From b56c0d8937e665a27d90517ee7a746d0aa05af46 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 29 Jun 2010 10:07:09 +0200 Subject: kthread: implement kthread_worker Implement simple work processor for kthread. This is to ease using kthread. Single thread workqueue used to be used for things like this but workqueue won't guarantee fixed kthread association anymore to enable worker sharing. This can be used in cases where specific kthread association is necessary, for example, when it should have RT priority or be assigned to certain cgroup. Signed-off-by: Tejun Heo Cc: Andrew Morton --- include/linux/kthread.h | 64 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 64 insertions(+) (limited to 'include/linux/kthread.h') 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 */ -- cgit v1.2.3 From 82805ab77d25643f579d90397dcd34f05d1b750a Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 29 Jun 2010 10:07:09 +0200 Subject: kthread: implement kthread_data() Implement kthread_data() which takes @task pointing to a kthread and returns @data specified when creating the kthread. The caller is responsible for ensuring the validity of @task when calling this function. Signed-off-by: Tejun Heo --- include/linux/kthread.h | 1 + kernel/kthread.c | 15 +++++++++++++++ 2 files changed, 16 insertions(+) (limited to 'include/linux/kthread.h') diff --git a/include/linux/kthread.h b/include/linux/kthread.h index f93cb6979edc..685ea65eb803 100644 --- a/include/linux/kthread.h +++ b/include/linux/kthread.h @@ -30,6 +30,7 @@ struct task_struct *kthread_create(int (*threadfn)(void *data), void kthread_bind(struct task_struct *k, unsigned int cpu); int kthread_stop(struct task_struct *k); int kthread_should_stop(void); +void *kthread_data(struct task_struct *k); int kthreadd(void *unused); extern struct task_struct *kthreadd_task; diff --git a/kernel/kthread.c b/kernel/kthread.c index 8b63c7fee73b..2dc3786349d1 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -37,6 +37,7 @@ struct kthread_create_info struct kthread { int should_stop; + void *data; struct completion exited; }; @@ -56,6 +57,19 @@ int kthread_should_stop(void) } EXPORT_SYMBOL(kthread_should_stop); +/** + * kthread_data - return data value specified on kthread creation + * @task: kthread task in question + * + * Return the data value specified when kthread @task was created. + * The caller is responsible for ensuring the validity of @task when + * calling this function. + */ +void *kthread_data(struct task_struct *task) +{ + return to_kthread(task)->data; +} + static int kthread(void *_create) { /* Copy data: it's on kthread's stack */ @@ -66,6 +80,7 @@ static int kthread(void *_create) int ret; self.should_stop = 0; + self.data = data; init_completion(&self.exited); current->vfork_done = &self.exited; -- cgit v1.2.3