[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>

diff --git a/drivers/s390/char/vmur.c b/drivers/s390/char/vmur.c
index 5dcef81..9245821 100644 (file)
--- a/drivers/s390/char/vmur.c
+++ b/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);
@@ -158,6 +160,28 @@ static void urdev_put(struct urdev *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
  *     free_chan_prog