[PATCH v6 05/20] kthread: Add destroy_kthread_worker()

Petr Mladek
2016-04-14T15:15:28Z

The current kthread worker users call flush() and stop() explicitly.
This function drains the worker, stops it, and frees the kthread_worker
struct in one call.

It is supposed to be used together with create_kthread_worker*() that
allocates struct kthread_worker.

Also note that drain() correctly handles self-queuing works in compare
with flush().

Signed-off-by: Petr Mladek <pmladek@suse.com>
---
include/linux/kthread.h | 2 ++
kernel/kthread.c | 21 +++++++++++++++++++++
2 files changed, 23 insertions(+)

diff --git a/include/linux/kthread.h b/include/linux/kthread.h
index 468011efa68d..a36604fa8aa2 100644
--- a/include/linux/kthread.h
+++ b/include/linux/kthread.h
@@ -136,4 +136,6 @@ bool queue_kthread_work(struct kthread_worker *worker,
void flush_kthread_work(struct kthread_work *work);
void flush_kthread_worker(struct kthread_worker *worker);

+void destroy_kthread_worker(struct kthread_worker *worker);
+
#endif /* _LINUX_KTHREAD_H */
diff --git a/kernel/kthread.c b/kernel/kthread.c
index 6051aa9d93c6..441651765f08 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -852,3 +852,24 @@ void drain_kthread_worker(struct kthread_worker *worker)
spin_unlock_irq(&worker->lock);
}
EXPORT_SYMBOL(drain_kthread_worker);
+
+/**
+ * destroy_kthread_worker - destroy a kthread worker
+ * @worker: worker to be destroyed
+ *
+ * Drain and destroy @worker. It has the same conditions
+ * for use as drain_kthread_worker(), see above.
+ */
+void destroy_kthread_worker(struct kthread_worker *worker)
+{
+ struct task_struct *task;
+
+ task = worker->task;
+ if (WARN_ON(!task))
+ return;
+
+ drain_kthread_worker(worker);
+ kthread_stop(task);
+ kfree(worker);
+}
+EXPORT_SYMBOL(destroy_kthread_worker);
--
1.8.5.6