PM: runtime: Drop runtime PM references to supplier on link removal

commit e0e398e204634db8fb71bd89cf2f6e3e5bd09b51 upstream.

While removing a device link, drop the supplier device's runtime PM
usage counter as many times as needed to drop all of the runtime PM
references to it from the consumer in addition to dropping the
consumer's link count.

Fixes: baa8809f6097 ("PM / runtime: Optimize the use of device links")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: 5.1+ <stable@vger.kernel.org> # 5.1+
Tested-by: Xiang Chen <chenxiang66@hisilicon.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 792b92439b77d9c70f2ff979359586f8f9c11201..91980be5543d3efc5a78f5307cc99318ed02a6ea 100644 (file)
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -763,8 +763,7 @@ static void __device_link_del(struct kref *kref)
        dev_dbg(link->consumer, "Dropping the link to %s\n",
                dev_name(link->supplier));
 
-       if (link->flags & DL_FLAG_PM_RUNTIME)
-               pm_runtime_drop_link(link->consumer);
+       pm_runtime_drop_link(link);
 
        list_del_rcu(&link->s_node);
        list_del_rcu(&link->c_node);
@@ -778,8 +777,7 @@ static void __device_link_del(struct kref *kref)
        dev_info(link->consumer, "Dropping the link to %s\n",
                 dev_name(link->supplier));
 
-       if (link->flags & DL_FLAG_PM_RUNTIME)
-               pm_runtime_drop_link(link->consumer);
+       pm_runtime_drop_link(link);
 
        list_del(&link->s_node);
        list_del(&link->c_node);

diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 6f605f7820bb5fe55707645b7dea56eb70d21b5c..6919f7fc226bb6a91e9c99040997e9c2281f7bb2 100644 (file)
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -1729,7 +1729,7 @@ void pm_runtime_new_link(struct device *dev)
        spin_unlock_irq(&dev->power.lock);
 }
 
-void pm_runtime_drop_link(struct device *dev)
+static void pm_runtime_drop_link_count(struct device *dev)
 {
        spin_lock_irq(&dev->power.lock);
        WARN_ON(dev->power.links_count == 0);
@@ -1737,6 +1737,25 @@ void pm_runtime_drop_link(struct device *dev)
        spin_unlock_irq(&dev->power.lock);
 }
 
+/**
+ * pm_runtime_drop_link - Prepare for device link removal.
+ * @link: Device link going away.
+ *
+ * Drop the link count of the consumer end of @link and decrement the supplier
+ * device's runtime PM usage counter as many times as needed to drop all of the
+ * PM runtime reference to it from the consumer.
+ */
+void pm_runtime_drop_link(struct device_link *link)
+{
+       if (!(link->flags & DL_FLAG_PM_RUNTIME))
+               return;
+
+       pm_runtime_drop_link_count(link->consumer);
+
+       while (refcount_dec_not_one(&link->rpm_active))
+               pm_runtime_put(link->supplier);
+}
+
 static bool pm_runtime_need_not_resume(struct device *dev)
 {
        return atomic_read(&dev->power.usage_count) <= 1 &&

diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h
index 6245caa18034c27028cd873b17980f98c2ee5f7b..07f2eea1df0aa6c729ad78779126925988954c47 100644 (file)
--- a/include/linux/pm_runtime.h
+++ b/include/linux/pm_runtime.h
@@ -58,7 +58,7 @@ extern void pm_runtime_clean_up_links(struct device *dev);
 extern void pm_runtime_get_suppliers(struct device *dev);
 extern void pm_runtime_put_suppliers(struct device *dev);
 extern void pm_runtime_new_link(struct device *dev);
-extern void pm_runtime_drop_link(struct device *dev);
+extern void pm_runtime_drop_link(struct device_link *link);
 
 /**
  * pm_runtime_get_if_in_use - Conditionally bump up runtime PM usage counter.
@@ -280,7 +280,7 @@ static inline void pm_runtime_clean_up_links(struct device *dev) {}
 static inline void pm_runtime_get_suppliers(struct device *dev) {}
 static inline void pm_runtime_put_suppliers(struct device *dev) {}
 static inline void pm_runtime_new_link(struct device *dev) {}
-static inline void pm_runtime_drop_link(struct device *dev) {}
+static inline void pm_runtime_drop_link(struct device_link *link) {}
 
 #endif /* !CONFIG_PM */