diff options
author | Peter Oberparleiter <peter.oberparleiter@de.ibm.com> | 2008-08-21 17:46:39 (GMT) |
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committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2008-08-21 17:46:41 (GMT) |
commit | 91c36919a456589f4f073671474a1f899e0d3c2b (patch) | |
tree | 63cb2ee1afd9b00bf2ea4959482d58f402bb21f3 /drivers/s390/cio/device_fsm.c | |
parent | 49fd38bdaa96f093fcad3176a781a4d0de8f8602 (diff) | |
download | linux-fsl-qoriq-91c36919a456589f4f073671474a1f899e0d3c2b.tar.xz |
[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 <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'drivers/s390/cio/device_fsm.c')
-rw-r--r-- | drivers/s390/cio/device_fsm.c | 31 |
1 files changed, 19 insertions, 12 deletions
diff --git a/drivers/s390/cio/device_fsm.c b/drivers/s390/cio/device_fsm.c index 8b5fe57..550508d 100644 --- a/drivers/s390/cio/device_fsm.c +++ b/drivers/s390/cio/device_fsm.c @@ -337,26 +337,34 @@ int ccw_device_notify(struct ccw_device *cdev, int event) return 0; if (!cdev->online) return 0; + CIO_MSG_EVENT(2, "notify called for 0.%x.%04x, event=%d\n", + cdev->private->dev_id.ssid, cdev->private->dev_id.devno, + event); return cdev->drv->notify ? cdev->drv->notify(cdev, event) : 0; } -static void -ccw_device_oper_notify(struct work_struct *work) +static void cmf_reenable_delayed(struct work_struct *work) { struct ccw_device_private *priv; struct ccw_device *cdev; - int ret; priv = container_of(work, struct ccw_device_private, kick_work); cdev = priv->cdev; - ret = ccw_device_notify(cdev, CIO_OPER); - if (ret) { + cmf_reenable(cdev); +} + +static void ccw_device_oper_notify(struct ccw_device *cdev) +{ + if (ccw_device_notify(cdev, CIO_OPER)) { /* Reenable channel measurements, if needed. */ - cmf_reenable(cdev); - wake_up(&cdev->private->wait_q); - } else - /* Driver doesn't want device back. */ - ccw_device_do_unreg_rereg(work); + PREPARE_WORK(&cdev->private->kick_work, cmf_reenable_delayed); + queue_work(ccw_device_work, &cdev->private->kick_work); + return; + } + /* Driver doesn't want device back. */ + ccw_device_set_notoper(cdev); + PREPARE_WORK(&cdev->private->kick_work, ccw_device_do_unreg_rereg); + queue_work(ccw_device_work, &cdev->private->kick_work); } /* @@ -386,8 +394,7 @@ ccw_device_done(struct ccw_device *cdev, int state) if (cdev->private->flags.donotify) { cdev->private->flags.donotify = 0; - PREPARE_WORK(&cdev->private->kick_work, ccw_device_oper_notify); - queue_work(ccw_device_notify_work, &cdev->private->kick_work); + ccw_device_oper_notify(cdev); } wake_up(&cdev->private->wait_q); |