3 files changed, 101 insertions, 16 deletions

diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 848ebbd2571..f48370dfc90 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -44,13 +44,11 @@ static int __ref cpu_subsys_online(struct device *dev)
 	struct cpu *cpu = container_of(dev, struct cpu, dev);
 	int cpuid = dev->id;
 	int from_nid, to_nid;
-	int ret = -ENODEV;
-
-	cpu_hotplug_driver_lock();
+	int ret;
 
 	from_nid = cpu_to_node(cpuid);
 	if (from_nid == NUMA_NO_NODE)
-		goto out;
+		return -ENODEV;
 
 	ret = cpu_up(cpuid);
 	/*
@@ -61,19 +59,12 @@ static int __ref cpu_subsys_online(struct device *dev)
 	if (from_nid != to_nid)
 		change_cpu_under_node(cpu, from_nid, to_nid);
 
- out:
-	cpu_hotplug_driver_unlock();
 	return ret;
 }
 
 static int cpu_subsys_offline(struct device *dev)
 {
-	int ret;
-
-	cpu_hotplug_driver_lock();
-	ret = cpu_down(dev->id);
-	cpu_hotplug_driver_unlock();
-	return ret;
+	return cpu_down(dev->id);
 }
 
 void unregister_cpu(struct cpu *cpu)
@@ -93,7 +84,17 @@ static ssize_t cpu_probe_store(struct device *dev,
 			       const char *buf,
 			       size_t count)
 {
-	return arch_cpu_probe(buf, count);
+	ssize_t cnt;
+	int ret;
+
+	ret = lock_device_hotplug_sysfs();
+	if (ret)
+		return ret;
+
+	cnt = arch_cpu_probe(buf, count);
+
+	unlock_device_hotplug();
+	return cnt;
 }
 
 static ssize_t cpu_release_store(struct device *dev,
@@ -101,7 +102,17 @@ static ssize_t cpu_release_store(struct device *dev,
 				 const char *buf,
 				 size_t count)
 {
-	return arch_cpu_release(buf, count);
+	ssize_t cnt;
+	int ret;
+
+	ret = lock_device_hotplug_sysfs();
+	if (ret)
+		return ret;
+
+	cnt = arch_cpu_release(buf, count);
+
+	unlock_device_hotplug();
+	return cnt;
 }
 
 static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store);
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 9f098a82cf0..ee039afe907 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/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 268a3509757..72e00e66ecc 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -258,7 +258,8 @@ static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
  * Check if the device's runtime PM status allows it to be suspended.  If
  * another idle notification has been started earlier, return immediately.  If
  * the RPM_ASYNC flag is set then queue an idle-notification request; otherwise
- * run the ->runtime_idle() callback directly.
+ * run the ->runtime_idle() callback directly. If the ->runtime_idle callback
+ * doesn't exist or if it returns 0, call rpm_suspend with the RPM_AUTO flag.
  *
  * This function must be called under dev->power.lock with interrupts disabled.
  */
@@ -331,7 +332,7 @@ static int rpm_idle(struct device *dev, int rpmflags)
 
  out:
 	trace_rpm_return_int(dev, _THIS_IP_, retval);
-	return retval ? retval : rpm_suspend(dev, rpmflags);
+	return retval ? retval : rpm_suspend(dev, rpmflags | RPM_AUTO);
 }
 
 /**