[ATM]: Clip timer race.

By inspection, the clip idle timer code is racy on SMP.
Here is a safe version of timer management.
Untested, I don't have ATM hardware.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 11 deletions

diff --git a/net/atm/clip.c b/net/atm/clip.c
index 5841c30384a..b1f12f6c5fd 100644
--- a/net/atm/clip.c
+++ b/net/atm/clip.c
@@ -54,8 +54,6 @@ static struct net_device *clip_devs;
 static struct atm_vcc *atmarpd;
 static struct neigh_table clip_tbl;
 static struct timer_list idle_timer;
-static int start_timer = 1;
-
 
 static int to_atmarpd(enum atmarp_ctrl_type type,int itf,unsigned long ip)
 {
@@ -725,13 +723,8 @@ static int atm_init_atmarp(struct atm_vcc *vcc)
                 return -EADDRINUSE;
         }
 
-        if (start_timer) {
-                start_timer = 0;
-                init_timer(&idle_timer);
-                idle_timer.expires = jiffies+CLIP_CHECK_INTERVAL*HZ;
-                idle_timer.function = idle_timer_check;
-                add_timer(&idle_timer);
-        }
+        mod_timer(&idle_timer, jiffies+CLIP_CHECK_INTERVAL*HZ);
+
         atmarpd = vcc;
         set_bit(ATM_VF_META,&vcc->flags);
         set_bit(ATM_VF_READY,&vcc->flags);
@@ -1002,6 +995,8 @@ static int __init atm_clip_init(void)
         register_netdevice_notifier(&clip_dev_notifier);
         register_inetaddr_notifier(&clip_inet_notifier);
 
+        setup_timer(&idle_timer, idle_timer_check, 0);
+
 #ifdef CONFIG_PROC_FS
 {
         struct proc_dir_entry *p;
@@ -1029,8 +1024,7 @@ static void __exit atm_clip_exit(void)
         /* First, stop the idle timer, so it stops banging
          * on the table.
          */
-        if (start_timer == 0)
-                del_timer(&idle_timer);
+        del_timer_sync(&idle_timer);
 
         /* Next, purge the table, so that the device
          * unregister loop below does not hang due to