[PATCH 4.18 025/123] printk: Split the code for storing a message into the log buffer

[Greg Kroah-Hartman]

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

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

From: Petr Mladek <pmladek@xxxxxxxx>

commit ba552399954dde1b388f7749fecad5c349216981 upstream.

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

Link: http://lkml.kernel.org/r/20180627140817.27764-2-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 |   43 ++++++++++++++++++++++++++-----------------
 1 file changed, 26 insertions(+), 17 deletions(-)

--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1824,28 +1824,16 @@ static size_t log_output(int facility, i
 	return log_store(facility, level, lflags, 0, dict, dictlen, text, text_len);
 }
 
-asmlinkage int vprintk_emit(int facility, int level,
-			    const char *dict, size_t dictlen,
-			    const char *fmt, va_list args)
+/* Must be called under logbuf_lock. */
+int vprintk_store(int facility, int level,
+		  const char *dict, size_t dictlen,
+		  const char *fmt, va_list args)
 {
 	static char textbuf[LOG_LINE_MAX];
 	char *text = textbuf;
 	size_t text_len;
 	enum log_flags lflags = 0;
-	unsigned long flags;
-	int printed_len;
-	bool in_sched = false;
-
-	if (level == LOGLEVEL_SCHED) {
-		level = LOGLEVEL_DEFAULT;
-		in_sched = true;
-	}
-
-	boot_delay_msec(level);
-	printk_delay();
 
-	/* This stops the holder of console_sem just where we want him */
-	logbuf_lock_irqsave(flags);
 	/*
 	 * The printf needs to come first; we need the syslog
 	 * prefix which might be passed-in as a parameter.
@@ -1886,8 +1874,29 @@ asmlinkage int vprintk_emit(int facility
 	if (dict)
 		lflags |= LOG_PREFIX|LOG_NEWLINE;
 
-	printed_len = log_output(facility, level, lflags, dict, dictlen, text, text_len);
+	return log_output(facility, level, lflags,
+			  dict, dictlen, text, text_len);
+}
 
+asmlinkage int vprintk_emit(int facility, int level,
+			    const char *dict, size_t dictlen,
+			    const char *fmt, va_list args)
+{
+	int printed_len;
+	bool in_sched = false;
+	unsigned long flags;
+
+	if (level == LOGLEVEL_SCHED) {
+		level = LOGLEVEL_DEFAULT;
+		in_sched = true;
+	}
+
+	boot_delay_msec(level);
+	printk_delay();
+
+	/* This stops the holder of console_sem just where we want him */
+	logbuf_lock_irqsave(flags);
+	printed_len = vprintk_store(facility, level, dict, dictlen, fmt, args);
 	logbuf_unlock_irqrestore(flags);
 
 	/* If called from the scheduler, we can not call up(). */