lkml.org 
[lkml]   [2014]   [Sep]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 28/38] Externalize string buffer for printk
Date
This patch splits off the actual logging from vprintk_emit()
into printk_emit_string(), with vprintk_emit() just being a
simple wrapper for formatting the message into a
static buffer.

With that the caller can pass in a local buffer for
printk_emit_string() without increasing the overall stack size.

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
include/linux/printk.h | 5 +++++
kernel/printk/printk.c | 36 ++++++++++++++++++++++++------------
2 files changed, 29 insertions(+), 12 deletions(-)

diff --git a/include/linux/printk.h b/include/linux/printk.h
index d78125f..9639900 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -130,6 +130,11 @@ int vprintk_emit(int facility, int level,
const char *dict, size_t dictlen,
const char *fmt, va_list args);

+asmlinkage
+int printk_emit_string(int facility, int level,
+ const char *dict, size_t dictlen,
+ char *textbuf, size_t text_len);
+
asmlinkage __printf(1, 0)
int vprintk(const char *fmt, va_list args);

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index d13675e..303a1fe 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1618,22 +1618,11 @@ asmlinkage int vprintk_emit(int facility, int level,
const char *dict, size_t dictlen,
const char *fmt, va_list args)
{
- static int recursion_bug;
static char textbuf[LOG_LINE_MAX];
char *text = textbuf;
size_t text_len = 0;
- enum log_flags lflags = 0;
- unsigned long flags;
- int this_cpu;
- int printed_len = 0;
- bool in_sched = false;
- /* cpu currently holding logbuf_lock in this function */
- static volatile unsigned int logbuf_cpu = UINT_MAX;

if (level == SCHED_MESSAGE_LOGLEVEL) {
- level = -1;
- in_sched = true;
-
/*
* The printf needs to come first; we need the syslog
* prefix which might be passed-in as a parameter.
@@ -1644,6 +1633,24 @@ asmlinkage int vprintk_emit(int facility, int level,

text_len += vscnprintf(text + text_len,
sizeof(textbuf) - text_len, fmt, args);
+ return printk_emit_string(facility, level, dict, dictlen,
+ textbuf, text_len);
+}
+EXPORT_SYMBOL(vprintk_emit);
+
+asmlinkage int printk_emit_string(int facility, int level,
+ const char *dict, size_t dictlen,
+ char *textbuf, size_t text_len)
+{
+ static int recursion_bug;
+ char *text = textbuf;
+ enum log_flags lflags = 0;
+ unsigned long flags;
+ int this_cpu;
+ int printed_len = 0;
+ bool in_sched = false;
+ /* cpu currently holding logbuf_lock in this function */
+ static volatile unsigned int logbuf_cpu = UINT_MAX;

boot_delay_msec(level);
printk_delay();
@@ -1652,6 +1659,11 @@ asmlinkage int vprintk_emit(int facility, int level,
local_irq_save(flags);
this_cpu = smp_processor_id();

+ if (level == SCHED_MESSAGE_LOGLEVEL) {
+ level = -1;
+ in_sched = true;
+ }
+
/*
* Ouch, printk recursed into itself!
*/
@@ -1789,7 +1801,7 @@ asmlinkage int vprintk_emit(int facility, int level,

return printed_len;
}
-EXPORT_SYMBOL(vprintk_emit);
+EXPORT_SYMBOL(printk_emit_string);

asmlinkage int vprintk(const char *fmt, va_list args)
{
--
1.8.5.2


\
 
 \ /
  Last update: 2014-09-29 14:21    [W:0.053 / U:1.076 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site