From stern@rowland.harvard.edu Wed Aug 10 14:16:54 2005 Date: Wed, 10 Aug 2005 17:12:31 -0400 (EDT) From: Alan Stern To: Greg KH Subject: USB: Disconnect children when unbinding the hub driver Message-ID: This patch (as554) makes the hub driver disconnect any child USB devices when it is unbound from a hub. Normally this will never happen, but there are a few oddball ways to unbind the hub driver while leaving the children intact. For example, the new "unbind" sysfs attribute can be used for this purpose. Given that unbinding hubs with children is now safe, the patch also removes the code that prevented people from doing so using usbfs. Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/devio.c | 10 ---------- drivers/usb/core/hub.c | 42 ++++++++++++++++++++++++++++++++++++++++-- 2 files changed, 40 insertions(+), 12 deletions(-) --- gregkh-2.6.orig/drivers/usb/core/hub.c 2005-08-10 14:44:29.000000000 -0700 +++ gregkh-2.6/drivers/usb/core/hub.c 2005-08-10 14:44:37.000000000 -0700 @@ -729,10 +729,29 @@ static unsigned highspeed_hubs; +/* Called after the hub driver is unbound from a hub with children */ +static void hub_remove_children_work(void *__hub) +{ + struct usb_hub *hub = __hub; + struct usb_device *hdev = hub->hdev; + int i; + + kfree(hub); + + usb_lock_device(hdev); + for (i = 0; i < hdev->maxchild; ++i) { + if (hdev->children[i]) + usb_disconnect(&hdev->children[i]); + } + usb_unlock_device(hdev); + usb_put_dev(hdev); +} + static void hub_disconnect(struct usb_interface *intf) { struct usb_hub *hub = usb_get_intfdata (intf); struct usb_device *hdev; + int n, port1; usb_set_intfdata (intf, NULL); hdev = hub->hdev; @@ -760,8 +779,27 @@ hub->buffer = NULL; } - /* Free the memory */ - kfree(hub); + /* If there are any children then this is an unbind only, not a + * physical disconnection. The active ports must be disabled + * and later on we must call usb_disconnect(). We can't call + * it now because we may not hold the hub's device lock. + */ + n = 0; + for (port1 = 1; port1 <= hdev->maxchild; ++port1) { + if (hdev->children[port1 - 1]) { + ++n; + hub_port_disable(hub, port1, 1); + } + } + + if (n == 0) + kfree(hub); + else { + /* Reuse the hub->leds work_struct for our own purposes */ + INIT_WORK(&hub->leds, hub_remove_children_work, hub); + schedule_work(&hub->leds); + usb_get_dev(hdev); + } } static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id) --- gregkh-2.6.orig/drivers/usb/core/devio.c 2005-08-10 14:44:01.000000000 -0700 +++ gregkh-2.6/drivers/usb/core/devio.c 2005-08-10 14:44:37.000000000 -0700 @@ -1238,7 +1238,6 @@ int retval = 0; struct usb_interface *intf = NULL; struct usb_driver *driver = NULL; - int i; /* get input parameters and alloc buffer */ if (copy_from_user(&ctrl, arg, sizeof (ctrl))) @@ -1270,15 +1269,6 @@ /* disconnect kernel driver from interface */ case USBDEVFS_DISCONNECT: - /* don't allow the user to unbind the hub driver from - * a hub with children to manage */ - for (i = 0; i < ps->dev->maxchild; ++i) { - if (ps->dev->children[i]) - retval = -EBUSY; - } - if (retval) - break; - down_write(&usb_bus_type.subsys.rwsem); if (intf->dev.driver) { driver = to_usb_driver(intf->dev.driver);