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