[PATCH V2 5/5] panic: add note that panic_print interface is deprecated

[Feng Tang <feng.tang@linux.alibaba.com>]

Long term wise, the 'panic_sys_info' should be the only controlling
interface, which can be referred by other modules.

Suggested-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Feng Tang <feng.tang@linux.alibaba.com>
---
 kernel/panic.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/kernel/panic.c b/kernel/panic.c
index ea238f7d4b54..e8a05fc6b733 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -76,6 +76,13 @@ ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
 EXPORT_SYMBOL(panic_notifier_list);
 
 #ifdef CONFIG_SYSCTL
+static int sysctl_panic_print_handler(const struct ctl_table *table, int write,
+			   void *buffer, size_t *lenp, loff_t *ppos)
+{
+	printk_once("panic: 'panic_print' sysctl interface will be obsoleted by 'panic_sys_info' interface.\n");
+	return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
+}
+
 static const struct ctl_table kern_panic_table[] = {
 #ifdef CONFIG_SMP
 	{
@@ -107,7 +114,7 @@ static const struct ctl_table kern_panic_table[] = {
 		.data		= &panic_print,
 		.maxlen		= sizeof(unsigned long),
 		.mode		= 0644,
-		.proc_handler	= proc_doulongvec_minmax,
+		.proc_handler	= sysctl_panic_print_handler,
 	},
 	{
 		.procname	= "panic_on_warn",
-- 
2.39.5 (Apple Git-154)