linux/include/asm-generic/bug.h
David Brownell af9379c712 documentation: when to BUG(), and when to not BUG()
Provide some basic advice about when to use BUG()/BUG_ON(): never, unless
there's really no better option.

This matches my understanding of the standard policy ...  which seems not
to be written down so far, outside of LKML messages that I haven't
bookmarked.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Hans Verkuil <hverkuil@xs4all.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-06 15:59:13 -08:00

143 lines
3.5 KiB
C

#ifndef _ASM_GENERIC_BUG_H
#define _ASM_GENERIC_BUG_H
#include <linux/compiler.h>
#ifdef CONFIG_BUG
#ifdef CONFIG_GENERIC_BUG
#ifndef __ASSEMBLY__
struct bug_entry {
#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
unsigned long bug_addr;
#else
signed int bug_addr_disp;
#endif
#ifdef CONFIG_DEBUG_BUGVERBOSE
#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
const char *file;
#else
signed int file_disp;
#endif
unsigned short line;
#endif
unsigned short flags;
};
#endif /* __ASSEMBLY__ */
#define BUGFLAG_WARNING (1<<0)
#endif /* CONFIG_GENERIC_BUG */
/*
* Don't use BUG() or BUG_ON() unless there's really no way out; one
* example might be detecting data structure corruption in the middle
* of an operation that can't be backed out of. If the (sub)system
* can somehow continue operating, perhaps with reduced functionality,
* it's probably not BUG-worthy.
*
* If you're tempted to BUG(), think again: is completely giving up
* really the *only* solution? There are usually better options, where
* users don't need to reboot ASAP and can mostly shut down cleanly.
*/
#ifndef HAVE_ARCH_BUG
#define BUG() do { \
printk("BUG: failure at %s:%d/%s()!\n", __FILE__, __LINE__, __func__); \
panic("BUG!"); \
} while (0)
#endif
#ifndef HAVE_ARCH_BUG_ON
#define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while(0)
#endif
/*
* WARN(), WARN_ON(), WARN_ON_ONCE, and so on can be used to report
* significant issues that need prompt attention if they should ever
* appear at runtime. Use the versions with printk format strings
* to provide better diagnostics.
*/
#ifndef __WARN
#ifndef __ASSEMBLY__
extern void warn_slowpath(const char *file, const int line,
const char *fmt, ...) __attribute__((format(printf, 3, 4)));
#define WANT_WARN_ON_SLOWPATH
#endif
#define __WARN() warn_slowpath(__FILE__, __LINE__, NULL)
#define __WARN_printf(arg...) warn_slowpath(__FILE__, __LINE__, arg)
#else
#define __WARN_printf(arg...) do { printk(arg); __WARN(); } while (0)
#endif
#ifndef WARN_ON
#define WARN_ON(condition) ({ \
int __ret_warn_on = !!(condition); \
if (unlikely(__ret_warn_on)) \
__WARN(); \
unlikely(__ret_warn_on); \
})
#endif
#ifndef WARN
#define WARN(condition, format...) ({ \
int __ret_warn_on = !!(condition); \
if (unlikely(__ret_warn_on)) \
__WARN_printf(format); \
unlikely(__ret_warn_on); \
})
#endif
#else /* !CONFIG_BUG */
#ifndef HAVE_ARCH_BUG
#define BUG()
#endif
#ifndef HAVE_ARCH_BUG_ON
#define BUG_ON(condition) do { if (condition) ; } while(0)
#endif
#ifndef HAVE_ARCH_WARN_ON
#define WARN_ON(condition) ({ \
int __ret_warn_on = !!(condition); \
unlikely(__ret_warn_on); \
})
#endif
#ifndef WARN
#define WARN(condition, format...) ({ \
int __ret_warn_on = !!(condition); \
unlikely(__ret_warn_on); \
})
#endif
#endif
#define WARN_ON_ONCE(condition) ({ \
static int __warned; \
int __ret_warn_once = !!(condition); \
\
if (unlikely(__ret_warn_once)) \
if (WARN_ON(!__warned)) \
__warned = 1; \
unlikely(__ret_warn_once); \
})
#define WARN_ONCE(condition, format...) ({ \
static int __warned; \
int __ret_warn_once = !!(condition); \
\
if (unlikely(__ret_warn_once)) \
if (WARN(!__warned, format)) \
__warned = 1; \
unlikely(__ret_warn_once); \
})
#define WARN_ON_RATELIMIT(condition, state) \
WARN_ON((condition) && __ratelimit(state))
#ifdef CONFIG_SMP
# define WARN_ON_SMP(x) WARN_ON(x)
#else
# define WARN_ON_SMP(x) do { } while (0)
#endif
#endif