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authorRalf Baechle <ralf@linux-mips.org>2000-06-19 22:45:37 +0000
committerRalf Baechle <ralf@linux-mips.org>2000-06-19 22:45:37 +0000
commit6d403070f28cd44860fdb3a53be5da0275c65cf4 (patch)
tree0d0e7fe7b5fb7568d19e11d7d862b77a866ce081 /kernel/sys.c
parentecf1bf5f6c2e668d03b0a9fb026db7aa41e292e1 (diff)
Merge with 2.4.0-test1-ac21 + pile of MIPS cleanups to make merging
possible. Chainsawed RM200 kernel to compile again. Jazz machine status unknown.
Diffstat (limited to 'kernel/sys.c')
-rw-r--r--kernel/sys.c120
1 files changed, 119 insertions, 1 deletions
diff --git a/kernel/sys.c b/kernel/sys.c
index 0c78f80b4..8bd07d55f 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -4,6 +4,7 @@
* Copyright (C) 1991, 1992 Linus Torvalds
*/
+#include <linux/module.h>
#include <linux/mm.h>
#include <linux/utsname.h>
#include <linux/mman.h>
@@ -46,13 +47,123 @@ int C_A_D = 1;
* and the like.
*/
-struct notifier_block *reboot_notifier_list = NULL;
+static struct notifier_block *reboot_notifier_list = NULL;
+rwlock_t notifier_lock = RW_LOCK_UNLOCKED;
+/**
+ * notifier_chain_register - Add notifier to a notifier chain
+ * @list: Pointer to root list pointer
+ * @n: New entry in notifier chain
+ *
+ * Adds a notifier to a notifier chain.
+ *
+ * Currently always returns zero.
+ */
+
+int notifier_chain_register(struct notifier_block **list, struct notifier_block *n)
+{
+ write_lock(&notifier_lock);
+ while(*list)
+ {
+ if(n->priority > (*list)->priority)
+ break;
+ list= &((*list)->next);
+ }
+ n->next = *list;
+ *list=n;
+ write_unlock(&notifier_lock);
+ return 0;
+}
+
+/**
+ * notifier_chain_unregister - Remove notifier from a notifier chain
+ * @nl: Pointer to root list pointer
+ * @n: New entry in notifier chain
+ *
+ * Removes a notifier from a notifier chain.
+ *
+ * Returns zero on success, or %-ENOENT on failure.
+ */
+
+int notifier_chain_unregister(struct notifier_block **nl, struct notifier_block *n)
+{
+ write_lock(&notifier_lock);
+ while((*nl)!=NULL)
+ {
+ if((*nl)==n)
+ {
+ *nl=n->next;
+ write_unlock(&notifier_lock);
+ return 0;
+ }
+ nl=&((*nl)->next);
+ }
+ write_unlock(&notifier_lock);
+ return -ENOENT;
+}
+
+/**
+ * notifier_call_chain - Call functions in a notifier chain
+ * @n: Pointer to root pointer of notifier chain
+ * @val: Value passed unmodified to notifier function
+ * @v: Pointer passed unmodified to notifier function
+ *
+ * Calls each function in a notifier chain in turn.
+ *
+ * If the return value of the notifier can be and'd
+ * with %NOTIFY_STOP_MASK, then notifier_call_chain
+ * will return immediately, with the return value of
+ * the notifier function which halted execution.
+ * Otherwise, the return value is the return value
+ * of the last notifier function called.
+ */
+
+int notifier_call_chain(struct notifier_block **n, unsigned long val, void *v)
+{
+ int ret=NOTIFY_DONE;
+ struct notifier_block *nb = *n;
+
+ read_lock(&notifier_lock);
+ while(nb)
+ {
+ ret=nb->notifier_call(nb,val,v);
+ if(ret&NOTIFY_STOP_MASK)
+ {
+ read_unlock(&notifier_lock);
+ return ret;
+ }
+ nb=nb->next;
+ }
+ read_unlock(&notifier_lock);
+ return ret;
+}
+
+/**
+ * register_reboot_notifier - Register function to be called at reboot time
+ * @nb: Info about notifier function to be called
+ *
+ * Registers a function with the list of functions
+ * to be called at reboot time.
+ *
+ * Currently always returns zero, as notifier_chain_register
+ * always returns zero.
+ */
+
int register_reboot_notifier(struct notifier_block * nb)
{
return notifier_chain_register(&reboot_notifier_list, nb);
}
+/**
+ * unregister_reboot_notifier - Unregister previously registered reboot notifier
+ * @nb: Hook to be unregistered
+ *
+ * Unregisters a previously registered reboot
+ * notifier function.
+ *
+ * Returns zero on success, or %-ENOENT on failure.
+ */
+
int unregister_reboot_notifier(struct notifier_block * nb)
{
return notifier_chain_unregister(&reboot_notifier_list, nb);
@@ -1109,3 +1220,10 @@ asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
return error;
}
+EXPORT_SYMBOL(notifier_chain_register);
+EXPORT_SYMBOL(notifier_chain_unregister);
+EXPORT_SYMBOL(notifier_call_chain);
+EXPORT_SYMBOL(register_reboot_notifier);
+EXPORT_SYMBOL(unregister_reboot_notifier);
+EXPORT_SYMBOL(in_group_p);
+EXPORT_SYMBOL(in_egroup_p);