Messages in this thread Patch in this message | | | Date | Fri, 13 Nov 2009 16:09:16 +0100 | From | Martin Schwidefsky <> | Subject | [patch 52/52] [PATCH] cio: dont unregister a busy device in ccw_device_set_offline |
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From: Sebastian Ott <sebott@linux.vnet.ibm.com>
If we detect a busy subchannel after the driver's set_offline callback returned in ccw_device_set_offline, the current behavior is to unregister the device, which may lead to undesired consequences. Change this to just quiesce the subchannel and go on with the offline processing.
Note: This is no excuse for not fixing these drivers - after the set_offline callback they should have no running IO!
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> ---
drivers/s390/cio/device.c | 29 ++++++++++++++++++++--------- 1 file changed, 20 insertions(+), 9 deletions(-)
Index: quilt-2.6/drivers/s390/cio/device.c =================================================================== --- quilt-2.6.orig/drivers/s390/cio/device.c 2009-11-13 16:08:23.000000000 +0100 +++ quilt-2.6/drivers/s390/cio/device.c 2009-11-13 16:08:23.000000000 +0100 @@ -314,6 +314,8 @@ } } +static void io_subchannel_quiesce(struct subchannel *); + /** * ccw_device_set_offline() - disable a ccw device for I/O * @cdev: target ccw device @@ -327,7 +329,8 @@ */ int ccw_device_set_offline(struct ccw_device *cdev) { - int ret; + struct subchannel *sch; + int ret, state; if (!cdev) return -ENODEV; @@ -341,6 +344,7 @@ } cdev->online = 0; spin_lock_irq(cdev->ccwlock); + sch = to_subchannel(cdev->dev.parent); /* Wait until a final state or DISCONNECTED is reached */ while (!dev_fsm_final_state(cdev) && cdev->private->state != DEV_STATE_DISCONNECTED) { @@ -349,9 +353,21 @@ cdev->private->state == DEV_STATE_DISCONNECTED)); spin_lock_irq(cdev->ccwlock); } - ret = ccw_device_offline(cdev); - if (ret) - goto error; + do { + ret = ccw_device_offline(cdev); + if (!ret) + break; + CIO_MSG_EVENT(0, "ccw_device_offline returned %d, device " + "0.%x.%04x\n", ret, cdev->private->dev_id.ssid, + cdev->private->dev_id.devno); + if (ret != -EBUSY) + goto error; + state = cdev->private->state; + spin_unlock_irq(cdev->ccwlock); + io_subchannel_quiesce(sch); + spin_lock_irq(cdev->ccwlock); + cdev->private->state = state; + } while (ret == -EBUSY); spin_unlock_irq(cdev->ccwlock); wait_event(cdev->private->wait_q, (dev_fsm_final_state(cdev) || cdev->private->state == DEV_STATE_DISCONNECTED)); @@ -368,9 +384,6 @@ return 0; error: - CIO_MSG_EVENT(0, "ccw_device_offline returned %d, device 0.%x.%04x\n", - ret, cdev->private->dev_id.ssid, - cdev->private->dev_id.devno); cdev->private->state = DEV_STATE_OFFLINE; dev_fsm_event(cdev, DEV_EVENT_NOTOPER); spin_unlock_irq(cdev->ccwlock); @@ -1059,8 +1072,6 @@ return 0; } -static void io_subchannel_quiesce(struct subchannel *); - static int io_subchannel_remove (struct subchannel *sch) {
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