linux-sg2042/include/linux/kthread.h

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#ifndef _LINUX_KTHREAD_H
#define _LINUX_KTHREAD_H
/* Simple interface for creating and stopping kernel threads without mess. */
#include <linux/err.h>
#include <linux/sched.h>
__printf(4, 5)
struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
void *data,
int node,
const char namefmt[], ...);
#define kthread_create(threadfn, data, namefmt, arg...) \
kthread_create_on_node(threadfn, data, -1, namefmt, ##arg)
/**
* kthread_run - create and wake a thread.
* @threadfn: the function to run until signal_pending(current).
* @data: data ptr for @threadfn.
* @namefmt: printf-style name for the thread.
*
* Description: Convenient wrapper for kthread_create() followed by
* wake_up_process(). Returns the kthread or ERR_PTR(-ENOMEM).
*/
#define kthread_run(threadfn, data, namefmt, ...) \
({ \
struct task_struct *__k \
= kthread_create(threadfn, data, namefmt, ## __VA_ARGS__); \
if (!IS_ERR(__k)) \
wake_up_process(__k); \
__k; \
})
void kthread_bind(struct task_struct *k, unsigned int cpu);
int kthread_stop(struct task_struct *k);
int kthread_should_stop(void);
bool kthread_freezable_should_stop(bool *was_frozen);
void *kthread_data(struct task_struct *k);
kthread: don't depend on work queues Currently there is a circular reference between work queue initialization and kthread initialization. This prevents the kthread infrastructure from initializing until after work queues have been initialized. We want the properties of tasks created with kthread_create to be as close as possible to the init_task and to not be contaminated by user processes. The later we start our kthreadd that creates these tasks the harder it is to avoid contamination from user processes and the more of a mess we have to clean up because the defaults have changed on us. So this patch modifies the kthread support to not use work queues but to instead use a simple list of structures, and to have kthreadd start from init_task immediately after our kernel thread that execs /sbin/init. By being a true child of init_task we only have to change those process settings that we want to have different from init_task, such as our process name, the cpus that are allowed, blocking all signals and setting SIGCHLD to SIG_IGN so that all of our children are reaped automatically. By being a true child of init_task we also naturally get our ppid set to 0 and do not wind up as a child of PID == 1. Ensuring that tasks generated by kthread_create will not slow down the functioning of the wait family of functions. [akpm@linux-foundation.org: use interruptible sleeps] Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09 17:34:32 +08:00
int kthreadd(void *unused);
extern struct task_struct *kthreadd_task;
extern int tsk_fork_get_node(struct task_struct *tsk);
kthread: don't depend on work queues Currently there is a circular reference between work queue initialization and kthread initialization. This prevents the kthread infrastructure from initializing until after work queues have been initialized. We want the properties of tasks created with kthread_create to be as close as possible to the init_task and to not be contaminated by user processes. The later we start our kthreadd that creates these tasks the harder it is to avoid contamination from user processes and the more of a mess we have to clean up because the defaults have changed on us. So this patch modifies the kthread support to not use work queues but to instead use a simple list of structures, and to have kthreadd start from init_task immediately after our kernel thread that execs /sbin/init. By being a true child of init_task we only have to change those process settings that we want to have different from init_task, such as our process name, the cpus that are allowed, blocking all signals and setting SIGCHLD to SIG_IGN so that all of our children are reaped automatically. By being a true child of init_task we also naturally get our ppid set to 0 and do not wind up as a child of PID == 1. Ensuring that tasks generated by kthread_create will not slow down the functioning of the wait family of functions. [akpm@linux-foundation.org: use interruptible sleeps] Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09 17:34:32 +08:00
/*
* 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((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), \
.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)
/*
* 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_H */