From 91c36919a456589f4f073671474a1f899e0d3c2b Mon Sep 17 00:00:00 2001 From: Peter Oberparleiter Date: Thu, 21 Aug 2008 19:46:39 +0200 Subject: [S390] cio: call ccw driver notify function with lock held Calling a ccw driver's notify function without the ccw device lock held opens up a race window between discovery and handling of a change in the device operational state. As a result, the device driver may encounter unexpected device malfunction, leading to out-of-retry situations or similar. Remove race by extending the ccw device lock from state change discovery to the calling of the notify function. Signed-off-by: Peter Oberparleiter Signed-off-by: Martin Schwidefsky --- drivers/s390/cio/device.c | 40 ++++++++++++++++++++-------------------- 1 file changed, 20 insertions(+), 20 deletions(-) (limited to 'drivers/s390/cio/device.c') diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c index e818d0c54c09..28221030b886 100644 --- a/drivers/s390/cio/device.c +++ b/drivers/s390/cio/device.c @@ -150,7 +150,6 @@ static struct css_driver io_subchannel_driver = { }; struct workqueue_struct *ccw_device_work; -struct workqueue_struct *ccw_device_notify_work; wait_queue_head_t ccw_device_init_wq; atomic_t ccw_device_init_count; @@ -168,11 +167,6 @@ init_ccw_bus_type (void) ccw_device_work = create_singlethread_workqueue("cio"); if (!ccw_device_work) return -ENOMEM; /* FIXME: better errno ? */ - ccw_device_notify_work = create_singlethread_workqueue("cio_notify"); - if (!ccw_device_notify_work) { - ret = -ENOMEM; /* FIXME: better errno ? */ - goto out_err; - } slow_path_wq = create_singlethread_workqueue("kslowcrw"); if (!slow_path_wq) { ret = -ENOMEM; /* FIXME: better errno ? */ @@ -192,8 +186,6 @@ init_ccw_bus_type (void) out_err: if (ccw_device_work) destroy_workqueue(ccw_device_work); - if (ccw_device_notify_work) - destroy_workqueue(ccw_device_notify_work); if (slow_path_wq) destroy_workqueue(slow_path_wq); return ret; @@ -204,7 +196,6 @@ cleanup_ccw_bus_type (void) { css_driver_unregister(&io_subchannel_driver); bus_unregister(&ccw_bus_type); - destroy_workqueue(ccw_device_notify_work); destroy_workqueue(ccw_device_work); } @@ -1496,11 +1487,22 @@ static void device_set_disconnected(struct ccw_device *cdev) ccw_device_schedule_recovery(); } +void ccw_device_set_notoper(struct ccw_device *cdev) +{ + struct subchannel *sch = to_subchannel(cdev->dev.parent); + + CIO_TRACE_EVENT(2, "notoper"); + CIO_TRACE_EVENT(2, sch->dev.bus_id); + ccw_device_set_timeout(cdev, 0); + cio_disable_subchannel(sch); + cdev->private->state = DEV_STATE_NOT_OPER; +} + static int io_subchannel_sch_event(struct subchannel *sch, int slow) { int event, ret, disc; unsigned long flags; - enum { NONE, UNREGISTER, UNREGISTER_PROBE, REPROBE } action; + enum { NONE, UNREGISTER, UNREGISTER_PROBE, REPROBE, DISC } action; struct ccw_device *cdev; spin_lock_irqsave(sch->lock, flags); @@ -1535,16 +1537,11 @@ static int io_subchannel_sch_event(struct subchannel *sch, int slow) } /* fall through */ case CIO_GONE: - /* Prevent unwanted effects when opening lock. */ - cio_disable_subchannel(sch); - device_set_disconnected(cdev); /* Ask driver what to do with device. */ - action = UNREGISTER; - spin_unlock_irqrestore(sch->lock, flags); - ret = io_subchannel_notify(sch, event); - spin_lock_irqsave(sch->lock, flags); - if (ret) - action = NONE; + if (io_subchannel_notify(sch, event)) + action = DISC; + else + action = UNREGISTER; break; case CIO_REVALIDATE: /* Device will be removed, so no notify necessary. */ @@ -1565,6 +1562,7 @@ static int io_subchannel_sch_event(struct subchannel *sch, int slow) switch (action) { case UNREGISTER: case UNREGISTER_PROBE: + ccw_device_set_notoper(cdev); /* Unregister device (will use subchannel lock). */ spin_unlock_irqrestore(sch->lock, flags); css_sch_device_unregister(sch); @@ -1577,6 +1575,9 @@ static int io_subchannel_sch_event(struct subchannel *sch, int slow) case REPROBE: ccw_device_trigger_reprobe(cdev); break; + case DISC: + device_set_disconnected(cdev); + break; default: break; } @@ -1828,5 +1829,4 @@ EXPORT_SYMBOL(ccw_driver_unregister); EXPORT_SYMBOL(get_ccwdev_by_busid); EXPORT_SYMBOL(ccw_bus_type); EXPORT_SYMBOL(ccw_device_work); -EXPORT_SYMBOL(ccw_device_notify_work); EXPORT_SYMBOL_GPL(ccw_device_get_subchannel_id); -- cgit v1.2.2