From 048b9c3549790af21eabd06a5ebdad305e75b1c5 Mon Sep 17 00:00:00 2001
From: Akinobu Mita <akinobu.mita@gmail.com>
Date: Mon, 30 Jul 2012 14:43:07 -0700
Subject: PM: PM notifier error injection module

This provides the ability to inject artifical errors to PM notifier chain
callbacks.  It is controlled through debugfs interface under
/sys/kernel/debug/notifier-error-inject/pm

Each of the files in "error" directory represents an event which can be
failed and contains the error code.  If the notifier call chain should be
failed with some events notified, write the error code to the files.

If the notifier call chain should be failed with some events notified,
write the error code to "actions/<notifier event>/error".

Example: Inject PM suspend error (-12 = -ENOMEM)

	# cd /sys/kernel/debug/notifier-error-inject/pm
	# echo -12 > actions/PM_SUSPEND_PREPARE/error
	# echo mem > /sys/power/state
	bash: echo: write error: Cannot allocate memory

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Greg KH <greg@kroah.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 lib/pm-notifier-error-inject.c | 49 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100644 lib/pm-notifier-error-inject.c

(limited to 'lib/pm-notifier-error-inject.c')

diff --git a/lib/pm-notifier-error-inject.c b/lib/pm-notifier-error-inject.c
new file mode 100644
index 000000000000..c094b2dedc23
--- /dev/null
+++ b/lib/pm-notifier-error-inject.c
@@ -0,0 +1,49 @@
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/suspend.h>
+
+#include "notifier-error-inject.h"
+
+static int priority;
+module_param(priority, int, 0);
+MODULE_PARM_DESC(priority, "specify PM notifier priority");
+
+static struct notifier_err_inject pm_notifier_err_inject = {
+	.actions = {
+		{ NOTIFIER_ERR_INJECT_ACTION(PM_HIBERNATION_PREPARE) },
+		{ NOTIFIER_ERR_INJECT_ACTION(PM_SUSPEND_PREPARE) },
+		{ NOTIFIER_ERR_INJECT_ACTION(PM_RESTORE_PREPARE) },
+		{}
+	}
+};
+
+static struct dentry *dir;
+
+static int err_inject_init(void)
+{
+	int err;
+
+	dir = notifier_err_inject_init("pm", notifier_err_inject_dir,
+					&pm_notifier_err_inject, priority);
+	if (IS_ERR(dir))
+		return PTR_ERR(dir);
+
+	err = register_pm_notifier(&pm_notifier_err_inject.nb);
+	if (err)
+		debugfs_remove_recursive(dir);
+
+	return err;
+}
+
+static void err_inject_exit(void)
+{
+	unregister_pm_notifier(&pm_notifier_err_inject.nb);
+	debugfs_remove_recursive(dir);
+}
+
+module_init(err_inject_init);
+module_exit(err_inject_exit);
+
+MODULE_DESCRIPTION("PM notifier error injection module");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
-- 
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