From: Sebastian Ott DEV_STATE_QUIESCE is used to stop all IO on a busy subchannel. This patch fixes the following problems related to the QUIESCE state: * Fix a potential race condition which could occur when the resulting state was DEV_STATE_OFFLINE. * Add missing locking around cio_disable_subchannel, ccw_device_cancel_halt_clear and the cdev's handler. * Loop until we know for sure that the subchannel is disabled. Signed-off-by: Sebastian Ott Signed-off-by: Martin Schwidefsky --- drivers/s390/cio/device.c | 35 +++++++++++++++++++---------------- drivers/s390/cio/device_fsm.c | 17 ++++------------- 2 files changed, 23 insertions(+), 29 deletions(-) Index: quilt-2.6/drivers/s390/cio/device.c =================================================================== --- quilt-2.6.orig/drivers/s390/cio/device.c 2009-11-13 16:08:22.000000000 +0100 +++ quilt-2.6/drivers/s390/cio/device.c 2009-11-13 16:08:22.000000000 +0100 @@ -1130,33 +1130,36 @@ return 0; } -static void -io_subchannel_shutdown(struct subchannel *sch) +static void io_subchannel_shutdown(struct subchannel *sch) { struct ccw_device *cdev; int ret; + spin_lock_irq(sch->lock); cdev = sch_get_cdev(sch); - if (cio_is_console(sch->schid)) - return; + goto out_unlock; if (!sch->schib.pmcw.ena) - /* Nothing to do. */ - return; + goto out_unlock; ret = cio_disable_subchannel(sch); if (ret != -EBUSY) - /* Subchannel is disabled, we're done. */ - return; - cdev->private->state = DEV_STATE_QUIESCE; + goto out_unlock; if (cdev->handler) - cdev->handler(cdev, cdev->private->intparm, - ERR_PTR(-EIO)); - ret = ccw_device_cancel_halt_clear(cdev); - if (ret == -EBUSY) { - ccw_device_set_timeout(cdev, HZ/10); - wait_event(cdev->private->wait_q, dev_fsm_final_state(cdev)); + cdev->handler(cdev, cdev->private->intparm, ERR_PTR(-EIO)); + while (ret == -EBUSY) { + cdev->private->state = DEV_STATE_QUIESCE; + ret = ccw_device_cancel_halt_clear(cdev); + if (ret == -EBUSY) { + ccw_device_set_timeout(cdev, HZ/10); + spin_unlock_irq(sch->lock); + wait_event(cdev->private->wait_q, + cdev->private->state != DEV_STATE_QUIESCE); + spin_lock_irq(sch->lock); + } + ret = cio_disable_subchannel(sch); } - cio_disable_subchannel(sch); +out_unlock: + spin_unlock_irq(sch->lock); } static int device_is_disconnected(struct ccw_device *cdev) Index: quilt-2.6/drivers/s390/cio/device_fsm.c =================================================================== --- quilt-2.6.orig/drivers/s390/cio/device_fsm.c 2009-11-13 16:08:21.000000000 +0100 +++ quilt-2.6/drivers/s390/cio/device_fsm.c 2009-11-13 16:08:22.000000000 +0100 @@ -911,10 +911,7 @@ ccw_device_quiesce_done(struct ccw_device *cdev, enum dev_event dev_event) { ccw_device_set_timeout(cdev, 0); - if (dev_event == DEV_EVENT_NOTOPER) - cdev->private->state = DEV_STATE_NOT_OPER; - else - cdev->private->state = DEV_STATE_OFFLINE; + cdev->private->state = DEV_STATE_NOT_OPER; wake_up(&cdev->private->wait_q); } @@ -924,17 +921,11 @@ int ret; ret = ccw_device_cancel_halt_clear(cdev); - switch (ret) { - case 0: - cdev->private->state = DEV_STATE_OFFLINE; - wake_up(&cdev->private->wait_q); - break; - case -ENODEV: + if (ret == -EBUSY) { + ccw_device_set_timeout(cdev, HZ/10); + } else { cdev->private->state = DEV_STATE_NOT_OPER; wake_up(&cdev->private->wait_q); - break; - default: - ccw_device_set_timeout(cdev, HZ/10); } } -- 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/