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, 6 insertions, 0 deletions

diff --git a/drivers/s390/cio/ccwgroup.c b/drivers/s390/cio/ccwgroup.c
index 34b9ad6b3143..e2f7b6e93efd 100644
--- a/drivers/s390/cio/ccwgroup.c
+++ b/drivers/s390/cio/ccwgroup.c
@@ -373,6 +373,12 @@ int ccwgroup_create_dev(struct device *parent, struct ccwgroup_driver *gdrv,
 		rc = -EINVAL;
 		goto error;
 	}
+	/* Check if the devices are bound to the required ccw driver. */
+	if (gdev->count && gdrv && gdrv->ccw_driver &&
+	    gdev->cdev[0]->drv != gdrv->ccw_driver) {
+		rc = -EINVAL;
+		goto error;
+	}
 
 	dev_set_name(&gdev->dev, "%s", dev_name(&gdev->cdev[0]->dev));
 	gdev->dev.groups = ccwgroup_attr_groups;