linux-kernel - [PATCH 08/10] printk: Detect scheduler messages in vprintk_format_and

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Date:	Mon, 25 May 2015 14:46:31 +0200
From:	Petr Mladek <pmladek@...e.cz>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Frederic Weisbecker <fweisbec@...il.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Dave Anderson <anderson@...hat.com>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Kay Sievers <kay@...y.org>, Jiri Kosina <jkosina@...e.cz>,
	Michal Hocko <mhocko@...e.cz>, Jan Kara <jack@...e.cz>,
	linux-kernel@...r.kernel.org, Wang Long <long.wanglong@...wei.com>,
	peifeiyue@...wei.com, dzickus@...hat.com, morgan.wang@...wei.com,
	sasha.levin@...cle.com, Petr Mladek <pmladek@...e.cz>
Subject: [PATCH 08/10] printk: Detect scheduler messages in vprintk_format_and_analyze()

The special hack for messages printed by the scheduler belongs to
the new vprintk_format_and_analyze().

This patch just shuffles the code. There is no change in
the functionality.

Signed-off-by: Petr Mladek <pmladek@...e.cz>
---
 kernel/printk/printk.c | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 7d009144f97f..6e53b6f60ca3 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1747,15 +1747,16 @@ static int vprintk_delayed_warnings(void)
  * @dict: pointer to the message dictionary
  * @facility: syslog facility
  * @level: syslog level; might be replaced by the one found in the fomatted text
+ * @in_sched: is set to true when the message is printed by the scheduler
  * @ftext: pointer to the formatted text after the syslog prefix
  * @ftext_len: length of the formatted text without the syslog prefix
  *
  * This function modifies the global textbuf and therefore it must be called
  * under lockbuf_lock!
  */
-static enum log_flags vprinkt_format_and_analyze(const char *fmt, va_list args,
+static enum log_flags vprintk_format_and_analyze(const char *fmt, va_list args,
 						 const char *dict, int facility,
-						 int *level,
+						 int *level, bool *in_sched,
 						 char **ftext,
 						 size_t *ftext_len)
 {
@@ -1775,6 +1776,15 @@ static enum log_flags vprinkt_format_and_analyze(const char *fmt, va_list args,
 		lflags |= LOG_NEWLINE;
 	}
 
+	/*
+	 * Messages printed by the scheduler must not wake up the console.
+	 * They are detected via a special @level, see printk_deferred().
+	 */
+	if (*level == LOGLEVEL_SCHED) {
+		*level = LOGLEVEL_DEFAULT;
+		*in_sched = true;
+	}
+
 	/* strip kernel syslog prefix and extract log level or control flags */
 	if (facility == 0) {
 		int kern_level = printk_get_level(text);
@@ -1824,11 +1834,6 @@ asmlinkage int vprintk_emit(int facility, int level,
 	int printed_len = 0;
 	bool in_sched = false;
 
-	if (level == LOGLEVEL_SCHED) {
-		level = LOGLEVEL_DEFAULT;
-		in_sched = true;
-	}
-
 	boot_delay_msec(level);
 	printk_delay();
 
@@ -1880,8 +1885,8 @@ asmlinkage int vprintk_emit(int facility, int level,
 
 	printed_len += vprintk_delayed_warnings();
 
-	lflags = vprinkt_format_and_analyze(fmt, args, dict, facility,
-					    &level,
+	lflags = vprintk_format_and_analyze(fmt, args, dict, facility,
+					    &level, &in_sched,
 					    &text, &text_len);
 
 	if (!(lflags & LOG_NEWLINE)) {
-- 
1.8.5.6

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