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Commit e75279c4 authored by Heinz Graalfs's avatar Heinz Graalfs Committed by Rusty Russell
Browse files

virtio_ccw: introduce device_lost in virtio_ccw_device 



When a device is lost, the common I/O layer calls the notification
handler with CIO_GONE: In that event, flag device_lost as true.

In case the device had been flagged as lost when the remove/offline callbacks
are called, call the new virtio_break_device() function prior to invoking
device_unregister(). This avoids hangs of I/O triggered via the device
unregistration callbacks.

Signed-off-by: default avatarHeinz Graalfs <graalfs@linux.vnet.ibm.com>
Reviewed-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent e2dcdfe9

drivers/s390/kvm/virtio_ccw.c

+37 −12
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 
#include <linux/module.h>

#include <linux/io.h>

#include <linux/kvm_para.h>

#include <linux/notifier.h>

#include <asm/setup.h>

#include <asm/irq.h>

#include <asm/cio.h>
@@ -62,6 +63,7 @@ struct virtio_ccw_device { 
	struct vq_config_block *config_block;

	bool is_thinint;

	bool going_away;

	bool device_lost;

	void *airq_info;

};
@@ -1010,11 +1012,14 @@ static void virtio_ccw_remove(struct ccw_device *cdev) 
	unsigned long flags;

	struct virtio_ccw_device *vcdev = virtio_grab_drvdata(cdev);



	if (vcdev && cdev->online)

	if (vcdev && cdev->online) {

		if (vcdev->device_lost)

			virtio_break_device(&vcdev->vdev);

		unregister_virtio_device(&vcdev->vdev);

		spin_lock_irqsave(get_ccwdev_lock(cdev), flags);

		dev_set_drvdata(&cdev->dev, NULL);

		spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);

	}

	cdev->handler = NULL;

}
@@ -1023,12 +1028,14 @@ static int virtio_ccw_offline(struct ccw_device *cdev) 
	unsigned long flags;

	struct virtio_ccw_device *vcdev = virtio_grab_drvdata(cdev);



	if (vcdev) {

	if (!vcdev)

		return 0;

	if (vcdev->device_lost)

		virtio_break_device(&vcdev->vdev);

	unregister_virtio_device(&vcdev->vdev);

	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);

	dev_set_drvdata(&cdev->dev, NULL);

	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);

	}

	return 0;

}
@@ -1096,8 +1103,26 @@ static int virtio_ccw_online(struct ccw_device *cdev) 


static int virtio_ccw_cio_notify(struct ccw_device *cdev, int event)

{

	/* TODO: Check whether we need special handling here. */

	return 0;

	int rc;

	struct virtio_ccw_device *vcdev = dev_get_drvdata(&cdev->dev);



	/*

	 * Make sure vcdev is set

	 * i.e. set_offline/remove callback not already running

	 */

	if (!vcdev)

		return NOTIFY_DONE;



	switch (event) {

	case CIO_GONE:

		vcdev->device_lost = true;

		rc = NOTIFY_DONE;

		break;

	default:

		rc = NOTIFY_DONE;

		break;

	}

	return rc;

}



static struct ccw_device_id virtio_ids[] = {