}
/**
- * probe_kthread_data - speculative version of kthread_data()
+ * kthread_probe_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
* 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)
+void *kthread_probe_data(struct task_struct *task)
{
struct kthread *kthread = to_kthread(task);
void *data = NULL;
}
}
-/**
- * kthread_create_on_node - create a kthread.
- * @threadfn: the function to run until signal_pending(current).
- * @data: data ptr for @threadfn.
- * @node: task and thread structures for the thread are allocated on this node
- * @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(). The new thread has SCHED_NORMAL policy and
- * is affine to all CPUs.
- *
- * 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 NUMA_NO_NODE.
- * 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) or ERR_PTR(-EINTR).
- */
-struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
- void *data, int node,
- const char namefmt[],
- ...)
+static struct task_struct *__kthread_create_on_node(int (*threadfn)(void *data),
+ void *data, int node,
+ const char namefmt[],
+ va_list args)
{
DECLARE_COMPLETION_ONSTACK(done);
struct task_struct *task;
task = create->result;
if (!IS_ERR(task)) {
static const struct sched_param param = { .sched_priority = 0 };
- va_list args;
- va_start(args, namefmt);
vsnprintf(task->comm, sizeof(task->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.
kfree(create);
return task;
}
+
+/**
+ * kthread_create_on_node - create a kthread.
+ * @threadfn: the function to run until signal_pending(current).
+ * @data: data ptr for @threadfn.
+ * @node: task and thread structures for the thread are allocated on this node
+ * @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(). The new thread has SCHED_NORMAL policy and
+ * is affine to all CPUs.
+ *
+ * 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 NUMA_NO_NODE.
+ * 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) or ERR_PTR(-EINTR).
+ */
+struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
+ void *data, int node,
+ const char namefmt[],
+ ...)
+{
+ struct task_struct *task;
+ va_list args;
+
+ va_start(args, namefmt);
+ task = __kthread_create_on_node(threadfn, data, node, namefmt, args);
+ va_end(args);
+
+ return task;
+}
EXPORT_SYMBOL(kthread_create_on_node);
static void __kthread_bind_mask(struct task_struct *p, const struct cpumask *mask, long state)
cpu);
if (IS_ERR(p))
return p;
+ kthread_bind(p, cpu);
+ /* CPU hotplug need to bind once again when unparking the thread. */
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;
}
* which might be about to be cleared.
*/
if (test_and_clear_bit(KTHREAD_IS_PARKED, &kthread->flags)) {
+ /*
+ * Newly created kthread was parked when the CPU was offline.
+ * The binding was lost and we need to set it again.
+ */
if (test_bit(KTHREAD_IS_PER_CPU, &kthread->flags))
__kthread_bind(k, kthread->cpu, TASK_PARKED);
wake_up_state(k, TASK_PARKED);
return 0;
}
-void __init_kthread_worker(struct kthread_worker *worker,
+void __kthread_init_worker(struct kthread_worker *worker,
const char *name,
struct lock_class_key *key)
{
INIT_LIST_HEAD(&worker->work_list);
worker->task = NULL;
}
-EXPORT_SYMBOL_GPL(__init_kthread_worker);
+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 */
}
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 insert_kthread_work(struct kthread_worker *worker,
+static void kthread_insert_work(struct kthread_worker *worker,
struct kthread_work *work,
struct list_head *pos)
{
}
/**
- * queue_kthread_work - queue a kthread_work
+ * kthread_queue_work - queue a kthread_work
* @worker: target kthread_worker
* @work: kthread_work to queue
*
* must have been created with kthread_worker_create(). Returns %true
* if @work was successfully queued, %false if it was already pending.
*/
-bool queue_kthread_work(struct kthread_worker *worker,
+bool kthread_queue_work(struct kthread_worker *worker,
struct kthread_work *work)
{
bool ret = false;
spin_lock_irqsave(&worker->lock, flags);
if (list_empty(&work->node)) {
- insert_kthread_work(worker, work, &worker->work_list);
+ kthread_insert_work(worker, work, &worker->work_list);
ret = true;
}
spin_unlock_irqrestore(&worker->lock, flags);
return ret;
}
-EXPORT_SYMBOL_GPL(queue_kthread_work);
+EXPORT_SYMBOL_GPL(kthread_queue_work);
struct kthread_flush_work {
struct kthread_work work;
}
/**
- * flush_kthread_work - flush a kthread_work
+ * kthread_flush_work - flush a kthread_work
* @work: work to flush
*
* If @work is queued or executing, wait for it to finish execution.
*/
-void flush_kthread_work(struct kthread_work *work)
+void kthread_flush_work(struct kthread_work *work)
{
struct kthread_flush_work fwork = {
KTHREAD_WORK_INIT(fwork.work, kthread_flush_work_fn),
}
if (!list_empty(&work->node))
- insert_kthread_work(worker, &fwork.work, work->node.next);
+ kthread_insert_work(worker, &fwork.work, work->node.next);
else if (worker->current_work == work)
- insert_kthread_work(worker, &fwork.work, worker->work_list.next);
+ kthread_insert_work(worker, &fwork.work,
+ worker->work_list.next);
else
noop = true;
if (!noop)
wait_for_completion(&fwork.done);
}
-EXPORT_SYMBOL_GPL(flush_kthread_work);
+EXPORT_SYMBOL_GPL(kthread_flush_work);
/**
- * flush_kthread_worker - flush all current works on a kthread_worker
+ * kthread_flush_worker - flush all current works on a kthread_worker
* @worker: worker to flush
*
* Wait until all currently executing or pending works on @worker are
* finished.
*/
-void flush_kthread_worker(struct kthread_worker *worker)
+void kthread_flush_worker(struct kthread_worker *worker)
{
struct kthread_flush_work fwork = {
KTHREAD_WORK_INIT(fwork.work, kthread_flush_work_fn),
COMPLETION_INITIALIZER_ONSTACK(fwork.done),
};
- queue_kthread_work(worker, &fwork.work);
+ kthread_queue_work(worker, &fwork.work);
wait_for_completion(&fwork.done);
}
-EXPORT_SYMBOL_GPL(flush_kthread_worker);
+EXPORT_SYMBOL_GPL(kthread_flush_worker);
projects / cascardo / linux.git / blobdiff