linux/include/linux/kthread.h
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   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
   8struct mm_struct;
   9
  10__printf(4, 5)
  11struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
  12                                           void *data,
  13                                           int node,
  14                                           const char namefmt[], ...);
  15
  16/**
  17 * kthread_create - create a kthread on the current node
  18 * @threadfn: the function to run in the thread
  19 * @data: data pointer for @threadfn()
  20 * @namefmt: printf-style format string for the thread name
  21 * @arg: arguments for @namefmt.
  22 *
  23 * This macro will create a kthread on the current node, leaving it in
  24 * the stopped state.  This is just a helper for kthread_create_on_node();
  25 * see the documentation there for more details.
  26 */
  27#define kthread_create(threadfn, data, namefmt, arg...) \
  28        kthread_create_on_node(threadfn, data, NUMA_NO_NODE, namefmt, ##arg)
  29
  30
  31struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data),
  32                                          void *data,
  33                                          unsigned int cpu,
  34                                          const char *namefmt);
  35
  36void set_kthread_struct(struct task_struct *p);
  37
  38void kthread_set_per_cpu(struct task_struct *k, int cpu);
  39bool kthread_is_per_cpu(struct task_struct *k);
  40
  41/**
  42 * kthread_run - create and wake a thread.
  43 * @threadfn: the function to run until signal_pending(current).
  44 * @data: data ptr for @threadfn.
  45 * @namefmt: printf-style name for the thread.
  46 *
  47 * Description: Convenient wrapper for kthread_create() followed by
  48 * wake_up_process().  Returns the kthread or ERR_PTR(-ENOMEM).
  49 */
  50#define kthread_run(threadfn, data, namefmt, ...)                          \
  51({                                                                         \
  52        struct task_struct *__k                                            \
  53                = kthread_create(threadfn, data, namefmt, ## __VA_ARGS__); \
  54        if (!IS_ERR(__k))                                                  \
  55                wake_up_process(__k);                                      \
  56        __k;                                                               \
  57})
  58
  59void free_kthread_struct(struct task_struct *k);
  60void kthread_bind(struct task_struct *k, unsigned int cpu);
  61void kthread_bind_mask(struct task_struct *k, const struct cpumask *mask);
  62int kthread_stop(struct task_struct *k);
  63bool kthread_should_stop(void);
  64bool kthread_should_park(void);
  65bool __kthread_should_park(struct task_struct *k);
  66bool kthread_freezable_should_stop(bool *was_frozen);
  67void *kthread_func(struct task_struct *k);
  68void *kthread_data(struct task_struct *k);
  69void *kthread_probe_data(struct task_struct *k);
  70int kthread_park(struct task_struct *k);
  71void kthread_unpark(struct task_struct *k);
  72void kthread_parkme(void);
  73
  74int kthreadd(void *unused);
  75extern struct task_struct *kthreadd_task;
  76extern int tsk_fork_get_node(struct task_struct *tsk);
  77
  78/*
  79 * Simple work processor based on kthread.
  80 *
  81 * This provides easier way to make use of kthreads.  A kthread_work
  82 * can be queued and flushed using queue/kthread_flush_work()
  83 * respectively.  Queued kthread_works are processed by a kthread
  84 * running kthread_worker_fn().
  85 */
  86struct kthread_work;
  87typedef void (*kthread_work_func_t)(struct kthread_work *work);
  88void kthread_delayed_work_timer_fn(struct timer_list *t);
  89
  90enum {
  91        KTW_FREEZABLE           = 1 << 0,       /* freeze during suspend */
  92};
  93
  94struct kthread_worker {
  95        unsigned int            flags;
  96        raw_spinlock_t          lock;
  97        struct list_head        work_list;
  98        struct list_head        delayed_work_list;
  99        struct task_struct      *task;
 100        struct kthread_work     *current_work;
 101};
 102
 103struct kthread_work {
 104        struct list_head        node;
 105        kthread_work_func_t     func;
 106        struct kthread_worker   *worker;
 107        /* Number of canceling calls that are running at the moment. */
 108        int                     canceling;
 109};
 110
 111struct kthread_delayed_work {
 112        struct kthread_work work;
 113        struct timer_list timer;
 114};
 115
 116#define KTHREAD_WORKER_INIT(worker)     {                               \
 117        .lock = __RAW_SPIN_LOCK_UNLOCKED((worker).lock),                \
 118        .work_list = LIST_HEAD_INIT((worker).work_list),                \
 119        .delayed_work_list = LIST_HEAD_INIT((worker).delayed_work_list),\
 120        }
 121
 122#define KTHREAD_WORK_INIT(work, fn)     {                               \
 123        .node = LIST_HEAD_INIT((work).node),                            \
 124        .func = (fn),                                                   \
 125        }
 126
 127#define KTHREAD_DELAYED_WORK_INIT(dwork, fn) {                          \
 128        .work = KTHREAD_WORK_INIT((dwork).work, (fn)),                  \
 129        .timer = __TIMER_INITIALIZER(kthread_delayed_work_timer_fn,\
 130                                     TIMER_IRQSAFE),                    \
 131        }
 132
 133#define DEFINE_KTHREAD_WORKER(worker)                                   \
 134        struct kthread_worker worker = KTHREAD_WORKER_INIT(worker)
 135
 136#define DEFINE_KTHREAD_WORK(work, fn)                                   \
 137        struct kthread_work work = KTHREAD_WORK_INIT(work, fn)
 138
 139#define DEFINE_KTHREAD_DELAYED_WORK(dwork, fn)                          \
 140        struct kthread_delayed_work dwork =                             \
 141                KTHREAD_DELAYED_WORK_INIT(dwork, fn)
 142
 143/*
 144 * kthread_worker.lock needs its own lockdep class key when defined on
 145 * stack with lockdep enabled.  Use the following macros in such cases.
 146 */
 147#ifdef CONFIG_LOCKDEP
 148# define KTHREAD_WORKER_INIT_ONSTACK(worker)                            \
 149        ({ kthread_init_worker(&worker); worker; })
 150# define DEFINE_KTHREAD_WORKER_ONSTACK(worker)                          \
 151        struct kthread_worker worker = KTHREAD_WORKER_INIT_ONSTACK(worker)
 152#else
 153# define DEFINE_KTHREAD_WORKER_ONSTACK(worker) DEFINE_KTHREAD_WORKER(worker)
 154#endif
 155
 156extern void __kthread_init_worker(struct kthread_worker *worker,
 157                        const char *name, struct lock_class_key *key);
 158
 159#define kthread_init_worker(worker)                                     \
 160        do {                                                            \
 161                static struct lock_class_key __key;                     \
 162                __kthread_init_worker((worker), "("#worker")->lock", &__key); \
 163        } while (0)
 164
 165#define kthread_init_work(work, fn)                                     \
 166        do {                                                            \
 167                memset((work), 0, sizeof(struct kthread_work));         \
 168                INIT_LIST_HEAD(&(work)->node);                          \
 169                (work)->func = (fn);                                    \
 170        } while (0)
 171
 172#define kthread_init_delayed_work(dwork, fn)                            \
 173        do {                                                            \
 174                kthread_init_work(&(dwork)->work, (fn));                \
 175                timer_setup(&(dwork)->timer,                            \
 176                             kthread_delayed_work_timer_fn,             \
 177                             TIMER_IRQSAFE);                            \
 178        } while (0)
 179
 180int kthread_worker_fn(void *worker_ptr);
 181
 182__printf(2, 3)
 183struct kthread_worker *
 184kthread_create_worker(unsigned int flags, const char namefmt[], ...);
 185
 186__printf(3, 4) struct kthread_worker *
 187kthread_create_worker_on_cpu(int cpu, unsigned int flags,
 188                             const char namefmt[], ...);
 189
 190bool kthread_queue_work(struct kthread_worker *worker,
 191                        struct kthread_work *work);
 192
 193bool kthread_queue_delayed_work(struct kthread_worker *worker,
 194                                struct kthread_delayed_work *dwork,
 195                                unsigned long delay);
 196
 197bool kthread_mod_delayed_work(struct kthread_worker *worker,
 198                              struct kthread_delayed_work *dwork,
 199                              unsigned long delay);
 200
 201void kthread_flush_work(struct kthread_work *work);
 202void kthread_flush_worker(struct kthread_worker *worker);
 203
 204bool kthread_cancel_work_sync(struct kthread_work *work);
 205bool kthread_cancel_delayed_work_sync(struct kthread_delayed_work *work);
 206
 207void kthread_destroy_worker(struct kthread_worker *worker);
 208
 209void kthread_use_mm(struct mm_struct *mm);
 210void kthread_unuse_mm(struct mm_struct *mm);
 211
 212struct cgroup_subsys_state;
 213
 214#ifdef CONFIG_BLK_CGROUP
 215void kthread_associate_blkcg(struct cgroup_subsys_state *css);
 216struct cgroup_subsys_state *kthread_blkcg(void);
 217#else
 218static inline void kthread_associate_blkcg(struct cgroup_subsys_state *css) { }
 219static inline struct cgroup_subsys_state *kthread_blkcg(void)
 220{
 221        return NULL;
 222}
 223#endif
 224#endif /* _LINUX_KTHREAD_H */
 225
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