linux-kernel - [PATCH 06/36] cpuidle: move to use bus_get_dev

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Date:   Mon, 13 Mar 2023 19:28:48 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     rafael@...nel.org, Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        linux-pm@...r.kernel.org
Subject: [PATCH 06/36] cpuidle: move to use bus_get_dev_root()

Direct access to the struct bus_type dev_root pointer is going away soon
so replace that with a call to bus_get_dev_root() instead, which is what
it is there for.

This allows us to clean up the cpuidle_add_interface() call a bit as it
was only called in one place, with the same argument so just put that
into the function itself.  Note that cpuidle_remove_interface() should
also probably be removed in the future as there are no callers of it for
some reason.

Cc: "Rafael J. Wysocki" <rafael@...nel.org>
Cc: Daniel Lezcano <daniel.lezcano@...aro.org>
Cc: linux-pm@...r.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
Note, this is a patch that is a prepatory cleanup as part of a larger
series of patches that is working on resolving some old driver core
design mistakes.  It will build and apply cleanly on top of 6.3-rc2 on
its own, but I'd prefer if I could take it through my driver-core tree
so that the driver core changes can be taken through there for 6.4-rc1.

 drivers/cpuidle/cpuidle.c |  2 +-
 drivers/cpuidle/cpuidle.h |  2 +-
 drivers/cpuidle/sysfs.c   | 12 +++++++++---
 3 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 0b00f21cefe3..8e929f6602ce 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -808,7 +808,7 @@ static int __init cpuidle_init(void)
 	if (cpuidle_disabled())
 		return -ENODEV;
 
-	return cpuidle_add_interface(cpu_subsys.dev_root);
+	return cpuidle_add_interface();
 }
 
 module_param(off, int, 0444);
diff --git a/drivers/cpuidle/cpuidle.h b/drivers/cpuidle/cpuidle.h
index 9f336af17fa6..52701d9588f1 100644
--- a/drivers/cpuidle/cpuidle.h
+++ b/drivers/cpuidle/cpuidle.h
@@ -30,7 +30,7 @@ extern int cpuidle_switch_governor(struct cpuidle_governor *gov);
 
 struct device;
 
-extern int cpuidle_add_interface(struct device *dev);
+extern int cpuidle_add_interface(void);
 extern void cpuidle_remove_interface(struct device *dev);
 extern int cpuidle_add_device_sysfs(struct cpuidle_device *device);
 extern void cpuidle_remove_device_sysfs(struct cpuidle_device *device);
diff --git a/drivers/cpuidle/sysfs.c b/drivers/cpuidle/sysfs.c
index 48948b171749..84e4946f1072 100644
--- a/drivers/cpuidle/sysfs.c
+++ b/drivers/cpuidle/sysfs.c
@@ -119,11 +119,17 @@ static struct attribute_group cpuidle_attr_group = {
 
 /**
  * cpuidle_add_interface - add CPU global sysfs attributes
- * @dev: the target device
  */
-int cpuidle_add_interface(struct device *dev)
+int cpuidle_add_interface(void)
 {
-	return sysfs_create_group(&dev->kobj, &cpuidle_attr_group);
+	struct device *dev_root = bus_get_dev_root(&cpu_subsys);
+	int retval = -EINVAL;
+
+	if (dev_root) {
+		retval = sysfs_create_group(&dev_root->kobj, &cpuidle_attr_group);
+		put_device(dev_root);
+	}
+	return retval;
 }
 
 /**
-- 
2.39.2