1 files changed, 22 insertions, 15 deletions

diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
index a12ee8ef27a8..c7c3b9bae938 100644
--- a/drivers/infiniband/core/device.c
+++ b/drivers/infiniband/core/device.c
@@ -1700,7 +1700,7 @@ static int assign_client_id(struct ib_client *client)
 {
 	int ret;
 
-	down_write(&clients_rwsem);
+	lockdep_assert_held(&clients_rwsem);
 	/*
 	 * The add/remove callbacks must be called in FIFO/LIFO order. To
 	 * achieve this we assign client_ids so they are sorted in
@@ -1709,14 +1709,11 @@ static int assign_client_id(struct ib_client *client)
 	client->client_id = highest_client_id;
 	ret = xa_insert(&clients, client->client_id, client, GFP_KERNEL);
 	if (ret)
-		goto out;
+		return ret;
 
 	highest_client_id++;
 	xa_set_mark(&clients, client->client_id, CLIENT_REGISTERED);
-
-out:
-	up_write(&clients_rwsem);
-	return ret;
+	return 0;
 }
 
 static void remove_client_id(struct ib_client *client)
@@ -1746,25 +1743,35 @@ int ib_register_client(struct ib_client *client)
 {
 	struct ib_device *device;
 	unsigned long index;
+	bool need_unreg = false;
 	int ret;
 
 	refcount_set(&client->uses, 1);
 	init_completion(&client->uses_zero);
+
+	/*
+	 * The devices_rwsem is held in write mode to ensure that a racing
+	 * ib_register_device() sees a consisent view of clients and devices.
+	 */
+	down_write(&devices_rwsem);
+	down_write(&clients_rwsem);
 	ret = assign_client_id(client);
 	if (ret)
-		return ret;
+		goto out;
 
-	down_read(&devices_rwsem);
+	need_unreg = true;
 	xa_for_each_marked (&devices, index, device, DEVICE_REGISTERED) {
 		ret = add_client_context(device, client);
-		if (ret) {
-			up_read(&devices_rwsem);
-			ib_unregister_client(client);
-			return ret;
-		}
+		if (ret)
+			goto out;
 	}
-	up_read(&devices_rwsem);
-	return 0;
+	ret = 0;
+out:
+	up_write(&clients_rwsem);
+	up_write(&devices_rwsem);
+	if (need_unreg && ret)
+		ib_unregister_client(client);
+	return ret;
 }
 EXPORT_SYMBOL(ib_register_client);