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

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Date:   Thu, 27 Oct 2016 17:52:54 +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 4/4] printk/sound: 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 tries to copy the entire header. Well, it limits it
to 4 bytes because it does not make sense to combine more message
headers except for KERN_CONT and some real level.

Signed-off-by: Petr Mladek <pmladek@...e.com>
---
 sound/core/misc.c | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/sound/core/misc.c b/sound/core/misc.c
index f2e8226c88fb..52b719cc875d 100644
--- a/sound/core/misc.c
+++ b/sound/core/misc.c
@@ -68,9 +68,10 @@ void __snd_printk(unsigned int level, const char *path, int line,
 {
 	va_list args;
 #ifdef CONFIG_SND_VERBOSE_PRINTK
-	int kern_level;
 	struct va_format vaf;
-	char verbose_fmt[] = KERN_DEFAULT "ALSA %s:%d %pV";
+	char header[5] = KERN_DEFAULT;
+	const char *end_of_header;
+	size_t size_of_header;
 #endif
 
 #ifdef CONFIG_SND_DEBUG
@@ -83,15 +84,18 @@ void __snd_printk(unsigned int level, const char *path, int line,
 	vaf.fmt = format;
 	vaf.va = &args;
 
-	kern_level = printk_get_level(format);
-	if (kern_level) {
-		const char *end_of_header = printk_skip_level(format);
-		memcpy(verbose_fmt, format, end_of_header - format);
+	end_of_header = printk_skip_headers(format);
+	size_of_header = min((size_t)(end_of_header - format),
+			     sizeof(header) - 1);
+	if (size_of_header) {
+		memcpy(header, format, size_of_header);
+		header[size_of_header] = '\0';
 		vaf.fmt = end_of_header;
-	} else if (level)
-		memcpy(verbose_fmt, KERN_DEBUG, sizeof(KERN_DEBUG) - 1);
-	printk(verbose_fmt, sanity_file_name(path), line, &vaf);
+	} else if (level) {
+		memcpy(header, KERN_DEBUG, sizeof(KERN_DEBUG) - 1);
+	}
 
+	printk("%sALSA %s:%d %pV", header, sanity_file_name(path), line, &vaf);
 #else
 	vprintk(format, args);
 #endif
-- 
1.8.5.6