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

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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: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Sebastian Ott 2009-12-07 12:51:41 +01:00 committed by Martin Schwidefsky
parent de1b04388f
commit d40f7b75a2
1 changed files with 20 additions and 9 deletions
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25
drivers/s390/cio/device.c
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@ -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 @@ static int io_subchannel_probe(struct subchannel *sch)
return 0;
}
static void io_subchannel_quiesce(struct subchannel *);
static int
io_subchannel_remove (struct subchannel *sch)
{