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Subject[patch/s390 24/46] cio: Use unbind/bind instead of unregister/register.
From: Cornelia Huck <cornelia.huck@de.ibm.com>

The common I/O layer may encounter a situation where the
device number of a ccw device has changed or a device
driver doesn't want to keep a formerly disconnected device
becoming operational again. Instead of using device_del()/
device_add() as now, we can just unbind the driver from the
device and rebind it to get the desired effect (rebinding)
with less overhead.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
drivers/s390/cio/device.c | 27 +++++++--------------------
drivers/s390/cio/device.h | 2 +-
drivers/s390/cio/device_fsm.c | 4 ++--
3 files changed, 10 insertions(+), 23 deletions(-)
Index: quilt-2.6/drivers/s390/cio/device.c
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/device.c
+++ quilt-2.6/drivers/s390/cio/device.c
@@ -681,35 +681,22 @@ get_orphaned_ccwdev_by_dev_id(struct cha
return dev ? to_ccwdev(dev) : NULL;
}

-static void
-ccw_device_add_changed(struct work_struct *work)
-{
- struct ccw_device_private *priv;
- struct ccw_device *cdev;
-
- priv = container_of(work, struct ccw_device_private, kick_work);
- cdev = priv->cdev;
- if (device_add(&cdev->dev)) {
- put_device(&cdev->dev);
- return;
- }
- set_bit(1, &cdev->private->registered);
-}
-
-void ccw_device_do_unreg_rereg(struct work_struct *work)
+void ccw_device_do_unbind_bind(struct work_struct *work)
{
struct ccw_device_private *priv;
struct ccw_device *cdev;
struct subchannel *sch;
+ int ret;

priv = container_of(work, struct ccw_device_private, kick_work);
cdev = priv->cdev;
sch = to_subchannel(cdev->dev.parent);

- ccw_device_unregister(cdev);
- PREPARE_WORK(&cdev->private->kick_work,
- ccw_device_add_changed);
- queue_work(ccw_device_work, &cdev->private->kick_work);
+ if (test_bit(1, &cdev->private->registered)) {
+ device_release_driver(&cdev->dev);
+ ret = device_attach(&cdev->dev);
+ WARN_ON(ret == -ENODEV);
+ }
}

static void
Index: quilt-2.6/drivers/s390/cio/device_fsm.c
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/device_fsm.c
+++ quilt-2.6/drivers/s390/cio/device_fsm.c
@@ -194,7 +194,7 @@ ccw_device_handle_oper(struct ccw_device
cdev->id.dev_type != cdev->private->senseid.dev_type ||
cdev->id.dev_model != cdev->private->senseid.dev_model) {
PREPARE_WORK(&cdev->private->kick_work,
- ccw_device_do_unreg_rereg);
+ ccw_device_do_unbind_bind);
queue_work(ccw_device_work, &cdev->private->kick_work);
return 0;
}
@@ -366,7 +366,7 @@ static void ccw_device_oper_notify(struc
}
/* Driver doesn't want device back. */
ccw_device_set_notoper(cdev);
- PREPARE_WORK(&cdev->private->kick_work, ccw_device_do_unreg_rereg);
+ PREPARE_WORK(&cdev->private->kick_work, ccw_device_do_unbind_bind);
queue_work(ccw_device_work, &cdev->private->kick_work);
}

Index: quilt-2.6/drivers/s390/cio/device.h
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/device.h
+++ quilt-2.6/drivers/s390/cio/device.h
@@ -80,7 +80,7 @@ void io_subchannel_init_config(struct su

int ccw_device_cancel_halt_clear(struct ccw_device *);

-void ccw_device_do_unreg_rereg(struct work_struct *);
+void ccw_device_do_unbind_bind(struct work_struct *);
void ccw_device_move_to_orphanage(struct work_struct *);
int ccw_device_is_orphan(struct ccw_device *);

--
blue skies,
Martin.

"Reality continues to ruin my life." - Calvin.



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