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