kthread.h

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/* 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;
 
/* opaque kthread data */
struct kthread;
 
/*
 * When "(p->flags & PF_KTHREAD)" is set the task is a kthread and will
 * always remain a kthread.  For kthreads p->worker_private always
 * points to a struct kthread.  For tasks that are not kthreads
 * p->worker_private is used to point to other things.
 *
 * Return NULL for any task that is not a kthread.
 */
static inline struct kthread *tsk_is_kthread(struct task_struct *p)
{
    if (p->flags & PF_KTHREAD)
        return p->worker_private;
    return NULL;
}
 
__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, NUMA_NO_NODE, namefmt, ##arg)
 
 
struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data),
                      void *data,
                      unsigned int cpu,
                      const char *namefmt);
 
void get_kthread_comm(char *buf, size_t buf_size, struct task_struct *tsk);
bool set_kthread_struct(struct task_struct *p);
 
void kthread_set_per_cpu(struct task_struct *k, int cpu);
bool kthread_is_per_cpu(struct task_struct *k);
 
#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;                                   \
})
 
static inline struct task_struct *
kthread_run_on_cpu(int (*threadfn)(void *data), void *data,
            unsigned int cpu, const char *namefmt)
{
    struct task_struct *p;
 
    p = kthread_create_on_cpu(threadfn, data, cpu, namefmt);
    if (!IS_ERR(p))
        wake_up_process(p);
 
    return p;
}
 
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_affine_preferred(struct task_struct *p, const struct cpumask *mask);
int kthread_stop(struct task_struct *k);
int kthread_stop_put(struct task_struct *k);
bool kthread_should_stop(void);
bool kthread_should_park(void);
bool kthread_should_stop_or_park(void);
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);
#define kthread_exit(result) do_exit(result)
void kthread_complete_and_exit(struct completion *, long) __noreturn;
int kthreads_update_housekeeping(void);
void kthread_do_exit(struct kthread *, long);
 
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_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_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)
 
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(3, 4)
struct kthread_worker *kthread_create_worker_on_node(unsigned int flags,
                             int node,
                             const char namefmt[], ...);
 
#define kthread_create_worker(flags, namefmt, ...) \
    kthread_create_worker_on_node(flags, NUMA_NO_NODE, namefmt, ## __VA_ARGS__);
 
#define kthread_run_worker(flags, namefmt, ...)                 \
({                                      \
    struct kthread_worker *__kw                     \
        = kthread_create_worker(flags, namefmt, ## __VA_ARGS__);    \
    if (!IS_ERR(__kw))                          \
        wake_up_process(__kw->task);                    \
    __kw;                                   \
})
 
struct kthread_worker *
kthread_create_worker_on_cpu(int cpu, unsigned int flags,
                 const char namefmt[]);
 
static inline struct kthread_worker *
kthread_run_worker_on_cpu(int cpu, unsigned int flags,
              const char namefmt[])
{
    struct kthread_worker *kw;
 
    kw = kthread_create_worker_on_cpu(cpu, flags, namefmt);
    if (!IS_ERR(kw))
        wake_up_process(kw->task);
 
    return kw;
}
 
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) { }
#endif
#endif /* _LINUX_KTHREAD_H */