On Fri, 7 Jul 2017, Bin Liu wrote:
> 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.
>
> Signed-off-by: Bin Liu <b-liu@xxxxxx>
> ---
> 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 5dea98358c05..6839c176c701 100644
> --- a/drivers/usb/core/hcd.c
> +++ b/drivers/usb/core/hcd.c
> @@ -1878,7 +1878,7 @@ 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)
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
But you might want to get rid of the extra space before the open paren
(what does checkpatch.pl say?).
Alan Stern
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