From: Peter Oberparleiter Use dedicated slow path work queue when unregistering a device due to a user action. This ensures serialialization of other register/ unregister requests. Signed-off-by: Peter Oberparleiter Signed-off-by: Martin Schwidefsky --- drivers/s390/cio/device.c | 56 ++++++++++++++++++++-------------------------- 1 file changed, 25 insertions(+), 31 deletions(-) Index: quilt-2.6/drivers/s390/cio/device.c =================================================================== --- quilt-2.6.orig/drivers/s390/cio/device.c +++ quilt-2.6/drivers/s390/cio/device.c @@ -296,36 +296,33 @@ static void ccw_device_unregister(struct device_del(&cdev->dev); } -static void ccw_device_remove_orphan_cb(struct device *dev) +static void ccw_device_remove_orphan_cb(struct work_struct *work) { - struct ccw_device *cdev = to_ccwdev(dev); + struct ccw_device_private *priv; + struct ccw_device *cdev; + priv = container_of(work, struct ccw_device_private, kick_work); + cdev = priv->cdev; ccw_device_unregister(cdev); put_device(&cdev->dev); + /* Release cdev reference for workqueue processing. */ + put_device(&cdev->dev); } -static void ccw_device_remove_sch_cb(struct device *dev) -{ - struct subchannel *sch; - - sch = to_subchannel(dev); - css_sch_device_unregister(sch); - /* Reset intparm to zeroes. */ - sch->schib.pmcw.intparm = 0; - cio_modify(sch); - put_device(&sch->dev); -} +static void ccw_device_call_sch_unregister(struct work_struct *work); static void ccw_device_remove_disconnected(struct ccw_device *cdev) { unsigned long flags; - int rc; /* * Forced offline in disconnected state means * 'throw away device'. */ + /* Get cdev reference for workqueue processing. */ + if (!get_device(&cdev->dev)) + return; if (ccw_device_is_orphan(cdev)) { /* * Deregister ccw device. @@ -335,23 +332,13 @@ ccw_device_remove_disconnected(struct cc spin_lock_irqsave(cdev->ccwlock, flags); cdev->private->state = DEV_STATE_NOT_OPER; spin_unlock_irqrestore(cdev->ccwlock, flags); - rc = device_schedule_callback(&cdev->dev, - ccw_device_remove_orphan_cb); - if (rc) - CIO_MSG_EVENT(0, "Couldn't unregister orphan " - "0.%x.%04x\n", - cdev->private->dev_id.ssid, - cdev->private->dev_id.devno); - return; - } - /* Deregister subchannel, which will kill the ccw device. */ - rc = device_schedule_callback(cdev->dev.parent, - ccw_device_remove_sch_cb); - if (rc) - CIO_MSG_EVENT(0, "Couldn't unregister disconnected device " - "0.%x.%04x\n", - cdev->private->dev_id.ssid, - cdev->private->dev_id.devno); + PREPARE_WORK(&cdev->private->kick_work, + ccw_device_remove_orphan_cb); + } else + /* Deregister subchannel, which will kill the ccw device. */ + PREPARE_WORK(&cdev->private->kick_work, + ccw_device_call_sch_unregister); + queue_work(slow_path_wq, &cdev->private->kick_work); } /** @@ -970,12 +957,17 @@ static void ccw_device_call_sch_unregist priv = container_of(work, struct ccw_device_private, kick_work); cdev = priv->cdev; + /* Get subchannel reference for local processing. */ + if (!get_device(cdev->dev.parent)) + return; sch = to_subchannel(cdev->dev.parent); css_sch_device_unregister(sch); /* Reset intparm to zeroes. */ sch->schib.pmcw.intparm = 0; cio_modify(sch); + /* Release cdev reference for workqueue processing.*/ put_device(&cdev->dev); + /* Release subchannel reference for local processing. */ put_device(&sch->dev); } @@ -1001,6 +993,8 @@ io_subchannel_recog_done(struct ccw_devi PREPARE_WORK(&cdev->private->kick_work, ccw_device_call_sch_unregister); queue_work(slow_path_wq, &cdev->private->kick_work); + /* Release subchannel reference for asynchronous recognition. */ + put_device(&sch->dev); if (atomic_dec_and_test(&ccw_device_init_count)) wake_up(&ccw_device_init_wq); break; -- blue skies, Martin. "Reality continues to ruin my life." - Calvin. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/