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/[email protected] Signed-off-by: Petr Mladek <[email protected]> Cc: Oleg Nesterov <[email protected]> Cc: Tejun Heo <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: "Paul E. McKenney" <[email protected]> Cc: Josh Triplett <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Jiri Kosina <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Michal Hocko <[email protected]> Cc: Vlastimil Babka <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
olifre · Oct 11, 2016 · 35033fe · 35033fe
1 parent fbae2d4
commit 35033fe
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diff --git 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
@@ -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);