s390/ccwgroup: tie a ccwgroup driver to its ccw driver

When grouping devices, the ccwgroup core only checks whether all of the
devices are bound to the same ccw_driver. It has no means of checking
if the requesting ccwgroup driver actually supports this device type.
qeth implements its own device matching in qeth_core_probe_device(),
while ctcm and lcs currently have no sanity-checking at all.

Enable ccwgroup drivers to optionally defer the device type checking to
the ccwgroup core, by specifying their supported ccw_driver.
This allows us drop the device type matching from qeth, and improves
the robustness of ctcm and lcs.

Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Acked-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/s390/include/asm/ccwgroup.h b/arch/s390/include/asm/ccwgroup.h
index 057ce0ca6377..6d50e86dd0e8 100644
--- a/arch/s390/include/asm/ccwgroup.h
+++ b/arch/s390/include/asm/ccwgroup.h
@@ -41,6 +41,7 @@ struct ccwgroup_device {
  * @thaw: undo work done in @freeze
  * @restore: callback for restoring after hibernation
  * @driver: embedded driver structure
+ * @ccw_driver: supported ccw_driver (optional)
  */
 struct ccwgroup_driver {
 	int (*setup) (struct ccwgroup_device *);
@@ -55,6 +56,7 @@ struct ccwgroup_driver {
 	int (*restore)(struct ccwgroup_device *);
 
 	struct device_driver driver;
+	struct ccw_driver *ccw_driver;
 };
 
 extern int  ccwgroup_driver_register   (struct ccwgroup_driver *cdriver);