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path: root/drivers/s390/char/vmwatchdog.c
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Diffstat (limited to 'drivers/s390/char/vmwatchdog.c')
-rw-r--r--drivers/s390/char/vmwatchdog.c81
1 files changed, 76 insertions, 5 deletions
diff --git a/drivers/s390/char/vmwatchdog.c b/drivers/s390/char/vmwatchdog.c
index 21a2a829bf4..cb7854c10c0 100644
--- a/drivers/s390/char/vmwatchdog.c
+++ b/drivers/s390/char/vmwatchdog.c
@@ -1,17 +1,23 @@
/*
* Watchdog implementation based on z/VM Watchdog Timer API
*
+ * Copyright IBM Corp. 2004,2009
+ *
* The user space watchdog daemon can use this driver as
* /dev/vmwatchdog to have z/VM execute the specified CP
* command when the timeout expires. The default command is
* "IPL", which which cause an immediate reboot.
*/
+#define KMSG_COMPONENT "vmwatchdog"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
+#include <linux/suspend.h>
#include <linux/watchdog.h>
#include <linux/smp_lock.h>
@@ -43,6 +49,9 @@ static unsigned int vmwdt_interval = 60;
static unsigned long vmwdt_is_open;
static int vmwdt_expect_close;
+#define VMWDT_OPEN 0 /* devnode is open or suspend in progress */
+#define VMWDT_RUNNING 1 /* The watchdog is armed */
+
enum vmwdt_func {
/* function codes */
wdt_init = 0,
@@ -92,6 +101,7 @@ static int vmwdt_keepalive(void)
EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);
func = vmwdt_conceal ? (wdt_init | wdt_conceal) : wdt_init;
+ set_bit(VMWDT_RUNNING, &vmwdt_is_open);
ret = __diag288(func, vmwdt_interval, ebc_cmd, len);
WARN_ON(ret != 0);
kfree(ebc_cmd);
@@ -102,6 +112,7 @@ static int vmwdt_disable(void)
{
int ret = __diag288(wdt_cancel, 0, "", 0);
WARN_ON(ret != 0);
+ clear_bit(VMWDT_RUNNING, &vmwdt_is_open);
return ret;
}
@@ -123,13 +134,13 @@ static int vmwdt_open(struct inode *i, struct file *f)
{
int ret;
lock_kernel();
- if (test_and_set_bit(0, &vmwdt_is_open)) {
+ if (test_and_set_bit(VMWDT_OPEN, &vmwdt_is_open)) {
unlock_kernel();
return -EBUSY;
}
ret = vmwdt_keepalive();
if (ret)
- clear_bit(0, &vmwdt_is_open);
+ clear_bit(VMWDT_OPEN, &vmwdt_is_open);
unlock_kernel();
return ret ? ret : nonseekable_open(i, f);
}
@@ -139,7 +150,7 @@ static int vmwdt_close(struct inode *i, struct file *f)
if (vmwdt_expect_close == 42)
vmwdt_disable();
vmwdt_expect_close = 0;
- clear_bit(0, &vmwdt_is_open);
+ clear_bit(VMWDT_OPEN, &vmwdt_is_open);
return 0;
}
@@ -223,6 +234,57 @@ static ssize_t vmwdt_write(struct file *f, const char __user *buf,
return count;
}
+static int vmwdt_resume(void)
+{
+ clear_bit(VMWDT_OPEN, &vmwdt_is_open);
+ return NOTIFY_DONE;
+}
+
+/*
+ * It makes no sense to go into suspend while the watchdog is running.
+ * Depending on the memory size, the watchdog might trigger, while we
+ * are still saving the memory.
+ * We reuse the open flag to ensure that suspend and watchdog open are
+ * exclusive operations
+ */
+static int vmwdt_suspend(void)
+{
+ if (test_and_set_bit(VMWDT_OPEN, &vmwdt_is_open)) {
+ pr_err("The watchdog is in use. "
+ "This prevents hibernation or suspend.\n");
+ return NOTIFY_BAD;
+ }
+ if (test_bit(VMWDT_RUNNING, &vmwdt_is_open)) {
+ clear_bit(VMWDT_OPEN, &vmwdt_is_open);
+ pr_err("The watchdog is running. "
+ "This prevents hibernation or suspend.\n");
+ return NOTIFY_BAD;
+ }
+ return NOTIFY_DONE;
+}
+
+/*
+ * This function is called for suspend and resume.
+ */
+static int vmwdt_power_event(struct notifier_block *this, unsigned long event,
+ void *ptr)
+{
+ switch (event) {
+ case PM_POST_HIBERNATION:
+ case PM_POST_SUSPEND:
+ return vmwdt_resume();
+ case PM_HIBERNATION_PREPARE:
+ case PM_SUSPEND_PREPARE:
+ return vmwdt_suspend();
+ default:
+ return NOTIFY_DONE;
+ }
+}
+
+static struct notifier_block vmwdt_power_notifier = {
+ .notifier_call = vmwdt_power_event,
+};
+
static const struct file_operations vmwdt_fops = {
.open = &vmwdt_open,
.release = &vmwdt_close,
@@ -244,12 +306,21 @@ static int __init vmwdt_init(void)
ret = vmwdt_probe();
if (ret)
return ret;
- return misc_register(&vmwdt_dev);
+ ret = register_pm_notifier(&vmwdt_power_notifier);
+ if (ret)
+ return ret;
+ ret = misc_register(&vmwdt_dev);
+ if (ret) {
+ unregister_pm_notifier(&vmwdt_power_notifier);
+ return ret;
+ }
+ return 0;
}
module_init(vmwdt_init);
static void __exit vmwdt_exit(void)
{
- WARN_ON(misc_deregister(&vmwdt_dev) != 0);
+ unregister_pm_notifier(&vmwdt_power_notifier);
+ misc_deregister(&vmwdt_dev);
}
module_exit(vmwdt_exit);