LXR linux/include/linux/kthread.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _LINUX_KTHREAD_H
   3#define _LINUX_KTHREAD_H
   4/* Simple interface for creating and stopping kernel threads without mess. */
   5#include <linux/err.h>
   6#include <linux/sched.h>
   7#include <linux/cgroup.h>
   8
   9__printf(4, 5)
  10struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
  11                                           void *data,
  12                                           int node,
  13                                           const char namefmt[], ...);
  14
  15/**
  16 * kthread_create - create a kthread on the current node
  17 * @threadfn: the function to run in the thread
  18 * @data: data pointer for @threadfn()
  19 * @namefmt: printf-style format string for the thread name
  20 * @arg...: arguments for @namefmt.
  21 *
  22 * This macro will create a kthread on the current node, leaving it in
  23 * the stopped state.  This is just a helper for kthread_create_on_node();
  24 * see the documentation there for more details.
  25 */
  26#define kthread_create(threadfn, data, namefmt, arg...) \
  27        kthread_create_on_node(threadfn, data, NUMA_NO_NODE, namefmt, ##arg)
  28
  29
  30struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data),
  31                                          void *data,
  32                                          unsigned int cpu,
  33                                          const char *namefmt);
  34
  35/**
  36 * kthread_run - create and wake a thread.
  37 * @threadfn: the function to run until signal_pending(current).
  38 * @data: data ptr for @threadfn.
  39 * @namefmt: printf-style name for the thread.
  40 *
  41 * Description: Convenient wrapper for kthread_create() followed by
  42 * wake_up_process().  Returns the kthread or ERR_PTR(-ENOMEM).
  43 */
  44#define kthread_run(threadfn, data, namefmt, ...)                          \
  45({                                                                         \
  46        struct task_struct *__k                                            \
  47                = kthread_create(threadfn, data, namefmt, ## __VA_ARGS__); \
  48        if (!IS_ERR(__k))                                                  \
  49                wake_up_process(__k);                                      \
  50        __k;                                                               \
  51})
  52
  53void free_kthread_struct(struct task_struct *k);
  54void kthread_bind(struct task_struct *k, unsigned int cpu);
  55void kthread_bind_mask(struct task_struct *k, const struct cpumask *mask);
  56int kthread_stop(struct task_struct *k);
  57bool kthread_should_stop(void);
  58bool kthread_should_park(void);
  59bool kthread_freezable_should_stop(bool *was_frozen);
  60void *kthread_data(struct task_struct *k);
  61void *kthread_probe_data(struct task_struct *k);
  62int kthread_park(struct task_struct *k);
  63void kthread_unpark(struct task_struct *k);
  64void kthread_parkme(void);
  65void kthread_park_complete(struct task_struct *k);
  66
  67int kthreadd(void *unused);
  68extern struct task_struct *kthreadd_task;
  69extern int tsk_fork_get_node(struct task_struct *tsk);
  70
  71/*
  72 * Simple work processor based on kthread.
  73 *
  74 * This provides easier way to make use of kthreads.  A kthread_work
  75 * can be queued and flushed using queue/kthread_flush_work()
  76 * respectively.  Queued kthread_works are processed by a kthread
  77 * running kthread_worker_fn().
  78 */
  79struct kthread_work;
  80typedef void (*kthread_work_func_t)(struct kthread_work *work);
  81void kthread_delayed_work_timer_fn(struct timer_list *t);
  82
  83enum {
  84        KTW_FREEZABLE           = 1 << 0,       /* freeze during suspend */
  85};
  86
  87struct kthread_worker {
  88        unsigned int            flags;
  89        spinlock_t              lock;
  90        struct list_head        work_list;
  91        struct list_head        delayed_work_list;
  92        struct task_struct      *task;
  93        struct kthread_work     *current_work;
  94};
  95
  96struct kthread_work {
  97        struct list_head        node;
  98        kthread_work_func_t     func;
  99        struct kthread_worker   *worker;
 100        /* Number of canceling calls that are running at the moment. */
 101        int                     canceling;
 102};
 103
 104struct kthread_delayed_work {
 105        struct kthread_work work;
 106        struct timer_list timer;
 107};
 108
 109#define KTHREAD_WORKER_INIT(worker)     {                               \
 110        .lock = __SPIN_LOCK_UNLOCKED((worker).lock),                    \
 111        .work_list = LIST_HEAD_INIT((worker).work_list),                \
 112        .delayed_work_list = LIST_HEAD_INIT((worker).delayed_work_list),\
 113        }
 114
 115#define KTHREAD_WORK_INIT(work, fn)     {                               \
 116        .node = LIST_HEAD_INIT((work).node),                            \
 117        .func = (fn),                                                   \
 118        }
 119
 120#define KTHREAD_DELAYED_WORK_INIT(dwork, fn) {                          \
 121        .work = KTHREAD_WORK_INIT((dwork).work, (fn)),                  \
 122        .timer = __TIMER_INITIALIZER(kthread_delayed_work_timer_fn,\
 123                                     TIMER_IRQSAFE),                    \
 124        }
 125
 126#define DEFINE_KTHREAD_WORKER(worker)                                   \
 127        struct kthread_worker worker = KTHREAD_WORKER_INIT(worker)
 128
 129#define DEFINE_KTHREAD_WORK(work, fn)                                   \
 130        struct kthread_work work = KTHREAD_WORK_INIT(work, fn)
 131
 132#define DEFINE_KTHREAD_DELAYED_WORK(dwork, fn)                          \
 133        struct kthread_delayed_work dwork =                             \
 134                KTHREAD_DELAYED_WORK_INIT(dwork, fn)
 135
 136/*
 137 * kthread_worker.lock needs its own lockdep class key when defined on
 138 * stack with lockdep enabled.  Use the following macros in such cases.
 139 */
 140#ifdef CONFIG_LOCKDEP
 141# define KTHREAD_WORKER_INIT_ONSTACK(worker)                            \
 142        ({ kthread_init_worker(&worker); worker; })
 143# define DEFINE_KTHREAD_WORKER_ONSTACK(worker)                          \
 144        struct kthread_worker worker = KTHREAD_WORKER_INIT_ONSTACK(worker)
 145#else
 146# define DEFINE_KTHREAD_WORKER_ONSTACK(worker) DEFINE_KTHREAD_WORKER(worker)
 147#endif
 148
 149extern void __kthread_init_worker(struct kthread_worker *worker,
 150                        const char *name, struct lock_class_key *key);
 151
 152#define kthread_init_worker(worker)                                     \
 153        do {                                                            \
 154                static struct lock_class_key __key;                     \
 155                __kthread_init_worker((worker), "("#worker")->lock", &__key); \
 156        } while (0)
 157
 158#define kthread_init_work(work, fn)                                     \
 159        do {                                                            \
 160                memset((work), 0, sizeof(struct kthread_work));         \
 161                INIT_LIST_HEAD(&(work)->node);                          \
 162                (work)->func = (fn);                                    \
 163        } while (0)
 164
 165#define kthread_init_delayed_work(dwork, fn)                            \
 166        do {                                                            \
 167                kthread_init_work(&(dwork)->work, (fn));                \
 168                __init_timer(&(dwork)->timer,                           \
 169                             kthread_delayed_work_timer_fn,             \
 170                             TIMER_IRQSAFE);                            \
 171        } while (0)
 172
 173int kthread_worker_fn(void *worker_ptr);
 174
 175__printf(2, 3)
 176struct kthread_worker *
 177kthread_create_worker(unsigned int flags, const char namefmt[], ...);
 178
 179__printf(3, 4) struct kthread_worker *
 180kthread_create_worker_on_cpu(int cpu, unsigned int flags,
 181                             const char namefmt[], ...);
 182
 183bool kthread_queue_work(struct kthread_worker *worker,
 184                        struct kthread_work *work);
 185
 186bool kthread_queue_delayed_work(struct kthread_worker *worker,
 187                                struct kthread_delayed_work *dwork,
 188                                unsigned long delay);
 189
 190bool kthread_mod_delayed_work(struct kthread_worker *worker,
 191                              struct kthread_delayed_work *dwork,
 192                              unsigned long delay);
 193
 194void kthread_flush_work(struct kthread_work *work);
 195void kthread_flush_worker(struct kthread_worker *worker);
 196
 197bool kthread_cancel_work_sync(struct kthread_work *work);
 198bool kthread_cancel_delayed_work_sync(struct kthread_delayed_work *work);
 199
 200void kthread_destroy_worker(struct kthread_worker *worker);
 201
 202#ifdef CONFIG_BLK_CGROUP
 203void kthread_associate_blkcg(struct cgroup_subsys_state *css);
 204struct cgroup_subsys_state *kthread_blkcg(void);
 205#else
 206static inline void kthread_associate_blkcg(struct cgroup_subsys_state *css) { }
 207static inline struct cgroup_subsys_state *kthread_blkcg(void)
 208{
 209        return NULL;
 210}
 211#endif
 212#endif /* _LINUX_KTHREAD_H */
 213