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 struct mm_struct;
   9
  10 __printf(4, 5)
  11 struct 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
  31 struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data),
  32                                           void *data,
  33                                           unsigned int cpu,
  34                                           const char *namefmt);
  35
  36 void set_kthread_struct(struct task_struct *p);
  37
  38 void kthread_set_per_cpu(struct task_struct *k, int cpu);
  39 bool 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
  59 void free_kthread_struct(struct task_struct *k);
  60 void kthread_bind(struct task_struct *k, unsigned int cpu);
  61 void kthread_bind_mask(struct task_struct *k, const struct cpumask *mask);
  62 int kthread_stop(struct task_struct *k);
  63 bool kthread_should_stop(void);
  64 bool kthread_should_park(void);
  65 bool __kthread_should_park(struct task_struct *k);
  66 bool kthread_freezable_should_stop(bool *was_frozen);
  67 void *kthread_func(struct task_struct *k);
  68 void *kthread_data(struct task_struct *k);
  69 void *kthread_probe_data(struct task_struct *k);
  70 int kthread_park(struct task_struct *k);
  71 void kthread_unpark(struct task_struct *k);
  72 void kthread_parkme(void);
  73
  74 int kthreadd(void *unused);
  75 extern struct task_struct *kthreadd_task;
  76 extern 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  */
  86 struct kthread_work;
  87 typedef void (*kthread_work_func_t)(struct kthread_work *work);
  88 void kthread_delayed_work_timer_fn(struct timer_list *t);
  89
  90 enum {
  91         KTW_FREEZABLE           = 1 << 0,       /* freeze during suspend */
  92 };
  93
  94 struct 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
 103 struct 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
 111 struct 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
 156 extern 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
 180 int kthread_worker_fn(void *worker_ptr);
 181
 182 __printf(2, 3)
 183 struct kthread_worker *
 184 kthread_create_worker(unsigned int flags, const char namefmt[], ...);
 185
 186 __printf(3, 4) struct kthread_worker *
 187 kthread_create_worker_on_cpu(int cpu, unsigned int flags,
 188                              const char namefmt[], ...);
 189
 190 bool kthread_queue_work(struct kthread_worker *worker,
 191                         struct kthread_work *work);
 192
 193 bool kthread_queue_delayed_work(struct kthread_worker *worker,
 194                                 struct kthread_delayed_work *dwork,
 195                                 unsigned long delay);
 196
 197 bool kthread_mod_delayed_work(struct kthread_worker *worker,
 198                               struct kthread_delayed_work *dwork,
 199                               unsigned long delay);
 200
 201 void kthread_flush_work(struct kthread_work *work);
 202 void kthread_flush_worker(struct kthread_worker *worker);
 203
 204 bool kthread_cancel_work_sync(struct kthread_work *work);
 205 bool kthread_cancel_delayed_work_sync(struct kthread_delayed_work *work);
 206
 207 void kthread_destroy_worker(struct kthread_worker *worker);
 208
 209 void kthread_use_mm(struct mm_struct *mm);
 210 void kthread_unuse_mm(struct mm_struct *mm);
 211
 212 struct cgroup_subsys_state;
 213
 214 #ifdef CONFIG_BLK_CGROUP
 215 void kthread_associate_blkcg(struct cgroup_subsys_state *css);
 216 struct cgroup_subsys_state *kthread_blkcg(void);
 217 #else
 218 static inline void kthread_associate_blkcg(struct cgroup_subsys_state *css) { }
 219 static inline struct cgroup_subsys_state *kthread_blkcg(void)
 220 {
 221         return NULL;
 222 }
 223 #endif
 224 #endif /* _LINUX_KTHREAD_H */