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From: Petr Mladek <pmladek@suse.com>
To: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
	Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
	linux-kernel@vger.kernel.org, stable@vger.kernel.org,
	Petr Mladek <pmladek@suse.com>
Subject: [PATCH v2 1/3] printk: Split the code for storing a message into the log buffer
Date: Wed, 27 Jun 2018 16:08:15 +0200	[thread overview]
Message-ID: <20180627140817.27764-2-pmladek@suse.com> (raw)
In-Reply-To: <20180627140817.27764-1-pmladek@suse.com>

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

Signed-off-by: Petr Mladek <pmladek@suse.com>
---
 kernel/printk/printk.c | 43 ++++++++++++++++++++++++++-----------------
 1 file changed, 26 insertions(+), 17 deletions(-)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 247808333ba4..a844c611b17c 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1824,28 +1824,16 @@ static size_t log_output(int facility, int level, enum log_flags lflags, const c
 	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, int level,
 	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(). */
-- 
2.13.7


  reply	other threads:[~2018-06-27 14:08 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-27 14:08 [PATCH v2 0/3] printk: Deadlock in NMI regression Petr Mladek
2018-06-27 14:08 ` Petr Mladek [this message]
2018-06-28  2:10   ` [PATCH v2 1/3] printk: Split the code for storing a message into the log buffer Sergey Senozhatsky
2018-06-27 14:08 ` [PATCH v2 2/3] printk: Create helper function to queue deferred console handling Petr Mladek
2018-06-28  2:16   ` Sergey Senozhatsky
2018-06-28  2:19     ` Sergey Senozhatsky
2018-06-27 14:16 ` [PATCH v2 0/3] printk: Deadlock in NMI regression Sergey Senozhatsky
2018-06-27 14:23   ` Sergey Senozhatsky
2018-06-27 14:34   ` Petr Mladek
2018-06-28  9:08     ` Sergey Senozhatsky
2018-06-27 14:20 ` [PATCH v2 3/3] printk/nmi: Prevent deadlock when accessing the main log buffer in NMI Petr Mladek
2018-06-28  2:25   ` Sergey Senozhatsky
2018-06-28  9:41     ` Petr Mladek
2018-06-29  1:47       ` Sergey Senozhatsky
2018-06-29  7:25         ` Petr Mladek
2018-06-29 10:01           ` Sergey Senozhatsky
2018-06-28  2:39 ` [PATCH v2 0/3] printk: Deadlock in NMI regression Sergey Senozhatsky
2018-06-28 10:54   ` Petr Mladek
2018-06-29  1:52     ` Sergey Senozhatsky
2018-07-09 13:27 ` Petr Mladek

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