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

1 files changed, 172 insertions, 259 deletions

diff --git a/net/ipv4/ipvs/ip_vs_sync.c b/net/ipv4/ipvs/ip_vs_sync.c
index 2d4a86f73325..45e9bd96c286 100644
--- a/net/ipv4/ipvs/ip_vs_sync.c
+++ b/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 */
-
-        /*
-         * 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;
-
-  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;
-        }
-
-        wait_for_completion(&startup);
-
-        return 0;
-}
+                if (!sync_master_thread)
+                        return -ESRCH;
 
+                IP_VS_INFO("stopping master sync thread %d ...\n",
+                           task_pid_nr(sync_master_thread));
 
-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;
 }