1 files changed, 64 insertions, 0 deletions

diff --git a/include/linux/kthread.h b/include/linux/kthread.h
index aabc8a13ba71..f93cb6979edc 100644
--- a/include/linux/kthread.h
+++ b/include/linux/kthread.h
@@ -34,4 +34,68 @@ int kthread_should_stop(void);
 int kthreadd(void *unused);
 extern struct task_struct *kthreadd_task;
 
+/*
+ * Simple work processor based on kthread.
+ *
+ * This provides easier way to make use of kthreads.  A kthread_work
+ * can be queued and flushed using queue/flush_kthread_work()
+ * respectively.  Queued kthread_works are processed by a kthread
+ * running kthread_worker_fn().
+ *
+ * A kthread_work can't be freed while it is executing.
+ */
+struct kthread_work;
+typedef void (*kthread_work_func_t)(struct kthread_work *work);
+
+struct kthread_worker {
+        spinlock_t              lock;
+        struct list_head        work_list;
+        struct task_struct      *task;
+};
+
+struct kthread_work {
+        struct list_head        node;
+        kthread_work_func_t     func;
+        wait_queue_head_t       done;
+        atomic_t                flushing;
+        int                     queue_seq;
+        int                     done_seq;
+};
+
+#define KTHREAD_WORKER_INIT(worker)     {                               \
+        .lock = SPIN_LOCK_UNLOCKED,                                     \
+        .work_list = LIST_HEAD_INIT((worker).work_list),                \
+        }
+
+#define KTHREAD_WORK_INIT(work, fn)     {                               \
+        .node = LIST_HEAD_INIT((work).node),                            \
+        .func = (fn),                                                   \
+        .done = __WAIT_QUEUE_HEAD_INITIALIZER((work).done),             \
+        .flushing = ATOMIC_INIT(0),                                     \
+        }
+
+#define DEFINE_KTHREAD_WORKER(worker)                                   \
+        struct kthread_worker worker = KTHREAD_WORKER_INIT(worker)
+
+#define DEFINE_KTHREAD_WORK(work, fn)                                   \
+        struct kthread_work work = KTHREAD_WORK_INIT(work, fn)
+
+static inline void init_kthread_worker(struct kthread_worker *worker)
+{
+        *worker = (struct kthread_worker)KTHREAD_WORKER_INIT(*worker);
+}
+
+static inline void init_kthread_work(struct kthread_work *work,
+                                     kthread_work_func_t fn)
+{
+        *work = (struct kthread_work)KTHREAD_WORK_INIT(*work, fn);
+}
+
+int kthread_worker_fn(void *worker_ptr);
+
+bool queue_kthread_work(struct kthread_worker *worker,
+                        struct kthread_work *work);
+void flush_kthread_work(struct kthread_work *work);
+void flush_kthread_worker(struct kthread_worker *worker);
+
 #endif /* _LINUX_KTHREAD_H */