1 files changed, 74 insertions, 27 deletions

diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index a2d22e3ecf3a..977db40378b0 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -292,11 +292,8 @@ static int rpm_get_suppliers(struct device *dev)
 	list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) {
 		int retval;
 
-		if (!(link->flags & DL_FLAG_PM_RUNTIME))
-			continue;
-
-		if (READ_ONCE(link->status) == DL_STATE_SUPPLIER_UNBIND ||
-		    link->rpm_active)
+		if (!(link->flags & DL_FLAG_PM_RUNTIME) ||
+		    READ_ONCE(link->status) == DL_STATE_SUPPLIER_UNBIND)
 			continue;
 
 		retval = pm_runtime_get_sync(link->supplier);
@@ -305,7 +302,7 @@ static int rpm_get_suppliers(struct device *dev)
 			pm_runtime_put_noidle(link->supplier);
 			return retval;
 		}
-		link->rpm_active = true;
+		refcount_inc(&link->rpm_active);
 	}
 	return 0;
 }
@@ -314,12 +311,13 @@ static void rpm_put_suppliers(struct device *dev)
 {
 	struct device_link *link;
 
-	list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
-		if (link->rpm_active &&
-		    READ_ONCE(link->status) != DL_STATE_SUPPLIER_UNBIND) {
+	list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) {
+		if (READ_ONCE(link->status) == DL_STATE_SUPPLIER_UNBIND)
+			continue;
+
+		while (refcount_dec_not_one(&link->rpm_active))
 			pm_runtime_put(link->supplier);
-			link->rpm_active = false;
-		}
+	}
 }
 
 /**
@@ -1124,24 +1122,57 @@ EXPORT_SYMBOL_GPL(pm_runtime_get_if_in_use);
  * and the device parent's counter of unsuspended children is modified to
  * reflect the new status.  If the new status is RPM_SUSPENDED, an idle
  * notification request for the parent is submitted.
+ *
+ * If @dev has any suppliers (as reflected by device links to them), and @status
+ * is RPM_ACTIVE, they will be activated upfront and if the activation of one
+ * of them fails, the status of @dev will be changed to RPM_SUSPENDED (instead
+ * of the @status value) and the suppliers will be deacticated on exit.  The
+ * error returned by the failing supplier activation will be returned in that
+ * case.
  */
 int __pm_runtime_set_status(struct device *dev, unsigned int status)
 {
 	struct device *parent = dev->parent;
-	unsigned long flags;
 	bool notify_parent = false;
 	int error = 0;
 
 	if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
 		return -EINVAL;
 
-	spin_lock_irqsave(&dev->power.lock, flags);
+	spin_lock_irq(&dev->power.lock);
 
-	if (!dev->power.runtime_error && !dev->power.disable_depth) {
+	/*
+	 * Prevent PM-runtime from being enabled for the device or return an
+	 * error if it is enabled already and working.
+	 */
+	if (dev->power.runtime_error || dev->power.disable_depth)
+		dev->power.disable_depth++;
+	else
 		error = -EAGAIN;
-		goto out;
+
+	spin_unlock_irq(&dev->power.lock);
+
+	if (error)
+		return error;
+
+	/*
+	 * If the new status is RPM_ACTIVE, the suppliers can be activated
+	 * upfront regardless of the current status, because next time
+	 * rpm_put_suppliers() runs, the rpm_active refcounts of the links
+	 * involved will be dropped down to one anyway.
+	 */
+	if (status == RPM_ACTIVE) {
+		int idx = device_links_read_lock();
+
+		error = rpm_get_suppliers(dev);
+		if (error)
+			status = RPM_SUSPENDED;
+
+		device_links_read_unlock(idx);
 	}
 
+	spin_lock_irq(&dev->power.lock);
+
 	if (dev->power.runtime_status == status || !parent)
 		goto out_set;
 
@@ -1169,19 +1200,33 @@ int __pm_runtime_set_status(struct device *dev, unsigned int status)
 
 		spin_unlock(&parent->power.lock);
 
-		if (error)
+		if (error) {
+			status = RPM_SUSPENDED;
 			goto out;
+		}
 	}
 
  out_set:
 	__update_runtime_status(dev, status);
-	dev->power.runtime_error = 0;
+	if (!error)
+		dev->power.runtime_error = 0;
+
  out:
-	spin_unlock_irqrestore(&dev->power.lock, flags);
+	spin_unlock_irq(&dev->power.lock);
 
 	if (notify_parent)
 		pm_request_idle(parent);
 
+	if (status == RPM_SUSPENDED) {
+		int idx = device_links_read_lock();
+
+		rpm_put_suppliers(dev);
+
+		device_links_read_unlock(idx);
+	}
+
+	pm_runtime_enable(dev);
+
 	return error;
 }
 EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
@@ -1579,7 +1624,7 @@ void pm_runtime_remove(struct device *dev)
  *
  * Check links from this device to any consumers and if any of them have active
  * runtime PM references to the device, drop the usage counter of the device
- * (once per link).
+ * (as many times as needed).
  *
  * Links with the DL_FLAG_STATELESS flag set are ignored.
  *
@@ -1601,10 +1646,8 @@ void pm_runtime_clean_up_links(struct device *dev)
 		if (link->flags & DL_FLAG_STATELESS)
 			continue;
 
-		if (link->rpm_active) {
+		while (refcount_dec_not_one(&link->rpm_active))
 			pm_runtime_put_noidle(dev);
-			link->rpm_active = false;
-		}
 	}
 
 	device_links_read_unlock(idx);
@@ -1622,8 +1665,11 @@ void pm_runtime_get_suppliers(struct device *dev)
 	idx = device_links_read_lock();
 
 	list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
-		if (link->flags & DL_FLAG_PM_RUNTIME)
+		if (link->flags & DL_FLAG_PM_RUNTIME) {
+			link->supplier_preactivated = true;
+			refcount_inc(&link->rpm_active);
 			pm_runtime_get_sync(link->supplier);
+		}
 
 	device_links_read_unlock(idx);
 }
@@ -1640,8 +1686,11 @@ void pm_runtime_put_suppliers(struct device *dev)
 	idx = device_links_read_lock();
 
 	list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
-		if (link->flags & DL_FLAG_PM_RUNTIME)
-			pm_runtime_put(link->supplier);
+		if (link->supplier_preactivated) {
+			link->supplier_preactivated = false;
+			if (refcount_dec_not_one(&link->rpm_active))
+				pm_runtime_put(link->supplier);
+		}
 
 	device_links_read_unlock(idx);
 }
@@ -1655,8 +1704,6 @@ void pm_runtime_new_link(struct device *dev)
 
 void pm_runtime_drop_link(struct device *dev)
 {
-	rpm_put_suppliers(dev);
-
 	spin_lock_irq(&dev->power.lock);
 	WARN_ON(dev->power.links_count == 0);
 	dev->power.links_count--;