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printk: Implement some unlocked kmsg_dump functions

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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>
This commit is contained in:
Anton Vorontsov
2012-07-20 17:28:07 -07:00
committed by Linus Torvalds
parent 1b499d05ee
commit 533827c921
2 changed files with 89 additions and 31 deletions
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16
include/linux/kmsg_dump.h
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@@ -55,12 +55,17 @@ struct kmsg_dumper {
#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);
@@ -71,6 +76,13 @@ 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)
{
@@ -83,6 +95,10 @@ static inline bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
return false;
}
static inline void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper)
{
}
static inline void kmsg_dump_rewind(struct kmsg_dumper *dumper)
{
}