[PATCH 54/61] Driver core: Fix device_move() vs. dpm list ordering, v2

Greg Kroah-Hartman
2009-03-25T00:49:43Z

From: Cornelia Huck <cornelia.huck@de.ibm.com>

dpm_list currently relies on the fact that child devices will
be registered after their parents to get a correct suspend
order. Using device_move() however destroys this assumption, as
an already registered device may be moved under a newly registered
one.

This patch adds a new argument to device_move(), allowing callers
to specify how dpm_list should be adapted.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/base/core.c | 19 ++++++++++++++++++-
drivers/base/power/main.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
drivers/base/power/power.h | 8 ++++++++
drivers/s390/cio/device.c | 9 +++++----
include/linux/device.h | 3 ++-
include/linux/pm.h | 11 +++++++++++
net/bluetooth/hci_sysfs.c | 2 +-
net/bluetooth/rfcomm/tty.c | 5 +++--
8 files changed, 92 insertions(+), 9 deletions(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 95c67ff..e73c92d 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -1561,8 +1561,10 @@ out:
* device_move - moves a device to a new parent
* @dev: the pointer to the struct device to be moved
* @new_parent: the new parent of the device (can by NULL)
+ * @dpm_order: how to reorder the dpm_list
*/
-int device_move(struct device *dev, struct device *new_parent)
+int device_move(struct device *dev, struct device *new_parent,
+ enum dpm_order dpm_order)
{
int error;
struct device *old_parent;
@@ -1572,6 +1574,7 @@ int device_move(struct device *dev, struct device *new_parent)
if (!dev)
return -EINVAL;

+ device_pm_lock();
new_parent = get_device(new_parent);
new_parent_kobj = get_device_parent(dev, new_parent);

@@ -1613,9 +1616,23 @@ int device_move(struct device *dev, struct device *new_parent)
put_device(new_parent);
goto out;
}
+ switch (dpm_order) {
+ case DPM_ORDER_NONE:
+ break;
+ case DPM_ORDER_DEV_AFTER_PARENT:
+ device_pm_move_after(dev, new_parent);
+ break;
+ case DPM_ORDER_PARENT_BEFORE_DEV:
+ device_pm_move_before(new_parent, dev);
+ break;
+ case DPM_ORDER_DEV_LAST:
+ device_pm_move_last(dev);
+ break;
+ }
out_put:
put_device(old_parent);
out:
+ device_pm_unlock();
put_device(dev);
return error;
}
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 2d14f4a..e255341 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -107,6 +107,50 @@ void device_pm_remove(struct device *dev)
}

/**
+ * device_pm_move_before - move device in dpm_list
+ * @deva: Device to move in dpm_list
+ * @devb: Device @deva should come before
+ */
+void device_pm_move_before(struct device *deva, struct device *devb)
+{
+ pr_debug("PM: Moving %s:%s before %s:%s\n",
+ deva->bus ? deva->bus->name : "No Bus",
+ kobject_name(&deva->kobj),
+ devb->bus ? devb->bus->name : "No Bus",
+ kobject_name(&devb->kobj));
+ /* Delete deva from dpm_list and reinsert before devb. */
+ list_move_tail(&deva->power.entry, &devb->power.entry);
+}
+
+/**
+ * device_pm_move_after - move device in dpm_list
+ * @deva: Device to move in dpm_list
+ * @devb: Device @deva should come after
+ */
+void device_pm_move_after(struct device *deva, struct device *devb)
+{
+ pr_debug("PM: Moving %s:%s after %s:%s\n",
+ deva->bus ? deva->bus->name : "No Bus",
+ kobject_name(&deva->kobj),
+ devb->bus ? devb->bus->name : "No Bus",
+ kobject_name(&devb->kobj));
+ /* Delete deva from dpm_list and reinsert after devb. */
+ list_move(&deva->power.entry, &devb->power.entry);
+}
+
+/**
+ * device_pm_move_last - move device to end of dpm_list
+ * @dev: Device to move in dpm_list
+ */
+void device_pm_move_last(struct device *dev)
+{
+ pr_debug("PM: Moving %s:%s to end of list\n",
+ dev->bus ? dev->bus->name : "No Bus",
+ kobject_name(&dev->kobj));
+ list_move_tail(&dev->power.entry, &dpm_list);
+}
+
+/**
* pm_op - execute the PM operation appropiate for given PM event
* @dev: Device.
* @ops: PM operations to choose from.
diff --git a/drivers/base/power/power.h b/drivers/base/power/power.h
index 41f51fa..c7cb4fc 100644
--- a/drivers/base/power/power.h
+++ b/drivers/base/power/power.h
@@ -18,11 +18,19 @@ static inline struct device *to_device(struct list_head *entry)

extern void device_pm_add(struct device *);
extern void device_pm_remove(struct device *);
+extern void device_pm_move_before(struct device *, struct device *);
+extern void device_pm_move_after(struct device *, struct device *);
+extern void device_pm_move_last(struct device *);

#else /* CONFIG_PM_SLEEP */

static inline void device_pm_add(struct device *dev) {}
static inline void device_pm_remove(struct device *dev) {}
+static inline void device_pm_move_before(struct device *deva,
+ struct device *devb) {}
+static inline void device_pm_move_after(struct device *deva,
+ struct device *devb) {}
+static inline void device_pm_move_last(struct device *dev) {}

#endif

diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
index 611d2e0..e28f8ae 100644
--- a/drivers/s390/cio/device.c
+++ b/drivers/s390/cio/device.c
@@ -799,7 +799,7 @@ static void sch_attach_disconnected_device(struct subchannel *sch,
return;
other_sch = to_subchannel(cdev->dev.parent);
/* Note: device_move() changes cdev->dev.parent */
- ret = device_move(&cdev->dev, &sch->dev);
+ 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,
@@ -830,7 +830,7 @@ static void sch_attach_orphaned_device(struct subchannel *sch,
* Try to move the ccw device to its new subchannel.
* Note: device_move() changes cdev->dev.parent
*/
- ret = device_move(&cdev->dev, &sch->dev);
+ 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",
@@ -897,7 +897,8 @@ void ccw_device_move_to_orphanage(struct work_struct *work)
* 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);
+ 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,
@@ -1129,7 +1130,7 @@ static void ccw_device_move_to_sch(struct work_struct *work)
* Try to move the ccw device to its new subchannel.
* Note: device_move() changes cdev->dev.parent
*/
- rc = device_move(&cdev->dev, &sch->dev);
+ 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 "
diff --git a/include/linux/device.h b/include/linux/device.h
index 914c101..f98d0cf 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -494,7 +494,8 @@ extern int device_for_each_child(struct device *dev, void *data,
extern struct device *device_find_child(struct device *dev, void *data,
int (*match)(struct device *dev, void *data));
extern int device_rename(struct device *dev, char *new_name);
-extern int device_move(struct device *dev, struct device *new_parent);
+extern int device_move(struct device *dev, struct device *new_parent,
+ enum dpm_order dpm_order);

/*
* Root device objects for grouping under /sys/devices
diff --git a/include/linux/pm.h b/include/linux/pm.h
index 24ba5f6..1d4e2d2 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -400,6 +400,9 @@ extern void __suspend_report_result(const char *function, void *fn, int ret);

#else /* !CONFIG_PM_SLEEP */

+#define device_pm_lock() do {} while (0)
+#define device_pm_unlock() do {} while (0)
+
static inline int device_suspend(pm_message_t state)
{
return 0;
@@ -409,6 +412,14 @@ static inline int device_suspend(pm_message_t state)

#endif /* !CONFIG_PM_SLEEP */

+/* How to reorder dpm_list after device_move() */
+enum dpm_order {
+ DPM_ORDER_NONE,
+ DPM_ORDER_DEV_AFTER_PARENT,
+ DPM_ORDER_PARENT_BEFORE_DEV,
+ DPM_ORDER_DEV_LAST,
+};
+
/*
* Global Power Management flags
* Used to keep APM and ACPI from both being active
diff --git a/net/bluetooth/hci_sysfs.c b/net/bluetooth/hci_sysfs.c
index 1a1f916..ed82796 100644
--- a/net/bluetooth/hci_sysfs.c
+++ b/net/bluetooth/hci_sysfs.c
@@ -140,7 +140,7 @@ static void del_conn(struct work_struct *work)
dev = device_find_child(&conn->dev, NULL, __match_tty);
if (!dev)
break;
- device_move(dev, NULL);
+ device_move(dev, NULL, DPM_ORDER_DEV_LAST);
put_device(dev);
}

diff --git a/net/bluetooth/rfcomm/tty.c b/net/bluetooth/rfcomm/tty.c
index d030c69..abdc703 100644
--- a/net/bluetooth/rfcomm/tty.c
+++ b/net/bluetooth/rfcomm/tty.c
@@ -731,7 +731,8 @@ static int rfcomm_tty_open(struct tty_struct *tty, struct file *filp)
remove_wait_queue(&dev->wait, &wait);

if (err == 0)
- device_move(dev->tty_dev, rfcomm_get_device(dev));
+ device_move(dev->tty_dev, rfcomm_get_device(dev),
+ DPM_ORDER_DEV_AFTER_PARENT);

rfcomm_tty_copy_pending(dev);

@@ -751,7 +752,7 @@ static void rfcomm_tty_close(struct tty_struct *tty, struct file *filp)

if (atomic_dec_and_test(&dev->opened)) {
if (dev->tty_dev->parent)
- device_move(dev->tty_dev, NULL);
+ device_move(dev->tty_dev, NULL, DPM_ORDER_DEV_LAST);

/* Close DLC and dettach TTY */
rfcomm_dlc_close(dev->dlc, 0);
--
1.6.2