[PATCH RESEND] panic: Add register_panic_notifier and unregister_panic_notifier

[Xu Qiang]

Add two methods to manipulate panic_notifier_list and export them.
Subsequently, panic_notifier_list is changed to static variable.

Signed-off-by: Xu Qiang <xuqiang36@xxxxxxxxxx>
---
 include/linux/panic_notifier.h |  3 +++
 kernel/panic.c                 | 12 ++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/include/linux/panic_notifier.h b/include/linux/panic_notifier.h
index 41e32483d7a7..9543d498b90b 100644
--- a/include/linux/panic_notifier.h
+++ b/include/linux/panic_notifier.h
@@ -5,6 +5,9 @@
 #include <linux/notifier.h>
 #include <linux/types.h>
 
+int register_panic_notifier(struct notifier_block *nb);
+int unregister_panic_notifier(struct notifier_block *nb);
+
 extern struct atomic_notifier_head panic_notifier_list;
 
 extern bool crash_kexec_post_notifiers;
diff --git a/kernel/panic.c b/kernel/panic.c
index 75fe389e8814..8f34dbd389cf 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -200,6 +200,18 @@ static void panic_print_sys_info(bool console_flush)
 		ftrace_dump(DUMP_ALL);
 }
 
+int register_panic_notifier(struct notifier_block *nb)
+{
+	return atomic_notifier_chain_register(&panic_notifier_list, nb);
+}
+EXPORT_SYMBOL(register_panic_notifier);
+
+int unregister_panic_notifier(struct notifier_block *nb)
+{
+	return atomic_notifier_chain_unregister(&panic_notifier_list, nb);
+}
+EXPORT_SYMBOL(unregister_panic_notifier);
+
 /**
  *	panic - halt the system
  *	@fmt: The text string to print
-- 
2.17.1