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Commit d6011f6f authored by Nicolas Saenz Julienne's avatar Nicolas Saenz Julienne Committed by Felipe Balbi
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usb: dwc3: gadget: don't rely on jiffies while holding spinlock 



__dwc3_gadget_wakeup() is called while holding a spinlock, then depends on
jiffies in order to timeout while polling the USB core for a link state
update. In the case the wakeup failed, the timeout will never happen and
will also cause the cpu to stall until rcu_preempt kicks in.

This switches to a "decrement variable and wait" timeout scheme.

Signed-off-by: default avatarNicolas Saenz Julienne <nicolassaenzj@gmail.com>
Signed-off-by: default avatarFelipe Balbi <felipe.balbi@linux.intel.com>
parent f4693b08

drivers/usb/dwc3/gadget.c

+3 −3
Original line number Diff line number Diff line
@@ -1433,7 +1433,7 @@ static int dwc3_gadget_get_frame(struct usb_gadget *g) 


static int __dwc3_gadget_wakeup(struct dwc3 *dwc)

{

	unsigned long		timeout;

	int			retries;



	int			ret;

	u32			reg;
@@ -1484,9 +1484,9 @@ static int __dwc3_gadget_wakeup(struct dwc3 *dwc) 
	}



	/* poll until Link State changes to ON */

	timeout = jiffies + msecs_to_jiffies(100);

	retries = 20000;



	while (!time_after(jiffies, timeout)) {

	while (retries--) {

		reg = dwc3_readl(dwc->regs, DWC3_DSTS);



		/* in HS, means ON */