Commit 5d6e6b6f authored by Peter Oberparleiter's avatar Peter Oberparleiter Committed by Martin Schwidefsky
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[S390] cio: introduce parent-initiated device move



Change the initiative to update subchannel-ccw device associations
to the subchannel: when there is an indication that the internal
association no longer reflects the current hardware state, mark
each affected subchannel as requiring attention. Once processing
reaches a subchannel, determine the correct association for that
subchannel at that time and perform the necessary device_move
operations.

This change fixes problems with the previous approach which would
leave devices in an inconsistent state when a new hardware change
occurred while a device_move was already scheduled.
Signed-off-by: default avatarPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 60e4dac1
......@@ -376,8 +376,8 @@ static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
/* Unusable - ignore. */
return 0;
}
CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, unknown, "
"slow path.\n", schid.ssid, schid.sch_no, CIO_OPER);
CIO_MSG_EVENT(4, "event: sch 0.%x.%04x, new\n", schid.ssid,
schid.sch_no);
return css_probe_device(schid);
}
......@@ -394,6 +394,10 @@ static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
"Got subchannel machine check but "
"no sch_event handler provided.\n");
}
if (ret != 0 && ret != -EAGAIN) {
CIO_MSG_EVENT(2, "eval: sch 0.%x.%04x, rc=%d\n",
sch->schid.ssid, sch->schid.sch_no, ret);
}
return ret;
}
......@@ -684,6 +688,7 @@ static int __init setup_css(int nr)
css->pseudo_subchannel->dev.parent = &css->device;
css->pseudo_subchannel->dev.release = css_subchannel_release;
dev_set_name(&css->pseudo_subchannel->dev, "defunct");
mutex_init(&css->pseudo_subchannel->reg_mutex);
ret = cio_create_sch_lock(css->pseudo_subchannel);
if (ret) {
kfree(css->pseudo_subchannel);
......
......@@ -673,57 +673,19 @@ static int ccw_device_register(struct ccw_device *cdev)
return ret;
}
struct match_data {
struct ccw_dev_id dev_id;
struct ccw_device * sibling;
};
static int
match_devno(struct device * dev, void * data)
{
struct match_data * d = data;
struct ccw_device * cdev;
cdev = to_ccwdev(dev);
if ((cdev->private->state == DEV_STATE_DISCONNECTED) &&
!ccw_device_is_orphan(cdev) &&
ccw_dev_id_is_equal(&cdev->private->dev_id, &d->dev_id) &&
(cdev != d->sibling))
return 1;
return 0;
}
static struct ccw_device * get_disc_ccwdev_by_dev_id(struct ccw_dev_id *dev_id,
struct ccw_device *sibling)
static int match_dev_id(struct device *dev, void *data)
{
struct device *dev;
struct match_data data;
data.dev_id = *dev_id;
data.sibling = sibling;
dev = bus_find_device(&ccw_bus_type, NULL, &data, match_devno);
return dev ? to_ccwdev(dev) : NULL;
}
static int match_orphan(struct device *dev, void *data)
{
struct ccw_dev_id *dev_id;
struct ccw_device *cdev;
struct ccw_device *cdev = to_ccwdev(dev);
struct ccw_dev_id *dev_id = data;
dev_id = data;
cdev = to_ccwdev(dev);
return ccw_dev_id_is_equal(&cdev->private->dev_id, dev_id);
}
static struct ccw_device *
get_orphaned_ccwdev_by_dev_id(struct channel_subsystem *css,
struct ccw_dev_id *dev_id)
static struct ccw_device *get_ccwdev_by_dev_id(struct ccw_dev_id *dev_id)
{
struct device *dev;
dev = device_find_child(&css->pseudo_subchannel->dev, dev_id,
match_orphan);
dev = bus_find_device(&ccw_bus_type, NULL, dev_id, match_dev_id);
return dev ? to_ccwdev(dev) : NULL;
}
......@@ -808,75 +770,6 @@ static struct ccw_device * io_subchannel_create_ccwdev(struct subchannel *sch)
static int io_subchannel_recog(struct ccw_device *, struct subchannel *);
static void sch_attach_device(struct subchannel *sch,
struct ccw_device *cdev)
{
css_update_ssd_info(sch);
spin_lock_irq(sch->lock);
sch_set_cdev(sch, cdev);
cdev->private->schid = sch->schid;
cdev->ccwlock = sch->lock;
ccw_device_trigger_reprobe(cdev);
spin_unlock_irq(sch->lock);
}
static void sch_attach_disconnected_device(struct subchannel *sch,
struct ccw_device *cdev)
{
struct subchannel *other_sch;
int ret;
/* Get reference for new parent. */
if (!get_device(&sch->dev))
return;
other_sch = to_subchannel(cdev->dev.parent);
/* Note: device_move() changes cdev->dev.parent */
ret = device_move(&cdev->dev, &sch->dev, DPM_ORDER_PARENT_BEFORE_DEV);
if (ret) {
CIO_MSG_EVENT(0, "Moving disconnected device 0.%x.%04x failed "
"(ret=%d)!\n", cdev->private->dev_id.ssid,
cdev->private->dev_id.devno, ret);
/* Put reference for new parent. */
put_device(&sch->dev);
return;
}
sch_set_cdev(other_sch, NULL);
/* No need to keep a subchannel without ccw device around. */
css_sch_device_unregister(other_sch);
sch_attach_device(sch, cdev);
/* Put reference for old parent. */
put_device(&other_sch->dev);
}
static void sch_attach_orphaned_device(struct subchannel *sch,
struct ccw_device *cdev)
{
int ret;
struct subchannel *pseudo_sch;
/* Get reference for new parent. */
if (!get_device(&sch->dev))
return;
pseudo_sch = to_subchannel(cdev->dev.parent);
/*
* Try to move the ccw device to its new subchannel.
* Note: device_move() changes cdev->dev.parent
*/
ret = device_move(&cdev->dev, &sch->dev, DPM_ORDER_PARENT_BEFORE_DEV);
if (ret) {
CIO_MSG_EVENT(0, "Moving device 0.%x.%04x from orphanage "
"failed (ret=%d)!\n",
cdev->private->dev_id.ssid,
cdev->private->dev_id.devno, ret);
/* Put reference for new parent. */
put_device(&sch->dev);
return;
}
sch_attach_device(sch, cdev);
/* Put reference on pseudo subchannel. */
put_device(&pseudo_sch->dev);
}
static void sch_create_and_recog_new_device(struct subchannel *sch)
{
struct ccw_device *cdev;
......@@ -901,70 +794,6 @@ static void sch_create_and_recog_new_device(struct subchannel *sch)
}
}
void ccw_device_move_to_orphanage(struct work_struct *work)
{
struct ccw_device_private *priv;
struct ccw_device *cdev;
struct ccw_device *replacing_cdev;
struct subchannel *sch;
int ret;
struct channel_subsystem *css;
struct ccw_dev_id dev_id;
priv = container_of(work, struct ccw_device_private, kick_work);
cdev = priv->cdev;
sch = to_subchannel(cdev->dev.parent);
css = to_css(sch->dev.parent);
dev_id.devno = sch->schib.pmcw.dev;
dev_id.ssid = sch->schid.ssid;
/* Increase refcount for pseudo subchannel. */
get_device(&css->pseudo_subchannel->dev);
/*
* Move the orphaned ccw device to the orphanage so the replacing
* ccw device can take its place on the subchannel.
* Note: device_move() changes cdev->dev.parent
*/
ret = device_move(&cdev->dev, &css->pseudo_subchannel->dev,
DPM_ORDER_NONE);
if (ret) {
CIO_MSG_EVENT(0, "Moving device 0.%x.%04x to orphanage failed "
"(ret=%d)!\n", cdev->private->dev_id.ssid,
cdev->private->dev_id.devno, ret);
/* Decrease refcount for pseudo subchannel again. */
put_device(&css->pseudo_subchannel->dev);
return;
}
cdev->ccwlock = css->pseudo_subchannel->lock;
/*
* Search for the replacing ccw device
* - among the disconnected devices
* - in the orphanage
*/
replacing_cdev = get_disc_ccwdev_by_dev_id(&dev_id, cdev);
if (replacing_cdev) {
sch_attach_disconnected_device(sch, replacing_cdev);
/* Release reference from get_disc_ccwdev_by_dev_id() */
put_device(&replacing_cdev->dev);
/* Release reference of subchannel from old cdev. */
put_device(&sch->dev);
return;
}
replacing_cdev = get_orphaned_ccwdev_by_dev_id(css, &dev_id);
if (replacing_cdev) {
sch_attach_orphaned_device(sch, replacing_cdev);
/* Release reference from get_orphaned_ccwdev_by_dev_id() */
put_device(&replacing_cdev->dev);
/* Release reference of subchannel from old cdev. */
put_device(&sch->dev);
return;
}
sch_create_and_recog_new_device(sch);
/* Release reference of subchannel from old cdev. */
put_device(&sch->dev);
}
/*
* Register recognized device.
*/
......@@ -1131,53 +960,56 @@ io_subchannel_recog(struct ccw_device *cdev, struct subchannel *sch)
return rc;
}
static void ccw_device_move_to_sch(struct work_struct *work)
static int ccw_device_move_to_sch(struct ccw_device *cdev,
struct subchannel *sch)
{
struct ccw_device_private *priv;
struct subchannel *old_sch;
int rc;
struct subchannel *sch;
struct ccw_device *cdev;
struct subchannel *former_parent;
priv = container_of(work, struct ccw_device_private, kick_work);
sch = priv->sch;
cdev = priv->cdev;
former_parent = to_subchannel(cdev->dev.parent);
/* Get reference for new parent. */
old_sch = to_subchannel(cdev->dev.parent);
/* Obtain child reference for new parent. */
if (!get_device(&sch->dev))
return;
return -ENODEV;
mutex_lock(&sch->reg_mutex);
/*
* Try to move the ccw device to its new subchannel.
* Note: device_move() changes cdev->dev.parent
*/
rc = device_move(&cdev->dev, &sch->dev, DPM_ORDER_PARENT_BEFORE_DEV);
mutex_unlock(&sch->reg_mutex);
if (rc) {
CIO_MSG_EVENT(0, "Moving device 0.%x.%04x to subchannel "
"0.%x.%04x failed (ret=%d)!\n",
CIO_MSG_EVENT(0, "device_move(0.%x.%04x,0.%x.%04x)=%d\n",
cdev->private->dev_id.ssid,
cdev->private->dev_id.devno, sch->schid.ssid,
sch->schid.sch_no, rc);
css_sch_device_unregister(sch);
/* Put reference for new parent again. */
sch->schib.pmcw.dev, rc);
/* Release child reference for new parent. */
put_device(&sch->dev);
goto out;
return rc;
}
if (!sch_is_pseudo_sch(former_parent)) {
spin_lock_irq(former_parent->lock);
sch_set_cdev(former_parent, NULL);
spin_unlock_irq(former_parent->lock);
css_sch_device_unregister(former_parent);
/* Reset intparm to zeroes. */
former_parent->config.intparm = 0;
cio_commit_config(former_parent);
/* Clean up old subchannel. */
if (!sch_is_pseudo_sch(old_sch)) {
spin_lock_irq(old_sch->lock);
sch_set_cdev(old_sch, NULL);
cio_disable_subchannel(old_sch);
spin_unlock_irq(old_sch->lock);
css_schedule_eval(old_sch->schid);
}
sch_attach_device(sch, cdev);
out:
/* Put reference for old parent. */
put_device(&former_parent->dev);
put_device(&cdev->dev);
/* Release child reference for old parent. */
put_device(&old_sch->dev);
/* Initialize new subchannel. */
spin_lock_irq(sch->lock);
cdev->private->schid = sch->schid;
cdev->ccwlock = sch->lock;
if (!sch_is_pseudo_sch(sch))
sch_set_cdev(sch, cdev);
spin_unlock_irq(sch->lock);
if (!sch_is_pseudo_sch(sch))
css_update_ssd_info(sch);
return 0;
}
static int ccw_device_move_to_orph(struct ccw_device *cdev)
{
struct subchannel *sch = to_subchannel(cdev->dev.parent);
struct channel_subsystem *css = to_css(sch->dev.parent);
return ccw_device_move_to_sch(cdev, css->pseudo_subchannel);
}
static void io_subchannel_irq(struct subchannel *sch)
......@@ -1244,8 +1076,6 @@ static int io_subchannel_probe(struct subchannel *sch)
{
struct ccw_device *cdev;
int rc;
unsigned long flags;
struct ccw_dev_id dev_id;
if (cio_is_console(sch->schid)) {
rc = sysfs_create_group(&sch->dev.kobj,
......@@ -1290,37 +1120,7 @@ static int io_subchannel_probe(struct subchannel *sch)
GFP_KERNEL | GFP_DMA);
if (!sch->private)
goto out_schedule;
/*
* First check if a fitting device may be found amongst the
* disconnected devices or in the orphanage.
*/
dev_id.devno = sch->schib.pmcw.dev;
dev_id.ssid = sch->schid.ssid;
cdev = get_disc_ccwdev_by_dev_id(&dev_id, NULL);
if (!cdev)
cdev = get_orphaned_ccwdev_by_dev_id(to_css(sch->dev.parent),
&dev_id);
if (cdev) {
/*
* Schedule moving the device until when we have a registered
* subchannel to move to and succeed the probe. We can
* unregister later again, when the probe is through.
*/
cdev->private->sch = sch;
PREPARE_WORK(&cdev->private->kick_work,
ccw_device_move_to_sch);
queue_work(slow_path_wq, &cdev->private->kick_work);
return 0;
}
cdev = io_subchannel_create_ccwdev(sch);
if (IS_ERR(cdev))
goto out_schedule;
rc = io_subchannel_recog(cdev, sch);
if (rc) {
spin_lock_irqsave(sch->lock, flags);
io_subchannel_recog_done(cdev);
spin_unlock_irqrestore(sch->lock, flags);
}
css_schedule_eval(sch->schid);
return 0;
out_schedule:
......@@ -1349,16 +1149,6 @@ out_free:
return 0;
}
static int io_subchannel_notify(struct subchannel *sch, int event)
{
struct ccw_device *cdev;
cdev = sch_get_cdev(sch);
if (!cdev)
return 0;
return ccw_device_notify(cdev, event);
}
static void io_subchannel_verify(struct subchannel *sch)
{
struct ccw_device *cdev;
......@@ -1482,19 +1272,6 @@ io_subchannel_shutdown(struct subchannel *sch)
cio_disable_subchannel(sch);
}
static int io_subchannel_get_status(struct subchannel *sch)
{
struct schib schib;
if (stsch(sch->schid, &schib) || !schib.pmcw.dnv)
return CIO_GONE;
if (sch->schib.pmcw.dnv && (schib.pmcw.dev != sch->schib.pmcw.dev))
return CIO_REVALIDATE;
if (!sch->lpm)
return CIO_NO_PATH;
return CIO_OPER;
}
static int device_is_disconnected(struct ccw_device *cdev)
{
if (!cdev)
......@@ -1626,91 +1403,165 @@ void ccw_device_set_notoper(struct ccw_device *cdev)
cdev->private->state = DEV_STATE_NOT_OPER;
}
static int io_subchannel_sch_event(struct subchannel *sch, int slow)
enum io_sch_action {
IO_SCH_UNREG,
IO_SCH_ORPH_UNREG,
IO_SCH_ATTACH,
IO_SCH_UNREG_ATTACH,
IO_SCH_ORPH_ATTACH,
IO_SCH_REPROBE,
IO_SCH_VERIFY,
IO_SCH_DISC,
IO_SCH_NOP,
};
static enum io_sch_action sch_get_action(struct subchannel *sch)
{
struct ccw_device *cdev;
cdev = sch_get_cdev(sch);
if (cio_update_schib(sch)) {
/* Not operational. */
if (!cdev)
return IO_SCH_UNREG;
if (!ccw_device_notify(cdev, CIO_GONE))
return IO_SCH_UNREG;
return IO_SCH_ORPH_UNREG;
}
/* Operational. */
if (!cdev)
return IO_SCH_ATTACH;
if (sch->schib.pmcw.dev != cdev->private->dev_id.devno) {
if (!ccw_device_notify(cdev, CIO_GONE))
return IO_SCH_UNREG_ATTACH;
return IO_SCH_ORPH_ATTACH;
}
if ((sch->schib.pmcw.pam & sch->opm) == 0) {
if (!ccw_device_notify(cdev, CIO_NO_PATH))
return IO_SCH_UNREG;
return IO_SCH_DISC;
}
if (device_is_disconnected(cdev))
return IO_SCH_REPROBE;
if (cdev->online)
return IO_SCH_VERIFY;
return IO_SCH_NOP;
}
/**
* io_subchannel_sch_event - process subchannel event
* @sch: subchannel
* @process: non-zero if function is called in process context
*
* An unspecified event occurred for this subchannel. Adjust data according
* to the current operational state of the subchannel and device. Return
* zero when the event has been handled sufficiently or -EAGAIN when this
* function should be called again in process context.
*/
static int io_subchannel_sch_event(struct subchannel *sch, int process)
{
int event, ret, disc;
unsigned long flags;
enum { NONE, UNREGISTER, UNREGISTER_PROBE, REPROBE, DISC } action;
struct ccw_device *cdev;
struct ccw_dev_id dev_id;
enum io_sch_action action;
int rc = -EAGAIN;
spin_lock_irqsave(sch->lock, flags);
if (!device_is_registered(&sch->dev))
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);
disc = device_is_disconnected(cdev);
if (disc && slow) {
/* Disconnected devices are evaluated directly only.*/
spin_unlock_irqrestore(sch->lock, flags);
return 0;
}
/* No interrupt after machine check - kill pending timers. */
if (cdev)
ccw_device_set_timeout(cdev, 0);
if (!disc && !slow) {
/* Non-disconnected devices are evaluated on the slow path. */
spin_unlock_irqrestore(sch->lock, flags);
return -EAGAIN;
switch (action) {
case IO_SCH_REPROBE:
/* Trigger device recognition. */
ccw_device_trigger_reprobe(cdev);
rc = 0;
goto out_unlock;
case IO_SCH_VERIFY:
/* Trigger path verification. */
io_subchannel_verify(sch);
rc = 0;
goto out_unlock;
case IO_SCH_DISC:
ccw_device_set_disconnected(cdev);
rc = 0;
goto out_unlock;
case IO_SCH_ORPH_UNREG:
case IO_SCH_ORPH_ATTACH:
ccw_device_set_disconnected(cdev);
break;
case IO_SCH_UNREG_ATTACH:
case IO_SCH_UNREG:
if (cdev)
ccw_device_set_notoper(cdev);
break;
case IO_SCH_NOP:
rc = 0;
goto out_unlock;
default:
break;
}
event = io_subchannel_get_status(sch);
CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, %s, %s path.\n",
sch->schid.ssid, sch->schid.sch_no, event,
disc ? "disconnected" : "normal",
slow ? "slow" : "fast");
/* Analyze subchannel status. */
action = NONE;
switch (event) {
case CIO_NO_PATH:
if (disc) {
/* Check if paths have become available. */
action = REPROBE;
break;
}
/* fall through */
case CIO_GONE:
/* Ask driver what to do with device. */
if (io_subchannel_notify(sch, event))
action = DISC;
else
action = UNREGISTER;
spin_unlock_irqrestore(sch->lock, flags);
/* All other actions require process context. */
if (!process)
goto out;
/* Handle attached ccw device. */
switch (action) {
case IO_SCH_ORPH_UNREG:
case IO_SCH_ORPH_ATTACH:
/* Move ccw device to orphanage. */
rc = ccw_device_move_to_orph(cdev);
if (rc)
goto out;
break;
case CIO_REVALIDATE:
/* Device will be removed, so no notify necessary. */
if (disc)
/* Reprobe because immediate unregister might block. */
action = REPROBE;
else
action = UNREGISTER_PROBE;
case IO_SCH_UNREG_ATTACH:
/* Unregister ccw device. */
ccw_device_unregister(cdev);
break;
case CIO_OPER:
if (disc)
/* Get device operational again. */
action = REPROBE;
default:
break;
}
/* Perform action. */
ret = 0;
/* Handle subchannel. */
switch (action) {
case UNREGISTER:
case UNREGISTER_PROBE:
ccw_device_set_notoper(cdev);
/* Unregister device (will use subchannel lock). */
spin_unlock_irqrestore(sch->lock, flags);
case IO_SCH_ORPH_UNREG:
case IO_SCH_UNREG:
css_sch_device_unregister(sch);
spin_lock_irqsave(sch->lock, flags);
break;
case REPROBE:
case IO_SCH_ORPH_ATTACH:
case IO_SCH_UNREG_ATTACH:
case IO_SCH_ATTACH:
dev_id.ssid = sch->schid.ssid;
dev_id.devno = sch->schib.pmcw.dev;
cdev = get_ccwdev_by_dev_id(&dev_id);
if (!cdev) {
sch_create_and_recog_new_device(sch);
break;
}
rc = ccw_device_move_to_sch(cdev, sch);
if (rc) {
/* Release reference from get_ccwdev_by_dev_id() */
put_device(&cdev->dev);
goto out;
}
spin_lock_irqsave(sch->lock, flags);
ccw_