Make use of the newly introduced device_pm_move_*() functions
in order to make sure that subchannels and their ccw device are
in the correct order in dpm_list after moving them around.
We don't need to do anything for devices in the orphanage, since
their parent is a pseudo subchannel which won't need suspending.
Signed-off-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
---
drivers/s390/cio/device.c | 46 +++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 45 insertions(+), 1 deletion(-)
--- linux-2.6.orig/drivers/s390/cio/device.c
+++ linux-2.6/drivers/s390/cio/device.c
@@ -788,6 +788,10 @@ static void sch_attach_device(struct sub
spin_unlock_irq(sch->lock);
}
+/*
+ * Note: This function is only called from ccw_device_move_to_orphanage,
+ * so we are guaranteed to hold the dpm_list mutex.
+ */
static void sch_attach_disconnected_device(struct subchannel *sch,
struct ccw_device *cdev)
{
@@ -801,6 +805,7 @@ static void sch_attach_disconnected_devi
/* Note: device_move() changes cdev->dev.parent */
ret = device_move(&cdev->dev, &sch->dev);
if (ret) {
+ device_pm_unlock();
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);
@@ -808,6 +813,15 @@ static void sch_attach_disconnected_devi
put_device(&sch->dev);
return;
}
+ /*
+ * We already reorder dpm_list here since we may not hold
+ * the dpm_list mutex when deregistering other_sch.
+ * Order of devices will be correct after moving sch since
+ * sch's parent (the css) is guaranteed to be after cdev
+ * already.
+ */
+ device_pm_move_after(&sch->dev, &cdev->dev);
+ device_pm_unlock();
sch_set_cdev(other_sch, NULL);
/* No need to keep a subchannel without ccw device around. */
css_sch_device_unregister(other_sch);
@@ -816,6 +830,10 @@ static void sch_attach_disconnected_devi
put_device(&other_sch->dev);
}
+/*
+ * Note: This function is only called from ccw_device_move_to_orphanage,
+ * so we are guaranteed to hold the dpm_list mutex.
+ */
static void sch_attach_orphaned_device(struct subchannel *sch,
struct ccw_device *cdev)
{
@@ -832,6 +850,7 @@ static void sch_attach_orphaned_device(s
*/
ret = device_move(&cdev->dev, &sch->dev);
if (ret) {
+ device_pm_unlock();
CIO_MSG_EVENT(0, "Moving device 0.%x.%04x from orphanage "
"failed (ret=%d)!\n",
cdev->private->dev_id.ssid,
@@ -840,6 +859,12 @@ static void sch_attach_orphaned_device(s
put_device(&sch->dev);
return;
}
+ /*
+ * sch's parent (the css) is guaranteed to be after cdev
+ * already (must have been registered earlier).
+ */
+ device_pm_move_after(&sch->dev, &cdev->dev);
+ device_pm_unlock();
sch_attach_device(sch, cdev);
/* Put reference on pseudo subchannel. */
put_device(&pseudo_sch->dev);
@@ -897,8 +922,10 @@ void ccw_device_move_to_orphanage(struct
* ccw device can take its place on the subchannel.
* Note: device_move() changes cdev->dev.parent
*/
+ device_pm_lock();
ret = device_move(&cdev->dev, &css->pseudo_subchannel->dev);
if (ret) {
+ device_pm_unlock();
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);
@@ -906,6 +933,11 @@ void ccw_device_move_to_orphanage(struct
put_device(&css->pseudo_subchannel->dev);
return;
}
+ /*
+ * No need to reorder dpm_list for devices in the orphanage,
+ * since they have not to be suspended before a subchannel
+ * (nothing needs to be done suspend-wise for the pseudo subchannel).
+ */
cdev->ccwlock = css->pseudo_subchannel->lock;
/*
* Search for the replacing ccw device
@@ -930,6 +962,7 @@ void ccw_device_move_to_orphanage(struct
put_device(&sch->dev);
return;
}
+ device_pm_unlock();
sch_create_and_recog_new_device(sch);
/* Release reference of subchannel from old cdev. */
put_device(&sch->dev);
@@ -1129,9 +1162,11 @@ static void ccw_device_move_to_sch(struc
* Try to move the ccw device to its new subchannel.
* Note: device_move() changes cdev->dev.parent
*/
+ device_pm_lock();
rc = device_move(&cdev->dev, &sch->dev);
- mutex_unlock(&sch->reg_mutex);
if (rc) {
+ device_pm_unlock();
+ mutex_unlock(&sch->reg_mutex);
CIO_MSG_EVENT(0, "Moving device 0.%x.%04x to subchannel "
"0.%x.%04x failed (ret=%d)!\n",
cdev->private->dev_id.ssid,
@@ -1142,6 +1177,15 @@ static void ccw_device_move_to_sch(struc
put_device(&sch->dev);
goto out;
}
+ /*
+ * We need to reorder the dpm_list here so that unregistering
+ * the former parent cannot deadlock.
+ * sch's parent (the css) is already guaranteed to come after
+ * cdev.
+ */
+ device_pm_move_after(&sch->dev, &cdev->dev);
+ device_pm_unlock();
+ mutex_unlock(&sch->reg_mutex);
if (!sch_is_pseudo_sch(former_parent)) {
spin_lock_irq(former_parent->lock);
sch_set_cdev(former_parent, NULL);
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