[S390] pm: vmur driver power management callbacks

Signed-off-by: Frank Munzert <munzert@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/char/vmur.c

@@ -2,7 +2,7 @@
  * Linux driver for System z and s390 unit record devices
  * (z/VM virtual punch, reader, printer)
  *
- * Copyright IBM Corp. 2001, 2007
+ * Copyright IBM Corp. 2001, 2009
  * Authors: Malcolm Beattie <beattiem@uk.ibm.com>
  *	    Michael Holzheu <holzheu@de.ibm.com>
  *	    Frank Munzert <munzert@de.ibm.com>
@@ -60,6 +60,7 @@ static int ur_probe(struct ccw_device *cdev);
 static void ur_remove(struct ccw_device *cdev);
 static int ur_set_online(struct ccw_device *cdev);
 static int ur_set_offline(struct ccw_device *cdev);
+static int ur_pm_suspend(struct ccw_device *cdev);
 
 static struct ccw_driver ur_driver = {
 	.name		= "vmur",
@@ -69,6 +70,7 @@ static struct ccw_driver ur_driver = {
 	.remove		= ur_remove,
 	.set_online	= ur_set_online,
 	.set_offline	= ur_set_offline,
+	.freeze		= ur_pm_suspend,
 };
 
 static DEFINE_MUTEX(vmur_mutex);
@@ -157,6 +159,28 @@ static void urdev_put(struct urdev *urd)
 		urdev_free(urd);
 }
 
+/*
+ * State and contents of ur devices can be changed by class D users issuing
+ * CP commands such as PURGE or TRANSFER, while the Linux guest is suspended.
+ * Also the Linux guest might be logged off, which causes all active spool
+ * files to be closed.
+ * So we cannot guarantee that spool files are still the same when the Linux
+ * guest is resumed. In order to avoid unpredictable results at resume time
+ * we simply refuse to suspend if a ur device node is open.
+ */
+static int ur_pm_suspend(struct ccw_device *cdev)
+{
+	struct urdev *urd = cdev->dev.driver_data;
+
+	TRACE("ur_pm_suspend: cdev=%p\n", cdev);
+	if (urd->open_flag) {
+		pr_err("Unit record device %s is busy, %s refusing to "
+		       "suspend.\n", dev_name(&cdev->dev), ur_banner);
+		return -EBUSY;
+	}
+	return 0;
+}
+
 /*
  * Low-level functions to do I/O to a ur device.
  *     alloc_chan_prog