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linux-next/include/linux/kmsg_dump.h
Anton Vorontsov 533827c921 printk: Implement some unlocked kmsg_dump functions
If used from KDB, the locked variants are prone to deadlocks (suppose we
got to the debugger w/ the logbuf lock held).

So, we have to implement a few routines that grab no logbuf lock.

Yet we don't need these functions in modules, so we don't export them.

Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-21 10:34:00 -07:00

118 lines
2.9 KiB
C

/*
* linux/include/kmsg_dump.h
*
* Copyright (C) 2009 Net Insight AB
*
* Author: Simon Kagstrom <simon.kagstrom@netinsight.net>
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file COPYING in the main directory of this archive
* for more details.
*/
#ifndef _LINUX_KMSG_DUMP_H
#define _LINUX_KMSG_DUMP_H
#include <linux/errno.h>
#include <linux/list.h>
/*
* Keep this list arranged in rough order of priority. Anything listed after
* KMSG_DUMP_OOPS will not be logged by default unless printk.always_kmsg_dump
* is passed to the kernel.
*/
enum kmsg_dump_reason {
KMSG_DUMP_UNDEF,
KMSG_DUMP_PANIC,
KMSG_DUMP_OOPS,
KMSG_DUMP_EMERG,
KMSG_DUMP_RESTART,
KMSG_DUMP_HALT,
KMSG_DUMP_POWEROFF,
};
/**
* struct kmsg_dumper - kernel crash message dumper structure
* @list: Entry in the dumper list (private)
* @dump: Call into dumping code which will retrieve the data with
* through the record iterator
* @max_reason: filter for highest reason number that should be dumped
* @registered: Flag that specifies if this is already registered
*/
struct kmsg_dumper {
struct list_head list;
void (*dump)(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason);
enum kmsg_dump_reason max_reason;
bool active;
bool registered;
/* private state of the kmsg iterator */
u32 cur_idx;
u32 next_idx;
u64 cur_seq;
u64 next_seq;
};
#ifdef CONFIG_PRINTK
void kmsg_dump(enum kmsg_dump_reason reason);
bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog,
char *line, size_t size, size_t *len);
bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
char *line, size_t size, size_t *len);
bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
char *buf, size_t size, size_t *len);
void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper);
void kmsg_dump_rewind(struct kmsg_dumper *dumper);
int kmsg_dump_register(struct kmsg_dumper *dumper);
int kmsg_dump_unregister(struct kmsg_dumper *dumper);
#else
static inline void kmsg_dump(enum kmsg_dump_reason reason)
{
}
static inline bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper,
bool syslog, const char *line,
size_t size, size_t *len)
{
return false;
}
static inline bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
const char *line, size_t size, size_t *len)
{
return false;
}
static inline bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
char *buf, size_t size, size_t *len)
{
return false;
}
static inline void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper)
{
}
static inline void kmsg_dump_rewind(struct kmsg_dumper *dumper)
{
}
static inline int kmsg_dump_register(struct kmsg_dumper *dumper)
{
return -EINVAL;
}
static inline int kmsg_dump_unregister(struct kmsg_dumper *dumper)
{
return -EINVAL;
}
#endif
#endif /* _LINUX_KMSG_DUMP_H */