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[S390] cio: introduce ccw device todos
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Introduce a central mechanism for performing delayed ccw device work
to ensure that different types of work do not overwrite each other.
Prioritization ensures that the most important work is always
performed while less important tasks are either obsoleted or repeated
later.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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Peter Oberparleiter authored and Martin Schwidefsky committed Dec 7, 2009
1 parent 390935a commit 37de53b
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Showing 4 changed files with 119 additions and 127 deletions.
203 changes: 100 additions & 103 deletions drivers/s390/cio/device.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -306,47 +306,6 @@ static void ccw_device_unregister(struct ccw_device *cdev)
}
}

static void ccw_device_remove_orphan_cb(struct work_struct *work)
{
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);
/* Release cdev reference for workqueue processing. */
put_device(&cdev->dev);
}

static void
ccw_device_remove_disconnected(struct ccw_device *cdev)
{
unsigned long flags;

/*
* Forced offline in disconnected state means
* 'throw away device'.
*/
if (ccw_device_is_orphan(cdev)) {
/*
* Deregister ccw device.
* Unfortunately, we cannot do this directly from the
* attribute method.
*/
/* Get cdev reference for workqueue processing. */
if (!get_device(&cdev->dev))
return;
spin_lock_irqsave(cdev->ccwlock, flags);
cdev->private->state = DEV_STATE_NOT_OPER;
spin_unlock_irqrestore(cdev->ccwlock, flags);
PREPARE_WORK(&cdev->private->kick_work,
ccw_device_remove_orphan_cb);
queue_work(slow_path_wq, &cdev->private->kick_work);
} else
/* Deregister subchannel, which will kill the ccw device. */
ccw_device_schedule_sch_unregister(cdev);
}

/**
* ccw_device_set_offline() - disable a ccw device for I/O
* @cdev: target ccw device
Expand Down Expand Up @@ -494,9 +453,11 @@ int ccw_device_set_online(struct ccw_device *cdev)

static int online_store_handle_offline(struct ccw_device *cdev)
{
if (cdev->private->state == DEV_STATE_DISCONNECTED)
ccw_device_remove_disconnected(cdev);
else if (cdev->online && cdev->drv && cdev->drv->set_offline)
if (cdev->private->state == DEV_STATE_DISCONNECTED) {
spin_lock_irq(cdev->ccwlock);
ccw_device_sched_todo(cdev, CDEV_TODO_UNREG_EVAL);
spin_unlock_irq(cdev->ccwlock);
} else if (cdev->online && cdev->drv && cdev->drv->set_offline)
return ccw_device_set_offline(cdev);
return 0;
}
Expand Down Expand Up @@ -690,17 +651,10 @@ static struct ccw_device *get_ccwdev_by_dev_id(struct ccw_dev_id *dev_id)
return dev ? to_ccwdev(dev) : NULL;
}

void ccw_device_do_unbind_bind(struct work_struct *work)
static void ccw_device_do_unbind_bind(struct ccw_device *cdev)
{
struct ccw_device_private *priv;
struct ccw_device *cdev;
struct subchannel *sch;
int ret;

priv = container_of(work, struct ccw_device_private, kick_work);
cdev = priv->cdev;
sch = to_subchannel(cdev->dev.parent);

if (test_bit(1, &cdev->private->registered)) {
device_release_driver(&cdev->dev);
ret = device_attach(&cdev->dev);
Expand Down Expand Up @@ -735,14 +689,16 @@ static struct ccw_device * io_subchannel_allocate_dev(struct subchannel *sch)
return ERR_PTR(-ENOMEM);
}

static void ccw_device_todo(struct work_struct *work);

static int io_subchannel_initialize_dev(struct subchannel *sch,
struct ccw_device *cdev)
{
cdev->private->cdev = cdev;
atomic_set(&cdev->private->onoff, 0);
cdev->dev.parent = &sch->dev;
cdev->dev.release = ccw_device_release;
INIT_WORK(&cdev->private->kick_work, NULL);
INIT_WORK(&cdev->private->todo_work, ccw_device_todo);
cdev->dev.groups = ccwdev_attr_groups;
/* Do first half of device_register. */
device_initialize(&cdev->dev);
Expand Down Expand Up @@ -797,17 +753,12 @@ static void sch_create_and_recog_new_device(struct subchannel *sch)
/*
* Register recognized device.
*/
static void
io_subchannel_register(struct work_struct *work)
static void io_subchannel_register(struct ccw_device *cdev)
{
struct ccw_device_private *priv;
struct ccw_device *cdev;
struct subchannel *sch;
int ret;
unsigned long flags;

priv = container_of(work, struct ccw_device_private, kick_work);
cdev = priv->cdev;
sch = to_subchannel(cdev->dev.parent);
/*
* Check if subchannel is still registered. It may have become
Expand Down Expand Up @@ -859,41 +810,23 @@ io_subchannel_register(struct work_struct *work)
cdev->private->flags.recog_done = 1;
wake_up(&cdev->private->wait_q);
out_err:
/* Release reference for workqueue processing. */
put_device(&cdev->dev);
if (atomic_dec_and_test(&ccw_device_init_count))
wake_up(&ccw_device_init_wq);
}

static void ccw_device_call_sch_unregister(struct work_struct *work)
static void ccw_device_call_sch_unregister(struct ccw_device *cdev)
{
struct ccw_device_private *priv;
struct ccw_device *cdev;
struct subchannel *sch;

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);
/* Release cdev reference for workqueue processing.*/
put_device(&cdev->dev);
/* Release subchannel reference for local processing. */
put_device(&sch->dev);
}

void ccw_device_schedule_sch_unregister(struct ccw_device *cdev)
{
/* Get cdev reference for workqueue processing. */
if (!get_device(&cdev->dev))
return;
PREPARE_WORK(&cdev->private->kick_work,
ccw_device_call_sch_unregister);
queue_work(slow_path_wq, &cdev->private->kick_work);
}

/*
* subchannel recognition done. Called from the state machine.
*/
Expand All @@ -909,7 +842,8 @@ io_subchannel_recog_done(struct ccw_device *cdev)
/* Device did not respond in time. */
case DEV_STATE_NOT_OPER:
cdev->private->flags.recog_done = 1;
ccw_device_schedule_sch_unregister(cdev);
/* Remove device found not operational. */
ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
if (atomic_dec_and_test(&ccw_device_init_count))
wake_up(&ccw_device_init_wq);
break;
Expand All @@ -918,11 +852,7 @@ io_subchannel_recog_done(struct ccw_device *cdev)
* We can't register the device in interrupt context so
* we schedule a work item.
*/
if (!get_device(&cdev->dev))
break;
PREPARE_WORK(&cdev->private->kick_work,
io_subchannel_register);
queue_work(slow_path_wq, &cdev->private->kick_work);
ccw_device_sched_todo(cdev, CDEV_TODO_REGISTER);
break;
}
}
Expand Down Expand Up @@ -1333,20 +1263,16 @@ static void ccw_device_schedule_recovery(void)
static int purge_fn(struct device *dev, void *data)
{
struct ccw_device *cdev = to_ccwdev(dev);
struct ccw_device_private *priv = cdev->private;
int unreg;
struct ccw_dev_id *id = &cdev->private->dev_id;

spin_lock_irq(cdev->ccwlock);
unreg = is_blacklisted(priv->dev_id.ssid, priv->dev_id.devno) &&
(priv->state == DEV_STATE_OFFLINE);
if (is_blacklisted(id->ssid, id->devno) &&
(cdev->private->state == DEV_STATE_OFFLINE)) {
CIO_MSG_EVENT(3, "ccw: purging 0.%x.%04x\n", id->ssid,
id->devno);
ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
}
spin_unlock_irq(cdev->ccwlock);
if (!unreg)
goto out;
CIO_MSG_EVENT(3, "ccw: purging 0.%x.%04x\n", priv->dev_id.ssid,
priv->dev_id.devno);
ccw_device_schedule_sch_unregister(cdev);

out:
/* Abort loop in case of pending signal. */
if (signal_pending(current))
return -EINTR;
Expand Down Expand Up @@ -1456,12 +1382,14 @@ static int io_subchannel_sch_event(struct subchannel *sch, int process)
goto out_unlock;
if (work_pending(&sch->todo_work))
goto out_unlock;
cdev = sch_get_cdev(sch);
if (cdev && work_pending(&cdev->private->todo_work))
goto out_unlock;
action = sch_get_action(sch);
CIO_MSG_EVENT(2, "event: sch 0.%x.%04x, process=%d, action=%d\n",
sch->schid.ssid, sch->schid.sch_no, process,
action);
/* Perform immediate actions while holding the lock. */
cdev = sch_get_cdev(sch);
switch (action) {
case IO_SCH_REPROBE:
/* Trigger device recognition. */
Expand Down Expand Up @@ -1753,7 +1681,7 @@ static int ccw_device_pm_prepare(struct device *dev)
{
struct ccw_device *cdev = to_ccwdev(dev);

if (work_pending(&cdev->private->kick_work))
if (work_pending(&cdev->private->todo_work))
return -EAGAIN;
/* Fail while device is being set online/offline. */
if (atomic_read(&cdev->private->onoff))
Expand Down Expand Up @@ -1874,7 +1802,7 @@ static int resume_handle_boxed(struct ccw_device *cdev)
cdev->private->state = DEV_STATE_BOXED;
if (ccw_device_notify(cdev, CIO_BOXED))
return 0;
ccw_device_schedule_sch_unregister(cdev);
ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
return -ENODEV;
}

Expand All @@ -1883,7 +1811,7 @@ static int resume_handle_disc(struct ccw_device *cdev)
cdev->private->state = DEV_STATE_DISCONNECTED;
if (ccw_device_notify(cdev, CIO_GONE))
return 0;
ccw_device_schedule_sch_unregister(cdev);
ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
return -ENODEV;
}

Expand Down Expand Up @@ -1928,9 +1856,7 @@ static int ccw_device_pm_restore(struct device *dev)
/* check if the device type has changed */
if (!ccw_device_test_sense_data(cdev)) {
ccw_device_update_sense_data(cdev);
PREPARE_WORK(&cdev->private->kick_work,
ccw_device_do_unbind_bind);
queue_work(ccw_device_work, &cdev->private->kick_work);
ccw_device_sched_todo(cdev, CDEV_TODO_REBIND);
ret = -ENODEV;
goto out_unlock;
}
Expand Down Expand Up @@ -1974,7 +1900,7 @@ static int ccw_device_pm_restore(struct device *dev)
goto out_restore;

out_unreg_unlock:
ccw_device_schedule_sch_unregister(cdev);
ccw_device_sched_todo(cdev, CDEV_TODO_UNREG_EVAL);
ret = -ENODEV;
out_unlock:
spin_unlock_irq(sch->lock);
Expand Down Expand Up @@ -2039,6 +1965,77 @@ ccw_device_get_subchannel_id(struct ccw_device *cdev)
return sch->schid;
}

static void ccw_device_todo(struct work_struct *work)
{
struct ccw_device_private *priv;
struct ccw_device *cdev;
struct subchannel *sch;
enum cdev_todo todo;

priv = container_of(work, struct ccw_device_private, todo_work);
cdev = priv->cdev;
sch = to_subchannel(cdev->dev.parent);
/* Find out todo. */
spin_lock_irq(cdev->ccwlock);
todo = priv->todo;
priv->todo = CDEV_TODO_NOTHING;
CIO_MSG_EVENT(4, "cdev_todo: cdev=0.%x.%04x todo=%d\n",
priv->dev_id.ssid, priv->dev_id.devno, todo);
spin_unlock_irq(cdev->ccwlock);
/* Perform todo. */
switch (todo) {
case CDEV_TODO_ENABLE_CMF:
cmf_reenable(cdev);
break;
case CDEV_TODO_REBIND:
ccw_device_do_unbind_bind(cdev);
break;
case CDEV_TODO_REGISTER:
io_subchannel_register(cdev);
break;
case CDEV_TODO_UNREG_EVAL:
if (!sch_is_pseudo_sch(sch))
css_schedule_eval(sch->schid);
/* fall-through */
case CDEV_TODO_UNREG:
if (sch_is_pseudo_sch(sch))
ccw_device_unregister(cdev);
else
ccw_device_call_sch_unregister(cdev);
break;
default:
break;
}
/* Release workqueue ref. */
put_device(&cdev->dev);
}

/**
* ccw_device_sched_todo - schedule ccw device operation
* @cdev: ccw device
* @todo: todo
*
* Schedule the operation identified by @todo to be performed on the slow path
* workqueue. Do nothing if another operation with higher priority is already
* scheduled. Needs to be called with ccwdev lock held.
*/
void ccw_device_sched_todo(struct ccw_device *cdev, enum cdev_todo todo)
{
CIO_MSG_EVENT(4, "cdev_todo: sched cdev=0.%x.%04x todo=%d\n",
cdev->private->dev_id.ssid, cdev->private->dev_id.devno,
todo);
if (cdev->private->todo >= todo)
return;
cdev->private->todo = todo;
/* Get workqueue ref. */
if (!get_device(&cdev->dev))
return;
if (!queue_work(slow_path_wq, &cdev->private->todo_work)) {
/* Already queued, release workqueue ref. */
put_device(&cdev->dev);
}
}

MODULE_LICENSE("GPL");
EXPORT_SYMBOL(ccw_device_set_online);
EXPORT_SYMBOL(ccw_device_set_offline);
Expand Down
3 changes: 1 addition & 2 deletions drivers/s390/cio/device.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -81,8 +81,6 @@ void io_subchannel_init_config(struct subchannel *sch);

int ccw_device_cancel_halt_clear(struct ccw_device *);

void ccw_device_do_unbind_bind(struct work_struct *);
void ccw_device_move_to_orphanage(struct work_struct *);
int ccw_device_is_orphan(struct ccw_device *);

int ccw_device_recognition(struct ccw_device *);
Expand All @@ -92,6 +90,7 @@ void ccw_device_update_sense_data(struct ccw_device *);
int ccw_device_test_sense_data(struct ccw_device *);
void ccw_device_schedule_sch_unregister(struct ccw_device *);
int ccw_purge_blacklisted(void);
void ccw_device_sched_todo(struct ccw_device *cdev, enum cdev_todo todo);

/* Function prototypes for device status and basic sense stuff. */
void ccw_device_accumulate_irb(struct ccw_device *, struct irb *);
Expand Down
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