[S390] cio: Fix reference counting for online/offline.

[deliverable/linux.git] / drivers / s390 / cio / device.c

diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
index 647cbaca298e98ad8032642fcd64439a86a332a1..039ef03cf217ff641771f96b4cff465b97911a6d 100644 (file)
--- a/drivers/s390/cio/device.c
+++ b/drivers/s390/cio/device.c
@@ -376,19 +376,23 @@ int ccw_device_set_offline(struct ccw_device *cdev)
                        dev_fsm_event(cdev, DEV_EVENT_NOTOPER);
                }
                spin_unlock_irq(cdev->ccwlock);
+               /* Give up reference from ccw_device_set_online(). */
+               put_device(&cdev->dev);
                return ret;
        }
        spin_unlock_irq(cdev->ccwlock);
-       if (ret == 0)
+       if (ret == 0) {
                wait_event(cdev->private->wait_q, dev_fsm_final_state(cdev));
-       else {
+               /* Give up reference from ccw_device_set_online(). */
+               put_device(&cdev->dev);
+       } else {
                CIO_MSG_EVENT(0, "ccw_device_offline returned %d, "
                              "device 0.%x.%04x\n",
                              ret, cdev->private->dev_id.ssid,
                              cdev->private->dev_id.devno);
                cdev->online = 1;
        }
-       return ret;
+       return ret;
 }
 
 /**
@@ -411,6 +415,9 @@ int ccw_device_set_online(struct ccw_device *cdev)
                return -ENODEV;
        if (cdev->online || !cdev->drv)
                return -EINVAL;
+       /* Hold on to an extra reference while device is online. */
+       if (!get_device(&cdev->dev))
+               return -ENODEV;
 
        spin_lock_irq(cdev->ccwlock);
        ret = ccw_device_online(cdev);
@@ -422,10 +429,15 @@ int ccw_device_set_online(struct ccw_device *cdev)
                              "device 0.%x.%04x\n",
                              ret, cdev->private->dev_id.ssid,
                              cdev->private->dev_id.devno);
+               /* Give up online reference since onlining failed. */
+               put_device(&cdev->dev);
                return ret;
        }
-       if (cdev->private->state != DEV_STATE_ONLINE)
+       if (cdev->private->state != DEV_STATE_ONLINE) {
+               /* Give up online reference since onlining failed. */
+               put_device(&cdev->dev);
                return -ENODEV;
+       }
        if (!cdev->drv->set_online || cdev->drv->set_online(cdev) == 0) {
                cdev->online = 1;
                return 0;
@@ -440,6 +452,8 @@ int ccw_device_set_online(struct ccw_device *cdev)
                              "device 0.%x.%04x\n",
                              ret, cdev->private->dev_id.ssid,
                              cdev->private->dev_id.devno);
+       /* Give up online reference since onlining failed. */
+       put_device(&cdev->dev);
        return (ret == 0) ? -ENODEV : ret;
 }
 
@@ -1168,9 +1182,8 @@ static int io_subchannel_probe(struct subchannel *sch)
                ccw_device_register(cdev);
                /*
                 * Check if the device is already online. If it is
-                * the reference count needs to be corrected
-                * (see ccw_device_online and css_init_done for the
-                * ugly details).
+                * the reference count needs to be corrected since we
+                * didn't obtain a reference in ccw_device_set_online.
                 */
                if (cdev->private->state != DEV_STATE_NOT_OPER &&
                    cdev->private->state != DEV_STATE_OFFLINE &&
@@ -1806,6 +1819,8 @@ ccw_device_remove (struct device *dev)
                                      "device 0.%x.%04x\n",
                                      ret, cdev->private->dev_id.ssid,
                                      cdev->private->dev_id.devno);
+               /* Give up reference obtained in ccw_device_set_online(). */
+               put_device(&cdev->dev);
        }
        ccw_device_set_timeout(cdev, 0);
        cdev->drv = NULL;