usb: typec: ucsi: add a common function ucsi_unregister_connectors()

In error path of ucsi_init(), it will unregister all valid ucsi connectors,
and similar operation also happen in ucsi_unregister(),
add a common function ucsi_unregister_connectors() for two places,
inside this function, if con->wq is NULL, it will break the loop,
if other kind of error happen after con->wq allocated,
ucsi/typec related API is safe to unregister.

Also in ucsi_init(), it allocate number of (ucsi->cap.num_connectors + 1)
connectors, there is one extra as the ending,
ucsi_unregister_connectors() is safe to unregister all ucsi connectors
according ucsi->cap.num_connectors,
remove the extra one connector to save memory.
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
Link: https://lore.kernel.org/r/1650881886-25530-2-git-send-email-quic_linyyuan@quicinc.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/typec/ucsi/ucsi.c

@@ -1186,6 +1186,32 @@ static int ucsi_register_port(struct ucsi *ucsi, int index)
 	return ret;
 }
 
+static void ucsi_unregister_connectors(struct ucsi *ucsi)
+{
+	struct ucsi_connector *con;
+	int i;
+
+	if (!ucsi->connector)
+		return;
+
+	for (i = 0; i < ucsi->cap.num_connectors; i++) {
+		con = &ucsi->connector[i];
+
+		if (!con->wq)
+			break;
+
+		cancel_work_sync(&con->work);
+		ucsi_unregister_partner(con);
+		ucsi_unregister_altmodes(con, UCSI_RECIPIENT_CON);
+		ucsi_unregister_port_psy(con);
+		destroy_workqueue(con->wq);
+		typec_unregister_port(con->port);
+	}
+
+	kfree(ucsi->connector);
+	ucsi->connector = NULL;
+}
+
 /**
  * ucsi_init - Initialize UCSI interface
  * @ucsi: UCSI to be initialized
@@ -1194,7 +1220,6 @@ static int ucsi_register_port(struct ucsi *ucsi, int index)
  */
 static int ucsi_init(struct ucsi *ucsi)
 {
-	struct ucsi_connector *con;
 	u64 command;
 	int ret;
 	int i;
@@ -1225,7 +1250,7 @@ static int ucsi_init(struct ucsi *ucsi)
 	}
 
 	/* Allocate the connectors. Released in ucsi_unregister() */
-	ucsi->connector = kcalloc(ucsi->cap.num_connectors + 1,
+	ucsi->connector = kcalloc(ucsi->cap.num_connectors,
 				  sizeof(*ucsi->connector), GFP_KERNEL);
 	if (!ucsi->connector) {
 		ret = -ENOMEM;
@@ -1249,15 +1274,7 @@ static int ucsi_init(struct ucsi *ucsi)
 	return 0;
 
 err_unregister:
-	for (con = ucsi->connector; con->port; con++) {
-		ucsi_unregister_partner(con);
-		ucsi_unregister_altmodes(con, UCSI_RECIPIENT_CON);
-		ucsi_unregister_port_psy(con);
-		if (con->wq)
-			destroy_workqueue(con->wq);
-		typec_unregister_port(con->port);
-		con->port = NULL;
-	}
+	ucsi_unregister_connectors(ucsi);
 
 err_reset:
 	memset(&ucsi->cap, 0, sizeof(ucsi->cap));
@@ -1363,7 +1380,6 @@ EXPORT_SYMBOL_GPL(ucsi_register);
 void ucsi_unregister(struct ucsi *ucsi)
 {
 	u64 cmd = UCSI_SET_NOTIFICATION_ENABLE;
-	int i;
 
 	/* Make sure that we are not in the middle of driver initialization */
 	cancel_work_sync(&ucsi->work);
@@ -1371,18 +1387,7 @@ void ucsi_unregister(struct ucsi *ucsi)
 	/* Disable notifications */
 	ucsi->ops->async_write(ucsi, UCSI_CONTROL, &cmd, sizeof(cmd));
 
-	for (i = 0; i < ucsi->cap.num_connectors; i++) {
-		cancel_work_sync(&ucsi->connector[i].work);
-		ucsi_unregister_partner(&ucsi->connector[i]);
-		ucsi_unregister_altmodes(&ucsi->connector[i],
-					 UCSI_RECIPIENT_CON);
-		ucsi_unregister_port_psy(&ucsi->connector[i]);
-		if (ucsi->connector[i].wq)
-			destroy_workqueue(ucsi->connector[i].wq);
-		typec_unregister_port(ucsi->connector[i].port);
-	}
-
-	kfree(ucsi->connector);
+	ucsi_unregister_connectors(ucsi);
 }
 EXPORT_SYMBOL_GPL(ucsi_unregister);