Driver core: Fix device_move() vs. dpm list ordering, v2

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>

2 files changed, 52 insertions, 0 deletions

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 2d14f4ae6c01..e255341682c8 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 41f51fae042f..c7cb4fc3735c 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