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SubjectRe: [PATCH] usb: dwc3: gadget: Handle dequeuing of non queued URB gracefully
Date
On Tue, 2019-11-12 at 15:41 +0100, Michael Olbrich wrote:
> [External]
>
> On Wed, Nov 06, 2019 at 04:45:53PM +0200, Alexandru Ardelean wrote:
> > From: Lars-Peter Clausen <lars@metafoo.de>
> >
> > 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@metafoo.de>
> > Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
>
> Thanks, no more "dwc3 fe200000.usb: request 00000000cdd42e4a was not
> queued
> to ep2in" messages with this patch applied.
>
> Tested-by: Michael Olbrich <m.olbrich@pengutronix.de>
>

I thought I replied here, but I guess I never hit the Send button.
Many thanks @Michael for testing this.

I'd also use the opportunity to make this a patch-ping message.

Thanks
Alex

> > ---
> > 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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