On Wed, Nov 06, 2019 at 04:45:53PM +0200, Alexandru Ardelean wrote:
> From: Lars-Peter Clausen <lars@xxxxxxxxxx>
>
> Trying to dequeue and URB that is currently not queued should be a no-op
> and be handled gracefully.
>
> Use the list field of the URB to indicate whether it is queued or not by
> setting it to the empty list when it is not queued.
>
> Handling this gracefully allows for race condition free synchronization
> between the complete callback being called to to a completed transfer and
> trying to call usb_ep_dequeue() at the same time.
>
> Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>
Thanks, no more "dwc3 fe200000.usb: request 00000000cdd42e4a was not queued
to ep2in" messages with this patch applied.
Tested-by: Michael Olbrich <m.olbrich@xxxxxxxxxxxxxx>
> ---
> drivers/usb/dwc3/gadget.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index a9aba716bf80..b500ec6b0aa8 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -174,7 +174,7 @@ static void dwc3_gadget_del_and_unmap_request(struct dwc3_ep *dep,
> {
> struct dwc3 *dwc = dep->dwc;
>
> - list_del(&req->list);
> + list_del_init(&req->list);
> req->remaining = 0;
> req->needs_extra_trb = false;
>
> @@ -844,6 +844,7 @@ static struct usb_request *dwc3_gadget_ep_alloc_request(struct usb_ep *ep,
> req->epnum = dep->number;
> req->dep = dep;
> req->status = DWC3_REQUEST_STATUS_UNKNOWN;
> + INIT_LIST_HEAD(&req->list);
>
> trace_dwc3_alloc_request(req);
>
> @@ -1540,6 +1541,10 @@ static int dwc3_gadget_ep_dequeue(struct usb_ep *ep,
>
> spin_lock_irqsave(&dwc->lock, flags);
>
> + /* Not queued, nothing to do */
> + if (list_empty(&req->list))
> + goto out0;
> +
> list_for_each_entry(r, &dep->pending_list, list) {
> if (r == req)
> break;
--
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