net: Fix recursive descent in __scm_destroy().

[linux-2.6-omap-h63xx.git] / kernel / notifier.c

diff --git a/kernel/notifier.c b/kernel/notifier.c
index 643360d1bb144fda223301b348059cd5381eb35e..4282c0a40a57ada651b86c7dcce2389abf489448 100644 (file)
--- a/kernel/notifier.c
+++ b/kernel/notifier.c
@@ -31,6 +31,21 @@ static int notifier_chain_register(struct notifier_block **nl,
        return 0;
 }
 
+static int notifier_chain_cond_register(struct notifier_block **nl,
+               struct notifier_block *n)
+{
+       while ((*nl) != NULL) {
+               if ((*nl) == n)
+                       return 0;
+               if (n->priority > (*nl)->priority)
+                       break;
+               nl = &((*nl)->next);
+       }
+       n->next = *nl;
+       rcu_assign_pointer(*nl, n);
+       return 0;
+}
+
 static int notifier_chain_unregister(struct notifier_block **nl,
                struct notifier_block *n)
 {
@@ -204,6 +219,29 @@ int blocking_notifier_chain_register(struct blocking_notifier_head *nh,
 }
 EXPORT_SYMBOL_GPL(blocking_notifier_chain_register);
 
+/**
+ *     blocking_notifier_chain_cond_register - Cond add notifier to a blocking notifier chain
+ *     @nh: Pointer to head of the blocking notifier chain
+ *     @n: New entry in notifier chain
+ *
+ *     Adds a notifier to a blocking notifier chain, only if not already
+ *     present in the chain.
+ *     Must be called in process context.
+ *
+ *     Currently always returns zero.
+ */
+int blocking_notifier_chain_cond_register(struct blocking_notifier_head *nh,
+               struct notifier_block *n)
+{
+       int ret;
+
+       down_write(&nh->rwsem);
+       ret = notifier_chain_cond_register(&nh->head, n);
+       up_write(&nh->rwsem);
+       return ret;
+}
+EXPORT_SYMBOL_GPL(blocking_notifier_chain_cond_register);
+
 /**
  *     blocking_notifier_chain_unregister - Remove notifier from a blocking notifier chain
  *     @nh: Pointer to head of the blocking notifier chain
@@ -512,7 +550,7 @@ EXPORT_SYMBOL(unregister_reboot_notifier);
 
 static ATOMIC_NOTIFIER_HEAD(die_chain);
 
-int notify_die(enum die_val val, const char *str,
+int notrace notify_die(enum die_val val, const char *str,
               struct pt_regs *regs, long err, int trap, int sig)
 {
        struct die_args args = {