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Commit 56e6b796 authored by Sebastian Ott's avatar Sebastian Ott Committed by Martin Schwidefsky
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[S390] cio: fix quiesce state 



DEV_STATE_QUIESCE is used to stop all IO on a busy subchannel.
This patch fixes the following problems related to the QUIESCE
state:

* Fix a potential race condition which could occur when the
resulting state was DEV_STATE_OFFLINE.

* Add missing locking around cio_disable_subchannel,
ccw_device_cancel_halt_clear and the cdev's handler.

* Loop until we know for sure that the subchannel is disabled.

Signed-off-by: default avatarSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 24a1872d

drivers/s390/cio/device.c

+19 −16
Original line number Diff line number Diff line
@@ -1130,33 +1130,36 @@ static int io_subchannel_chp_event(struct subchannel *sch, 
	return 0;

}



static void

io_subchannel_shutdown(struct subchannel *sch)

static void io_subchannel_shutdown(struct subchannel *sch)

{

	struct ccw_device *cdev;

	int ret;



	spin_lock_irq(sch->lock);

	cdev = sch_get_cdev(sch);



	if (cio_is_console(sch->schid))

		return;

		goto out_unlock;

	if (!sch->schib.pmcw.ena)

		/* Nothing to do. */

		return;

		goto out_unlock;

	ret = cio_disable_subchannel(sch);

	if (ret != -EBUSY)

		/* Subchannel is disabled, we're done. */

		return;

	cdev->private->state = DEV_STATE_QUIESCE;

		goto out_unlock;

	if (cdev->handler)

		cdev->handler(cdev, cdev->private->intparm,

			      ERR_PTR(-EIO));

		cdev->handler(cdev, cdev->private->intparm, ERR_PTR(-EIO));

	while (ret == -EBUSY) {

		cdev->private->state = DEV_STATE_QUIESCE;

		ret = ccw_device_cancel_halt_clear(cdev);

		if (ret == -EBUSY) {

			ccw_device_set_timeout(cdev, HZ/10);

		wait_event(cdev->private->wait_q, dev_fsm_final_state(cdev));

			spin_unlock_irq(sch->lock);

			wait_event(cdev->private->wait_q,

				   cdev->private->state != DEV_STATE_QUIESCE);

			spin_lock_irq(sch->lock);

		}

	cio_disable_subchannel(sch);

		ret = cio_disable_subchannel(sch);

	}

out_unlock:

	spin_unlock_irq(sch->lock);

}



static int device_is_disconnected(struct ccw_device *cdev)

drivers/s390/cio/device_fsm.c

+4 −13
Original line number Diff line number Diff line
@@ -911,10 +911,7 @@ static void 
ccw_device_quiesce_done(struct ccw_device *cdev, enum dev_event dev_event)

{

	ccw_device_set_timeout(cdev, 0);

	if (dev_event == DEV_EVENT_NOTOPER)

	cdev->private->state = DEV_STATE_NOT_OPER;

	else

		cdev->private->state = DEV_STATE_OFFLINE;

	wake_up(&cdev->private->wait_q);

}
@@ -924,17 +921,11 @@ ccw_device_quiesce_timeout(struct ccw_device *cdev, enum dev_event dev_event) 
	int ret;



	ret = ccw_device_cancel_halt_clear(cdev);

	switch (ret) {

	case 0:

		cdev->private->state = DEV_STATE_OFFLINE;

		wake_up(&cdev->private->wait_q);

		break;

	case -ENODEV:

	if (ret == -EBUSY) {

		ccw_device_set_timeout(cdev, HZ/10);

	} else {

		cdev->private->state = DEV_STATE_NOT_OPER;

		wake_up(&cdev->private->wait_q);

		break;

	default:

		ccw_device_set_timeout(cdev, HZ/10);

	}

}