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