From: Felipe Balbi Date: Mon, 10 Nov 2014 20:39:44 +0000 (-0600) Subject: usb: dwc3: ep0: fix for dead code X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=520fe7633692181bb6d1560d655fbdfbb7c05aaa;p=linux-beck.git usb: dwc3: ep0: fix for dead code commit 6856d30 (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 Signed-off-by: Felipe Balbi --- diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c index 711b23019d54..df38e7ef4976 100644 --- a/drivers/usb/dwc3/ep0.c +++ b/drivers/usb/dwc3/ep0.c @@ -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;