[ATM]: deregistration removes device from atm_devs list immediately

atm_dev_deregister() removes device from atm_dev list immediately to
prevent operations on a phantom device.  Decision to free device based
only on ->refcnt  now. Remove shutdown_atm_dev() use atm_dev_deregister()
instead.  atm_dev_deregister() also asynchronously releases all vccs
related to device.

Signed-off-by: Stanislaw Gruszka <stf_xl@wp.pl>
Signed-off-by: Chas Williams <chas@cmf.nrl.navy.mil>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 12 insertions, 27 deletions

diff --git a/net/atm/resources.c b/net/atm/resources.c
index ad533b02b84f..c8c459fcb038 100644
--- a/net/atm/resources.c
+++ b/net/atm/resources.c
@@ -70,6 +70,7 @@ struct atm_dev *atm_dev_lookup(int number)
         return dev;
 }
 
+
 struct atm_dev *atm_dev_register(const char *type, const struct atmdev_ops *ops,
                                  int number, unsigned long *flags)
 {
@@ -123,37 +124,22 @@ struct atm_dev *atm_dev_register(const char *type, const struct atmdev_ops *ops,
 
 void atm_dev_deregister(struct atm_dev *dev)
 {
-        unsigned long warning_time;
-
-        atm_proc_dev_deregister(dev);
-
+        BUG_ON(test_bit(ATM_DF_REMOVED, &dev->flags));
+        set_bit(ATM_DF_REMOVED, &dev->flags);
+
+        /*
+         * if we remove current device from atm_devs list, new device 
+         * with same number can appear, such we need deregister proc, 
+         * release async all vccs and remove them from vccs list too
+         */
         down(&atm_dev_mutex);
         list_del(&dev->dev_list);
         up(&atm_dev_mutex);
 
-        warning_time = jiffies;
-        while (atomic_read(&dev->refcnt) != 1) {
-                msleep(250);
-                if ((jiffies - warning_time) > 10 * HZ) {
-                        printk(KERN_EMERG "atm_dev_deregister: waiting for "
-                               "dev %d to become free. Usage count = %d\n",
-                               dev->number, atomic_read(&dev->refcnt));
-                        warning_time = jiffies;
-                }
-        }
-
-        kfree(dev);
-}
+        atm_dev_release_vccs(dev);
+        atm_proc_dev_deregister(dev);
 
-void shutdown_atm_dev(struct atm_dev *dev)
-{
-        if (atomic_read(&dev->refcnt) > 1) {
-                set_bit(ATM_DF_CLOSE, &dev->flags);
-                return;
-        }
-        if (dev->ops->dev_close)
-                dev->ops->dev_close(dev);
-        atm_dev_deregister(dev);
+        atm_dev_put(dev);
 }
 
 
@@ -433,4 +419,3 @@ void *atm_dev_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 EXPORT_SYMBOL(atm_dev_register);
 EXPORT_SYMBOL(atm_dev_deregister);
 EXPORT_SYMBOL(atm_dev_lookup);
-EXPORT_SYMBOL(shutdown_atm_dev);