_nr(sync_master_thread));
 
-	wait_for_completion(&startup);
-
-	return 0;
-}
-
-
-int stop_sync_thread(int state)
-{
-	DECLARE_WAITQUEUE(wait, current);
+		/*
+		 * 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.
+		 */
 
-	if ((state == IP_VS_STATE_MASTER && !sync_master_pid) ||
-	    (state == IP_VS_STATE_BACKUP && !sync_backup_pid))
-		return -ESRCH;
+		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;
+
+		IP_VS_INFO("stopping backup sync thread %d ...\n",
+			   task_pid_nr(sync_backup_thread));
+
+		ip_vs_sync_state &= ~IP_VS_STATE_BACKUP;
+		kthread_stop(sync_backup_thread);
+		sync_backup_thread = NULL;
+	} else {
+		return -EINVAL;
+	}
 
-	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;
 }
-- 
1.5.6.1

[PATCH 4/5] ipvs: Put backup thread on mcast socket wait queue

[Sven Wegener]

Instead of doing an endless loop with sleeping for one second, we now put the
backup thread onto the mcast socket wait queue and it gets woken up as soon as
we have data to process.

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
---
 net/ipv4/ipvs/ip_vs_sync.c |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/ipvs/ip_vs_sync.c b/net/ipv4/ipvs/ip_vs_sync.c
index 26d58a6..fa49c24 100644
--- a/net/ipv4/ipvs/ip_vs_sync.c
+++ b/net/ipv4/ipvs/ip_vs_sync.c
@@ -31,6 +31,7 @@
 #include <linux/udp.h>
 #include <linux/err.h>
 #include <linux/kthread.h>
+#include <linux/wait.h>
 
 #include <net/ip.h>
 #include <net/sock.h>
@@ -774,6 +775,10 @@ static int sync_thread_backup(void *data)
 		   ip_vs_backup_mcast_ifn, ip_vs_backup_syncid);
 
 	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,
@@ -789,8 +794,6 @@ static int sync_thread_backup(void *data)
 			ip_vs_process_message(tinfo->buf, len);
 			local_bh_enable();
 		}
-
-		msleep_interruptible(1000);
 	}
 
 	/* release the sending multicast socket */
-- 
1.5.6.1

[PATCH 5/5] ipvs: Use schedule_timeout_interruptible() instead of msleep_interruptible()

[Sven Wegener]

So that kthread_stop() can wake up the thread and we don't have to wait one
second in the worst case for the daemon to actually stop.

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
---
 net/ipv4/ipvs/ip_vs_sync.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/net/ipv4/ipvs/ip_vs_sync.c b/net/ipv4/ipvs/ip_vs_sync.c
index fa49c24..259e611 100644
--- a/net/ipv4/ipvs/ip_vs_sync.c
+++ b/net/ipv4/ipvs/ip_vs_sync.c
@@ -744,7 +744,7 @@ static int sync_thread_master(void *data)
 			ip_vs_sync_buff_release(sb);
 		}
 
-		msleep_interruptible(1000);
+		schedule_timeout_interruptible(HZ);
 	}
 
 	/* clean up the sync_buff queue */
-- 
1.5.6.1

Re: [PATCHv2] ipvs: Cleanup sync daemon code

[Simon Horman]

On Sun, Jun 29, 2008 at 07:32:41PM +0200, Sven Wegener wrote:
> It's been a while since my last post of this patch series, but here we go gain.
> 
> Changes since last post:
> - Dropped the master daemon sleep change for now, that needs some more work.
> - Splitted up the patch into a couple of logical chunks.
> 
> The patches are
> 
> Sven Wegener (5):
>       ipvs: Initialize mcast addr at compile time
>       ipvs: Use ERR_PTR for returning errors from make_receive_sock() and make_send_sock()
>       ipvs: Use kthread_run() instead of doing a double-fork via kernel_thread()
>       ipvs: Put backup thread on mcast socket wait queue
>       ipvs: Use schedule_timeout_interruptible() instead of msleep_interruptible()
> 
> The overall difstat looks like
> 
>  ip_vs_sync.c |  431 +++++++++++++++++++++++------------------------------------
>   1 file changed, 172 insertions(+), 259 deletions(-)
> 
> The patches are based on v2.6.26-rc8. If someone wants to pull them, that can
> be done from
> 
> git://git.stealer.net/linux-2.6.git stealer/ipvs/sync-daemon-cleanup

These patches look good to me.

-- 
Horms

Re: [PATCHv2] ipvs: Cleanup sync daemon code

[Sven Wegener]

On Mon, 30 Jun 2008, Simon Horman wrote:

> On Sun, Jun 29, 2008 at 07:32:41PM +0200, Sven Wegener wrote:
> > It's been a while since my last post of this patch series, but here we go gain.
> > 
> > Changes since last post:
> > - Dropped the master daemon sleep change for now, that needs some more work.
> > - Splitted up the patch into a couple of logical chunks.
> > 
> > The patches are
> > 
> > Sven Wegener (5):
> >       ipvs: Initialize mcast addr at compile time
> >       ipvs: Use ERR_PTR for returning errors from make_receive_sock() and make_send_sock()
> >       ipvs: Use kthread_run() instead of doing a double-fork via kernel_thread()
> >       ipvs: Put backup thread on mcast socket wait queue
> >       ipvs: Use schedule_timeout_interruptible() instead of msleep_interruptible()
> > 
> > The overall difstat looks like
> > 
> >  ip_vs_sync.c |  431 +++++++++++++++++++++++------------------------------------
> >   1 file changed, 172 insertions(+), 259 deletions(-)
> > 
> > The patches are based on v2.6.26-rc8. If someone wants to pull them, that can
> > be done from
> > 
> > git://git.stealer.net/linux-2.6.git stealer/ipvs/sync-daemon-cleanup
> 
> These patches look good to me.

So, who is going to take these patches? I expect them to go through 
davem's net-next tree, so I've rebased them onto his tree and appended 
your acked-by. The hton -> __constant_hton change is included.

The changes 0b57664..375c6bb are available at

git://git.stealer.net/linux-2.6.git stealer/ipvs/sync-daemon-cleanup-for-next

Sven

Re: [PATCHv2] ipvs: Cleanup sync daemon code

[Simon Horman]

On Thu, Jul 17, 2008 at 01:33:44AM +0200, Sven Wegener wrote:
> On Mon, 30 Jun 2008, Simon Horman wrote:
> 
> > On Sun, Jun 29, 2008 at 07:32:41PM +0200, Sven Wegener wrote:
> > > It's been a while since my last post of this patch series, but here we go gain.
> > > 
> > > Changes since last post:
> > > - Dropped the master daemon sleep change for now, that needs some more work.
> > > - Splitted up the patch into a couple of logical chunks.
> > > 
> > > The patches are
> > > 
> > > Sven Wegener (5):
> > >       ipvs: Initialize mcast addr at compile time
> > >       ipvs: Use ERR_PTR for returning errors from make_receive_sock() and make_send_sock()
> > >       ipvs: Use kthread_run() instead of doing a double-fork via kernel_thread()
> > >       ipvs: Put backup thread on mcast socket wait queue
> > >       ipvs: Use schedule_timeout_interruptible() instead of msleep_interruptible()
> > > 
> > > The overall difstat looks like
> > > 
> > >  ip_vs_sync.c |  431 +++++++++++++++++++++++------------------------------------
> > >   1 file changed, 172 insertions(+), 259 deletions(-)
> > > 
> > > The patches are based on v2.6.26-rc8. If someone wants to pull them, that can
> > > be done from
> > > 
> > > git://git.stealer.net/linux-2.6.git stealer/ipvs/sync-daemon-cleanup
> > 
> > These patches look good to me.
> 
> So, who is going to take these patches? I expect them to go through 
> davem's net-next tree, so I've rebased them onto his tree and appended 
> your acked-by. The hton -> __constant_hton change is included.
> 
> The changes 0b57664..375c6bb are available at
> 
> git://git.stealer.net/linux-2.6.git stealer/ipvs/sync-daemon-cleanup-for-next

Thanks, verified, they look good to me :-)

Dave, is there anything I can do to make merging these patches easier for you?

-- 
Horms

Re: [PATCHv2] ipvs: Cleanup sync daemon code

[David Miller]

From: Simon Horman <horms@verge.net.au>
Date: Thu, 17 Jul 2008 12:48:50 +1000

> Dave, is there anything I can do to make merging these patches easier for you?

I can take care of it directly, thanks Simon.

Re: [PATCHv2] ipvs: Cleanup sync daemon code

[David Miller]

From: Sven Wegener <sven.wegener@stealer.net>
Date: Thu, 17 Jul 2008 01:33:44 +0200 (CEST)

> The changes 0b57664..375c6bb are available at
> 
> git://git.stealer.net/linux-2.6.git stealer/ipvs/sync-daemon-cleanup-for-next

Pulled, thanks.