Commit 87191ca9 authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
Browse files

USB: UDC: Implement udc_async_callbacks in net2272 



This patch adds a udc_async_callbacks handler to the net2272 UDC
driver, which will prevent a theoretical race during gadget unbinding.

The net2272 driver is sufficiently complicated that I didn't want to
mess around with IRQ settings.  Instead, the patch simply adds a new
flag to control async callbacks, and checks the flag before issuing
any of them.

Acked-by: default avatarFelipe Balbi <balbi@kernel.org>
Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20210520202206.GF1216852@rowland.harvard.edu


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b42e8090

drivers/usb/gadget/udc/net2272.c

+27 −14
Original line number Diff line number Diff line
@@ -1150,6 +1150,7 @@ net2272_pullup(struct usb_gadget *_gadget, int is_on) 
static int net2272_start(struct usb_gadget *_gadget,

		struct usb_gadget_driver *driver);

static int net2272_stop(struct usb_gadget *_gadget);

static void net2272_async_callbacks(struct usb_gadget *_gadget, bool enable);



static const struct usb_gadget_ops net2272_ops = {

	.get_frame	= net2272_get_frame,
@@ -1158,6 +1159,7 @@ static const struct usb_gadget_ops net2272_ops = { 
	.pullup		= net2272_pullup,

	.udc_start	= net2272_start,

	.udc_stop	= net2272_stop,

	.udc_async_callbacks = net2272_async_callbacks,

};



/*---------------------------------------------------------------------------*/
@@ -1476,7 +1478,7 @@ stop_activity(struct net2272 *dev, struct usb_gadget_driver *driver) 
		net2272_dequeue_all(&dev->ep[i]);



	/* report disconnect; the driver is already quiesced */

	if (driver) {

	if (dev->async_callbacks && driver) {

		spin_unlock(&dev->lock);

		driver->disconnect(&dev->gadget);

		spin_lock(&dev->lock);
@@ -1501,6 +1503,15 @@ static int net2272_stop(struct usb_gadget *_gadget) 
	return 0;

}



static void net2272_async_callbacks(struct usb_gadget *_gadget, bool enable)

{

	struct net2272	*dev = container_of(_gadget, struct net2272, gadget);



	spin_lock_irq(&dev->lock);

	dev->async_callbacks = enable;

	spin_unlock_irq(&dev->lock);

}



/*---------------------------------------------------------------------------*/

/* handle ep-a/ep-b dma completions */

static void
@@ -1910,10 +1921,12 @@ net2272_handle_stat0_irqs(struct net2272 *dev, u8 stat) 
				u.r.bRequestType, u.r.bRequest,

				u.r.wValue, u.r.wIndex,

				net2272_ep_read(ep, EP_CFG));

			if (dev->async_callbacks) {

				spin_unlock(&dev->lock);

				tmp = dev->driver->setup(&dev->gadget, &u.r);

				spin_lock(&dev->lock);

			}

		}



		/* stall ep0 on error */

		if (tmp < 0) {
@@ -1994,14 +2007,14 @@ net2272_handle_stat1_irqs(struct net2272 *dev, u8 stat) 
			if (disconnect || reset) {

				stop_activity(dev, dev->driver);

				net2272_ep0_start(dev);

				if (dev->async_callbacks) {

					spin_unlock(&dev->lock);

					if (reset)

					usb_gadget_udc_reset

						(&dev->gadget, dev->driver);

						usb_gadget_udc_reset(&dev->gadget, dev->driver);

					else

					(dev->driver->disconnect)

						(&dev->gadget);

						(dev->driver->disconnect)(&dev->gadget);

					spin_lock(&dev->lock);

				}

				return;

			}

		}
@@ -2015,14 +2028,14 @@ net2272_handle_stat1_irqs(struct net2272 *dev, u8 stat) 
	if (stat & tmp) {

		net2272_write(dev, IRQSTAT1, tmp);

		if (stat & (1 << SUSPEND_REQUEST_INTERRUPT)) {

			if (dev->driver->suspend)

			if (dev->async_callbacks && dev->driver->suspend)

				dev->driver->suspend(&dev->gadget);

			if (!enable_suspend) {

				stat &= ~(1 << SUSPEND_REQUEST_INTERRUPT);

				dev_dbg(dev->dev, "Suspend disabled, ignoring\n");

			}

		} else {

			if (dev->driver->resume)

			if (dev->async_callbacks && dev->driver->resume)

				dev->driver->resume(&dev->gadget);

		}

		stat &= ~tmp;

drivers/usb/gadget/udc/net2272.h

+1 −0
Original line number Diff line number Diff line
@@ -442,6 +442,7 @@ struct net2272 { 
	         softconnect:1,

	         wakeup:1,

		 added:1,

		 async_callbacks:1,

	         dma_eot_polarity:1,

	         dma_dack_polarity:1,

	         dma_dreq_polarity:1,