Commit 520fe763 authored Nov 10, 2014 by Felipe Balbi

usb: dwc3: ep0: fix for dead code



commit 6856d30c (usb: dwc3: ep0: return early
on NULL requests) tried to fix a minor corner
case where we could dereference a NULL pointer
but it also ended up introducing some dead code.

Unfortunately, that dead code, if reached, could
end up starving the endpoint request list because
a request would never be given back when it should.

Fix this by moving the check for empty request list
before its first use.

Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

parent 206c5f60

drivers/usb/dwc3/ep0.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -791,6 +791,10 @@ static void dwc3_ep0_complete_data(struct dwc3 *dwc,

		trb = dwc->ep0_trb;

		r = next_request(&ep0->request_list);
		if (!r)
		return;

		status = DWC3_TRB_SIZE_TRBSTS(trb->size);
		if (status == DWC3_TRBSTS_SETUP_PENDING) {
		dwc3_trace(trace_dwc3_ep0, "Setup Pending received");
		@@ -801,10 +805,6 @@ static void dwc3_ep0_complete_data(struct dwc3 *dwc,
		return;
		}

		r = next_request(&ep0->request_list);
		if (!r)
		return;

		ur = &r->request;

		length = trb->size & DWC3_TRB_SIZE_MASK;