Subject: [PATCH 24/33] kthread: Refine naming of affinity related fields

From: Frederic Weisbecker <[email-masked]>
Date: Thu, 1 Jan 2026 23:13:49 +0100

The kthreads preferred affinity related fields use "hotplug" as the base
of their naming because the affinity management was initially deemed to
deal with CPU hotplug.

The scope of this role is going to broaden now and also deal with
cpuset isolated partition updates.

Switch the naming accordingly.

Signed-off-by: Frederic Weisbecker <[email-masked]>
Acked-by: Waiman Long <[email-masked]>
---
 kernel/kthread.c | 38 +++++++++++++++++++-------------------
 1 file changed, 19 insertions(+), 19 deletions(-)

diff --git a/kernel/kthread.c b/kernel/kthread.c
index 99a3808d086f..f1e4f1f35cae 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -35,8 +35,8 @@ static DEFINE_SPINLOCK(kthread_create_lock);
 static LIST_HEAD(kthread_create_list);
 struct task_struct *kthreadd_task;
 
-static LIST_HEAD(kthreads_hotplug);
-static DEFINE_MUTEX(kthreads_hotplug_lock);
+static LIST_HEAD(kthread_affinity_list);
+static DEFINE_MUTEX(kthread_affinity_lock);
 
 struct kthread_create_info
 {
@@ -69,7 +69,7 @@ struct kthread {
 	/* To store the full name if task comm is truncated. */
 	char *full_name;
 	struct task_struct *task;
-	struct list_head hotplug_node;
+	struct list_head affinity_node;
 	struct cpumask *preferred_affinity;
 };
 
@@ -128,7 +128,7 @@ bool set_kthread_struct(struct task_struct *p)
 
 	init_completion(&kthread->exited);
 	init_completion(&kthread->parked);
-	INIT_LIST_HEAD(&kthread->hotplug_node);
+	INIT_LIST_HEAD(&kthread->affinity_node);
 	p->vfork_done = &kthread->exited;
 
 	kthread->task = p;
@@ -323,10 +323,10 @@ void __noreturn kthread_exit(long result)
 {
 	struct kthread *kthread = to_kthread(current);
 	kthread->result = result;
-	if (!list_empty(&kthread->hotplug_node)) {
-		mutex_lock(&kthreads_hotplug_lock);
-		list_del(&kthread->hotplug_node);
-		mutex_unlock(&kthreads_hotplug_lock);
+	if (!list_empty(&kthread->affinity_node)) {
+		mutex_lock(&kthread_affinity_lock);
+		list_del(&kthread->affinity_node);
+		mutex_unlock(&kthread_affinity_lock);
 
 		if (kthread->preferred_affinity) {
 			kfree(kthread->preferred_affinity);
@@ -390,9 +390,9 @@ static void kthread_affine_node(void)
 			return;
 		}
 
-		mutex_lock(&kthreads_hotplug_lock);
-		WARN_ON_ONCE(!list_empty(&kthread->hotplug_node));
-		list_add_tail(&kthread->hotplug_node, &kthreads_hotplug);
+		mutex_lock(&kthread_affinity_lock);
+		WARN_ON_ONCE(!list_empty(&kthread->affinity_node));
+		list_add_tail(&kthread->affinity_node, &kthread_affinity_list);
 		/*
 		 * The node cpumask is racy when read from kthread() but:
 		 * - a racing CPU going down will either fail on the subsequent
@@ -402,7 +402,7 @@ static void kthread_affine_node(void)
 		 */
 		kthread_fetch_affinity(kthread, affinity);
 		set_cpus_allowed_ptr(current, affinity);
-		mutex_unlock(&kthreads_hotplug_lock);
+		mutex_unlock(&kthread_affinity_lock);
 
 		free_cpumask_var(affinity);
 	}
@@ -873,16 +873,16 @@ int kthread_affine_preferred(struct task_struct *p, const struct cpumask *mask)
 		goto out;
 	}
 
-	mutex_lock(&kthreads_hotplug_lock);
+	mutex_lock(&kthread_affinity_lock);
 	cpumask_copy(kthread->preferred_affinity, mask);
-	WARN_ON_ONCE(!list_empty(&kthread->hotplug_node));
-	list_add_tail(&kthread->hotplug_node, &kthreads_hotplug);
+	WARN_ON_ONCE(!list_empty(&kthread->affinity_node));
+	list_add_tail(&kthread->affinity_node, &kthread_affinity_list);
 	kthread_fetch_affinity(kthread, affinity);
 
 	scoped_guard (raw_spinlock_irqsave, &p->pi_lock)
 		set_cpus_allowed_force(p, affinity);
 
-	mutex_unlock(&kthreads_hotplug_lock);
+	mutex_unlock(&kthread_affinity_lock);
 out:
 	free_cpumask_var(affinity);
 
@@ -903,9 +903,9 @@ static int kthreads_online_cpu(unsigned int cpu)
 	struct kthread *k;
 	int ret;
 
-	guard(mutex)(&kthreads_hotplug_lock);
+	guard(mutex)(&kthread_affinity_lock);
 
-	if (list_empty(&kthreads_hotplug))
+	if (list_empty(&kthread_affinity_list))
 		return 0;
 
 	if (!zalloc_cpumask_var(&affinity, GFP_KERNEL))
@@ -913,7 +913,7 @@ static int kthreads_online_cpu(unsigned int cpu)
 
 	ret = 0;
 
-	list_for_each_entry(k, &kthreads_hotplug, hotplug_node) {
+	list_for_each_entry(k, &kthread_affinity_list, affinity_node) {
 		if (WARN_ON_ONCE((k->task->flags & PF_NO_SETAFFINITY) ||
 				 kthread_is_per_cpu(k->task))) {
 			ret = -EINVAL;
-- 
2.51.1