Commit d6e10bf2 authored Sep 09, 2016 by Arnd Bergmann Committed by Felipe Balbi Sep 09, 2016

usb: dwc3: avoid -Wmaybe-uninitialized warning

Cleaning up the loop in dwc3_cleanup_done_reqs() introduced a
gcc warning if built with "-Wmaybe-uninitialized":

drivers/usb/dwc3/gadget.c: In function 'dwc3_endpoint_transfer_complete':
drivers/usb/dwc3/gadget.c:2015:9: 'trb' may be used uninitialized in this function [-Wmaybe-uninitialized]

I believe it is a false positive and we always have a valid 'trb'
pointer at the end of the function, but neither I nor the compiler
are able to prove that.

This works around the warning by computing a flag earlier in the function
when it's guaranteed to be valid, which tells the compiler that it's
safe and makes it easier to understand to me.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 31162af4 ("usb: dwc3: gadget: avoid while (1) loop on completion")
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

parent c9ffc787

drivers/usb/dwc3/gadget.c

+9 −5

Original line number	Diff line number	Diff line
		@@ -1934,6 +1934,7 @@ static int dwc3_cleanup_done_reqs(struct dwc3 dwc, struct dwc3_ep dep,
		{
		struct dwc3_request req, n;
		struct dwc3_trb *trb;
		bool ioc = false;
		int ret;

		list_for_each_entry_safe(req, n, &dep->started_list, list) {
		@@ -1981,9 +1982,13 @@ static int dwc3_cleanup_done_reqs(struct dwc3 dwc, struct dwc3_ep dep,

		dwc3_gadget_giveback(dep, req, status);

		if (ret)
		if (ret) {
		if ((event->status & DEPEVT_STATUS_IOC) &&
		(trb->ctrl & DWC3_TRB_CTRL_IOC))
		ioc = true;
		break;
		}
		}

		/*
		* Our endpoint might get disabled by another thread during
		@@ -2010,10 +2015,9 @@ static int dwc3_cleanup_done_reqs(struct dwc3 dwc, struct dwc3_ep dep,
		return 1;
		}

		if (usb_endpoint_xfer_isoc(dep->endpoint.desc))
		if ((event->status & DEPEVT_STATUS_IOC) &&
		(trb->ctrl & DWC3_TRB_CTRL_IOC))
		if (usb_endpoint_xfer_isoc(dep->endpoint.desc) && ioc)
		return 0;

		return 1;
		}