On Mon, 14 Sep 2015, Igor Kotrasinski wrote:
> dummy_timer uses transfer() to update transfer limit. However,
> limit passed to dummy_timer changes depending on transfer type,
> so the actual limit is overwritten.
>
> This can cause unpredictably slow / fast bulk transfers when
> coupled with control / interrupt transfers.
>
> Fix by returning actual amount of data sent in transfer() and
> substracting from total.
>
> Signed-off-by: Igor Kotrasinski <i.kotrasinsk@xxxxxxxxxxx>
> ---
> drivers/usb/gadget/udc/dummy_hcd.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/gadget/udc/dummy_hcd.c b/drivers/usb/gadget/udc/dummy_hcd.c
> index 0ba0ab3..38f51ff 100644
> --- a/drivers/usb/gadget/udc/dummy_hcd.c
> +++ b/drivers/usb/gadget/udc/dummy_hcd.c
> @@ -1283,6 +1283,7 @@ static int transfer(struct dummy_hcd *dum_hcd, struct urb *urb,
> {
> struct dummy *dum = dum_hcd->dum;
> struct dummy_request *req;
> + int sent = 0;
>
> top:
> /* if there's no request queued, the device is NAKing; return */
> @@ -1345,6 +1346,7 @@ top:
> req->req.status = len;
> } else {
> limit -= len;
> + sent += len;
> urb->actual_length += len;
> req->req.actual += len;
> }
> @@ -1414,7 +1416,7 @@ top:
> if (rescan)
> goto top;
> }
> - return limit;
> + return sent;
> }
>
> static int periodic_bytes(struct dummy *dum, struct dummy_ep *ep)
> @@ -1844,7 +1846,7 @@ restart:
> default:
> treat_control_like_bulk:
> ep->last_io = jiffies;
> - total = transfer(dum_hcd, urb, ep, limit, &status);
> + total -= transfer(dum_hcd, urb, ep, limit, &status);
> break;
> }
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
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