lkml.org 
[lkml]   [2015]   [Dec]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
SubjectRe: [PATCH v2] printk: help pr_debug and pr_devel to optimize out arguments
Date
On Friday 04 December 2015 16:51:42 Aaron Conole wrote:
> --- a/include/linux/printk.h
> +++ b/include/linux/printk.h
> @@ -106,13 +106,14 @@ struct va_format {
>
> /*
> * Dummy printk for disabled debugging statements to use whilst maintaining
> - * gcc's format and side-effect checking.
> + * gcc's format checking.
> */
> -static inline __printf(1, 2)
> -int no_printk(const char *fmt, ...)
> -{
> - return 0;
> -}
> +#define no_printk(fmt, ...) \
> +do { \
> + if (0) { \
> + printk(fmt, ##__VA_ARGS__); \
> + } \
> +} while (0)
>

This change breaks compiling lib/842/, at least in some configurations:

lib/842/842_decompress.c: In function '__do_index':
lib/842/842_decompress.c:205:12422: error: implicit declaration of function 'no_printk'

Using a gcc style vararg macro instead of the C99 style makes it work, but
I don't know why the original version didn't work.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

diff --git a/include/linux/printk.h b/include/linux/printk.h
index cc3803a8f73e..4d1851a82254 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -108,10 +108,10 @@ struct va_format {
* Dummy printk for disabled debugging statements to use whilst maintaining
* gcc's format checking.
*/
-#define no_printk(fmt, ...) \
+#define no_printk(arg ...) \
do { \
if (0) { \
- printk(fmt, ##__VA_ARGS__); \
+ printk(arg); \
} \
} while (0)



\
 
 \ /
  Last update: 2015-12-09 13:21    [W:1.153 / U:0.020 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site