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Commit 376ae475 authored by Peter Oberparleiter's avatar Peter Oberparleiter Committed by Martin Schwidefsky
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[S390] cio: fix I/O cancel function 



Function ccw_device_cancel_halt_clear may cause an unexpected kernel
panic if a clear function is currently active at the subchannel for
which it is called. In that case, the iretry counter used to determine
the number of retries is never initialized, leading to an immediate
failure of the function which results in a kernel panic.

Fix this by initializing the iretry counter when the function is
first called. Also replace the kernel panic with a return code: a
single malfunctioning I/O device should not automatically cause a
system-wide kernel panic.

Signed-off-by: default avatarPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent c9af3fa9

drivers/s390/cio/device.c

+1 −0
Original line number Diff line number Diff line
@@ -1205,6 +1205,7 @@ static void io_subchannel_quiesce(struct subchannel *sch) 
		cdev->handler(cdev, cdev->private->intparm, ERR_PTR(-EIO));

	while (ret == -EBUSY) {

		cdev->private->state = DEV_STATE_QUIESCE;

		cdev->private->iretry = 255;

		ret = ccw_device_cancel_halt_clear(cdev);

		if (ret == -EBUSY) {

			ccw_device_set_timeout(cdev, HZ/10);

drivers/s390/cio/device_fsm.c

+7 −2
Original line number Diff line number Diff line
@@ -174,7 +174,10 @@ ccw_device_cancel_halt_clear(struct ccw_device *cdev) 
		ret = cio_clear (sch);

		return (ret == 0) ? -EBUSY : ret;

	}

	panic("Can't stop i/o on subchannel.\n");

	/* Function was unsuccessful */

	CIO_MSG_EVENT(0, "0.%x.%04x: could not stop I/O\n",

		      cdev->private->dev_id.ssid, cdev->private->dev_id.devno);

	return -EIO;

}



void ccw_device_update_sense_data(struct ccw_device *cdev)
@@ -766,13 +769,14 @@ ccw_device_online_timeout(struct ccw_device *cdev, enum dev_event dev_event) 
	int ret;



	ccw_device_set_timeout(cdev, 0);

	cdev->private->iretry = 255;

	ret = ccw_device_cancel_halt_clear(cdev);

	if (ret == -EBUSY) {

		ccw_device_set_timeout(cdev, 3*HZ);

		cdev->private->state = DEV_STATE_TIMEOUT_KILL;

		return;

	}

	if (ret == -ENODEV)

	if (ret)

		dev_fsm_event(cdev, DEV_EVENT_NOTOPER);

	else if (cdev->handler)

		cdev->handler(cdev, cdev->private->intparm,
@@ -869,6 +873,7 @@ void ccw_device_kill_io(struct ccw_device *cdev) 
{

	int ret;



	cdev->private->iretry = 255;

	ret = ccw_device_cancel_halt_clear(cdev);

	if (ret == -EBUSY) {

		ccw_device_set_timeout(cdev, 3*HZ);