Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1287440

Re: [PATCH v2] printk: help pr_debug and pr_devel to optimize out arguments

Show all headers | View raw

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)
 

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH] printk: fix pr_debug and pr_devel to elide function calls Aaron Conole <aconole@redhat.com> - 2015-12-03 23:50 +0100
  Re: [PATCH] printk: fix pr_debug and pr_devel to elide function  calls Joe Perches <joe@perches.com> - 2015-12-04 00:20 +0100
  Re: [PATCH] printk: fix pr_debug and pr_devel to elide function calls Aaron Conole <aconole@redhat.com> - 2015-12-04 17:40 +0100
    Re: [PATCH] printk: fix pr_debug and pr_devel to elide function  calls Joe Perches <joe@perches.com> - 2015-12-04 17:50 +0100
  Re: [PATCH] printk: fix pr_debug and pr_devel to elide function calls Jason Baron <jbaron@akamai.com> - 2015-12-04 17:40 +0100
    [PATCH v2] printk: help pr_debug and pr_devel to optimize out arguments Aaron Conole <aconole@redhat.com> - 2015-12-04 23:00 +0100
      Re: [PATCH v2] printk: help pr_debug and pr_devel to optimize out arguments Arnd Bergmann <arnd@arndb.de> - 2015-12-09 13:00 +0100
        Re: [PATCH v2] printk: help pr_debug and pr_devel to optimize out arguments Aaron Conole <aconole@redhat.com> - 2015-12-09 16:20 +0100
        Re: [PATCH v2] printk: help pr_debug and pr_devel to optimize out  arguments Joe Perches <joe@perches.com> - 2015-12-09 16:50 +0100

csiph-web