This is a note to let you know that I've just added the patch titled
PM: runtime: Drop runtime PM references to supplier on link removal
to the 5.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
pm-runtime-drop-runtime-pm-references-to-supplier-on-link-removal.patch
and it can be found in the queue-5.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From e0e398e204634db8fb71bd89cf2f6e3e5bd09b51 Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <rafael.j.wysocki@xxxxxxxxx>
Date: Wed, 21 Oct 2020 21:12:15 +0200
Subject: PM: runtime: Drop runtime PM references to supplier on link removal
From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
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@xxxxxxxxx>
Cc: 5.1+ <stable@xxxxxxxxxxxxxxx> # 5.1+
Tested-by: Xiang Chen <chenxiang66@xxxxxxxxxxxxx>
Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/base/core.c | 6 ++----
drivers/base/power/runtime.c | 21 ++++++++++++++++++++-
include/linux/pm_runtime.h | 4 ++--
3 files changed, 24 insertions(+), 7 deletions(-)
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -763,8 +763,7 @@ static void __device_link_del(struct kre
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 kre
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);
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -1729,7 +1729,7 @@ void pm_runtime_new_link(struct device *
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
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 &&
--- a/include/linux/pm_runtime.h
+++ b/include/linux/pm_runtime.h
@@ -58,7 +58,7 @@ extern void pm_runtime_clean_up_links(st
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_l
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 */
Patches currently in stable-queue which might be from rafael.j.wysocki@xxxxxxxxx are
queue-5.9/acpi-nfit-fix-comparison-to-enxio.patch
queue-5.9/pm-runtime-drop-runtime-pm-references-to-supplier-on-link-removal.patch
queue-5.9/pm-runtime-drop-pm_runtime_clean_up_links.patch
queue-5.9/pm-runtime-resume-the-device-earlier-in-__device_release_driver.patch
