linux-kernel - [PATCH 2/4] printk/kdb: Handle more message headers

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Date:   Thu, 27 Oct 2016 17:52:52 +0200
From:   Petr Mladek <pmladek@...e.com>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     Joe Perches <joe@...ches.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Jason Wessel <jason.wessel@...driver.com>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>, Chris Mason <clm@...com>,
        Josef Bacik <jbacik@...com>, David Sterba <dsterba@...e.com>,
        linux-kernel@...r.kernel.org, Petr Mladek <pmladek@...e.com>
Subject: [PATCH 2/4] printk/kdb: Handle more message headers

The commit 4bcc595ccd80decb4245096e ("printk: reinstate KERN_CONT for
printing continuation lines") allows to define more message headers
for a single message. The motivation is that continuous lines might
get mixed. Therefore it make sense to define the right log level
for every piece of a cont line.

This patch introduces printk_skip_headers() that will skip all
headers and uses it in the kdb code instead of printk_skip_level().

This approach helps to fix other printk_skip_level() users
independently.

Signed-off-by: Petr Mladek <pmladek@...e.com>
---
 include/linux/printk.h    | 8 ++++++++
 kernel/debug/kdb/kdb_io.c | 2 +-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/include/linux/printk.h b/include/linux/printk.h
index 6fdced13d2c9..ebe8918a1f0f 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -31,6 +31,14 @@ static inline const char *printk_skip_level(const char *buffer)
 	return buffer;
 }
 
+static inline const char *printk_skip_headers(const char *buffer)
+{
+	while (printk_get_level(buffer))
+		buffer += 2;
+
+	return buffer;
+}
+
 #define PRINTK_POKE_CONSOLE	0x01
 #define PRINTK_POKE_LOGGERS	0x02
 
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index fc1ef736253c..98c9011eac78 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -697,7 +697,7 @@ int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap)
 	 * Write to all consoles.
 	 */
 	retlen = strlen(kdb_buffer);
-	cp = (char *) printk_skip_level(kdb_buffer);
+	cp = (char *) printk_skip_headers(kdb_buffer);
 	if (!dbg_kdb_mode && kgdb_connected) {
 		gdbstub_msg_write(cp, retlen - (cp - kdb_buffer));
 	} else {
-- 
1.8.5.6