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linux-next/include/linux/pstore.h
Seiji Aguchi 755d4fe465 efi_pstore: Add a sequence counter to a variable name
[Issue]

Currently, a variable name, which identifies each entry, consists of type, id and ctime.
But if multiple events happens in a short time, a second/third event may fail to log because
efi_pstore can't distinguish each event with current variable name.

[Solution]

A reasonable way to identify all events precisely is introducing a sequence counter to
the variable name.

The sequence counter has already supported in a pstore layer with "oopscount".
So, this patch adds it to a variable name.
Also, it is passed to read/erase callbacks of platform drivers in accordance with
the modification of the variable name.

  <before applying this patch>
 a variable name of first event: dump-type0-1-12345678
 a variable name of second event: dump-type0-1-12345678

  type:0
  id:1
  ctime:12345678

 If multiple events happen in a short time, efi_pstore can't distinguish them because
 variable names are same among them.

  <after applying this patch>

 it can be distinguishable by adding a sequence counter as follows.

 a variable name of first event: dump-type0-1-1-12345678
 a variable name of Second event: dump-type0-1-2-12345678

  type:0
  id:1
  sequence counter: 1(first event), 2(second event)
  ctime:12345678

In case of a write callback executed in pstore_console_write(), "0" is added to
an argument of the write callback because it just logs all kernel messages and
doesn't need to care about multiple events.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2012-11-26 16:07:44 -08:00

80 lines
2.3 KiB
C

/*
* Persistent Storage - pstore.h
*
* Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
*
* This code is the generic layer to export data records from platform
* level persistent storage via a file system.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef _LINUX_PSTORE_H
#define _LINUX_PSTORE_H
#include <linux/time.h>
#include <linux/kmsg_dump.h>
#include <linux/mutex.h>
#include <linux/types.h>
#include <linux/spinlock.h>
#include <linux/errno.h>
/* types */
enum pstore_type_id {
PSTORE_TYPE_DMESG = 0,
PSTORE_TYPE_MCE = 1,
PSTORE_TYPE_CONSOLE = 2,
PSTORE_TYPE_FTRACE = 3,
PSTORE_TYPE_UNKNOWN = 255
};
struct module;
struct pstore_info {
struct module *owner;
char *name;
spinlock_t buf_lock; /* serialize access to 'buf' */
char *buf;
size_t bufsize;
struct mutex read_mutex; /* serialize open/read/close */
int (*open)(struct pstore_info *psi);
int (*close)(struct pstore_info *psi);
ssize_t (*read)(u64 *id, enum pstore_type_id *type,
int *count, struct timespec *time, char **buf,
struct pstore_info *psi);
int (*write)(enum pstore_type_id type,
enum kmsg_dump_reason reason, u64 *id,
unsigned int part, int count, size_t size,
struct pstore_info *psi);
int (*write_buf)(enum pstore_type_id type,
enum kmsg_dump_reason reason, u64 *id,
unsigned int part, const char *buf, size_t size,
struct pstore_info *psi);
int (*erase)(enum pstore_type_id type, u64 id,
int count, struct timespec time,
struct pstore_info *psi);
void *data;
};
#ifdef CONFIG_PSTORE
extern int pstore_register(struct pstore_info *);
#else
static inline int
pstore_register(struct pstore_info *psi)
{
return -ENODEV;
}
#endif
#endif /*_LINUX_PSTORE_H*/