PM: Reference counting of power.subsys_data

Since the power.subsys_data device field will be used by multiple
filesystems, introduce a reference counting mechanism for it to avoid
freeing it prematurely or changing its value at a wrong time.

Make the PM clocks management code that currently is the only user of
power.subsys_data use the new reference counting.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/linux/pm.h b/include/linux/pm.h
index bf5ee37388d4..c6b5a0a41ab3 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -423,6 +423,7 @@ struct wakeup_source;
 
 struct pm_subsys_data {
         spinlock_t lock;
+        unsigned int refcount;
 #ifdef CONFIG_PM_CLK
         struct list_head clock_list;
 #endif
@@ -473,6 +474,8 @@ struct dev_pm_info {
 };
 
 extern void update_pm_runtime_accounting(struct device *dev);
+extern int dev_pm_get_subsys_data(struct device *dev);
+extern int dev_pm_put_subsys_data(struct device *dev);
 
 /*
  * Power domains provide callbacks that are executed during system suspend,