[PATCH 07/36] cpu/hotplug: move to use bus_get_dev_root()

[Greg Kroah-Hartman]

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.

Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Valentin Schneider <vschneid@xxxxxxxxxx>
Cc: Phil Auld <pauld@xxxxxxxxxx>
Cc: Steven Price <steven.price@xxxxxxx>
Cc: Juri Lelli <juri.lelli@xxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Vincent Donnefort <vdonnefort@xxxxxxxxxx>
Cc: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
Cc: "Jason A. Donenfeld" <Jason@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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.

 kernel/cpu.c | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 6c0a92ca6bb5..c59b73d13a3a 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -2569,22 +2569,33 @@ static const struct attribute_group cpuhp_smt_attr_group = {
 
 static int __init cpu_smt_sysfs_init(void)
 {
-	return sysfs_create_group(&cpu_subsys.dev_root->kobj,
-				  &cpuhp_smt_attr_group);
+	struct device *dev_root;
+	int ret = -ENODEV;
+
+	dev_root = bus_get_dev_root(&cpu_subsys);
+	if (dev_root) {
+		ret = sysfs_create_group(&dev_root->kobj, &cpuhp_smt_attr_group);
+		put_device(dev_root);
+	}
+	return ret;
 }
 
 static int __init cpuhp_sysfs_init(void)
 {
+	struct device *dev_root;
 	int cpu, ret;
 
 	ret = cpu_smt_sysfs_init();
 	if (ret)
 		return ret;
 
-	ret = sysfs_create_group(&cpu_subsys.dev_root->kobj,
-				 &cpuhp_cpu_root_attr_group);
-	if (ret)
-		return ret;
+	dev_root = bus_get_dev_root(&cpu_subsys);
+	if (dev_root) {
+		ret = sysfs_create_group(&dev_root->kobj, &cpuhp_cpu_root_attr_group);
+		put_device(dev_root);
+		if (ret)
+			return ret;
+	}
 
 	for_each_possible_cpu(cpu) {
 		struct device *dev = get_cpu_device(cpu);
-- 
2.39.2