From 2eac13624364db5b5e1666ae0bb3a4d36bc56b6e Mon Sep 17 00:00:00 2001 From: Bin Liu Date: Tue, 25 Jul 2017 09:31:33 -0500 Subject: [PATCH] usb: core: unlink urbs from the tail of the endpoint's urb_list While unlink an urb, if the urb has been programmed in the controller, the controller driver might do some hw related actions to tear down the urb. Currently usb_hcd_flush_endpoint() passes each urb from the head of the endpoint's urb_list to the controller driver, which could make the controller driver think each urb has been programmed and take the unnecessary actions for each urb. This patch changes the behavior in usb_hcd_flush_endpoint() to pass the urbs from the tail of the list, to avoid any unnecessary actions in an controller driver. Cc: stable@vger.kernel.org # v4.4+ Acked-by: Alan Stern Signed-off-by: Bin Liu Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/hcd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c index e518f6438877..7f277b092b5b 100644 --- a/drivers/usb/core/hcd.c +++ b/drivers/usb/core/hcd.c @@ -1888,7 +1888,7 @@ void usb_hcd_flush_endpoint(struct usb_device *udev, /* No more submits can occur */ spin_lock_irq(&hcd_urb_list_lock); rescan: - list_for_each_entry (urb, &ep->urb_list, urb_list) { + list_for_each_entry_reverse(urb, &ep->urb_list, urb_list) { int is_in; if (urb->unlinked)