From: Nicolas Saenz Julienne Date: Tue, 16 Aug 2016 09:22:38 +0000 (+0100) Subject: usb: dwc3: gadget: don't rely on jiffies while holding spinlock X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=d6011f6fc21b4d4ab1586f01c4f62becaa0a28d7;p=linux-beck.git 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: Nicolas Saenz Julienne Signed-off-by: Felipe Balbi --- diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index 1f5597ef945d..122e64df2f4d 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -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 */