1 files changed, 59 insertions, 11 deletions

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 36622b52e419..9d3c15d4dde8 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -178,10 +178,10 @@ void device_pm_move_to_tail(struct device *dev)
  * of the link.  If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
  * ignored.
  *
- * If the DL_FLAG_AUTOREMOVE is set, the link will be removed automatically
- * when the consumer device driver unbinds from it.  The combination of both
- * DL_FLAG_AUTOREMOVE and DL_FLAG_STATELESS set is invalid and will cause NULL
- * to be returned.
+ * If the DL_FLAG_AUTOREMOVE_CONSUMER is set, the link will be removed
+ * automatically when the consumer device driver unbinds from it.
+ * The combination of both DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_STATELESS
+ * set is invalid and will cause NULL to be returned.
  *
  * A side effect of the link creation is re-ordering of dpm_list and the
  * devices_kset list by moving the consumer device and all devices depending
@@ -198,7 +198,8 @@ struct device_link *device_link_add(struct device *consumer,
 	struct device_link *link;
 
 	if (!consumer || !supplier ||
-	    ((flags & DL_FLAG_STATELESS) && (flags & DL_FLAG_AUTOREMOVE)))
+	    ((flags & DL_FLAG_STATELESS) &&
+	     (flags & DL_FLAG_AUTOREMOVE_CONSUMER)))
 		return NULL;
 
 	device_links_write_lock();
@@ -236,6 +237,13 @@ struct device_link *device_link_add(struct device *consumer,
 			link->rpm_active = true;
 		}
 		pm_runtime_new_link(consumer);
+		/*
+		 * If the link is being added by the consumer driver at probe
+		 * time, balance the decrementation of the supplier's runtime PM
+		 * usage counter after consumer probe in driver_probe_device().
+		 */
+		if (consumer->links.status == DL_DEV_PROBING)
+			pm_runtime_get_noresume(supplier);
 	}
 	get_device(supplier);
 	link->supplier = supplier;
@@ -255,12 +263,12 @@ struct device_link *device_link_add(struct device *consumer,
 			switch (consumer->links.status) {
 			case DL_DEV_PROBING:
 				/*
-				 * Balance the decrementation of the supplier's
-				 * runtime PM usage counter after consumer probe
-				 * in driver_probe_device().
+				 * Some callers expect the link creation during
+				 * consumer driver probe to resume the supplier
+				 * even without DL_FLAG_RPM_ACTIVE.
 				 */
 				if (flags & DL_FLAG_PM_RUNTIME)
-					pm_runtime_get_sync(supplier);
+					pm_runtime_resume(supplier);
 
 				link->status = DL_STATE_CONSUMER_PROBE;
 				break;
@@ -365,6 +373,36 @@ void device_link_del(struct device_link *link)
 }
 EXPORT_SYMBOL_GPL(device_link_del);
 
+/**
+ * device_link_remove - remove a link between two devices.
+ * @consumer: Consumer end of the link.
+ * @supplier: Supplier end of the link.
+ *
+ * The caller must ensure proper synchronization of this function with runtime
+ * PM.
+ */
+void device_link_remove(void *consumer, struct device *supplier)
+{
+	struct device_link *link;
+
+	if (WARN_ON(consumer == supplier))
+		return;
+
+	device_links_write_lock();
+	device_pm_lock();
+
+	list_for_each_entry(link, &supplier->links.consumers, s_node) {
+		if (link->consumer == consumer) {
+			kref_put(&link->kref, __device_link_del);
+			break;
+		}
+	}
+
+	device_pm_unlock();
+	device_links_write_unlock();
+}
+EXPORT_SYMBOL_GPL(device_link_remove);
+
 static void device_links_missing_supplier(struct device *dev)
 {
 	struct device_link *link;
@@ -472,7 +510,7 @@ static void __device_links_no_driver(struct device *dev)
 		if (link->flags & DL_FLAG_STATELESS)
 			continue;
 
-		if (link->flags & DL_FLAG_AUTOREMOVE)
+		if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
 			kref_put(&link->kref, __device_link_del);
 		else if (link->status != DL_STATE_SUPPLIER_UNBIND)
 			WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
@@ -508,8 +546,18 @@ void device_links_driver_cleanup(struct device *dev)
 		if (link->flags & DL_FLAG_STATELESS)
 			continue;
 
-		WARN_ON(link->flags & DL_FLAG_AUTOREMOVE);
+		WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER);
 		WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
+
+		/*
+		 * autoremove the links between this @dev and its consumer
+		 * devices that are not active, i.e. where the link state
+		 * has moved to DL_STATE_SUPPLIER_UNBIND.
+		 */
+		if (link->status == DL_STATE_SUPPLIER_UNBIND &&
+		    link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
+			kref_put(&link->kref, __device_link_del);
+
 		WRITE_ONCE(link->status, DL_STATE_DORMANT);
 	}