On Thu, 13 Jul 2017, Bin Liu wrote:
> On Fri, Jul 07, 2017 at 11:56:53AM -0400, Alan Stern wrote:
> > 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>
>
> Hi Alan, do you see any issue to tag this for stable v4.4+, in which
> the issue that [PATCH 2/2] tries to solve is introduced?
No issues.
Alan Stern
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
