/* SPDX-License-Identifier: GPL-2.0 */
#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>

struct mm_struct;

__printf(4, 5)
struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
                                           void *data,
                                           int node,
                                           const char namefmt[], ...);

/**
 * kthread_create - create a kthread on the current node
 * @threadfn: the function to run in the thread
 * @data: data pointer for @threadfn()
 * @namefmt: printf-style format string for the thread name
 * @arg...: arguments for @namefmt.
 *
 * This macro will create a kthread on the current node, leaving it in
 * the stopped state.  This is just a helper for kthread_create_on_node();
 * see the documentation there for more details.
 */
#define kthread_create(threadfn, data, namefmt, arg...) \
        kthread_create_on_node(threadfn, data, NUMA_NO_NODE, namefmt, ##arg)


struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data),
                                          void *data,
                                          unsigned int cpu,
                                          const char *namefmt);

/**
 * 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 free_kthread_struct(struct task_struct *k);
void kthread_bind(struct task_struct *k, unsigned int cpu);
void kthread_bind_mask(struct task_struct *k, const struct cpumask *mask);
int kthread_stop(struct task_struct *k);
bool kthread_should_stop(void);
bool kthread_should_park(void);
bool __kthread_should_park(struct task_struct *k);
bool kthread_freezable_should_stop(bool *was_frozen);
void *kthread_func(struct task_struct *k);
void *kthread_data(struct task_struct *k);
void *kthread_probe_data(struct task_struct *k);
int kthread_park(struct task_struct *k);
void kthread_unpark(struct task_struct *k);
void kthread_parkme(void);

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/kthread_flush_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);
void kthread_delayed_work_timer_fn(struct timer_list *t);

enum {
        KTW_FREEZABLE           = 1 << 0,       /* freeze during suspend */
};

struct kthread_worker {
        unsigned int            flags;
        raw_spinlock_t          lock;
        struct list_head        work_list;
        struct list_head        delayed_work_list;
        struct task_struct      *task;
        struct kthread_work     *current_work;
};

struct kthread_work {
        struct list_head        node;
        kthread_work_func_t     func;
        struct kthread_worker   *worker;
        /* Number of canceling calls that are running at the moment. */
        int                     canceling;
};

struct kthread_delayed_work {
        struct kthread_work work;
        struct timer_list timer;
};

#define KTHREAD_WORKER_INIT(worker)     {                               \
        .lock = __RAW_SPIN_LOCK_UNLOCKED((worker).lock),                \
        .work_list = LIST_HEAD_INIT((worker).work_list),                \
        .delayed_work_list = LIST_HEAD_INIT((worker).delayed_work_list),\
        }

#define KTHREAD_WORK_INIT(work, fn)     {                               \
        .node = LIST_HEAD_INIT((work).node),                            \
        .func = (fn),                                                   \
        }

#define KTHREAD_DELAYED_WORK_INIT(dwork, fn) {                          \
        .work = KTHREAD_WORK_INIT((dwork).work, (fn)),                  \
        .timer = __TIMER_INITIALIZER(kthread_delayed_work_timer_fn,\
                                     TIMER_IRQSAFE),                    \
        }

#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)

#define DEFINE_KTHREAD_DELAYED_WORK(dwork, fn)                          \
        struct kthread_delayed_work dwork =                             \
                KTHREAD_DELAYED_WORK_INIT(dwork, fn)

/*
 * kthread_worker.lock needs its own lockdep class key when defined on
 * stack with lockdep enabled.  Use the following macros in such cases.
 */
#ifdef CONFIG_LOCKDEP
# define KTHREAD_WORKER_INIT_ONSTACK(worker)                            \
        ({ kthread_init_worker(&worker); worker; })
# define DEFINE_KTHREAD_WORKER_ONSTACK(worker)                          \
        struct kthread_worker worker = KTHREAD_WORKER_INIT_ONSTACK(worker)
#else
# define DEFINE_KTHREAD_WORKER_ONSTACK(worker) DEFINE_KTHREAD_WORKER(worker)
#endif

extern void __kthread_init_worker(struct kthread_worker *worker,
                        const char *name, struct lock_class_key *key);

#define kthread_init_worker(worker)                                     \
        do {                                                            \
                static struct lock_class_key __key;                     \
                __kthread_init_worker((worker), "("#worker")->lock", &__key); \
        } while (0)

#define kthread_init_work(work, fn)                                     \
        do {                                                            \
                memset((work), 0, sizeof(struct kthread_work));         \
                INIT_LIST_HEAD(&(work)->node);                          \
                (work)->func = (fn);                                    \
        } while (0)

#define kthread_init_delayed_work(dwork, fn)                            \
        do {                                                            \
                kthread_init_work(&(dwork)->work, (fn));                \
                timer_setup(&(dwork)->timer,                            \
                             kthread_delayed_work_timer_fn,             \
                             TIMER_IRQSAFE);                            \
        } while (0)

int kthread_worker_fn(void *worker_ptr);

__printf(2, 3)
struct kthread_worker *
kthread_create_worker(unsigned int flags, const char namefmt[], ...);

__printf(3, 4) struct kthread_worker *
kthread_create_worker_on_cpu(int cpu, unsigned int flags,
                             const char namefmt[], ...);

bool kthread_queue_work(struct kthread_worker *worker,
                        struct kthread_work *work);

bool kthread_queue_delayed_work(struct kthread_worker *worker,
                                struct kthread_delayed_work *dwork,
                                unsigned long delay);

bool kthread_mod_delayed_work(struct kthread_worker *worker,
                              struct kthread_delayed_work *dwork,
                              unsigned long delay);

void kthread_flush_work(struct kthread_work *work);
void kthread_flush_worker(struct kthread_worker *worker);

bool kthread_cancel_work_sync(struct kthread_work *work);
bool kthread_cancel_delayed_work_sync(struct kthread_delayed_work *work);

void kthread_destroy_worker(struct kthread_worker *worker);

void kthread_use_mm(struct mm_struct *mm);
void kthread_unuse_mm(struct mm_struct *mm);

struct cgroup_subsys_state;

#ifdef CONFIG_BLK_CGROUP
void kthread_associate_blkcg(struct cgroup_subsys_state *css);
struct cgroup_subsys_state *kthread_blkcg(void);
#else
static inline void kthread_associate_blkcg(struct cgroup_subsys_state *css) { }
static inline struct cgroup_subsys_state *kthread_blkcg(void)
{
        return NULL;
}
#endif
#endif /* _LINUX_KTHREAD_H */