[PATCH 4.20 026/117] USB: leds: fix regression in usbport led trigger

[Greg Kroah-Hartman]

4.20-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Christian Lamparter <chunkeey@xxxxxxxxx>

commit 91f7d2e89868fcac0e750a28230fdb1ad4512137 upstream.

The patch "usb: simplify usbport trigger" together with "leds: triggers:
add device attribute support" caused an regression for the usbport
trigger. it will no longer enumerate any active usb hub ports under the
"ports" directory in the sysfs class directory, if the usb host drivers
are fully initialized before the usbport trigger was loaded.

The reason is that the usbport driver tries to register the sysfs
entries during the activate() callback. And this will fail with -2 /
ENOENT because the patch "leds: triggers: add device attribute support"
made it so that the sysfs "ports" group was only being added after the
activate() callback succeeded.

This version of the patch reverts parts of the "usb: simplify usbport
trigger" patch and restores usbport trigger's functionality.

Fixes: 6f7b0bad8839 ("usb: simplify usbport trigger")
Signed-off-by: Christian Lamparter <chunkeey@xxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Acked-by: Jacek Anaszewski <jacek.anaszewski@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/usb/core/ledtrig-usbport.c |   17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

--- a/drivers/usb/core/ledtrig-usbport.c
+++ b/drivers/usb/core/ledtrig-usbport.c
@@ -119,11 +119,6 @@ static const struct attribute_group port
 	.attrs = ports_attrs,
 };
 
-static const struct attribute_group *ports_groups[] = {
-	&ports_group,
-	NULL
-};
-
 /***************************************
  * Adding & removing ports
  ***************************************/
@@ -307,6 +302,7 @@ static int usbport_trig_notify(struct no
 static int usbport_trig_activate(struct led_classdev *led_cdev)
 {
 	struct usbport_trig_data *usbport_data;
+	int err;
 
 	usbport_data = kzalloc(sizeof(*usbport_data), GFP_KERNEL);
 	if (!usbport_data)
@@ -315,6 +311,9 @@ static int usbport_trig_activate(struct
 
 	/* List of ports */
 	INIT_LIST_HEAD(&usbport_data->ports);
+	err = sysfs_create_group(&led_cdev->dev->kobj, &ports_group);
+	if (err)
+		goto err_free;
 	usb_for_each_dev(usbport_data, usbport_trig_add_usb_dev_ports);
 	usbport_trig_update_count(usbport_data);
 
@@ -322,8 +321,11 @@ static int usbport_trig_activate(struct
 	usbport_data->nb.notifier_call = usbport_trig_notify;
 	led_set_trigger_data(led_cdev, usbport_data);
 	usb_register_notify(&usbport_data->nb);
-
 	return 0;
+
+err_free:
+	kfree(usbport_data);
+	return err;
 }
 
 static void usbport_trig_deactivate(struct led_classdev *led_cdev)
@@ -335,6 +337,8 @@ static void usbport_trig_deactivate(stru
 		usbport_trig_remove_port(usbport_data, port);
 	}
 
+	sysfs_remove_group(&led_cdev->dev->kobj, &ports_group);
+
 	usb_unregister_notify(&usbport_data->nb);
 
 	kfree(usbport_data);
@@ -344,7 +348,6 @@ static struct led_trigger usbport_led_tr
 	.name     = "usbport",
 	.activate = usbport_trig_activate,
 	.deactivate = usbport_trig_deactivate,
-	.groups = ports_groups,
 };
 
 static int __init usbport_trig_init(void)