Commit d40f7b75 authored by Sebastian Ott's avatar Sebastian Ott Committed by Martin Schwidefsky
Browse files

[S390] cio: dont unregister a busy device in ccw_device_set_offline 



If we detect a busy subchannel after the driver's set_offline
callback returned in ccw_device_set_offline, the current behavior
is to unregister the device, which may lead to undesired
consequences. Change this to just quiesce the subchannel and go on
with the offline processing.

Note: This is no excuse for not fixing these drivers -
after the set_offline callback they should have no running IO!

Signed-off-by: default avatarSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent de1b0438

drivers/s390/cio/device.c

+20 −9
Original line number Diff line number Diff line
@@ -314,6 +314,8 @@ static void ccw_device_unregister(struct ccw_device *cdev) 
	}

}



static void io_subchannel_quiesce(struct subchannel *);



/**

 * ccw_device_set_offline() - disable a ccw device for I/O

 * @cdev: target ccw device
@@ -327,7 +329,8 @@ static void ccw_device_unregister(struct ccw_device *cdev) 
 */

int ccw_device_set_offline(struct ccw_device *cdev)

{

	int ret;

	struct subchannel *sch;

	int ret, state;



	if (!cdev)

		return -ENODEV;
@@ -341,6 +344,7 @@ int ccw_device_set_offline(struct ccw_device *cdev) 
	}

	cdev->online = 0;

	spin_lock_irq(cdev->ccwlock);

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

	/* Wait until a final state or DISCONNECTED is reached */

	while (!dev_fsm_final_state(cdev) &&

	       cdev->private->state != DEV_STATE_DISCONNECTED) {
@@ -349,9 +353,21 @@ int ccw_device_set_offline(struct ccw_device *cdev) 
			   cdev->private->state == DEV_STATE_DISCONNECTED));

		spin_lock_irq(cdev->ccwlock);

	}

	do {

		ret = ccw_device_offline(cdev);

	if (ret)

		if (!ret)

			break;

		CIO_MSG_EVENT(0, "ccw_device_offline returned %d, device "

			      "0.%x.%04x\n", ret, cdev->private->dev_id.ssid,

			      cdev->private->dev_id.devno);

		if (ret != -EBUSY)

			goto error;

		state = cdev->private->state;

		spin_unlock_irq(cdev->ccwlock);

		io_subchannel_quiesce(sch);

		spin_lock_irq(cdev->ccwlock);

		cdev->private->state = state;

	} while (ret == -EBUSY);

	spin_unlock_irq(cdev->ccwlock);

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

		   cdev->private->state == DEV_STATE_DISCONNECTED));
@@ -368,9 +384,6 @@ int ccw_device_set_offline(struct ccw_device *cdev) 
	return 0;



error:

	CIO_MSG_EVENT(0, "ccw_device_offline returned %d, device 0.%x.%04x\n",

		      ret, cdev->private->dev_id.ssid,

		      cdev->private->dev_id.devno);

	cdev->private->state = DEV_STATE_OFFLINE;

	dev_fsm_event(cdev, DEV_EVENT_NOTOPER);

	spin_unlock_irq(cdev->ccwlock);
@@ -1059,8 +1072,6 @@ out_schedule: 
	return 0;

}



static void io_subchannel_quiesce(struct subchannel *);



static int

io_subchannel_remove (struct subchannel *sch)

{

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