notifier error injection

This provides kernel modules that can be used to test the error handling
of notifier call chain failures by injecting artifical errors to the
following notifier chain callbacks.

 * CPU notifier
 * PM notifier
 * memory hotplug notifier
 * powerpc pSeries reconfig notifier

Example: Inject CPU offline error (-1 == -EPERM)

	# cd /sys/kernel/debug/notifier-error-inject/cpu
	# echo -1 > actions/CPU_DOWN_PREPARE/error
	# echo 0 > /sys/devices/system/cpu/cpu1/online
	bash: echo: write error: Operation not permitted

This also adds cpu and memory hotplug tests to tools/testing/selftests 
These tests first do simple online and offline test and then do fault
injection tests if notifier error injection module is available.

Changelog:

* v5 (change only testing scripts)
- make testing scripts a part of tools/testing/selftests
- do simple on/offline tests even if no notifier error injection support

* v4 (It is about 11 months since v3)
- prefix all APIs with notifier_err_inject_*
- rearrange debugfs interface
  (e.g. $DEBUGFS/cpu-notifier-error-inject/CPU_DOWN_PREPARE -->
        $DEBUGFS/notifier-error-inject/cpu/actions/CPU_DOWN_PREPARE/error)
- update modules to follow new interface
- add -r option for memory-notifier.sh to specify percent of offlining
  memory blocks

* v3
- rewrite to be kernel modules instead of initializing at late_initcall()s
  (it makes the diffstat look different but most code remains unchanged)
- export err_inject_notifier_block_{init,cleanup} for modules
- export pSeries_reconfig_notifier_{,un}register symbols for a module
- notifier priority can be specified as a module parameter
- add testing scripts in tools/testing/fault-injection

* v2
- "PM: Improve error code of pm_notifier_call_chain()" is now in -next
- "debugfs: add debugfs_create_int" is dropped
- put a comment in err_inject_notifier_block_init()
- only allow valid errno to be injected (-MAX_ERRNO <= errno <= 0)
- improve Kconfig help text
- make CONFIG_PM_NOTIFIER_ERROR_INJECTION visible even if PM_DEBUG is disabled
- make CONFIG_PM_NOTIFIER_ERROR_INJECTION default if PM_DEBUG is enabled

Akinobu Mita (6):
  fault-injection: notifier error injection
  cpu: rewrite cpu-notifier-error-inject module
  PM: PM notifier error injection module
  memory: memory notifier error injection module
  powerpc: pSeries reconfig notifier error injection module
  fault-injection: add selftests for cpu and memory hotplug

 lib/Kconfig.debug                                  |   91 +++++++-
 lib/Makefile                                       |    5 +
 lib/cpu-notifier-error-inject.c                    |   63 +++---
 lib/memory-notifier-error-inject.c                 |   48 ++++
 lib/notifier-error-inject.c                        |  112 ++++++++++
 lib/notifier-error-inject.h                        |   24 ++
 lib/pSeries-reconfig-notifier-error-inject.c       |   51 +++++
 lib/pm-notifier-error-inject.c                     |   49 +++++
 tools/testing/selftests/Makefile                   |    2 +-
 tools/testing/selftests/cpu-hotplug/Makefile       |    6 +
 tools/testing/selftests/cpu-hotplug/on-off-test.sh |  221 +++++++++++++++++++
 tools/testing/selftests/memory-hotplug/Makefile    |    6 +
 .../selftests/memory-hotplug/on-off-test.sh        |  230 ++++++++++++++++++++
 13 files changed, 867 insertions(+), 41 deletions(-)
 create mode 100644 lib/memory-notifier-error-inject.c
 create mode 100644 lib/notifier-error-inject.c
 create mode 100644 lib/notifier-error-inject.h
 create mode 100644 lib/pSeries-reconfig-notifier-error-inject.c
 create mode 100644 lib/pm-notifier-error-inject.c
 create mode 100644 tools/testing/selftests/cpu-hotplug/Makefile
 create mode 100755 tools/testing/selftests/cpu-hotplug/on-off-test.sh
 create mode 100644 tools/testing/selftests/memory-hotplug/Makefile
 create mode 100755 tools/testing/selftests/memory-hotplug/on-off-test.sh

Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: linux-pm@lists.linux-foundation.org
Cc: Greg KH <greg@kroah.com>
Cc: linux-mm@kvack.org
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Américo Wang <xiyou.wangcong@gmail.com>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Dave Jones <davej@redhat.com>
-- 
1.7.10.4

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