Commit ef99516c authored by Cornelia Huck's avatar Cornelia Huck Committed by Martin Schwidefsky
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[S390] cio: Unregister ccw devices directly. 



We used to unregister ccw devices not directly from the I/O
subchannel remove function in order to avoid lifelocks on the
css bus semaphore. This semaphore is gone, and there is no reason
to not unregister the ccw device directly (it is even better since
it is more in keeping with the goal of immediate disconnect).

Signed-off-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 8c4941c5

drivers/s390/cio/device.c

+12 −44
Original line number Diff line number Diff line
@@ -290,16 +290,10 @@ int ccw_device_is_orphan(struct ccw_device *cdev) 
	return sch_is_pseudo_sch(to_subchannel(cdev->dev.parent));

}



static void ccw_device_unregister(struct work_struct *work)

static void ccw_device_unregister(struct ccw_device *cdev)

{

	struct ccw_device_private *priv;

	struct ccw_device *cdev;



	priv = container_of(work, struct ccw_device_private, kick_work);

	cdev = priv->cdev;

	if (test_and_clear_bit(1, &cdev->private->registered))

		device_unregister(&cdev->dev);

	put_device(&cdev->dev);

		device_del(&cdev->dev);

}



static void
@@ -316,11 +310,8 @@ ccw_device_remove_disconnected(struct ccw_device *cdev) 
		spin_lock_irqsave(cdev->ccwlock, flags);

		cdev->private->state = DEV_STATE_NOT_OPER;

		spin_unlock_irqrestore(cdev->ccwlock, flags);

		if (get_device(&cdev->dev)) {

			PREPARE_WORK(&cdev->private->kick_work,

				     ccw_device_unregister);

			queue_work(ccw_device_work, &cdev->private->kick_work);

		}

		ccw_device_unregister(cdev);

		put_device(&cdev->dev);

		return ;

	}

	sch = to_subchannel(cdev->dev.parent);
@@ -555,17 +546,10 @@ static struct attribute_group ccwdev_attr_group = { 
	.attrs = ccwdev_attrs,

};



static int

device_add_files (struct device *dev)

{

	return sysfs_create_group(&dev->kobj, &ccwdev_attr_group);

}



static void

device_remove_files(struct device *dev)

{

	sysfs_remove_group(&dev->kobj, &ccwdev_attr_group);

}

struct attribute_group *ccwdev_attr_groups[] = {

	&ccwdev_attr_group,

	NULL,

};



/* this is a simple abstraction for device_register that sets the

 * correct bus type and adds the bus specific files */
@@ -580,10 +564,6 @@ static int ccw_device_register(struct ccw_device *cdev) 
		return ret;



	set_bit(1, &cdev->private->registered);

	if ((ret = device_add_files(dev))) {

		if (test_and_clear_bit(1, &cdev->private->registered))

			device_del(dev);

	}

	return ret;

}
@@ -655,10 +635,6 @@ ccw_device_add_changed(struct work_struct *work) 
		return;

	}

	set_bit(1, &cdev->private->registered);

	if (device_add_files(&cdev->dev)) {

		if (test_and_clear_bit(1, &cdev->private->registered))

			device_unregister(&cdev->dev);

	}

}



void ccw_device_do_unreg_rereg(struct work_struct *work)
@@ -671,9 +647,7 @@ void ccw_device_do_unreg_rereg(struct work_struct *work) 
	cdev = priv->cdev;

	sch = to_subchannel(cdev->dev.parent);



	device_remove_files(&cdev->dev);

	if (test_and_clear_bit(1, &cdev->private->registered))

		device_del(&cdev->dev);

	ccw_device_unregister(cdev);

	PREPARE_WORK(&cdev->private->kick_work,

		     ccw_device_add_changed);

	queue_work(ccw_device_work, &cdev->private->kick_work);
@@ -712,6 +686,7 @@ static int io_subchannel_initialize_dev(struct subchannel *sch, 
	cdev->dev.parent = &sch->dev;

	cdev->dev.release = ccw_device_release;

	INIT_LIST_HEAD(&cdev->private->kick_work.entry);

	cdev->dev.groups = ccwdev_attr_groups;

	/* Do first half of device_register. */

	device_initialize(&cdev->dev);

	if (!get_device(&sch->dev)) {
@@ -1141,15 +1116,8 @@ io_subchannel_remove (struct subchannel *sch) 
	sch->dev.driver_data = NULL;

	cdev->private->state = DEV_STATE_NOT_OPER;

	spin_unlock_irqrestore(cdev->ccwlock, flags);

	/*

	 * Put unregistration on workqueue to avoid livelocks on the css bus

	 * semaphore.

	 */

	if (get_device(&cdev->dev)) {

		PREPARE_WORK(&cdev->private->kick_work,

			     ccw_device_unregister);

		queue_work(ccw_device_work, &cdev->private->kick_work);

	}

	ccw_device_unregister(cdev);

	put_device(&cdev->dev);

	return 0;

}

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