Merge branch 'pm-sleep'

* pm-sleep:
  PM / Hibernate: Use bool for boolean fields of struct snapshot_data
  PM / Sleep: Detect device suspend/resume lockup and log event

3 files changed, 99 insertions, 10 deletions

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 9f098a82cf04..ee039afe9078 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -30,6 +30,8 @@
 #include <linux/suspend.h>
 #include <trace/events/power.h>
 #include <linux/cpuidle.h>
+#include <linux/timer.h>
+
 #include "../base.h"
 #include "power.h"
 
@@ -390,6 +392,71 @@ static int dpm_run_callback(pm_callback_t cb, struct device *dev,
 	return error;
 }
 
+#ifdef CONFIG_DPM_WATCHDOG
+struct dpm_watchdog {
+	struct device		*dev;
+	struct task_struct	*tsk;
+	struct timer_list	timer;
+};
+
+#define DECLARE_DPM_WATCHDOG_ON_STACK(wd) \
+	struct dpm_watchdog wd
+
+/**
+ * dpm_watchdog_handler - Driver suspend / resume watchdog handler.
+ * @data: Watchdog object address.
+ *
+ * Called when a driver has timed out suspending or resuming.
+ * There's not much we can do here to recover so panic() to
+ * capture a crash-dump in pstore.
+ */
+static void dpm_watchdog_handler(unsigned long data)
+{
+	struct dpm_watchdog *wd = (void *)data;
+
+	dev_emerg(wd->dev, "**** DPM device timeout ****\n");
+	show_stack(wd->tsk, NULL);
+	panic("%s %s: unrecoverable failure\n",
+		dev_driver_string(wd->dev), dev_name(wd->dev));
+}
+
+/**
+ * dpm_watchdog_set - Enable pm watchdog for given device.
+ * @wd: Watchdog. Must be allocated on the stack.
+ * @dev: Device to handle.
+ */
+static void dpm_watchdog_set(struct dpm_watchdog *wd, struct device *dev)
+{
+	struct timer_list *timer = &wd->timer;
+
+	wd->dev = dev;
+	wd->tsk = current;
+
+	init_timer_on_stack(timer);
+	/* use same timeout value for both suspend and resume */
+	timer->expires = jiffies + HZ * CONFIG_DPM_WATCHDOG_TIMEOUT;
+	timer->function = dpm_watchdog_handler;
+	timer->data = (unsigned long)wd;
+	add_timer(timer);
+}
+
+/**
+ * dpm_watchdog_clear - Disable suspend/resume watchdog.
+ * @wd: Watchdog to disable.
+ */
+static void dpm_watchdog_clear(struct dpm_watchdog *wd)
+{
+	struct timer_list *timer = &wd->timer;
+
+	del_timer_sync(timer);
+	destroy_timer_on_stack(timer);
+}
+#else
+#define DECLARE_DPM_WATCHDOG_ON_STACK(wd)
+#define dpm_watchdog_set(x, y)
+#define dpm_watchdog_clear(x)
+#endif
+
 /*------------------------- Resume routines -------------------------*/
 
 /**
@@ -576,6 +643,7 @@ static int device_resume(struct device *dev, pm_message_t state, bool async)
 	pm_callback_t callback = NULL;
 	char *info = NULL;
 	int error = 0;
+	DECLARE_DPM_WATCHDOG_ON_STACK(wd);
 
 	TRACE_DEVICE(dev);
 	TRACE_RESUME(0);
@@ -584,6 +652,7 @@ static int device_resume(struct device *dev, pm_message_t state, bool async)
 		goto Complete;
 
 	dpm_wait(dev->parent, async);
+	dpm_watchdog_set(&wd, dev);
 	device_lock(dev);
 
 	/*
@@ -642,6 +711,7 @@ static int device_resume(struct device *dev, pm_message_t state, bool async)
 
  Unlock:
 	device_unlock(dev);
+	dpm_watchdog_clear(&wd);
 
  Complete:
 	complete_all(&dev->power.completion);
@@ -1060,6 +1130,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 	pm_callback_t callback = NULL;
 	char *info = NULL;
 	int error = 0;
+	DECLARE_DPM_WATCHDOG_ON_STACK(wd);
 
 	dpm_wait_for_children(dev, async);
 
@@ -1083,6 +1154,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 	if (dev->power.syscore)
 		goto Complete;
 
+	dpm_watchdog_set(&wd, dev);
 	device_lock(dev);
 
 	if (dev->pm_domain) {
@@ -1139,6 +1211,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 	}
 
 	device_unlock(dev);
+	dpm_watchdog_clear(&wd);
 
  Complete:
 	complete_all(&dev->power.completion);
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index d444c4e834f4..2fac9cc79b3d 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -178,6 +178,22 @@ config PM_SLEEP_DEBUG
 	def_bool y
 	depends on PM_DEBUG && PM_SLEEP
 
+config DPM_WATCHDOG
+	bool "Device suspend/resume watchdog"
+	depends on PM_DEBUG && PSTORE
+	---help---
+	  Sets up a watchdog timer to capture drivers that are
+	  locked up attempting to suspend/resume a device.
+	  A detected lockup causes system panic with message
+	  captured in pstore device for inspection in subsequent
+	  boot session.
+
+config DPM_WATCHDOG_TIMEOUT
+	int "Watchdog timeout in seconds"
+	range 1 120
+	default 12
+	depends on DPM_WATCHDOG
+
 config PM_TRACE
 	bool
 	help
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 957f06164ad1..24850270c802 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -36,9 +36,9 @@ static struct snapshot_data {
 	struct snapshot_handle handle;
 	int swap;
 	int mode;
-	char frozen;
-	char ready;
-	char platform_support;
+	bool frozen;
+	bool ready;
+	bool platform_support;
 	bool free_bitmaps;
 } snapshot_state;
 
@@ -93,9 +93,9 @@ static int snapshot_open(struct inode *inode, struct file *filp)
 	if (error)
 		atomic_inc(&snapshot_device_available);
 
-	data->frozen = 0;
-	data->ready = 0;
-	data->platform_support = 0;
+	data->frozen = false;
+	data->ready = false;
+	data->platform_support = false;
 
  Unlock:
 	unlock_system_sleep();
@@ -229,7 +229,7 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
 		if (error)
 			thaw_processes();
 		else
-			data->frozen = 1;
+			data->frozen = true;
 
 		break;
 
@@ -240,7 +240,7 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
 		free_basic_memory_bitmaps();
 		data->free_bitmaps = false;
 		thaw_processes();
-		data->frozen = 0;
+		data->frozen = false;
 		break;
 
 	case SNAPSHOT_CREATE_IMAGE:
@@ -270,7 +270,7 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
 	case SNAPSHOT_FREE:
 		swsusp_free();
 		memset(&data->handle, 0, sizeof(struct snapshot_handle));
-		data->ready = 0;
+		data->ready = false;
 		/*
 		 * It is necessary to thaw kernel threads here, because
 		 * SNAPSHOT_CREATE_IMAGE may be invoked directly after
@@ -334,7 +334,7 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
 		 * PM_HIBERNATION_PREPARE
 		 */
 		error = suspend_devices_and_enter(PM_SUSPEND_MEM);
-		data->ready = 0;
+		data->ready = false;
 		break;
 
 	case SNAPSHOT_PLATFORM_SUPPORT: