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linux-next/fs/pstore
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
..
ftrace.c pstore/ftrace: Convert to its own enable/disable debugfs knob 2012-09-06 22:16:58 -07:00
inode.c efi_pstore: Add a sequence counter to a variable name 2012-11-26 16:07:44 -08:00
internal.h efi_pstore: Add a sequence counter to a variable name 2012-11-26 16:07:44 -08:00
Kconfig pstore/ftrace: Convert to its own enable/disable debugfs knob 2012-09-06 22:16:58 -07:00
Makefile pstore: Add persistent function tracing 2012-07-17 10:05:52 -07:00
platform.c efi_pstore: Add a sequence counter to a variable name 2012-11-26 16:07:44 -08:00
ram_core.c pstore/ram: Make tracing log versioned 2012-07-17 16:48:09 -07:00
ram.c efi_pstore: Add a sequence counter to a variable name 2012-11-26 16:07:44 -08:00