1 files changed, 17 insertions, 8 deletions

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 5847364f25d9..b610816eb887 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -196,8 +196,10 @@ struct device_link *device_link_add(struct device *consumer,
 	}
 
 	list_for_each_entry(link, &supplier->links.consumers, s_node)
-		if (link->consumer == consumer)
+		if (link->consumer == consumer) {
+			kref_get(&link->kref);
 			goto out;
+		}
 
 	link = kzalloc(sizeof(*link), GFP_KERNEL);
 	if (!link)
@@ -222,6 +224,7 @@ struct device_link *device_link_add(struct device *consumer,
 	link->consumer = consumer;
 	INIT_LIST_HEAD(&link->c_node);
 	link->flags = flags;
+	kref_init(&link->kref);
 
 	/* Determine the initial link state. */
 	if (flags & DL_FLAG_STATELESS) {
@@ -292,8 +295,10 @@ static void __device_link_free_srcu(struct rcu_head *rhead)
 	device_link_free(container_of(rhead, struct device_link, rcu_head));
 }
 
-static void __device_link_del(struct device_link *link)
+static void __device_link_del(struct kref *kref)
 {
+	struct device_link *link = container_of(kref, struct device_link, kref);
+
 	dev_info(link->consumer, "Dropping the link to %s\n",
 		 dev_name(link->supplier));
 
@@ -305,8 +310,10 @@ static void __device_link_del(struct device_link *link)
 	call_srcu(&device_links_srcu, &link->rcu_head, __device_link_free_srcu);
 }
 #else /* !CONFIG_SRCU */
-static void __device_link_del(struct device_link *link)
+static void __device_link_del(struct kref *kref)
 {
+	struct device_link *link = container_of(kref, struct device_link, kref);
+
 	dev_info(link->consumer, "Dropping the link to %s\n",
 		 dev_name(link->supplier));
 
@@ -324,13 +331,15 @@ static void __device_link_del(struct device_link *link)
  * @link: Device link to delete.
  *
  * The caller must ensure proper synchronization of this function with runtime
- * PM.
+ * PM.  If the link was added multiple times, it needs to be deleted as often.
+ * Care is required for hotplugged devices:  Their links are purged on removal
+ * and calling device_link_del() is then no longer allowed.
  */
 void device_link_del(struct device_link *link)
 {
 	device_links_write_lock();
 	device_pm_lock();
-	__device_link_del(link);
+	kref_put(&link->kref, __device_link_del);
 	device_pm_unlock();
 	device_links_write_unlock();
 }
@@ -444,7 +453,7 @@ static void __device_links_no_driver(struct device *dev)
 			continue;
 
 		if (link->flags & DL_FLAG_AUTOREMOVE)
-			__device_link_del(link);
+			kref_put(&link->kref, __device_link_del);
 		else if (link->status != DL_STATE_SUPPLIER_UNBIND)
 			WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
 	}
@@ -597,13 +606,13 @@ static void device_links_purge(struct device *dev)
 
 	list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
 		WARN_ON(link->status == DL_STATE_ACTIVE);
-		__device_link_del(link);
+		__device_link_del(&link->kref);
 	}
 
 	list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
 		WARN_ON(link->status != DL_STATE_DORMANT &&
 			link->status != DL_STATE_NONE);
-		__device_link_del(link);
+		__device_link_del(&link->kref);
 	}
 
 	device_links_write_unlock();