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s390/cio: dont unregister subchannel from child-drivers

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The devices owned by the parent-driver (css) was getting unregistered
from the io-subchannel driver is clearly a layering violation.
Remove the subchannel unregistration from the child-drivers.

This also means, if the device connected to the subchannel is not
operational, or not accessible, the subchannel will not be unregistered.
Instead the CIO layer will allow valid subchannels without any operational
devices in sysfs. And the userspace tooling might need to be modified to
optimally handle this new situation.

Signed-off-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
This commit is contained in:
Vineeth Vijayan 2021-04-25 10:41:59 +02:00 committed by Heiko Carstens
parent c7a5238ef6
commit 2297791c92
2 changed files with 8 additions and 18 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

5
drivers/s390/cio/blacklist.c
View file

@ -262,7 +262,10 @@ static int blacklist_parse_proc_parameters(char *buf)
if (strcmp("free", parm) == 0) {
rc = blacklist_parse_parameters(buf, free, 0);
css_schedule_eval_all_unreg(0);
/* There could be subchannels without proper devices connected.
* evaluate all the entries
*/
css_schedule_eval_all();
} else if (strcmp("add", parm) == 0)
rc = blacklist_parse_parameters(buf, add, 0);
else if (strcmp("purge", parm) == 0)

21
drivers/s390/cio/device.c
View file

@ -867,19 +867,6 @@ static void io_subchannel_register(struct ccw_device *cdev)
wake_up(&ccw_device_init_wq);
}
static void ccw_device_call_sch_unregister(struct ccw_device *cdev)
{
struct subchannel *sch;
/* Get subchannel reference for local processing. */
if (!get_device(cdev->dev.parent))
return;
sch = to_subchannel(cdev->dev.parent);
css_sch_device_unregister(sch);
/* Release subchannel reference for local processing. */
put_device(&sch->dev);
}
/*
* subchannel recognition done. Called from the state machine.
*/
@ -1860,10 +1847,10 @@ static void ccw_device_todo(struct work_struct *work)
css_schedule_eval(sch->schid);
fallthrough;
case CDEV_TODO_UNREG:
if (sch_is_pseudo_sch(sch))
ccw_device_unregister(cdev);
else
ccw_device_call_sch_unregister(cdev);
spin_lock_irq(sch->lock);
sch_set_cdev(sch, NULL);
spin_unlock_irq(sch->lock);
ccw_device_unregister(cdev);
break;
default:
break;