From 4ccb457966391295bd9b3644f6bdc9ddd97b6051 Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Thu, 9 Apr 2009 14:48:24 -0700 Subject: [PATCH] dynamic debug: resurrect old pr_debug() semantics as pr_devel() pr_debug() used to produce zero code unless DEBUG was #defined. This is now no longer the case in practice[1]. There are places where it's useful to have debugging printks, but we don't want them to generate any code in production kernels. So add a new macro, pr_devel(), for _devel_opment, to provide the old semantics, ie. if the programmer doesn't explicitly enable debugging, no code is produced. [1]: You can turn CONFIG_DYNAMIC_DEBUG off, but it's enabled in at least one distro kernel, so it's not really a solution. Signed-off-by: Michael Ellerman Cc: Jason Baron Cc: Greg Banks Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- include/linux/kernel.h | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/include/linux/kernel.h b/include/linux/kernel.h index d9e75ec7def..883cd44ff76 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -377,6 +377,15 @@ static inline char *pack_hex_byte(char *buf, u8 byte) #define pr_cont(fmt, ...) \ printk(KERN_CONT fmt, ##__VA_ARGS__) +/* pr_devel() should produce zero code unless DEBUG is defined */ +#ifdef DEBUG +#define pr_devel(fmt, ...) \ + printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__) +#else +#define pr_devel(fmt, ...) \ + ({ if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); 0; }) +#endif + /* If you are writing a driver, please use dev_dbg instead */ #if defined(DEBUG) #define pr_debug(fmt, ...) \ -- 2.20.1