[PATCH 4.18 026/123] printk: Create helper function to queue deferred console handling

[Greg Kroah-Hartman]

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Petr Mladek <pmladek@xxxxxxxx>

commit a338f84dc196f44b63ba0863d2f34fd9b1613572 upstream.

It is just a preparation step. The patch does not change
the existing behavior.

Link: http://lkml.kernel.org/r/20180627140817.27764-3-pmladek@xxxxxxxx
To: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@xxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Signed-off-by: Petr Mladek <pmladek@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 kernel/printk/printk.c |   14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2887,16 +2887,20 @@ void wake_up_klogd(void)
 	preempt_enable();
 }
 
-int vprintk_deferred(const char *fmt, va_list args)
+void defer_console_output(void)
 {
-	int r;
-
-	r = vprintk_emit(0, LOGLEVEL_SCHED, NULL, 0, fmt, args);
-
 	preempt_disable();
 	__this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT);
 	irq_work_queue(this_cpu_ptr(&wake_up_klogd_work));
 	preempt_enable();
+}
+
+int vprintk_deferred(const char *fmt, va_list args)
+{
+	int r;
+
+	r = vprintk_emit(0, LOGLEVEL_SCHED, NULL, 0, fmt, args);
+	defer_console_output();
 
 	return r;
 }