From 35033fe9cbbf18415dfeb7e27f0d4228dfc7458a Mon Sep 17 00:00:00 2001
From: Petr Mladek <pmladek@suse.com>
Date: Tue, 11 Oct 2016 13:55:33 -0700
Subject: [PATCH] kthread: add kthread_destroy_worker()
The current kthread worker users call flush() and stop() explicitly.
This function does the same plus it frees the kthread_worker struct
in one call.
It is supposed to be used together with kthread_create_worker*() that
allocates struct kthread_worker.
Link: http://lkml.kernel.org/r/1470754545-17632-7-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
include/linux/kthread.h | 2 ++
kernel/kthread.c | 23 +++++++++++++++++++++++
2 files changed, 25 insertions(+)
diff --git a/include/linux/kthread.h b/include/linux/kthread.h
index daeb2befbabf..afc8939da861 100644
--- a/include/linux/kthread.h
+++ b/include/linux/kthread.h
@@ -136,4 +136,6 @@ bool kthread_queue_work(struct kthread_worker *worker,
void kthread_flush_work(struct kthread_work *work);
void kthread_flush_worker(struct kthread_worker *worker);
+void kthread_destroy_worker(struct kthread_worker *worker);
+
#endif /* _LINUX_KTHREAD_H */
diff --git a/kernel/kthread.c b/kernel/kthread.c
index 12695e68ed00..f874300dfce5 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -823,3 +823,26 @@ void kthread_flush_worker(struct kthread_worker *worker)
wait_for_completion(&fwork.done);
}
EXPORT_SYMBOL_GPL(kthread_flush_worker);
+
+/**
+ * kthread_destroy_worker - destroy a kthread worker
+ * @worker: worker to be destroyed
+ *
+ * Flush and destroy @worker. The simple flush is enough because the kthread
+ * worker API is used only in trivial scenarios. There are no multi-step state
+ * machines needed.
+ */
+void kthread_destroy_worker(struct kthread_worker *worker)
+{
+ struct task_struct *task;
+
+ task = worker->task;
+ if (WARN_ON(!task))
+ return;
+
+ kthread_flush_worker(worker);
+ kthread_stop(task);
+ WARN_ON(!list_empty(&worker->work_list));
+ kfree(worker);
+}
+EXPORT_SYMBOL(kthread_destroy_worker);