1 files changed, 108 insertions, 49 deletions

diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index d504cd4ab3cb..b52049098d4e 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -263,7 +263,7 @@ static int rpm_check_suspend_allowed(struct device *dev)
 		retval = -EINVAL;
 	else if (dev->power.disable_depth > 0)
 		retval = -EACCES;
-	else if (atomic_read(&dev->power.usage_count) > 0)
+	else if (atomic_read(&dev->power.usage_count))
 		retval = -EAGAIN;
 	else if (!dev->power.ignore_children &&
 			atomic_read(&dev->power.child_count))
@@ -305,16 +305,34 @@ static int rpm_get_suppliers(struct device *dev)
 	return 0;
 }
 
+/**
+ * pm_runtime_release_supplier - Drop references to device link's supplier.
+ * @link: Target device link.
+ *
+ * Drop all runtime PM references associated with @link to its supplier device.
+ */
+void pm_runtime_release_supplier(struct device_link *link)
+{
+	struct device *supplier = link->supplier;
+
+	/*
+	 * The additional power.usage_count check is a safety net in case
+	 * the rpm_active refcount becomes saturated, in which case
+	 * refcount_dec_not_one() would return true forever, but it is not
+	 * strictly necessary.
+	 */
+	while (refcount_dec_not_one(&link->rpm_active) &&
+	       atomic_read(&supplier->power.usage_count) > 0)
+		pm_runtime_put_noidle(supplier);
+}
+
 static void __rpm_put_suppliers(struct device *dev, bool try_to_suspend)
 {
 	struct device_link *link;
 
 	list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
 				device_links_read_lock_held()) {
-
-		while (refcount_dec_not_one(&link->rpm_active))
-			pm_runtime_put_noidle(link->supplier);
-
+		pm_runtime_release_supplier(link);
 		if (try_to_suspend)
 			pm_request_idle(link->supplier);
 	}
@@ -742,13 +760,15 @@ static int rpm_resume(struct device *dev, int rpmflags)
 	trace_rpm_resume_rcuidle(dev, rpmflags);
 
  repeat:
-	if (dev->power.runtime_error)
+	if (dev->power.runtime_error) {
 		retval = -EINVAL;
-	else if (dev->power.disable_depth == 1 && dev->power.is_suspended
-	    && dev->power.runtime_status == RPM_ACTIVE)
-		retval = 1;
-	else if (dev->power.disable_depth > 0)
-		retval = -EACCES;
+	} else if (dev->power.disable_depth > 0) {
+		if (dev->power.runtime_status == RPM_ACTIVE &&
+		    dev->power.last_status == RPM_ACTIVE)
+			retval = 1;
+		else
+			retval = -EACCES;
+	}
 	if (retval)
 		goto out;
 
@@ -772,10 +792,13 @@ static int rpm_resume(struct device *dev, int rpmflags)
 		DEFINE_WAIT(wait);
 
 		if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
-			if (dev->power.runtime_status == RPM_SUSPENDING)
+			if (dev->power.runtime_status == RPM_SUSPENDING) {
 				dev->power.deferred_resume = true;
-			else
+				if (rpmflags & RPM_NOWAIT)
+					retval = -EINPROGRESS;
+			} else {
 				retval = -EINPROGRESS;
+			}
 			goto out;
 		}
 
@@ -1016,13 +1039,33 @@ int pm_schedule_suspend(struct device *dev, unsigned int delay)
 }
 EXPORT_SYMBOL_GPL(pm_schedule_suspend);
 
+static int rpm_drop_usage_count(struct device *dev)
+{
+	int ret;
+
+	ret = atomic_sub_return(1, &dev->power.usage_count);
+	if (ret >= 0)
+		return ret;
+
+	/*
+	 * Because rpm_resume() does not check the usage counter, it will resume
+	 * the device even if the usage counter is 0 or negative, so it is
+	 * sufficient to increment the usage counter here to reverse the change
+	 * made above.
+	 */
+	atomic_inc(&dev->power.usage_count);
+	dev_warn(dev, "Runtime PM usage count underflow!\n");
+	return -EINVAL;
+}
+
 /**
  * __pm_runtime_idle - Entry point for runtime idle operations.
  * @dev: Device to send idle notification for.
  * @rpmflags: Flag bits.
  *
  * If the RPM_GET_PUT flag is set, decrement the device's usage count and
- * return immediately if it is larger than zero.  Then carry out an idle
+ * return immediately if it is larger than zero (if it becomes negative, log a
+ * warning, increment it, and return an error).  Then carry out an idle
  * notification, either synchronous or asynchronous.
  *
  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
@@ -1034,7 +1077,10 @@ int __pm_runtime_idle(struct device *dev, int rpmflags)
 	int retval;
 
 	if (rpmflags & RPM_GET_PUT) {
-		if (!atomic_dec_and_test(&dev->power.usage_count)) {
+		retval = rpm_drop_usage_count(dev);
+		if (retval < 0) {
+			return retval;
+		} else if (retval > 0) {
 			trace_rpm_usage_rcuidle(dev, rpmflags);
 			return 0;
 		}
@@ -1056,7 +1102,8 @@ EXPORT_SYMBOL_GPL(__pm_runtime_idle);
  * @rpmflags: Flag bits.
  *
  * If the RPM_GET_PUT flag is set, decrement the device's usage count and
- * return immediately if it is larger than zero.  Then carry out a suspend,
+ * return immediately if it is larger than zero (if it becomes negative, log a
+ * warning, increment it, and return an error).  Then carry out a suspend,
  * either synchronous or asynchronous.
  *
  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
@@ -1068,7 +1115,10 @@ int __pm_runtime_suspend(struct device *dev, int rpmflags)
 	int retval;
 
 	if (rpmflags & RPM_GET_PUT) {
-		if (!atomic_dec_and_test(&dev->power.usage_count)) {
+		retval = rpm_drop_usage_count(dev);
+		if (retval < 0) {
+			return retval;
+		} else if (retval > 0) {
 			trace_rpm_usage_rcuidle(dev, rpmflags);
 			return 0;
 		}
@@ -1187,12 +1237,13 @@ int __pm_runtime_set_status(struct device *dev, unsigned int status)
 {
 	struct device *parent = dev->parent;
 	bool notify_parent = false;
+	unsigned long flags;
 	int error = 0;
 
 	if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
 		return -EINVAL;
 
-	spin_lock_irq(&dev->power.lock);
+	spin_lock_irqsave(&dev->power.lock, flags);
 
 	/*
 	 * Prevent PM-runtime from being enabled for the device or return an
@@ -1203,7 +1254,7 @@ int __pm_runtime_set_status(struct device *dev, unsigned int status)
 	else
 		error = -EAGAIN;
 
-	spin_unlock_irq(&dev->power.lock);
+	spin_unlock_irqrestore(&dev->power.lock, flags);
 
 	if (error)
 		return error;
@@ -1224,7 +1275,7 @@ int __pm_runtime_set_status(struct device *dev, unsigned int status)
 		device_links_read_unlock(idx);
 	}
 
-	spin_lock_irq(&dev->power.lock);
+	spin_lock_irqsave(&dev->power.lock, flags);
 
 	if (dev->power.runtime_status == status || !parent)
 		goto out_set;
@@ -1265,7 +1316,7 @@ int __pm_runtime_set_status(struct device *dev, unsigned int status)
 		dev->power.runtime_error = 0;
 
  out:
-	spin_unlock_irq(&dev->power.lock);
+	spin_unlock_irqrestore(&dev->power.lock, flags);
 
 	if (notify_parent)
 		pm_request_idle(parent);
@@ -1410,8 +1461,10 @@ void __pm_runtime_disable(struct device *dev, bool check_resume)
 	/* Update time accounting before disabling PM-runtime. */
 	update_pm_runtime_accounting(dev);
 
-	if (!dev->power.disable_depth++)
+	if (!dev->power.disable_depth++) {
 		__pm_runtime_barrier(dev);
+		dev->power.last_status = dev->power.runtime_status;
+	}
 
  out:
 	spin_unlock_irq(&dev->power.lock);
@@ -1428,34 +1481,39 @@ void pm_runtime_enable(struct device *dev)
 
 	spin_lock_irqsave(&dev->power.lock, flags);
 
-	if (dev->power.disable_depth > 0) {
-		dev->power.disable_depth--;
-
-		/* About to enable runtime pm, set accounting_timestamp to now */
-		if (!dev->power.disable_depth)
-			dev->power.accounting_timestamp = ktime_get_mono_fast_ns();
-	} else {
+	if (!dev->power.disable_depth) {
 		dev_warn(dev, "Unbalanced %s!\n", __func__);
+		goto out;
 	}
 
-	WARN(!dev->power.disable_depth &&
-	     dev->power.runtime_status == RPM_SUSPENDED &&
-	     !dev->power.ignore_children &&
-	     atomic_read(&dev->power.child_count) > 0,
-	     "Enabling runtime PM for inactive device (%s) with active children\n",
-	     dev_name(dev));
+	if (--dev->power.disable_depth > 0)
+		goto out;
+
+	dev->power.last_status = RPM_INVALID;
+	dev->power.accounting_timestamp = ktime_get_mono_fast_ns();
 
+	if (dev->power.runtime_status == RPM_SUSPENDED &&
+	    !dev->power.ignore_children &&
+	    atomic_read(&dev->power.child_count) > 0)
+		dev_warn(dev, "Enabling runtime PM for inactive device with active children\n");
+
+out:
 	spin_unlock_irqrestore(&dev->power.lock, flags);
 }
 EXPORT_SYMBOL_GPL(pm_runtime_enable);
 
 static void pm_runtime_disable_action(void *data)
 {
+	pm_runtime_dont_use_autosuspend(data);
 	pm_runtime_disable(data);
 }
 
 /**
  * devm_pm_runtime_enable - devres-enabled version of pm_runtime_enable.
+ *
+ * NOTE: this will also handle calling pm_runtime_dont_use_autosuspend() for
+ * you at driver exit time if needed.
+ *
  * @dev: Device to handle.
  */
 int devm_pm_runtime_enable(struct device *dev)
@@ -1497,14 +1555,17 @@ EXPORT_SYMBOL_GPL(pm_runtime_forbid);
  */
 void pm_runtime_allow(struct device *dev)
 {
+	int ret;
+
 	spin_lock_irq(&dev->power.lock);
 	if (dev->power.runtime_auto)
 		goto out;
 
 	dev->power.runtime_auto = true;
-	if (atomic_dec_and_test(&dev->power.usage_count))
+	ret = rpm_drop_usage_count(dev);
+	if (ret == 0)
 		rpm_idle(dev, RPM_AUTO | RPM_ASYNC);
-	else
+	else if (ret > 0)
 		trace_rpm_usage_rcuidle(dev, RPM_AUTO | RPM_ASYNC);
 
  out:
@@ -1640,6 +1701,7 @@ EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
 void pm_runtime_init(struct device *dev)
 {
 	dev->power.runtime_status = RPM_SUSPENDED;
+	dev->power.last_status = RPM_INVALID;
 	dev->power.idle_notification = false;
 
 	dev->power.disable_depth = 1;
@@ -1709,7 +1771,6 @@ void pm_runtime_get_suppliers(struct device *dev)
 		if (link->flags & DL_FLAG_PM_RUNTIME) {
 			link->supplier_preactivated = true;
 			pm_runtime_get_sync(link->supplier);
-			refcount_inc(&link->rpm_active);
 		}
 
 	device_links_read_unlock(idx);
@@ -1722,8 +1783,6 @@ void pm_runtime_get_suppliers(struct device *dev)
 void pm_runtime_put_suppliers(struct device *dev)
 {
 	struct device_link *link;
-	unsigned long flags;
-	bool put;
 	int idx;
 
 	idx = device_links_read_lock();
@@ -1732,12 +1791,7 @@ void pm_runtime_put_suppliers(struct device *dev)
 				device_links_read_lock_held())
 		if (link->supplier_preactivated) {
 			link->supplier_preactivated = false;
-			spin_lock_irqsave(&dev->power.lock, flags);
-			put = pm_runtime_status_suspended(dev) &&
-			      refcount_dec_not_one(&link->rpm_active);
-			spin_unlock_irqrestore(&dev->power.lock, flags);
-			if (put)
-				pm_runtime_put(link->supplier);
+			pm_runtime_put(link->supplier);
 		}
 
 	device_links_read_unlock(idx);
@@ -1772,9 +1826,8 @@ void pm_runtime_drop_link(struct device_link *link)
 		return;
 
 	pm_runtime_drop_link_count(link->consumer);
-
-	while (refcount_dec_not_one(&link->rpm_active))
-		pm_runtime_put(link->supplier);
+	pm_runtime_release_supplier(link);
+	pm_request_idle(link->supplier);
 }
 
 static bool pm_runtime_need_not_resume(struct device *dev)
@@ -1812,10 +1865,13 @@ int pm_runtime_force_suspend(struct device *dev)
 
 	callback = RPM_GET_CALLBACK(dev, runtime_suspend);
 
+	dev_pm_enable_wake_irq_check(dev, true);
 	ret = callback ? callback(dev) : 0;
 	if (ret)
 		goto err;
 
+	dev_pm_enable_wake_irq_complete(dev);
+
 	/*
 	 * If the device can stay in suspend after the system-wide transition
 	 * to the working state that will follow, drop the children counter of
@@ -1832,6 +1888,7 @@ int pm_runtime_force_suspend(struct device *dev)
 	return 0;
 
 err:
+	dev_pm_disable_wake_irq_check(dev, true);
 	pm_runtime_enable(dev);
 	return ret;
 }
@@ -1865,9 +1922,11 @@ int pm_runtime_force_resume(struct device *dev)
 
 	callback = RPM_GET_CALLBACK(dev, runtime_resume);
 
+	dev_pm_disable_wake_irq_check(dev, false);
 	ret = callback ? callback(dev) : 0;
 	if (ret) {
 		pm_runtime_set_suspended(dev);
+		dev_pm_enable_wake_irq_check(dev, false);
 		goto out;
 	}