In subsequent patches, we will want to declare variables of kthread-work and
kthread-worker structures within mmzone.h. But trying to include kthread.h
inside mmzone.h to get the structure definitions, will lead to the following
circular header-file dependency.
mmzone.h -> kthread.h -> sched.h -> gfp.h -> mmzone.h
We can avoid this by not including sched.h in kthread.h. But sched.h is quite
handy for call-sites which use the core kthread start/stop infrastructure such
as kthread-create-on-cpu/node etc. However, the kthread-work/worker framework
doesn't actually depend on sched.h.
So extract the definitions related to kthread-work/worker from kthread.h into
a new header-file named kthread-work.h (which doesn't include sched.h), so that
it can be easily included inside mmzone.h when required.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>
---
include/linux/kthread-work.h | 92 ++++++++++++++++++++++++++++++++++++++++++
include/linux/kthread.h | 85 ---------------------------------------
2 files changed, 93 insertions(+), 84 deletions(-)
create mode 100644 include/linux/kthread-work.h
diff --git a/include/linux/kthread-work.h b/include/linux/kthread-work.h
new file mode 100644
index 0000000..6dae2ab
--- /dev/null
+++ b/include/linux/kthread-work.h
@@ -0,0 +1,92 @@
+#ifndef _LINUX_KTHREAD_WORK_H
+#define _LINUX_KTHREAD_WORK_H
+#include <linux/err.h>
+
+__printf(4, 5)
+
+/*
+ * 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().
+ */
+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 *current_work;
+};
+
+struct kthread_work {
+ struct list_head node;
+ kthread_work_func_t func;
+ wait_queue_head_t done;
+ struct kthread_worker *worker;
+};
+
+#define KTHREAD_WORKER_INIT(worker) { \
+ .lock = __SPIN_LOCK_UNLOCKED((worker).lock), \
+ .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), \
+ }
+
+#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)
+
+/*
+ * kthread_worker.lock and kthread_work.done need their own lockdep class
+ * keys if they are defined on stack with lockdep enabled. Use the
+ * following macros when defining them on stack.
+ */
+#ifdef CONFIG_LOCKDEP
+# define KTHREAD_WORKER_INIT_ONSTACK(worker) \
+ ({ init_kthread_worker(&worker); worker; })
+# define DEFINE_KTHREAD_WORKER_ONSTACK(worker) \
+ struct kthread_worker worker = KTHREAD_WORKER_INIT_ONSTACK(worker)
+# define KTHREAD_WORK_INIT_ONSTACK(work, fn) \
+ ({ init_kthread_work((&work), fn); work; })
+# define DEFINE_KTHREAD_WORK_ONSTACK(work, fn) \
+ struct kthread_work work = KTHREAD_WORK_INIT_ONSTACK(work, fn)
+#else
+# define DEFINE_KTHREAD_WORKER_ONSTACK(worker) DEFINE_KTHREAD_WORKER(worker)
+# define DEFINE_KTHREAD_WORK_ONSTACK(work, fn) DEFINE_KTHREAD_WORK(work, fn)
+#endif
+
+extern void __init_kthread_worker(struct kthread_worker *worker,
+ const char *name, struct lock_class_key *key);
+
+#define init_kthread_worker(worker) \
+ do { \
+ static struct lock_class_key __key; \
+ __init_kthread_worker((worker), "("#worker")->lock", &__key); \
+ } while (0)
+
+#define init_kthread_work(work, fn) \
+ do { \
+ memset((work), 0, sizeof(struct kthread_work)); \
+ INIT_LIST_HEAD(&(work)->node); \
+ (work)->func = (fn); \
+ init_waitqueue_head(&(work)->done); \
+ } while (0)
+
+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_WORK_H */
diff --git a/include/linux/kthread.h b/include/linux/kthread.h
index 7dcef33..cbefb16 100644
--- a/include/linux/kthread.h
+++ b/include/linux/kthread.h
@@ -52,89 +52,6 @@ int kthreadd(void *unused);
extern struct task_struct *kthreadd_task;
extern int tsk_fork_get_node(struct task_struct *tsk);
-/*
- * 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().
- */
-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 *current_work;
-};
-
-struct kthread_work {
- struct list_head node;
- kthread_work_func_t func;
- wait_queue_head_t done;
- struct kthread_worker *worker;
-};
-
-#define KTHREAD_WORKER_INIT(worker) { \
- .lock = __SPIN_LOCK_UNLOCKED((worker).lock), \
- .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), \
- }
-
-#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)
-
-/*
- * kthread_worker.lock and kthread_work.done need their own lockdep class
- * keys if they are defined on stack with lockdep enabled. Use the
- * following macros when defining them on stack.
- */
-#ifdef CONFIG_LOCKDEP
-# define KTHREAD_WORKER_INIT_ONSTACK(worker) \
- ({ init_kthread_worker(&worker); worker; })
-# define DEFINE_KTHREAD_WORKER_ONSTACK(worker) \
- struct kthread_worker worker = KTHREAD_WORKER_INIT_ONSTACK(worker)
-# define KTHREAD_WORK_INIT_ONSTACK(work, fn) \
- ({ init_kthread_work((&work), fn); work; })
-# define DEFINE_KTHREAD_WORK_ONSTACK(work, fn) \
- struct kthread_work work = KTHREAD_WORK_INIT_ONSTACK(work, fn)
-#else
-# define DEFINE_KTHREAD_WORKER_ONSTACK(worker) DEFINE_KTHREAD_WORKER(worker)
-# define DEFINE_KTHREAD_WORK_ONSTACK(work, fn) DEFINE_KTHREAD_WORK(work, fn)
-#endif
-
-extern void __init_kthread_worker(struct kthread_worker *worker,
- const char *name, struct lock_class_key *key);
-
-#define init_kthread_worker(worker) \
- do { \
- static struct lock_class_key __key; \
- __init_kthread_worker((worker), "("#worker")->lock", &__key); \
- } while (0)
-
-#define init_kthread_work(work, fn) \
- do { \
- memset((work), 0, sizeof(struct kthread_work)); \
- INIT_LIST_HEAD(&(work)->node); \
- (work)->func = (fn); \
- init_waitqueue_head(&(work)->done); \
- } while (0)
-
-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);
+#include <linux/kthread-work.h>
#endif /* _LINUX_KTHREAD_H */
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