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Commit 88044202 authored by Bjørn Mork's avatar Bjørn Mork Committed by Greg Kroah-Hartman
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usb: cdc-wdm: make reset work with blocking IO 



Add a flag to tell wdm_read/wdm_write that a reset is in progress,
and wake any blocking read/write before taking the mutexes.  This
allows the device to reset without waiting for blocking IO to
finish.

Signed-off-by: default avatarBjørn Mork <bjorn@mork.no>
Acked-by: default avatarOliver Neukum <oneukum@suse.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7483948f

drivers/usb/class/cdc-wdm.c

+17 −4
Original line number Diff line number Diff line
@@ -70,6 +70,7 @@ MODULE_DEVICE_TABLE (usb, wdm_ids); 
#define WDM_POLL_RUNNING	6

#define WDM_RESPONDING		7

#define WDM_SUSPENDING		8

#define WDM_RESETTING		9



#define WDM_MAX			16
@@ -340,6 +341,10 @@ static ssize_t wdm_write 
	else

		if (test_bit(WDM_IN_USE, &desc->flags))

			r = -EAGAIN;



	if (test_bit(WDM_RESETTING, &desc->flags))

		r = -EIO;



	if (r < 0) {

		kfree(buf);

		goto out;
@@ -419,6 +424,10 @@ static ssize_t wdm_read 
			rv = -ENODEV;

			goto err;

		}

		if (test_bit(WDM_RESETTING, &desc->flags)) {

			rv = -EIO;

			goto err;

		}

		usb_mark_last_busy(interface_to_usbdev(desc->intf));

		if (rv < 0) {

			rv = -ERESTARTSYS;
@@ -859,10 +868,6 @@ static int wdm_pre_reset(struct usb_interface *intf) 
{

	struct wdm_device *desc = usb_get_intfdata(intf);



	mutex_lock(&desc->rlock);

	mutex_lock(&desc->wlock);

	kill_urbs(desc);



	/*

	 * we notify everybody using poll of

	 * an exceptional situation
@@ -870,9 +875,16 @@ static int wdm_pre_reset(struct usb_interface *intf) 
	 * message from the device is lost

	 */

	spin_lock_irq(&desc->iuspin);

	set_bit(WDM_RESETTING, &desc->flags);	/* inform read/write */

	set_bit(WDM_READ, &desc->flags);	/* unblock read */

	clear_bit(WDM_IN_USE, &desc->flags);	/* unblock write */

	desc->rerr = -EINTR;

	spin_unlock_irq(&desc->iuspin);

	wake_up_all(&desc->wait);

	mutex_lock(&desc->rlock);

	mutex_lock(&desc->wlock);

	kill_urbs(desc);

	cancel_work_sync(&desc->rxwork);

	return 0;

}
@@ -881,6 +893,7 @@ static int wdm_post_reset(struct usb_interface *intf) 
	struct wdm_device *desc = usb_get_intfdata(intf);

	int rv;



	clear_bit(WDM_RESETTING, &desc->flags);

	rv = recover_from_urb_loss(desc);

	mutex_unlock(&desc->wlock);

	mutex_unlock(&desc->rlock);