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authorCornelia Huck <cornelia.huck@de.ibm.com>2007-10-12 16:11:26 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2007-10-12 16:13:02 +0200
commit3f4cf6e72f9f6a0b046b32881acc4f829f3aaa46 (patch)
tree84302932647aed49fa65b506fd0f5652af276915 /drivers/s390/cio
parent3952c8d43aa23862181ad23ecdf72895b4be3143 (diff)
[S390] cio: Avoid machine check vs. not operational races.
There was the possibilty that an action like ccw_device_set_offline() triggered by a device gone machine check might trigger a not oper event. Unfortunately, this could lead to the situation that we tried to unregister a subchannel twice: Once from the slow path evaluation, and once via the not oper event. Fix this by always using the same mechanism (css_schedule_eval()) for triggering the unregister. This makes sure that unregistration will only be done once. As an added bonus, it also simplyfies the code. Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'drivers/s390/cio')
-rw-r--r--drivers/s390/cio/device.c3
-rw-r--r--drivers/s390/cio/device.h1
-rw-r--r--drivers/s390/cio/device_fsm.c144
3 files changed, 21 insertions, 127 deletions
diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
index c96380db013..39f02b48e4c 100644
--- a/drivers/s390/cio/device.c
+++ b/drivers/s390/cio/device.c
@@ -969,8 +969,7 @@ out:
wake_up(&ccw_device_init_wq);
}
-void
-ccw_device_call_sch_unregister(struct work_struct *work)
+static void ccw_device_call_sch_unregister(struct work_struct *work)
{
struct ccw_device_private *priv;
struct ccw_device *cdev;
diff --git a/drivers/s390/cio/device.h b/drivers/s390/cio/device.h
index b66338b7657..0d408960043 100644
--- a/drivers/s390/cio/device.h
+++ b/drivers/s390/cio/device.h
@@ -80,7 +80,6 @@ void io_subchannel_recog_done(struct ccw_device *cdev);
int ccw_device_cancel_halt_clear(struct ccw_device *);
void ccw_device_do_unreg_rereg(struct work_struct *);
-void ccw_device_call_sch_unregister(struct work_struct *);
void ccw_device_move_to_orphanage(struct work_struct *);
int ccw_device_is_orphan(struct ccw_device *);
diff --git a/drivers/s390/cio/device_fsm.c b/drivers/s390/cio/device_fsm.c
index f772ef0a4f2..8867443b806 100644
--- a/drivers/s390/cio/device_fsm.c
+++ b/drivers/s390/cio/device_fsm.c
@@ -544,51 +544,6 @@ ccw_device_recog_timeout(struct ccw_device *cdev, enum dev_event dev_event)
}
-static void
-ccw_device_nopath_notify(struct work_struct *work)
-{
- struct ccw_device_private *priv;
- struct ccw_device *cdev;
- struct subchannel *sch;
- int ret;
- unsigned long flags;
-
- priv = container_of(work, struct ccw_device_private, kick_work);
- cdev = priv->cdev;
- spin_lock_irqsave(cdev->ccwlock, flags);
- sch = to_subchannel(cdev->dev.parent);
- /* Extra sanity. */
- if (sch->lpm)
- goto out_unlock;
- if (sch->driver && sch->driver->notify) {
- spin_unlock_irqrestore(cdev->ccwlock, flags);
- ret = sch->driver->notify(&sch->dev, CIO_NO_PATH);
- spin_lock_irqsave(cdev->ccwlock, flags);
- } else
- ret = 0;
- if (!ret) {
- if (get_device(&sch->dev)) {
- /* Driver doesn't want to keep device. */
- cio_disable_subchannel(sch);
- if (get_device(&cdev->dev)) {
- PREPARE_WORK(&cdev->private->kick_work,
- ccw_device_call_sch_unregister);
- queue_work(ccw_device_work,
- &cdev->private->kick_work);
- } else
- put_device(&sch->dev);
- }
- } else {
- cio_disable_subchannel(sch);
- ccw_device_set_timeout(cdev, 0);
- cdev->private->flags.fake_irb = 0;
- cdev->private->state = DEV_STATE_DISCONNECTED;
- wake_up(&cdev->private->wait_q);
- }
-out_unlock:
- spin_unlock_irqrestore(cdev->ccwlock, flags);
-}
-
void
ccw_device_verify_done(struct ccw_device *cdev, int err)
{
@@ -632,12 +587,9 @@ ccw_device_verify_done(struct ccw_device *cdev, int err)
default:
/* Reset oper notify indication after verify error. */
cdev->private->flags.donotify = 0;
- if (cdev->online) {
- PREPARE_WORK(&cdev->private->kick_work,
- ccw_device_nopath_notify);
- queue_work(ccw_device_notify_work,
- &cdev->private->kick_work);
- } else
+ if (cdev->online)
+ dev_fsm_event(cdev, DEV_EVENT_NOTOPER);
+ else
ccw_device_done(cdev, DEV_STATE_NOT_OPER);
break;
}
@@ -691,11 +643,7 @@ ccw_device_disband_done(struct ccw_device *cdev, int err)
break;
default:
cdev->private->flags.donotify = 0;
- if (get_device(&cdev->dev)) {
- PREPARE_WORK(&cdev->private->kick_work,
- ccw_device_call_sch_unregister);
- queue_work(ccw_device_work, &cdev->private->kick_work);
- }
+ dev_fsm_event(cdev, DEV_EVENT_NOTOPER);
ccw_device_done(cdev, DEV_STATE_NOT_OPER);
break;
}
@@ -766,59 +714,16 @@ ccw_device_recog_notoper(struct ccw_device *cdev, enum dev_event dev_event)
}
/*
- * Handle not operational event while offline.
+ * Handle not operational event in non-special state.
*/
-static void
-ccw_device_offline_notoper(struct ccw_device *cdev, enum dev_event dev_event)
+static void ccw_device_generic_notoper(struct ccw_device *cdev,
+ enum dev_event dev_event)
{
struct subchannel *sch;
cdev->private->state = DEV_STATE_NOT_OPER;
sch = to_subchannel(cdev->dev.parent);
- if (get_device(&cdev->dev)) {
- PREPARE_WORK(&cdev->private->kick_work,
- ccw_device_call_sch_unregister);
- queue_work(ccw_device_work, &cdev->private->kick_work);
- }
- wake_up(&cdev->private->wait_q);
-}
-
-/*
- * Handle not operational event while online.
- */
-static void
-ccw_device_online_notoper(struct ccw_device *cdev, enum dev_event dev_event)
-{
- struct subchannel *sch;
- int ret;
-
- sch = to_subchannel(cdev->dev.parent);
- if (sch->driver->notify) {
- spin_unlock_irq(cdev->ccwlock);
- ret = sch->driver->notify(&sch->dev,
- sch->lpm ? CIO_GONE : CIO_NO_PATH);
- spin_lock_irq(cdev->ccwlock);
- } else
- ret = 0;
- if (ret) {
- ccw_device_set_timeout(cdev, 0);
- cdev->private->flags.fake_irb = 0;
- cdev->private->state = DEV_STATE_DISCONNECTED;
- wake_up(&cdev->private->wait_q);
- return;
- }
- cdev->private->state = DEV_STATE_NOT_OPER;
- cio_disable_subchannel(sch);
- if (sch->schib.scsw.actl != 0) {
- // FIXME: not-oper indication to device driver ?
- ccw_device_call_handler(cdev);
- }
- if (get_device(&cdev->dev)) {
- PREPARE_WORK(&cdev->private->kick_work,
- ccw_device_call_sch_unregister);
- queue_work(ccw_device_work, &cdev->private->kick_work);
- }
- wake_up(&cdev->private->wait_q);
+ css_schedule_eval(sch->schid);
}
/*
@@ -916,18 +821,9 @@ ccw_device_online_timeout(struct ccw_device *cdev, enum dev_event dev_event)
cdev->private->state = DEV_STATE_TIMEOUT_KILL;
return;
}
- if (ret == -ENODEV) {
- struct subchannel *sch;
-
- sch = to_subchannel(cdev->dev.parent);
- if (!sch->lpm) {
- PREPARE_WORK(&cdev->private->kick_work,
- ccw_device_nopath_notify);
- queue_work(ccw_device_notify_work,
- &cdev->private->kick_work);
- } else
- dev_fsm_event(cdev, DEV_EVENT_NOTOPER);
- } else if (cdev->handler)
+ if (ret == -ENODEV)
+ dev_fsm_event(cdev, DEV_EVENT_NOTOPER);
+ else if (cdev->handler)
cdev->handler(cdev, cdev->private->intparm,
ERR_PTR(-ETIMEDOUT));
}
@@ -1234,7 +1130,7 @@ fsm_func_t *dev_jumptable[NR_DEV_STATES][NR_DEV_EVENTS] = {
[DEV_EVENT_VERIFY] = ccw_device_nop,
},
[DEV_STATE_SENSE_PGID] = {
- [DEV_EVENT_NOTOPER] = ccw_device_online_notoper,
+ [DEV_EVENT_NOTOPER] = ccw_device_generic_notoper,
[DEV_EVENT_INTERRUPT] = ccw_device_sense_pgid_irq,
[DEV_EVENT_TIMEOUT] = ccw_device_onoff_timeout,
[DEV_EVENT_VERIFY] = ccw_device_nop,
@@ -1246,50 +1142,50 @@ fsm_func_t *dev_jumptable[NR_DEV_STATES][NR_DEV_EVENTS] = {
[DEV_EVENT_VERIFY] = ccw_device_nop,
},
[DEV_STATE_OFFLINE] = {
- [DEV_EVENT_NOTOPER] = ccw_device_offline_notoper,
+ [DEV_EVENT_NOTOPER] = ccw_device_generic_notoper,
[DEV_EVENT_INTERRUPT] = ccw_device_offline_irq,
[DEV_EVENT_TIMEOUT] = ccw_device_nop,
[DEV_EVENT_VERIFY] = ccw_device_nop,
},
[DEV_STATE_VERIFY] = {
- [DEV_EVENT_NOTOPER] = ccw_device_online_notoper,
+ [DEV_EVENT_NOTOPER] = ccw_device_generic_notoper,
[DEV_EVENT_INTERRUPT] = ccw_device_verify_irq,
[DEV_EVENT_TIMEOUT] = ccw_device_onoff_timeout,
[DEV_EVENT_VERIFY] = ccw_device_delay_verify,
},
[DEV_STATE_ONLINE] = {
- [DEV_EVENT_NOTOPER] = ccw_device_online_notoper,
+ [DEV_EVENT_NOTOPER] = ccw_device_generic_notoper,
[DEV_EVENT_INTERRUPT] = ccw_device_irq,
[DEV_EVENT_TIMEOUT] = ccw_device_online_timeout,
[DEV_EVENT_VERIFY] = ccw_device_online_verify,
},
[DEV_STATE_W4SENSE] = {
- [DEV_EVENT_NOTOPER] = ccw_device_online_notoper,
+ [DEV_EVENT_NOTOPER] = ccw_device_generic_notoper,
[DEV_EVENT_INTERRUPT] = ccw_device_w4sense,
[DEV_EVENT_TIMEOUT] = ccw_device_nop,
[DEV_EVENT_VERIFY] = ccw_device_online_verify,
},
[DEV_STATE_DISBAND_PGID] = {
- [DEV_EVENT_NOTOPER] = ccw_device_online_notoper,
+ [DEV_EVENT_NOTOPER] = ccw_device_generic_notoper,
[DEV_EVENT_INTERRUPT] = ccw_device_disband_irq,
[DEV_EVENT_TIMEOUT] = ccw_device_onoff_timeout,
[DEV_EVENT_VERIFY] = ccw_device_nop,
},
[DEV_STATE_BOXED] = {
- [DEV_EVENT_NOTOPER] = ccw_device_offline_notoper,
+ [DEV_EVENT_NOTOPER] = ccw_device_generic_notoper,
[DEV_EVENT_INTERRUPT] = ccw_device_stlck_done,
[DEV_EVENT_TIMEOUT] = ccw_device_stlck_done,
[DEV_EVENT_VERIFY] = ccw_device_nop,
},
/* states to wait for i/o completion before doing something */
[DEV_STATE_CLEAR_VERIFY] = {
- [DEV_EVENT_NOTOPER] = ccw_device_online_notoper,
+ [DEV_EVENT_NOTOPER] = ccw_device_generic_notoper,
[DEV_EVENT_INTERRUPT] = ccw_device_clear_verify,
[DEV_EVENT_TIMEOUT] = ccw_device_nop,
[DEV_EVENT_VERIFY] = ccw_device_nop,
},
[DEV_STATE_TIMEOUT_KILL] = {
- [DEV_EVENT_NOTOPER] = ccw_device_online_notoper,
+ [DEV_EVENT_NOTOPER] = ccw_device_generic_notoper,
[DEV_EVENT_INTERRUPT] = ccw_device_killing_irq,
[DEV_EVENT_TIMEOUT] = ccw_device_killing_timeout,
[DEV_EVENT_VERIFY] = ccw_device_nop, //FIXME