Revert "PM / runtime: Fixup reference counting of device link suppliers at probe"

Revert commit 1e83786 (PM / runtime: Fixup reference counting of
device link suppliers at probe), as it has introduced a regression
and the condition it was designed to address should be covered by the
existing code.

Reported-by: Marek Szyprowski <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>

Author: rafaeljw

drivers/base/dd.c

@@ -580,7 +580,7 @@ int driver_probe_device(struct device_driver *drv, struct device *dev)
 	pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
 		 drv->bus->name, __func__, dev_name(dev), drv->name);
 
-	pm_runtime_resume_suppliers(dev);
+	pm_runtime_get_suppliers(dev);
 	if (dev->parent)
 		pm_runtime_get_sync(dev->parent);
 
@@ -591,6 +591,7 @@ int driver_probe_device(struct device_driver *drv, struct device *dev)
 	if (dev->parent)
 		pm_runtime_put(dev->parent);
 
+	pm_runtime_put_suppliers(dev);
 	return ret;
 }
 

drivers/base/power/runtime.c

@@ -1563,16 +1563,37 @@ void pm_runtime_clean_up_links(struct device *dev)
 }
 
 /**
- * pm_runtime_resume_suppliers - Resume supplier devices.
+ * pm_runtime_get_suppliers - Resume and reference-count supplier devices.
  * @dev: Consumer device.
  */
-void pm_runtime_resume_suppliers(struct device *dev)
+void pm_runtime_get_suppliers(struct device *dev)
 {
+	struct device_link *link;
 	int idx;
 
 	idx = device_links_read_lock();
 
-	rpm_get_suppliers(dev);
+	list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
+		if (link->flags & DL_FLAG_PM_RUNTIME)
+			pm_runtime_get_sync(link->supplier);
+
+	device_links_read_unlock(idx);
+}
+
+/**
+ * pm_runtime_put_suppliers - Drop references to supplier devices.
+ * @dev: Consumer device.
+ */
+void pm_runtime_put_suppliers(struct device *dev)
+{
+	struct device_link *link;
+	int idx;
+
+	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);
 
 	device_links_read_unlock(idx);
 }

include/linux/pm_runtime.h

@@ -56,7 +56,8 @@ extern void pm_runtime_update_max_time_suspended(struct device *dev,
 						 s64 delta_ns);
 extern void pm_runtime_set_memalloc_noio(struct device *dev, bool enable);
 extern void pm_runtime_clean_up_links(struct device *dev);
-extern void pm_runtime_resume_suppliers(struct device *dev);
+extern void pm_runtime_get_suppliers(struct device *dev);
+extern void pm_runtime_put_suppliers(struct device *dev);
 extern void pm_runtime_new_link(struct device *dev);
 extern void pm_runtime_drop_link(struct device *dev);
 
@@ -172,7 +173,8 @@ static inline unsigned long pm_runtime_autosuspend_expiration(
 static inline void pm_runtime_set_memalloc_noio(struct device *dev,
 						bool enable){}
 static inline void pm_runtime_clean_up_links(struct device *dev) {}
-static inline void pm_runtime_resume_suppliers(struct device *dev) {}
+static inline void pm_runtime_get_suppliers(struct device *dev) {}
+static inline void pm_runtime_put_suppliers(struct device *dev) {}
 static inline void pm_runtime_new_link(struct device *dev) {}
 static inline void pm_runtime_drop_link(struct device *dev) {}