diff options
| -rw-r--r-- | include/linux/kthread.h | 7 | ||||
| -rw-r--r-- | kernel/kthread.c | 113 |
2 files changed, 110 insertions, 10 deletions
diff --git a/include/linux/kthread.h b/include/linux/kthread.h index e2b095b8ca47..daeb2befbabf 100644 --- a/include/linux/kthread.h +++ b/include/linux/kthread.h @@ -124,6 +124,13 @@ extern void __kthread_init_worker(struct kthread_worker *worker, int kthread_worker_fn(void *worker_ptr); +__printf(1, 2) +struct kthread_worker * +kthread_create_worker(const char namefmt[], ...); + +struct kthread_worker * +kthread_create_worker_on_cpu(int cpu, const char namefmt[], ...); + bool kthread_queue_work(struct kthread_worker *worker, struct kthread_work *work); void kthread_flush_work(struct kthread_work *work); diff --git a/kernel/kthread.c b/kernel/kthread.c index 36fd751a769f..12695e68ed00 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -571,23 +571,24 @@ EXPORT_SYMBOL_GPL(__kthread_init_worker); * 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. + * This function implements the main cycle of kthread worker. It processes + * work_list until it is stopped with kthread_stop(). It sleeps when the queue + * is empty. * - * 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. + * The works are not allowed to keep any locks, disable preemption or interrupts + * when they finish. There is defined a safe point for freezing when one work + * finishes and before a new one is started. */ int kthread_worker_fn(void *worker_ptr) { struct kthread_worker *worker = worker_ptr; struct kthread_work *work; - WARN_ON(worker->task); + /* + * FIXME: Update the check and remove the assignment when all kthread + * worker users are created using kthread_create_worker*() functions. + */ + WARN_ON(worker->task && worker->task != current); worker->task = current; repeat: set_current_state(TASK_INTERRUPTIBLE); /* mb paired w/ kthread_stop */ @@ -621,6 +622,98 @@ repeat: } EXPORT_SYMBOL_GPL(kthread_worker_fn); +static struct kthread_worker * +__kthread_create_worker(int cpu, const char namefmt[], va_list args) +{ + struct kthread_worker *worker; + struct task_struct *task; + + worker = kzalloc(sizeof(*worker), GFP_KERNEL); + if (!worker) + return ERR_PTR(-ENOMEM); + + kthread_init_worker(worker); + + if (cpu >= 0) { + char name[TASK_COMM_LEN]; + + /* + * kthread_create_worker_on_cpu() allows to pass a generic + * namefmt in compare with kthread_create_on_cpu. We need + * to format it here. + */ + vsnprintf(name, sizeof(name), namefmt, args); + task = kthread_create_on_cpu(kthread_worker_fn, worker, + cpu, name); + } else { + task = __kthread_create_on_node(kthread_worker_fn, worker, + -1, namefmt, args); + } + + if (IS_ERR(task)) + goto fail_task; + + worker->task = task; + wake_up_process(task); + return worker; + +fail_task: + kfree(worker); + return ERR_CAST(task); +} + +/** + * kthread_create_worker - create a kthread worker + * @namefmt: printf-style name for the kthread worker (task). + * + * Returns a pointer to the allocated worker on success, ERR_PTR(-ENOMEM) + * when the needed structures could not get allocated, and ERR_PTR(-EINTR) + * when the worker was SIGKILLed. + */ +struct kthread_worker * +kthread_create_worker(const char namefmt[], ...) +{ + struct kthread_worker *worker; + va_list args; + + va_start(args, namefmt); + worker = __kthread_create_worker(-1, namefmt, args); + va_end(args); + + return worker; +} +EXPORT_SYMBOL(kthread_create_worker); + +/** + * kthread_create_worker_on_cpu - create a kthread worker and bind it + * it to a given CPU and the associated NUMA node. + * @cpu: CPU number + * @namefmt: printf-style name for the kthread worker (task). + * + * Use a valid CPU number if you want to bind the kthread worker + * to the given CPU and the associated NUMA node. + * + * A good practice is to add the cpu number also into the worker name. + * For example, use kthread_create_worker_on_cpu(cpu, "helper/%d", cpu). + * + * Returns a pointer to the allocated worker on success, ERR_PTR(-ENOMEM) + * when the needed structures could not get allocated, and ERR_PTR(-EINTR) + * when the worker was SIGKILLed. + */ +struct kthread_worker * +kthread_create_worker_on_cpu(int cpu, const char namefmt[], ...) +{ + struct kthread_worker *worker; + va_list args; + + va_start(args, namefmt); + worker = __kthread_create_worker(cpu, namefmt, args); + va_end(args); + + return worker; +} +EXPORT_SYMBOL(kthread_create_worker_on_cpu); + /* insert @work before @pos in @worker */ static void kthread_insert_work(struct kthread_worker *worker, struct kthread_work *work, |