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authorPeter Oberparleiter <peter.oberparleiter@de.ibm.com>2008-08-21 19:46:39 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2008-08-21 19:46:41 +0200
commit91c36919a456589f4f073671474a1f899e0d3c2b (patch)
tree63cb2ee1afd9b00bf2ea4959482d58f402bb21f3
parent49fd38bdaa96f093fcad3176a781a4d0de8f8602 (diff)
[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>
-rw-r--r--drivers/s390/block/dasd.c5
-rw-r--r--drivers/s390/cio/css.c1
-rw-r--r--drivers/s390/cio/device.c40
-rw-r--r--drivers/s390/cio/device.h2
-rw-r--r--drivers/s390/cio/device_fsm.c31
5 files changed, 41 insertions, 38 deletions
diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 1b6c52ef733..acb78017e7d 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -2333,13 +2333,11 @@ int dasd_generic_notify(struct ccw_device *cdev, int event)
{
struct dasd_device *device;
struct dasd_ccw_req *cqr;
- unsigned long flags;
int ret;
- device = dasd_device_from_cdev(cdev);
+ device = dasd_device_from_cdev_locked(cdev);
if (IS_ERR(device))
return 0;
- spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
ret = 0;
switch (event) {
case CIO_GONE:
@@ -2369,7 +2367,6 @@ int dasd_generic_notify(struct ccw_device *cdev, int event)
ret = 1;
break;
}
- spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
dasd_put_device(device);
return ret;
}
diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c
index 46c021d880d..51489eff6b0 100644
--- a/drivers/s390/cio/css.c
+++ b/drivers/s390/cio/css.c
@@ -477,7 +477,6 @@ void css_schedule_eval_all(void)
void css_wait_for_slow_path(void)
{
- flush_workqueue(ccw_device_notify_work);
flush_workqueue(slow_path_wq);
}
diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
index e818d0c54c0..28221030b88 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);
diff --git a/drivers/s390/cio/device.h b/drivers/s390/cio/device.h
index 9800a8335a3..6f5c3f2b358 100644
--- a/drivers/s390/cio/device.h
+++ b/drivers/s390/cio/device.h
@@ -72,7 +72,6 @@ dev_fsm_final_state(struct ccw_device *cdev)
}
extern struct workqueue_struct *ccw_device_work;
-extern struct workqueue_struct *ccw_device_notify_work;
extern wait_queue_head_t ccw_device_init_wq;
extern atomic_t ccw_device_init_count;
@@ -120,6 +119,7 @@ int ccw_device_stlck(struct ccw_device *);
void ccw_device_trigger_reprobe(struct ccw_device *);
void ccw_device_kill_io(struct ccw_device *);
int ccw_device_notify(struct ccw_device *, int);
+void ccw_device_set_notoper(struct ccw_device *cdev);
/* qdio needs this. */
void ccw_device_set_timeout(struct ccw_device *, int);
diff --git a/drivers/s390/cio/device_fsm.c b/drivers/s390/cio/device_fsm.c
index 8b5fe57fb2f..550508df952 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);