[S390] ccwgroup device unregister.

Work around the problem that a device cannot be unregistered from
driver_for_each_device() because of klist node refcounting: Get device
after device owned by the driver to be unregistered with driver_find_device()
and then unregister it. This works because driver_get_device() gets us out of
the region of the elevated klist node refcount. driver_find_device() will
always get the next device in the list after the found one has been
unregistered.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/drivers/s390/cio/ccwgroup.c b/drivers/s390/cio/ccwgroup.c
index bdfee7f..c7319a0 100644 (file)
--- a/drivers/s390/cio/ccwgroup.c
+++ b/drivers/s390/cio/ccwgroup.c
@@ -404,21 +404,24 @@ ccwgroup_driver_register (struct ccwgroup_driver *cdriver)
 }
 
 static int
-__ccwgroup_driver_unregister_device(struct device *dev, void *data)
+__ccwgroup_match_all(struct device *dev, void *data)
 {
-       __ccwgroup_remove_symlinks(to_ccwgroupdev(dev));
-       device_unregister(dev);
-       put_device(dev);
-       return 0;
+       return 1;
 }
 
 void
 ccwgroup_driver_unregister (struct ccwgroup_driver *cdriver)
 {
+       struct device *dev;
+
        /* We don't want ccwgroup devices to live longer than their driver. */
        get_driver(&cdriver->driver);
-       driver_for_each_device(&cdriver->driver, NULL, NULL,
-                              __ccwgroup_driver_unregister_device);
+       while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
+                                        __ccwgroup_match_all))) {
+               __ccwgroup_remove_symlinks(to_ccwgroupdev(dev));
+               device_unregister(dev);
+               put_device(dev);
+       }
        put_driver(&cdriver->driver);
        driver_unregister(&cdriver->driver);
 }