From 3f4cf6e72f9f6a0b046b32881acc4f829f3aaa46 Mon Sep 17 00:00:00 2001 From: Cornelia Huck Date: Fri, 12 Oct 2007 16:11:26 +0200 Subject: [PATCH] [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 Signed-off-by: Martin Schwidefsky --- drivers/s390/cio/device.c | 3 +- drivers/s390/cio/device.h | 1 - drivers/s390/cio/device_fsm.c | 144 ++++++------------------------------------ 3 files changed, 21 insertions(+), 127 deletions(-) diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c index c96380d..39f02b4 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 b66338b..0d40896 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 f772ef0..8867443 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 -- 1.8.2.3