USB: cdc-acm: Update to new autopm API

commit 97d35f95 upstream.

Update cdc-acm to the async methods eliminating the workqueue

[This fixes a reported lockup for the cdc-acm driver - gregkh]
Signed-off-by: Oliver Neukum <oliver@neukum.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/class/cdc-acm.c

@@ -170,6 +170,7 @@ static void acm_write_done(struct acm *acm, struct acm_wb *wb)
 {
 	wb->use = 0;
 	acm->transmitting--;
+	usb_autopm_put_interface_async(acm->control);
 }
 
 /*
@@ -211,9 +212,12 @@ static int acm_write_start(struct acm *acm, int wbn)
 	}
 
 	dbg("%s susp_count: %d", __func__, acm->susp_count);
+	usb_autopm_get_interface_async(acm->control);
 	if (acm->susp_count) {
+		if (!acm->delayed_wb)
 			acm->delayed_wb = wb;
-		schedule_work(&acm->waker);
+		else
+			usb_autopm_put_interface_async(acm->control);
 		spin_unlock_irqrestore(&acm->write_lock, flags);
 		return 0;	/* A white lie */
 	}
@@ -534,23 +538,6 @@ static void acm_softint(struct work_struct *work)
 	tty_kref_put(tty);
 }
 
-static void acm_waker(struct work_struct *waker)
-{
-	struct acm *acm = container_of(waker, struct acm, waker);
-	int rv;
-
-	rv = usb_autopm_get_interface(acm->control);
-	if (rv < 0) {
-		dev_err(&acm->dev->dev, "Autopm failure in %s\n", __func__);
-		return;
-	}
-	if (acm->delayed_wb) {
-		acm_start_wb(acm, acm->delayed_wb);
-		acm->delayed_wb = NULL;
-	}
-	usb_autopm_put_interface(acm->control);
-}
-
 /*
  * TTY handlers
  */
@@ -1178,7 +1165,6 @@ static int acm_probe(struct usb_interface *intf,
 	acm->urb_task.func = acm_rx_tasklet;
 	acm->urb_task.data = (unsigned long) acm;
 	INIT_WORK(&acm->work, acm_softint);
-	INIT_WORK(&acm->waker, acm_waker);
 	init_waitqueue_head(&acm->drain_wait);
 	spin_lock_init(&acm->throttle_lock);
 	spin_lock_init(&acm->write_lock);
@@ -1343,7 +1329,6 @@ static void stop_data_traffic(struct acm *acm)
 	tasklet_enable(&acm->urb_task);
 
 	cancel_work_sync(&acm->work);
-	cancel_work_sync(&acm->waker);
 }
 
 static void acm_disconnect(struct usb_interface *intf)
@@ -1435,6 +1420,7 @@ static int acm_suspend(struct usb_interface *intf, pm_message_t message)
 static int acm_resume(struct usb_interface *intf)
 {
 	struct acm *acm = usb_get_intfdata(intf);
+	struct acm_wb *wb;
 	int rv = 0;
 	int cnt;
 
@@ -1449,6 +1435,21 @@ static int acm_resume(struct usb_interface *intf)
 	mutex_lock(&acm->mutex);
 	if (acm->port.count) {
 		rv = usb_submit_urb(acm->ctrlurb, GFP_NOIO);
+
+		spin_lock_irq(&acm->write_lock);
+		if (acm->delayed_wb) {
+			wb = acm->delayed_wb;
+			acm->delayed_wb = NULL;
+			spin_unlock_irq(&acm->write_lock);
+			acm_start_wb(acm, acm->delayed_wb);
+		} else {
+			spin_unlock_irq(&acm->write_lock);
+		}
+
+		/*
+		 * delayed error checking because we must
+		 * do the write path at all cost
+		 */
 		if (rv < 0)
 			goto err_out;
 

drivers/usb/class/cdc-acm.h

@@ -112,7 +112,6 @@ struct acm {
 	struct mutex mutex;
 	struct usb_cdc_line_coding line;		/* bits, stop, parity */
 	struct work_struct work;			/* work queue entry for line discipline waking up */
-	struct work_struct waker;
 	wait_queue_head_t drain_wait;			/* close processing */
 	struct tasklet_struct urb_task;                 /* rx processing */
 	spinlock_t throttle_lock;			/* synchronize throtteling and read callback */