Commit 46fbe4e4 authored by Peter Oberparleiter's avatar Peter Oberparleiter Committed by Martin Schwidefsky
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[S390] cio: move device unregistration to dedicated work queue 



Use dedicated slow path work queue when unregistering a device due to
a user action. This ensures serialialization of other register/
unregister requests.

Signed-off-by: default avatarPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 4bcb3a37

drivers/s390/cio/device.c

+25 −31
Original line number Diff line number Diff line
@@ -296,36 +296,33 @@ static void ccw_device_unregister(struct ccw_device *cdev) 
		device_del(&cdev->dev);

}



static void ccw_device_remove_orphan_cb(struct device *dev)

static void ccw_device_remove_orphan_cb(struct work_struct *work)

{

	struct ccw_device *cdev = to_ccwdev(dev);

	struct ccw_device_private *priv;

	struct ccw_device *cdev;



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

	cdev = priv->cdev;

	ccw_device_unregister(cdev);

	put_device(&cdev->dev);

	/* Release cdev reference for workqueue processing. */

	put_device(&cdev->dev);

}



static void ccw_device_remove_sch_cb(struct device *dev)

{

	struct subchannel *sch;



	sch = to_subchannel(dev);

	css_sch_device_unregister(sch);

	/* Reset intparm to zeroes. */

	sch->schib.pmcw.intparm = 0;

	cio_modify(sch);

	put_device(&sch->dev);

}

static void ccw_device_call_sch_unregister(struct work_struct *work);



static void

ccw_device_remove_disconnected(struct ccw_device *cdev)

{

	unsigned long flags;

	int rc;



	/*

	 * Forced offline in disconnected state means

	 * 'throw away device'.

	 */

	/* Get cdev reference for workqueue processing. */

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

		return;

	if (ccw_device_is_orphan(cdev)) {

		/*

		 * Deregister ccw device.
@@ -335,23 +332,13 @@ 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);

		rc = device_schedule_callback(&cdev->dev,

		PREPARE_WORK(&cdev->private->kick_work,

				ccw_device_remove_orphan_cb);

		if (rc)

			CIO_MSG_EVENT(0, "Couldn't unregister orphan "

				      "0.%x.%04x\n",

				      cdev->private->dev_id.ssid,

				      cdev->private->dev_id.devno);

		return;

	}

	} else

		/* Deregister subchannel, which will kill the ccw device. */

	rc = device_schedule_callback(cdev->dev.parent,

				      ccw_device_remove_sch_cb);

	if (rc)

		CIO_MSG_EVENT(0, "Couldn't unregister disconnected device "

			      "0.%x.%04x\n",

			      cdev->private->dev_id.ssid,

			      cdev->private->dev_id.devno);

		PREPARE_WORK(&cdev->private->kick_work,

				ccw_device_call_sch_unregister);

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

}



/**
@@ -970,12 +957,17 @@ static void ccw_device_call_sch_unregister(struct work_struct *work) 


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

	cdev = priv->cdev;

	/* Get subchannel reference for local processing. */

	if (!get_device(cdev->dev.parent))

		return;

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

	css_sch_device_unregister(sch);

	/* Reset intparm to zeroes. */

	sch->schib.pmcw.intparm = 0;

	cio_modify(sch);

	/* Release cdev reference for workqueue processing.*/

	put_device(&cdev->dev);

	/* Release subchannel reference for local processing. */

	put_device(&sch->dev);

}
@@ -1001,6 +993,8 @@ io_subchannel_recog_done(struct ccw_device *cdev) 
		PREPARE_WORK(&cdev->private->kick_work,

			     ccw_device_call_sch_unregister);

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

		/* Release subchannel reference for asynchronous recognition. */

		put_device(&sch->dev);

		if (atomic_dec_and_test(&ccw_device_init_count))

			wake_up(&ccw_device_init_wq);

		break;