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