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 #include <linux/cgroup.h>
   8
   9 __printf(4, 5)
  10 struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
  11                                            void *data,
  12                                            int node,
  13                                            const char namefmt[], ...);
  14
  15 /**
  16  * kthread_create - create a kthread on the current node
  17  * @threadfn: the function to run in the thread
  18  * @data: data pointer for @threadfn()
  19  * @namefmt: printf-style format string for the thread name
  20  * @arg...: arguments for @namefmt.
  21  *
  22  * This macro will create a kthread on the current node, leaving it in
  23  * the stopped state.  This is just a helper for kthread_create_on_node();
  24  * see the documentation there for more details.
  25  */
  26 #define kthread_create(threadfn, data, namefmt, arg...) \
  27         kthread_create_on_node(threadfn, data, NUMA_NO_NODE, namefmt, ##arg)
  28
  29
  30 struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data),
  31                                           void *data,
  32                                           unsigned int cpu,
  33                                           const char *namefmt);
  34
  35 /**
  36  * kthread_run - create and wake a thread.
  37  * @threadfn: the function to run until signal_pending(current).
  38  * @data: data ptr for @threadfn.
  39  * @namefmt: printf-style name for the thread.
  40  *
  41  * Description: Convenient wrapper for kthread_create() followed by
  42  * wake_up_process().  Returns the kthread or ERR_PTR(-ENOMEM).
  43  */
  44 #define kthread_run(threadfn, data, namefmt, ...)                          \
  45 ({                                                                         \
  46         struct task_struct *__k                                            \
  47                 = kthread_create(threadfn, data, namefmt, ## __VA_ARGS__); \
  48         if (!IS_ERR(__k))                                                  \
  49                 wake_up_process(__k);                                      \
  50         __k;                                                               \
  51 })
  52
  53 void free_kthread_struct(struct task_struct *k);
  54 void kthread_bind(struct task_struct *k, unsigned int cpu);
  55 void kthread_bind_mask(struct task_struct *k, const struct cpumask *mask);
  56 int kthread_stop(struct task_struct *k);
  57 bool kthread_should_stop(void);
  58 bool kthread_should_park(void);
  59 bool kthread_freezable_should_stop(bool *was_frozen);
  60 void *kthread_data(struct task_struct *k);
  61 void *kthread_probe_data(struct task_struct *k);
  62 int kthread_park(struct task_struct *k);
  63 void kthread_unpark(struct task_struct *k);
  64 void kthread_parkme(void);
  65 void kthread_park_complete(struct task_struct *k);
  66
  67 int kthreadd(void *unused);
  68 extern struct task_struct *kthreadd_task;
  69 extern int tsk_fork_get_node(struct task_struct *tsk);
  70
  71 /*
  72  * Simple work processor based on kthread.
  73  *
  74  * This provides easier way to make use of kthreads.  A kthread_work
  75  * can be queued and flushed using queue/kthread_flush_work()
  76  * respectively.  Queued kthread_works are processed by a kthread
  77  * running kthread_worker_fn().
  78  */
  79 struct kthread_work;
  80 typedef void (*kthread_work_func_t)(struct kthread_work *work);
  81 void kthread_delayed_work_timer_fn(struct timer_list *t);
  82
  83 enum {
  84         KTW_FREEZABLE           = 1 << 0,       /* freeze during suspend */
  85 };
  86
  87 struct kthread_worker {
  88         unsigned int            flags;
  89         spinlock_t              lock;
  90         struct list_head        work_list;
  91         struct list_head        delayed_work_list;
  92         struct task_struct      *task;
  93         struct kthread_work     *current_work;
  94 };
  95
  96 struct kthread_work {
  97         struct list_head        node;
  98         kthread_work_func_t     func;
  99         struct kthread_worker   *worker;
 100         /* Number of canceling calls that are running at the moment. */
 101         int                     canceling;
 102 };
 103
 104 struct kthread_delayed_work {
 105         struct kthread_work work;
 106         struct timer_list timer;
 107 };
 108
 109 #define KTHREAD_WORKER_INIT(worker)     {                               \
 110         .lock = __SPIN_LOCK_UNLOCKED((worker).lock),                    \
 111         .work_list = LIST_HEAD_INIT((worker).work_list),                \
 112         .delayed_work_list = LIST_HEAD_INIT((worker).delayed_work_list),\
 113         }
 114
 115 #define KTHREAD_WORK_INIT(work, fn)     {                               \
 116         .node = LIST_HEAD_INIT((work).node),                            \
 117         .func = (fn),                                                   \
 118         }
 119
 120 #define KTHREAD_DELAYED_WORK_INIT(dwork, fn) {                          \
 121         .work = KTHREAD_WORK_INIT((dwork).work, (fn)),                  \
 122         .timer = __TIMER_INITIALIZER(kthread_delayed_work_timer_fn,\
 123                                      TIMER_IRQSAFE),                    \
 124         }
 125
 126 #define DEFINE_KTHREAD_WORKER(worker)                                   \
 127         struct kthread_worker worker = KTHREAD_WORKER_INIT(worker)
 128
 129 #define DEFINE_KTHREAD_WORK(work, fn)                                   \
 130         struct kthread_work work = KTHREAD_WORK_INIT(work, fn)
 131
 132 #define DEFINE_KTHREAD_DELAYED_WORK(dwork, fn)                          \
 133         struct kthread_delayed_work dwork =                             \
 134                 KTHREAD_DELAYED_WORK_INIT(dwork, fn)
 135
 136 /*
 137  * kthread_worker.lock needs its own lockdep class key when defined on
 138  * stack with lockdep enabled.  Use the following macros in such cases.
 139  */
 140 #ifdef CONFIG_LOCKDEP
 141 # define KTHREAD_WORKER_INIT_ONSTACK(worker)                            \
 142         ({ kthread_init_worker(&worker); worker; })
 143 # define DEFINE_KTHREAD_WORKER_ONSTACK(worker)                          \
 144         struct kthread_worker worker = KTHREAD_WORKER_INIT_ONSTACK(worker)
 145 #else
 146 # define DEFINE_KTHREAD_WORKER_ONSTACK(worker) DEFINE_KTHREAD_WORKER(worker)
 147 #endif
 148
 149 extern void __kthread_init_worker(struct kthread_worker *worker,
 150                         const char *name, struct lock_class_key *key);
 151
 152 #define kthread_init_worker(worker)                                     \
 153         do {                                                            \
 154                 static struct lock_class_key __key;                     \
 155                 __kthread_init_worker((worker), "("#worker")->lock", &__key); \
 156         } while (0)
 157
 158 #define kthread_init_work(work, fn)                                     \
 159         do {                                                            \
 160                 memset((work), 0, sizeof(struct kthread_work));         \
 161                 INIT_LIST_HEAD(&(work)->node);                          \
 162                 (work)->func = (fn);                                    \
 163         } while (0)
 164
 165 #define kthread_init_delayed_work(dwork, fn)                            \
 166         do {                                                            \
 167                 kthread_init_work(&(dwork)->work, (fn));                \
 168                 __init_timer(&(dwork)->timer,                           \
 169                              kthread_delayed_work_timer_fn,             \
 170                              TIMER_IRQSAFE);                            \
 171         } while (0)
 172
 173 int kthread_worker_fn(void *worker_ptr);
 174
 175 __printf(2, 3)
 176 struct kthread_worker *
 177 kthread_create_worker(unsigned int flags, const char namefmt[], ...);
 178
 179 __printf(3, 4) struct kthread_worker *
 180 kthread_create_worker_on_cpu(int cpu, unsigned int flags,
 181                              const char namefmt[], ...);
 182
 183 bool kthread_queue_work(struct kthread_worker *worker,
 184                         struct kthread_work *work);
 185
 186 bool kthread_queue_delayed_work(struct kthread_worker *worker,
 187                                 struct kthread_delayed_work *dwork,
 188                                 unsigned long delay);
 189
 190 bool kthread_mod_delayed_work(struct kthread_worker *worker,
 191                               struct kthread_delayed_work *dwork,
 192                               unsigned long delay);
 193
 194 void kthread_flush_work(struct kthread_work *work);
 195 void kthread_flush_worker(struct kthread_worker *worker);
 196
 197 bool kthread_cancel_work_sync(struct kthread_work *work);
 198 bool kthread_cancel_delayed_work_sync(struct kthread_delayed_work *work);
 199
 200 void kthread_destroy_worker(struct kthread_worker *worker);
 201
 202 #ifdef CONFIG_BLK_CGROUP
 203 void kthread_associate_blkcg(struct cgroup_subsys_state *css);
 204 struct cgroup_subsys_state *kthread_blkcg(void);
 205 #else
 206 static inline void kthread_associate_blkcg(struct cgroup_subsys_state *css) { }
 207 static inline struct cgroup_subsys_state *kthread_blkcg(void)
 208 {
 209         return NULL;
 210 }
 211 #endif
 212 #endif /* _LINUX_KTHREAD_H */