/** * kthread_create_on_cpu - Create a cpu bound kthread * @threadfn: the function to run until signal_pending(current). * @data: data ptr for @threadfn. * @cpu: The cpu on which the thread should be bound, * @namefmt: printf-style name for the thread. Format is restricted * to "name.*%u". Code fills in cpu number. * * Description: This helper function creates and names a kernel thread * The thread will be woken and put into park mode. */ struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data), void *data, unsigned int cpu, const char *namefmt) { struct task_struct *p; p = kthread_create_on_node(threadfn, data, cpu_to_mem(cpu), namefmt, cpu); if (IS_ERR(p)) return p; set_bit(KTHREAD_IS_PER_CPU, &to_kthread(p)->flags); to_kthread(p)->cpu = cpu; /* Park the thread to get it out of TASK_UNINTERRUPTIBLE state */ kthread_park(p); return p; }
/** * probe_kthread_data - speculative version of kthread_data() * @task: possible kthread task in question * * @task could be a kthread task. Return the data value specified when it * was created if accessible. If @task isn't a kthread task or its data is * inaccessible for any reason, %NULL is returned. This function requires * that @task itself is safe to dereference. */ void *probe_kthread_data(struct task_struct *task) { struct kthread *kthread = to_kthread(task); void *data = NULL; probe_kernel_read(&data, &kthread->data, sizeof(data)); return data; }
static struct kthread *task_get_live_kthread(struct task_struct *k) { struct kthread *kthread; get_task_struct(k); kthread = to_kthread(k); /* It might have exited */ barrier(); if (k->vfork_done != NULL) return kthread; return NULL; }
/** * kthread_data - return data value specified on kthread creation * @task: kthread task in question * * Return the data value specified when kthread @task was created. * The caller is responsible for ensuring the validity of @task when * calling this function. */ void *kthread_data(struct task_struct *task) { return to_kthread(task)->data; }
/** * kthread_should_stop - should this kthread return now? * * When someone calls kthread_stop() on your kthread, it will be woken * and this will return true. You should then return, and your return * value will be passed through to kthread_stop(). */ int kthread_should_stop(void) { return to_kthread(current)->should_stop; }
/** * kthread_create_on_node - create a kthread. * @threadfn: the function to run until signal_pending(current). * @data: data ptr for @threadfn. * @node: memory node number. * @namefmt: printf-style name for the thread. * * Description: This helper function creates and names a kernel * thread. The thread will be stopped: use wake_up_process() to start * it. See also kthread_run(). * * If thread is going to be bound on a particular cpu, give its node * in @node, to get NUMA affinity for kthread stack, or else give -1. * When woken, the thread will run @threadfn() with @data as its * argument. @threadfn() can either call do_exit() directly if it is a * standalone thread for which no one will call kthread_stop(), or * return when 'kthread_should_stop()' is true (which means * kthread_stop() has been called). The return value should be zero * or a negative error number; it will be passed to kthread_stop(). * * Returns a task_struct or ERR_PTR(-ENOMEM). */ struct task_struct *kthread_create_on_node(int (*threadfn)(void *data), void *data, int node, const char namefmt[], ...) { struct kthread_create_info create; create.threadfn = threadfn; create.data = data; create.node = node; init_completion(&create.done); spin_lock(&kthread_create_lock); list_add_tail(&create.list, &kthread_create_list); spin_unlock(&kthread_create_lock); wake_up_process(kthreadd_task); wait_for_completion(&create.done); if (!IS_ERR(create.result)) { static const struct sched_param param = { .sched_priority = 0 }; va_list args; va_start(args, namefmt); vsnprintf(create.result->comm, sizeof(create.result->comm), namefmt, args); va_end(args); /* * root may have changed our (kthreadd's) priority or CPU mask. * The kernel thread should not inherit these properties. */ sched_setscheduler_nocheck(create.result, SCHED_NORMAL, ¶m); set_cpus_allowed_ptr(create.result, cpu_all_mask); } return create.result; } EXPORT_SYMBOL(kthread_create_on_node); /** * kthread_bind - bind a just-created kthread to a cpu. * @p: thread created by kthread_create(). * @cpu: cpu (might not be online, must be possible) for @k to run on. * * Description: This function is equivalent to set_cpus_allowed(), * except that @cpu doesn't need to be online, and the thread must be * stopped (i.e., just returned from kthread_create()). */ void kthread_bind(struct task_struct *p, unsigned int cpu) { /* Must have done schedule() in kthread() before we set_task_cpu */ if (!wait_task_inactive(p, TASK_UNINTERRUPTIBLE)) { WARN_ON(1); return; } /* It's safe because the task is inactive. */ do_set_cpus_allowed(p, cpumask_of(cpu)); p->flags |= PF_THREAD_BOUND; } EXPORT_SYMBOL(kthread_bind); /** * kthread_stop - stop a thread created by kthread_create(). * @k: thread created by kthread_create(). * * Sets kthread_should_stop() for @k to return true, wakes it, and * waits for it to exit. This can also be called after kthread_create() * instead of calling wake_up_process(): the thread will exit without * calling threadfn(). * * If threadfn() may call do_exit() itself, the caller must ensure * task_struct can't go away. * * Returns the result of threadfn(), or %-EINTR if wake_up_process() * was never called. */ int kthread_stop(struct task_struct *k) { struct kthread *kthread; int ret; trace_sched_kthread_stop(k); get_task_struct(k); kthread = to_kthread(k); barrier(); /* it might have exited */ if (k->vfork_done != NULL) { kthread->should_stop = 1; wake_up_process(k); wait_for_completion(&kthread->exited); } ret = k->exit_code; put_task_struct(k); trace_sched_kthread_stop_ret(ret); return ret; } EXPORT_SYMBOL(kthread_stop); int kthreadd(void *unused) { struct task_struct *tsk = current; /* Setup a clean context for our children to inherit. */ set_task_comm(tsk, "kthreadd"); ignore_signals(tsk); set_cpus_allowed_ptr(tsk, cpu_all_mask); set_mems_allowed(node_states[N_HIGH_MEMORY]); current->flags |= PF_NOFREEZE | PF_FREEZER_NOSIG; for (;;) { set_current_state(TASK_INTERRUPTIBLE); if (list_empty(&kthread_create_list)) schedule(); __set_current_state(TASK_RUNNING); spin_lock(&kthread_create_lock); while (!list_empty(&kthread_create_list)) { struct kthread_create_info *create; create = list_entry(kthread_create_list.next, struct kthread_create_info, list); list_del_init(&create->list); spin_unlock(&kthread_create_lock); create_kthread(create); spin_lock(&kthread_create_lock); } spin_unlock(&kthread_create_lock); } return 0; } void __init_kthread_worker(struct kthread_worker *worker, const char *name, struct lock_class_key *key) { spin_lock_init(&worker->lock); lockdep_set_class_and_name(&worker->lock, key, name); INIT_LIST_HEAD(&worker->work_list); worker->task = NULL; }
/** * kthread_should_park - should this kthread park now? * * When someone calls kthread_park() on your kthread, it will be woken * and this will return true. You should then do the necessary * cleanup and call kthread_parkme() * * Similar to kthread_should_stop(), but this keeps the thread alive * and in a park position. kthread_unpark() "restarts" the thread and * calls the thread function again. */ bool kthread_should_park(void) { return test_bit(KTHREAD_SHOULD_PARK, &to_kthread(current)->flags); }
/** * kthread_should_stop - should this kthread return now? * * When someone calls kthread_stop() on your kthread, it will be woken * and this will return true. You should then return, and your return * value will be passed through to kthread_stop(). */ bool kthread_should_stop(void) { return test_bit(KTHREAD_SHOULD_STOP, &to_kthread(current)->flags); }
void kthread_parkme(void) { __kthread_parkme(to_kthread(current)); }
struct task_struct *kthread_create_on_node(int (*threadfn)(void *data), void *data, int node, const char namefmt[], ...) { struct kthread_create_info create; create.threadfn = threadfn; create.data = data; create.node = node; init_completion(&create.done); spin_lock(&kthread_create_lock); list_add_tail(&create.list, &kthread_create_list); spin_unlock(&kthread_create_lock); wake_up_process(kthreadd_task); wait_for_completion(&create.done); if (!IS_ERR(create.result)) { static const struct sched_param param = { .sched_priority = 0 }; va_list args; va_start(args, namefmt); vsnprintf(create.result->comm, sizeof(create.result->comm), namefmt, args); va_end(args); /* */ sched_setscheduler_nocheck(create.result, SCHED_NORMAL, ¶m); set_cpus_allowed_ptr(create.result, cpu_all_mask); } return create.result; } EXPORT_SYMBOL(kthread_create_on_node); /* */ void kthread_bind(struct task_struct *p, unsigned int cpu) { /* */ if (!wait_task_inactive(p, TASK_UNINTERRUPTIBLE)) { WARN_ON(1); return; } /* */ do_set_cpus_allowed(p, cpumask_of(cpu)); p->flags |= PF_THREAD_BOUND; } EXPORT_SYMBOL(kthread_bind); /* */ int kthread_stop(struct task_struct *k) { struct kthread *kthread; int ret; trace_sched_kthread_stop(k); get_task_struct(k); kthread = to_kthread(k); barrier(); /* */ if (k->vfork_done != NULL) { kthread->should_stop = 1; wake_up_process(k); wait_for_completion(&kthread->exited); } ret = k->exit_code; put_task_struct(k); trace_sched_kthread_stop_ret(ret); return ret; } EXPORT_SYMBOL(kthread_stop); int kthreadd(void *unused) { struct task_struct *tsk = current; /* */ set_task_comm(tsk, "kthreadd"); ignore_signals(tsk); set_cpus_allowed_ptr(tsk, cpu_all_mask); set_mems_allowed(node_states[N_HIGH_MEMORY]); current->flags |= PF_NOFREEZE; for (;;) { set_current_state(TASK_INTERRUPTIBLE); if (list_empty(&kthread_create_list)) schedule(); __set_current_state(TASK_RUNNING); spin_lock(&kthread_create_lock); while (!list_empty(&kthread_create_list)) { struct kthread_create_info *create; create = list_entry(kthread_create_list.next, struct kthread_create_info, list); list_del_init(&create->list); spin_unlock(&kthread_create_lock); create_kthread(create); spin_lock(&kthread_create_lock); } spin_unlock(&kthread_create_lock); } return 0; } void __init_kthread_worker(struct kthread_worker *worker, const char *name, struct lock_class_key *key) { spin_lock_init(&worker->lock); lockdep_set_class_and_name(&worker->lock, key, name); INIT_LIST_HEAD(&worker->work_list); worker->task = NULL; }
/** * kthread_create - create a kthread. * @threadfn: the function to run until signal_pending(current). * @data: data ptr for @threadfn. * @namefmt: printf-style name for the thread. * * Description: This helper function creates and names a kernel * thread. The thread will be stopped: use wake_up_process() to start * it. See also kthread_run(), kthread_create_on_cpu(). * * When woken, the thread will run @threadfn() with @data as its * argument. @threadfn() can either call do_exit() directly if it is a * standalone thread for which noone will call kthread_stop(), or * return when 'kthread_should_stop()' is true (which means * kthread_stop() has been called). The return value should be zero * or a negative error number; it will be passed to kthread_stop(). * * Returns a task_struct or ERR_PTR(-ENOMEM). */ struct task_struct *kthread_create(int (*threadfn)(void *data), void *data, const char namefmt[], ...) { struct kthread_create_info create; create.threadfn = threadfn; create.data = data; init_completion(&create.done); spin_lock(&kthread_create_lock); list_add_tail(&create.list, &kthread_create_list); spin_unlock(&kthread_create_lock); wake_up_process(kthreadd_task); wait_for_completion(&create.done); if (!IS_ERR(create.result)) { struct sched_param param = { .sched_priority = 0 }; va_list args; va_start(args, namefmt); vsnprintf(create.result->comm, sizeof(create.result->comm), namefmt, args); va_end(args); /* * root may have changed our (kthreadd's) priority or CPU mask. * The kernel thread should not inherit these properties. */ sched_setscheduler_nocheck(create.result, SCHED_NORMAL, ¶m); set_cpus_allowed_ptr(create.result, cpu_all_mask); } return create.result; } EXPORT_SYMBOL(kthread_create); /** * kthread_stop - stop a thread created by kthread_create(). * @k: thread created by kthread_create(). * * Sets kthread_should_stop() for @k to return true, wakes it, and * waits for it to exit. This can also be called after kthread_create() * instead of calling wake_up_process(): the thread will exit without * calling threadfn(). * * If threadfn() may call do_exit() itself, the caller must ensure * task_struct can't go away. * * Returns the result of threadfn(), or %-EINTR if wake_up_process() * was never called. */ int kthread_stop(struct task_struct *k) { struct kthread *kthread; int ret; trace_sched_kthread_stop(k); get_task_struct(k); kthread = to_kthread(k); barrier(); /* it might have exited */ if (k->vfork_done != NULL) { kthread->should_stop = 1; wake_up_process(k); wait_for_completion(&kthread->exited); } ret = k->exit_code; put_task_struct(k); trace_sched_kthread_stop_ret(ret); return ret; } EXPORT_SYMBOL(kthread_stop); int kthreadd(void *unused) { struct task_struct *tsk = current; /* Setup a clean context for our children to inherit. */ set_task_comm(tsk, "kthreadd"); ignore_signals(tsk); set_cpus_allowed_ptr(tsk, cpu_all_mask); set_mems_allowed(node_states[N_HIGH_MEMORY]); current->flags |= PF_NOFREEZE | PF_FREEZER_NOSIG; for (;;) { set_current_state(TASK_INTERRUPTIBLE); if (list_empty(&kthread_create_list)) schedule(); __set_current_state(TASK_RUNNING); spin_lock(&kthread_create_lock); while (!list_empty(&kthread_create_list)) { struct kthread_create_info *create; create = list_entry(kthread_create_list.next, struct kthread_create_info, list); list_del_init(&create->list); spin_unlock(&kthread_create_lock); create_kthread(create); spin_lock(&kthread_create_lock); } spin_unlock(&kthread_create_lock); } return 0; }
/** * kthread_create_ve - create a kthread. * @threadfn: the function to run until signal_pending(current). * @data: data ptr for @threadfn. * @namefmt: printf-style name for the thread. * * Description: This helper function creates and names a kernel * thread. The thread will be stopped: use wake_up_process() to start * it. See also kthread_run(), kthread_create_on_cpu(). * * When woken, the thread will run @threadfn() with @data as its * argument. @threadfn() can either call do_exit() directly if it is a * standalone thread for which noone will call kthread_stop(), or * return when 'kthread_should_stop()' is true (which means * kthread_stop() has been called). The return value should be zero * or a negative error number; it will be passed to kthread_stop(). * * Returns a task_struct or ERR_PTR(-ENOMEM). */ struct task_struct *kthread_create_ve(struct ve_struct *ve, int (*threadfn)(void *data), void *data, const char namefmt[], ...) { struct kthread_create_info create; struct ve_struct *old_ve; old_ve = set_exec_env(ve); create.threadfn = threadfn; create.data = data; init_completion(&create.done); spin_lock(&kthread_create_lock); list_add_tail(&create.list, &kthread_create_list); spin_unlock(&kthread_create_lock); wake_up_process(kthreadd_task); wait_for_completion(&create.done); if (!IS_ERR(create.result)) { struct sched_param param = { .sched_priority = 0 }; va_list args; va_start(args, namefmt); vsnprintf(create.result->comm, sizeof(create.result->comm), namefmt, args); va_end(args); /* * root may have changed our (kthreadd's) priority or CPU mask. * The kernel thread should not inherit these properties. */ sched_setscheduler_nocheck(create.result, SCHED_NORMAL, ¶m); set_cpus_allowed_ptr(create.result, cpu_all_mask); } set_exec_env(old_ve); return create.result; } EXPORT_SYMBOL(kthread_create_ve); /** * kthread_stop - stop a thread created by kthread_create(). * @k: thread created by kthread_create(). * * Sets kthread_should_stop() for @k to return true, wakes it, and * waits for it to exit. This can also be called after kthread_create() * instead of calling wake_up_process(): the thread will exit without * calling threadfn(). * * If threadfn() may call do_exit() itself, the caller must ensure * task_struct can't go away. * * Returns the result of threadfn(), or %-EINTR if wake_up_process() * was never called. */ int kthread_stop(struct task_struct *k) { struct kthread *kthread; int ret; trace_sched_kthread_stop(k); get_task_struct(k); kthread = to_kthread(k); barrier(); /* it might have exited */ if (k->vfork_done != NULL) { kthread->should_stop = 1; wake_up_process(k); wait_for_completion(&kthread->exited); } ret = k->exit_code; put_task_struct(k); trace_sched_kthread_stop_ret(ret); return ret; } EXPORT_SYMBOL(kthread_stop); int kthreadd(void *data) { struct task_struct *tsk = current; struct kthreadd_create_info *kcreate; struct kthread self; int rc; self.should_stop = 0; kcreate = (struct kthreadd_create_info *) data; if (kcreate) { daemonize("kthreadd/%d", get_exec_env()->veid); kcreate->result = current; set_fs(KERNEL_DS); init_completion(&self.exited); current->vfork_done = &self.exited; } else set_task_comm(tsk, "kthreadd"); /* Setup a clean context for our children to inherit. */ ignore_signals(tsk); set_cpus_allowed_ptr(tsk, cpu_all_mask); set_mems_allowed(node_states[N_HIGH_MEMORY]); current->flags |= PF_NOFREEZE | PF_FREEZER_NOSIG; if (kcreate) complete(&kcreate->done); for (;;) { set_current_state(TASK_INTERRUPTIBLE); if (list_empty(&kthread_create_list)) { if (self.should_stop) break; else schedule(); } __set_current_state(TASK_RUNNING); spin_lock(&kthread_create_lock); while (!list_empty(&kthread_create_list)) { struct kthread_create_info *create; create = list_entry(kthread_create_list.next, struct kthread_create_info, list); list_del_init(&create->list); spin_unlock(&kthread_create_lock); create_kthread(create); spin_lock(&kthread_create_lock); } spin_unlock(&kthread_create_lock); } do { clear_thread_flag(TIF_SIGPENDING); rc = sys_wait4(-1, NULL, __WALL, NULL); } while (rc != -ECHILD); do_exit(0); } int kthreadd_create() { struct kthreadd_create_info create; int ret; struct ve_struct *ve = get_exec_env(); BUG_ON(ve->_kthreadd_task); INIT_LIST_HEAD(&ve->_kthread_create_list); init_completion(&create.done); ret = kernel_thread(kthreadd, (void *) &create, CLONE_FS); if (ret < 0) { return ret; } wait_for_completion(&create.done); ve->_kthreadd_task = create.result; return 0; } EXPORT_SYMBOL(kthreadd_create); void kthreadd_stop(struct ve_struct *ve) { struct kthread *kthread; int ret; struct task_struct *k; if (!ve->_kthreadd_task) return; k = ve->_kthreadd_task; trace_sched_kthread_stop(k); get_task_struct(k); BUG_ON(!k->vfork_done); kthread = container_of(k->vfork_done, struct kthread, exited); kthread->should_stop = 1; wake_up_process(k); wait_for_completion(&kthread->exited); ret = k->exit_code; put_task_struct(k); trace_sched_kthread_stop_ret(ret); } EXPORT_SYMBOL(kthreadd_stop);
/** * kthread_create - create a kthread. * @threadfn: the function to run until signal_pending(current). * @data: data ptr for @threadfn. * @namefmt: printf-style name for the thread. * * Description: This helper function creates and names a kernel * thread. The thread will be stopped: use wake_up_process() to start * it. See also kthread_run(), kthread_create_on_cpu(). * * When woken, the thread will run @threadfn() with @data as its * argument. @threadfn() can either call do_exit() directly if it is a * standalone thread for which noone will call kthread_stop(), or * return when 'kthread_should_stop()' is true (which means * kthread_stop() has been called). The return value should be zero * or a negative error number; it will be passed to kthread_stop(). * * Returns a task_struct or ERR_PTR(-ENOMEM). */ struct task_struct *kthread_create(int (*threadfn)(void *data), void *data, const char namefmt[], ...) { struct kthread_create_info create; create.threadfn = threadfn; create.data = data; init_completion(&create.done); spin_lock(&kthread_create_lock); list_add_tail(&create.list, &kthread_create_list); spin_unlock(&kthread_create_lock); wake_up_process(kthreadd_task); wait_for_completion(&create.done); if (!IS_ERR(create.result)) { struct sched_param param = { .sched_priority = 0 }; va_list args; va_start(args, namefmt); vsnprintf(create.result->comm, sizeof(create.result->comm), namefmt, args); va_end(args); /* * root may have changed our (kthreadd's) priority or CPU mask. * The kernel thread should not inherit these properties. */ sched_setscheduler_nocheck(create.result, SCHED_NORMAL, ¶m); set_cpus_allowed_ptr(create.result, cpu_all_mask); } return create.result; } EXPORT_SYMBOL(kthread_create); /** * kthread_stop - stop a thread created by kthread_create(). * @k: thread created by kthread_create(). * * Sets kthread_should_stop() for @k to return true, wakes it, and * waits for it to exit. This can also be called after kthread_create() * instead of calling wake_up_process(): the thread will exit without * calling threadfn(). * * If threadfn() may call do_exit() itself, the caller must ensure * task_struct can't go away. * * Returns the result of threadfn(), or %-EINTR if wake_up_process() * was never called. */ int kthread_stop(struct task_struct *k) { struct kthread *kthread; int ret; trace_sched_kthread_stop(k); get_task_struct(k); kthread = to_kthread(k); barrier(); /* it might have exited */ if (k->vfork_done != NULL) { kthread->should_stop = 1; wake_up_process(k); wait_for_completion(&kthread->exited); } ret = k->exit_code; put_task_struct(k); trace_sched_kthread_stop_ret(ret); return ret; } EXPORT_SYMBOL(kthread_stop); int kthreadd(void *unused) { struct task_struct *tsk = current; /* Setup a clean context for our children to inherit. */ set_task_comm(tsk, "kthreadd"); ignore_signals(tsk); set_cpus_allowed_ptr(tsk, cpu_all_mask); set_mems_allowed(node_states[N_HIGH_MEMORY]); current->flags |= PF_NOFREEZE | PF_FREEZER_NOSIG; for (;;) { set_current_state(TASK_INTERRUPTIBLE); if (list_empty(&kthread_create_list)) schedule(); __set_current_state(TASK_RUNNING); spin_lock(&kthread_create_lock); while (!list_empty(&kthread_create_list)) { struct kthread_create_info *create; create = list_entry(kthread_create_list.next, struct kthread_create_info, list); list_del_init(&create->list); spin_unlock(&kthread_create_lock); create_kthread(create); spin_lock(&kthread_create_lock); } spin_unlock(&kthread_create_lock); } return 0; } /** * kthread_worker_fn - kthread function to process kthread_worker * @worker_ptr: pointer to initialized kthread_worker * * This function can be used as @threadfn to kthread_create() or * kthread_run() with @worker_ptr argument pointing to an initialized * kthread_worker. The started kthread will process work_list until * the it is stopped with kthread_stop(). A kthread can also call * this function directly after extra initialization. * * Different kthreads can be used for the same kthread_worker as long * as there's only one kthread attached to it at any given time. A * kthread_worker without an attached kthread simply collects queued * kthread_works. */ int kthread_worker_fn(void *worker_ptr) { struct kthread_worker *worker = worker_ptr; struct kthread_work *work; WARN_ON(worker->task); worker->task = current; repeat: set_current_state(TASK_INTERRUPTIBLE); /* mb paired w/ kthread_stop */ if (kthread_should_stop()) { __set_current_state(TASK_RUNNING); spin_lock_irq(&worker->lock); worker->task = NULL; spin_unlock_irq(&worker->lock); return 0; } work = NULL; spin_lock_irq(&worker->lock); if (!list_empty(&worker->work_list)) { work = list_first_entry(&worker->work_list, struct kthread_work, node); list_del_init(&work->node); } worker->current_work = work; spin_unlock_irq(&worker->lock); if (work) { __set_current_state(TASK_RUNNING); work->func(work); } else if (!freezing(current)) schedule(); try_to_freeze(); goto repeat; }
/** * kthread_create - create a kthread. * @threadfn: the function to run until signal_pending(current). * @data: data ptr for @threadfn. * @namefmt: printf-style name for the thread. * * Description: This helper function creates and names a kernel * thread. The thread will be stopped: use wake_up_process() to start * it. See also kthread_run(), kthread_create_on_cpu(). * * When woken, the thread will run @threadfn() with @data as its * argument. @threadfn() can either call do_exit() directly if it is a * standalone thread for which noone will call kthread_stop(), or * return when 'kthread_should_stop()' is true (which means * kthread_stop() has been called). The return value should be zero * or a negative error number; it will be passed to kthread_stop(). * * Returns a task_struct or ERR_PTR(-ENOMEM). */ struct task_struct *kthread_create(int (*threadfn)(void *data), void *data, const char namefmt[], ...) { struct kthread_create_info create; create.threadfn = threadfn; create.data = data; init_completion(&create.done); spin_lock(&kthread_create_lock); list_add_tail(&create.list, &kthread_create_list); spin_unlock(&kthread_create_lock); wake_up_process(kthreadd_task); wait_for_completion(&create.done); if (!IS_ERR(create.result)) { struct sched_param param = { .sched_priority = 0 }; va_list args; va_start(args, namefmt); vsnprintf(create.result->comm, sizeof(create.result->comm), namefmt, args); va_end(args); int policy = SCHED_NORMAL; #ifdef CONFIG_TIVO int i; int bFound = 0; for (i=0; i<sizeof(s_tvKthreadInfoTable)/sizeof(TvKthreadInfo); i++) { if (!strcmp(s_tvKthreadInfoTable[i].name, create.result->comm)) { if (s_tvKthreadInfoTable[i].policy != -1) { policy = s_tvKthreadInfoTable[i].policy; param.sched_priority = s_tvKthreadInfoTable[i].rt_priority; } bFound = 1; break; } } if (!bFound) { printk("--- Unknown kthread %s is lanched?\n", create.result->comm); } #endif /* * root may have changed our (kthreadd's) priority or CPU mask. * The kernel thread should not inherit these properties, and should * use specific RT priorities for some threads. */ sched_setscheduler_nocheck(create.result, policy, ¶m); set_user_nice(create.result, KTHREAD_NICE_LEVEL); set_cpus_allowed_ptr(create.result, cpu_all_mask); } return create.result; } EXPORT_SYMBOL(kthread_create); /** * kthread_bind - bind a just-created kthread to a cpu. * @k: thread created by kthread_create(). * @cpu: cpu (might not be online, must be possible) for @k to run on. * * Description: This function is equivalent to set_cpus_allowed(), * except that @cpu doesn't need to be online, and the thread must be * stopped (i.e., just returned from kthread_create()). */ void kthread_bind(struct task_struct *k, unsigned int cpu) { /* Must have done schedule() in kthread() before we set_task_cpu */ if (!wait_task_inactive(k, TASK_UNINTERRUPTIBLE)) { WARN_ON(1); return; } set_task_cpu(k, cpu); k->cpus_allowed = cpumask_of_cpu(cpu); k->rt.nr_cpus_allowed = 1; k->flags |= PF_THREAD_BOUND; } EXPORT_SYMBOL(kthread_bind); /** * kthread_stop - stop a thread created by kthread_create(). * @k: thread created by kthread_create(). * * Sets kthread_should_stop() for @k to return true, wakes it, and * waits for it to exit. This can also be called after kthread_create() * instead of calling wake_up_process(): the thread will exit without * calling threadfn(). * * If threadfn() may call do_exit() itself, the caller must ensure * task_struct can't go away. * * Returns the result of threadfn(), or %-EINTR if wake_up_process() * was never called. */ int kthread_stop(struct task_struct *k) { struct kthread *kthread; int ret; trace_sched_kthread_stop(k); get_task_struct(k); kthread = to_kthread(k); barrier(); /* it might have exited */ if (k->vfork_done != NULL) { kthread->should_stop = 1; wake_up_process(k); wait_for_completion(&kthread->exited); } ret = k->exit_code; put_task_struct(k); trace_sched_kthread_stop_ret(ret); return ret; } EXPORT_SYMBOL(kthread_stop); int kthreadd(void *unused) { struct task_struct *tsk = current; /* Setup a clean context for our children to inherit. */ set_task_comm(tsk, "kthreadd"); ignore_signals(tsk); set_user_nice(tsk, KTHREAD_NICE_LEVEL); set_cpus_allowed_ptr(tsk, cpu_all_mask); set_mems_allowed(node_possible_map); current->flags |= PF_NOFREEZE | PF_FREEZER_NOSIG; for (;;) { set_current_state(TASK_INTERRUPTIBLE); if (list_empty(&kthread_create_list)) schedule(); __set_current_state(TASK_RUNNING); spin_lock(&kthread_create_lock); while (!list_empty(&kthread_create_list)) { struct kthread_create_info *create; create = list_entry(kthread_create_list.next, struct kthread_create_info, list); list_del_init(&create->list); spin_unlock(&kthread_create_lock); create_kthread(create); spin_lock(&kthread_create_lock); } spin_unlock(&kthread_create_lock); } return 0; }