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* [PATCH 4/5] cpufreq: schedutil: convert to kthread_create_worker
@ 2026-08-29 16:00 Bradley Morgan
  0 siblings, 0 replies; 2+ messages in thread
From: Bradley Morgan @ 2026-08-29 16:00 UTC (permalink / raw)
  To: Rafael J . Wysocki, Viresh Kumar
  Cc: Ingo Molnar, Peter Zijlstra, linux-pm, linux-kernel, brads

From: Bradley Morgan <brads@mainlining.org>

Embedding a kthread_worker and running kthread_worker_fn yourself is
the old way. Convert cpufreq_schedutil to kthread_create_worker(),
dropping the separate thread pointer.

This is part of removing the worker->task self-assignment in
kthread_worker_fn().

Signed-off-by: Bradley Morgan <brads@mainlining.org>
---
 kernel/sched/cpufreq_schedutil.c | 33 ++++++++++++++------------------
 1 file changed, 14 insertions(+), 19 deletions(-)

diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index 49ccd6f1c185..5023c24d8a21 100644
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -31,8 +31,7 @@ struct sugov_policy {
 	struct			irq_work irq_work;
 	struct			kthread_work work;
 	struct			mutex work_lock;
-	struct			kthread_worker worker;
-	struct task_struct	*thread;
+	struct			kthread_worker *worker;
 	bool			work_in_progress;
 
 	bool			limits_changed;
@@ -586,7 +585,7 @@ static void sugov_irq_work(struct irq_work *irq_work)
 
 	sg_policy = container_of(irq_work, struct sugov_policy, irq_work);
 
-	kthread_queue_work(&sg_policy->worker, &sg_policy->work);
+	kthread_queue_work(sg_policy->worker, &sg_policy->work);
 }
 
 /************************** sysfs interface ************************/
@@ -669,7 +668,6 @@ static void sugov_policy_free(struct sugov_policy *sg_policy)
 
 static int sugov_kthread_create(struct sugov_policy *sg_policy)
 {
-	struct task_struct *thread;
 	struct sched_attr attr = {
 		.size		= sizeof(struct sched_attr),
 		.sched_policy	= SCHED_DEADLINE,
@@ -692,32 +690,29 @@ static int sugov_kthread_create(struct sugov_policy *sg_policy)
 		return 0;
 
 	kthread_init_work(&sg_policy->work, sugov_work);
-	kthread_init_worker(&sg_policy->worker);
-	thread = kthread_create(kthread_worker_fn, &sg_policy->worker,
-				"sugov:%d",
-				cpumask_first(policy->related_cpus));
-	if (IS_ERR(thread)) {
-		pr_err("failed to create sugov thread: %pe\n", thread);
-		return PTR_ERR(thread);
+	sg_policy->worker = kthread_create_worker(0, "sugov:%d",
+						cpumask_first(policy->related_cpus));
+	if (IS_ERR(sg_policy->worker)) {
+		pr_err("failed to create sugov thread: %pe\n", sg_policy->worker);
+		return PTR_ERR(sg_policy->worker);
 	}
 
-	ret = sched_setattr_nocheck(thread, &attr);
+	ret = sched_setattr_nocheck(sg_policy->worker->task, &attr);
 	if (ret) {
-		kthread_stop(thread);
+		kthread_destroy_worker(sg_policy->worker);
 		pr_warn("%s: failed to set SCHED_DEADLINE\n", __func__);
 		return ret;
 	}
 
-	sg_policy->thread = thread;
 	if (policy->dvfs_possible_from_any_cpu)
-		set_cpus_allowed_ptr(thread, policy->related_cpus);
+		set_cpus_allowed_ptr(sg_policy->worker->task, policy->related_cpus);
 	else
-		kthread_bind_mask(thread, policy->related_cpus);
+		kthread_bind_mask(sg_policy->worker->task, policy->related_cpus);
 
 	init_irq_work(&sg_policy->irq_work, sugov_irq_work);
 	mutex_init(&sg_policy->work_lock);
 
-	wake_up_process(thread);
+	wake_up_process(sg_policy->worker->task);
 
 	return 0;
 }
@@ -728,8 +723,8 @@ static void sugov_kthread_stop(struct sugov_policy *sg_policy)
 	if (sg_policy->policy->fast_switch_enabled)
 		return;
 
-	kthread_flush_worker(&sg_policy->worker);
-	kthread_stop(sg_policy->thread);
+	kthread_flush_worker(sg_policy->worker);
+	kthread_destroy_worker(sg_policy->worker);
 	mutex_destroy(&sg_policy->work_lock);
 }
 
-- 
2.47.3


^ permalink raw reply	[flat|nested] 2+ messages in thread
* [RESEND PATCH 0/5] kthread: remove worker->task self-assignment
@ 2026-08-29 16:11 Bradley Morgan
  2026-08-29 16:17 ` [PATCH 4/5] cpufreq: schedutil: convert to kthread_create_worker Bradley Morgan
  0 siblings, 1 reply; 2+ messages in thread
From: Bradley Morgan @ 2026-08-29 16:11 UTC (permalink / raw)
  To: linux-kernel; +Cc: brads

From: Bradley Morgan <brads@mainlining.org>

Resent as a proper series with cover letter. The first send went out as
five separate threads instead of one.

kthread_worker_fn() has carried a FIXME for a decade: it assigns
worker->task = current because the old kthread_run(kthread_worker_fn)
callers never told the worker what task it was. The new
kthread_create_worker*() API sets worker->task before the worker even
starts, so the self-assignment is dead code.

Four drivers were still on the old API. Convert them, then remove the
FIXME.

No functional change intended.

Bradley Morgan (5):
  media: ivtv: convert to kthread_run_worker
  net: encx24j600: convert to kthread_run_worker
  tty: sc16is7xx: convert to kthread_run_worker
  cpufreq: schedutil: convert to kthread_create_worker
  kthread: remove worker->task self-assignment

 drivers/media/pci/ivtv/ivtv-driver.c    | 11 ++++-------
 drivers/media/pci/ivtv/ivtv-driver.h    |  3 +--
 drivers/net/ethernet/microchip/encx24j600.c | 12 ++++--------
 drivers/tty/serial/sc16is7xx.c        | 17 +++++++----------
 kernel/sched/cpufreq_schedutil.c       | 14 +++++--------
 kernel/kthread.c                      |  7 -------
 6 files changed, 21 insertions(+), 63 deletions(-)

^ permalink raw reply	[flat|nested] 2+ messages in thread
end of thread, other threads:[~2026-08-29 16:17 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
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2026-08-29 16:00 [PATCH 4/5] cpufreq: schedutil: convert to kthread_create_worker Bradley Morgan
2026-08-29 16:11 [RESEND PATCH 0/5] kthread: remove worker->task self-assignment Bradley Morgan
2026-08-29 16:17 ` [PATCH 4/5] cpufreq: schedutil: convert to kthread_create_worker Bradley Morgan

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