linux-kernel - [PATCH 2/2] kthread: Do not use TIMER

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Message-Id: <20190212162554.19779-2-bigeasy@linutronix.de>
Date:   Tue, 12 Feb 2019 17:25:54 +0100
From:   Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To:     linux-kernel@...r.kernel.org
Cc:     Ingo Molnar <mingo@...nel.org>, tglx@...utronix.de,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Petr Mladek <pmladek@...e.com>
Subject: [PATCH 2/2] kthread: Do not use TIMER_IRQSAFE

The TIMER_IRQSAFE was introduced in commit

  22597dc3d97b1 ("kthread: initial support for delayed kthread work")

which modelled the delayed kthread code after workqueue's code. The
workqueue code requires the flag TIMER_IRQSAFE for synchronisation
purpose. This is not true for kthread's delay timer since all
operations occur under a lock.

Remove TIMER_IRQSAFE from the timer initialisation.
Use timer_setup() for initialisation purpose which is the official
function.

Cc: Petr Mladek <pmladek@...e.com>
Cc: Ingo Molnar <mingo@...nel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
---
 include/linux/kthread.h | 5 ++---
 kernel/kthread.c        | 5 +++--
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/linux/kthread.h b/include/linux/kthread.h
index 6b8c064f0cbcd..3d9d834c66a25 100644
--- a/include/linux/kthread.h
+++ b/include/linux/kthread.h
@@ -164,9 +164,8 @@ extern void __kthread_init_worker(struct kthread_worker *worker,
 #define kthread_init_delayed_work(dwork, fn)				\
 	do {								\
 		kthread_init_work(&(dwork)->work, (fn));		\
-		__init_timer(&(dwork)->timer,				\
-			     kthread_delayed_work_timer_fn,		\
-			     TIMER_IRQSAFE);				\
+		timer_setup(&(dwork)->timer,				\
+			     kthread_delayed_work_timer_fn, 0);		\
 	} while (0)
 
 int kthread_worker_fn(void *worker_ptr);
diff --git a/kernel/kthread.c b/kernel/kthread.c
index 5641b55783a6f..5373355412672 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -835,6 +835,7 @@ void kthread_delayed_work_timer_fn(struct timer_list *t)
 	struct kthread_delayed_work *dwork = from_timer(dwork, t, timer);
 	struct kthread_work *work = &dwork->work;
 	struct kthread_worker *worker = work->worker;
+	unsigned long flags;
 
 	/*
 	 * This might happen when a pending work is reinitialized.
@@ -843,7 +844,7 @@ void kthread_delayed_work_timer_fn(struct timer_list *t)
 	if (WARN_ON_ONCE(!worker))
 		return;
 
-	raw_spin_lock(&worker->lock);
+	raw_spin_lock_irqsave(&worker->lock, flags);
 	/* Work must not be used with >1 worker, see kthread_queue_work(). */
 	WARN_ON_ONCE(work->worker != worker);
 
@@ -852,7 +853,7 @@ void kthread_delayed_work_timer_fn(struct timer_list *t)
 	list_del_init(&work->node);
 	kthread_insert_work(worker, work, &worker->work_list);
 
-	raw_spin_unlock(&worker->lock);
+	raw_spin_unlock_irqrestore(&worker->lock, flags);
 }
 EXPORT_SYMBOL(kthread_delayed_work_timer_fn);
 
-- 
2.20.1