USB: whci-hcd: check return value of usb_hcd_link_urb_to_ep()

Check the return value of usb_hcd_link_urb_to_ep() and do not add the
urb to the ASL/PZL if it returns an error.

Omitting the check results in urbs that appear to be submitted
successfully but then cannot be unliked (because
usb_hcd_check_unlink_urb() returns an error).  This can cause khubd (for
example) to block forever in usb_kill_urb().

Signed-off-by: David Vrabel <david.vrabel@csr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/host/whci/asl.c

@@ -255,23 +255,29 @@ int asl_urb_enqueue(struct whc *whc, struct urb *urb, gfp_t mem_flags)
 
 	spin_lock_irqsave(&whc->lock, flags);
 
+	err = usb_hcd_link_urb_to_ep(&whc->wusbhc.usb_hcd, urb);
+	if (err < 0) {
+		spin_unlock_irqrestore(&whc->lock, flags);
+		return err;
+	}
+
 	qset = get_qset(whc, urb, GFP_ATOMIC);
 	if (qset == NULL)
 		err = -ENOMEM;
 	else
 		err = qset_add_urb(whc, qset, urb, GFP_ATOMIC);
 	if (!err) {
-		usb_hcd_link_urb_to_ep(&whc->wusbhc.usb_hcd, urb);
 		if (!qset->in_sw_list)
 			asl_qset_insert_begin(whc, qset);
-	}
+	} else
+		usb_hcd_unlink_urb_from_ep(&whc->wusbhc.usb_hcd, urb);
 
 	spin_unlock_irqrestore(&whc->lock, flags);
 
 	if (!err)
 		queue_work(whc->workqueue, &whc->async_work);
 
-	return 0;
+	return err;
 }
 
 /**

drivers/usb/host/whci/pzl.c

@@ -283,23 +283,29 @@ int pzl_urb_enqueue(struct whc *whc, struct urb *urb, gfp_t mem_flags)
 
 	spin_lock_irqsave(&whc->lock, flags);
 
+	err = usb_hcd_link_urb_to_ep(&whc->wusbhc.usb_hcd, urb);
+	if (err < 0) {
+		spin_unlock_irqrestore(&whc->lock, flags);
+		return err;
+	}
+
 	qset = get_qset(whc, urb, GFP_ATOMIC);
 	if (qset == NULL)
 		err = -ENOMEM;
 	else
 		err = qset_add_urb(whc, qset, urb, GFP_ATOMIC);
 	if (!err) {
-		usb_hcd_link_urb_to_ep(&whc->wusbhc.usb_hcd, urb);
 		if (!qset->in_sw_list)
 			qset_insert_in_sw_list(whc, qset);
-	}
+	} else
+		usb_hcd_unlink_urb_from_ep(&whc->wusbhc.usb_hcd, urb);
 
 	spin_unlock_irqrestore(&whc->lock, flags);
 
 	if (!err)
 		queue_work(whc->workqueue, &whc->periodic_work);
 
-	return 0;
+	return err;
 }
 
 /**