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 get_kthread_comm(char *buf, size_t buf_size, struct task_struct *tsk);
  37 bool set_kthread_struct(struct task_struct *p);
  38
  39 void kthread_set_per_cpu(struct task_struct *k, int cpu);
  40 bool kthread_is_per_cpu(struct task_struct *k);
  41
  42 /**
  43  * kthread_run - create and wake a thread.
  44  * @threadfn: the function to run until signal_pending(current).
  45  * @data: data ptr for @threadfn.
  46  * @namefmt: printf-style name for the thread.
  47  *
  48  * Description: Convenient wrapper for kthread_create() followed by
  49  * wake_up_process().  Returns the kthread or ERR_PTR(-ENOMEM).
  50  */
  51 #define kthread_run(threadfn, data, namefmt, ...)                          \
  52 ({                                                                         \
  53         struct task_struct *__k                                            \
  54                 = kthread_create(threadfn, data, namefmt, ## __VA_ARGS__); \
  55         if (!IS_ERR(__k))                                                  \
  56                 wake_up_process(__k);                                      \
  57         __k;                                                               \
  58 })
  59
  60 /**
  61  * kthread_run_on_cpu - create and wake a cpu bound thread.
  62  * @threadfn: the function to run until signal_pending(current).
  63  * @data: data ptr for @threadfn.
  64  * @cpu: The cpu on which the thread should be bound,
  65  * @namefmt: printf-style name for the thread. Format is restricted
  66  *           to "name.*%u". Code fills in cpu number.
  67  *
  68  * Description: Convenient wrapper for kthread_create_on_cpu()
  69  * followed by wake_up_process().  Returns the kthread or
  70  * ERR_PTR(-ENOMEM).
  71  */
  72 static inline struct task_struct *
  73 kthread_run_on_cpu(int (*threadfn)(void *data), void *data,
  74                         unsigned int cpu, const char *namefmt)
  75 {
  76         struct task_struct *p;
  77
  78         p = kthread_create_on_cpu(threadfn, data, cpu, namefmt);
  79         if (!IS_ERR(p))
  80                 wake_up_process(p);
  81
  82         return p;
  83 }
  84
  85 void free_kthread_struct(struct task_struct *k);
  86 void kthread_bind(struct task_struct *k, unsigned int cpu);
  87 void kthread_bind_mask(struct task_struct *k, const struct cpumask *mask);
  88 int kthread_stop(struct task_struct *k);
  89 bool kthread_should_stop(void);
  90 bool kthread_should_park(void);
  91 bool __kthread_should_park(struct task_struct *k);
  92 bool kthread_freezable_should_stop(bool *was_frozen);
  93 void *kthread_func(struct task_struct *k);
  94 void *kthread_data(struct task_struct *k);
  95 void *kthread_probe_data(struct task_struct *k);
  96 int kthread_park(struct task_struct *k);
  97 void kthread_unpark(struct task_struct *k);
  98 void kthread_parkme(void);
  99 void kthread_exit(long result) __noreturn;
 100 void kthread_complete_and_exit(struct completion *, long) __noreturn;
 101
 102 int kthreadd(void *unused);
 103 extern struct task_struct *kthreadd_task;
 104 extern int tsk_fork_get_node(struct task_struct *tsk);
 105
 106 /*
 107  * Simple work processor based on kthread.
 108  *
 109  * This provides easier way to make use of kthreads.  A kthread_work
 110  * can be queued and flushed using queue/kthread_flush_work()
 111  * respectively.  Queued kthread_works are processed by a kthread
 112  * running kthread_worker_fn().
 113  */
 114 struct kthread_work;
 115 typedef void (*kthread_work_func_t)(struct kthread_work *work);
 116 void kthread_delayed_work_timer_fn(struct timer_list *t);
 117
 118 enum {
 119         KTW_FREEZABLE           = 1 << 0,       /* freeze during suspend */
 120 };
 121
 122 struct kthread_worker {
 123         unsigned int            flags;
 124         raw_spinlock_t          lock;
 125         struct list_head        work_list;
 126         struct list_head        delayed_work_list;
 127         struct task_struct      *task;
 128         struct kthread_work     *current_work;
 129 };
 130
 131 struct kthread_work {
 132         struct list_head        node;
 133         kthread_work_func_t     func;
 134         struct kthread_worker   *worker;
 135         /* Number of canceling calls that are running at the moment. */
 136         int                     canceling;
 137 };
 138
 139 struct kthread_delayed_work {
 140         struct kthread_work work;
 141         struct timer_list timer;
 142 };
 143
 144 #define KTHREAD_WORKER_INIT(worker)     {                               \
 145         .lock = __RAW_SPIN_LOCK_UNLOCKED((worker).lock),                \
 146         .work_list = LIST_HEAD_INIT((worker).work_list),                \
 147         .delayed_work_list = LIST_HEAD_INIT((worker).delayed_work_list),\
 148         }
 149
 150 #define KTHREAD_WORK_INIT(work, fn)     {                               \
 151         .node = LIST_HEAD_INIT((work).node),                            \
 152         .func = (fn),                                                   \
 153         }
 154
 155 #define KTHREAD_DELAYED_WORK_INIT(dwork, fn) {                          \
 156         .work = KTHREAD_WORK_INIT((dwork).work, (fn)),                  \
 157         .timer = __TIMER_INITIALIZER(kthread_delayed_work_timer_fn,\
 158                                      TIMER_IRQSAFE),                    \
 159         }
 160
 161 #define DEFINE_KTHREAD_WORKER(worker)                                   \
 162         struct kthread_worker worker = KTHREAD_WORKER_INIT(worker)
 163
 164 #define DEFINE_KTHREAD_WORK(work, fn)                                   \
 165         struct kthread_work work = KTHREAD_WORK_INIT(work, fn)
 166
 167 #define DEFINE_KTHREAD_DELAYED_WORK(dwork, fn)                          \
 168         struct kthread_delayed_work dwork =                             \
 169                 KTHREAD_DELAYED_WORK_INIT(dwork, fn)
 170
 171 /*
 172  * kthread_worker.lock needs its own lockdep class key when defined on
 173  * stack with lockdep enabled.  Use the following macros in such cases.
 174  */
 175 #ifdef CONFIG_LOCKDEP
 176 # define KTHREAD_WORKER_INIT_ONSTACK(worker)                            \
 177         ({ kthread_init_worker(&worker); worker; })
 178 # define DEFINE_KTHREAD_WORKER_ONSTACK(worker)                          \
 179         struct kthread_worker worker = KTHREAD_WORKER_INIT_ONSTACK(worker)
 180 #else
 181 # define DEFINE_KTHREAD_WORKER_ONSTACK(worker) DEFINE_KTHREAD_WORKER(worker)
 182 #endif
 183
 184 extern void __kthread_init_worker(struct kthread_worker *worker,
 185                         const char *name, struct lock_class_key *key);
 186
 187 #define kthread_init_worker(worker)                                     \
 188         do {                                                            \
 189                 static struct lock_class_key __key;                     \
 190                 __kthread_init_worker((worker), "("#worker")->lock", &__key); \
 191         } while (0)
 192
 193 #define kthread_init_work(work, fn)                                     \
 194         do {                                                            \
 195                 memset((work), 0, sizeof(struct kthread_work));         \
 196                 INIT_LIST_HEAD(&(work)->node);                          \
 197                 (work)->func = (fn);                                    \
 198         } while (0)
 199
 200 #define kthread_init_delayed_work(dwork, fn)                            \
 201         do {                                                            \
 202                 kthread_init_work(&(dwork)->work, (fn));                \
 203                 timer_setup(&(dwork)->timer,                            \
 204                              kthread_delayed_work_timer_fn,             \
 205                              TIMER_IRQSAFE);                            \
 206         } while (0)
 207
 208 int kthread_worker_fn(void *worker_ptr);
 209
 210 __printf(2, 3)
 211 struct kthread_worker *
 212 kthread_create_worker(unsigned int flags, const char namefmt[], ...);
 213
 214 __printf(3, 4) struct kthread_worker *
 215 kthread_create_worker_on_cpu(int cpu, unsigned int flags,
 216                              const char namefmt[], ...);
 217
 218 bool kthread_queue_work(struct kthread_worker *worker,
 219                         struct kthread_work *work);
 220
 221 bool kthread_queue_delayed_work(struct kthread_worker *worker,
 222                                 struct kthread_delayed_work *dwork,
 223                                 unsigned long delay);
 224
 225 bool kthread_mod_delayed_work(struct kthread_worker *worker,
 226                               struct kthread_delayed_work *dwork,
 227                               unsigned long delay);
 228
 229 void kthread_flush_work(struct kthread_work *work);
 230 void kthread_flush_worker(struct kthread_worker *worker);
 231
 232 bool kthread_cancel_work_sync(struct kthread_work *work);
 233 bool kthread_cancel_delayed_work_sync(struct kthread_delayed_work *work);
 234
 235 void kthread_destroy_worker(struct kthread_worker *worker);
 236
 237 void kthread_use_mm(struct mm_struct *mm);
 238 void kthread_unuse_mm(struct mm_struct *mm);
 239
 240 struct cgroup_subsys_state;
 241
 242 #ifdef CONFIG_BLK_CGROUP
 243 void kthread_associate_blkcg(struct cgroup_subsys_state *css);
 244 struct cgroup_subsys_state *kthread_blkcg(void);
 245 #else
 246 static inline void kthread_associate_blkcg(struct cgroup_subsys_state *css) { }
 247 static inline struct cgroup_subsys_state *kthread_blkcg(void)
 248 {
 249         return NULL;
 250 }
 251 #endif
 252 #endif /* _LINUX_KTHREAD_H */