#include <linux/mutex.h>
#include <trace/events/sched.h>
-#define KTHREAD_NICE_LEVEL (-5)
-
static DEFINE_SPINLOCK(kthread_create_lock);
static LIST_HEAD(kthread_create_list);
struct task_struct *kthreadd_task;
struct list_head list;
};
-struct kthread_stop_info
-{
- struct task_struct *k;
- int err;
- struct completion done;
+struct kthread {
+ int should_stop;
+ struct completion exited;
};
-/* Thread stopping is done by setthing this var: lock serializes
- * multiple kthread_stop calls. */
-static DEFINE_MUTEX(kthread_stop_lock);
-static struct kthread_stop_info kthread_stop_info;
+#define to_kthread(tsk) \
+ container_of((tsk)->vfork_done, struct kthread, exited)
/**
* kthread_should_stop - should this kthread return now?
*/
int kthread_should_stop(void)
{
- return (kthread_stop_info.k == current);
+ return to_kthread(current)->should_stop;
}
EXPORT_SYMBOL(kthread_should_stop);
static int kthread(void *_create)
{
+ /* Copy data: it's on kthread's stack */
struct kthread_create_info *create = _create;
- int (*threadfn)(void *data);
- void *data;
- int ret = -EINTR;
+ int (*threadfn)(void *data) = create->threadfn;
+ void *data = create->data;
+ struct kthread self;
+ int ret;
- /* Copy data: it's on kthread's stack */
- threadfn = create->threadfn;
- data = create->data;
+ self.should_stop = 0;
+ init_completion(&self.exited);
+ current->vfork_done = &self.exited;
/* OK, tell user we're spawned, wait for stop or wakeup */
__set_current_state(TASK_UNINTERRUPTIBLE);
complete(&create->done);
schedule();
- if (!kthread_should_stop())
+ ret = -EINTR;
+ if (!self.should_stop)
ret = threadfn(data);
- /* It might have exited on its own, w/o kthread_stop. Check. */
- if (kthread_should_stop()) {
- kthread_stop_info.err = ret;
- complete(&kthread_stop_info.done);
- }
- return 0;
+ /* we can't just return, we must preserve "self" on stack */
+ do_exit(ret);
}
static void create_kthread(struct kthread_create_info *create)
* The kernel thread should not inherit these properties.
*/
sched_setscheduler_nocheck(create.result, SCHED_NORMAL, ¶m);
- set_user_nice(create.result, KTHREAD_NICE_LEVEL);
set_cpus_allowed_ptr(create.result, cpu_all_mask);
}
return create.result;
/**
* kthread_bind - bind a just-created kthread to a cpu.
- * @k: thread created by kthread_create().
+ * @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 *k, unsigned int cpu)
+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(k, TASK_UNINTERRUPTIBLE)) {
+ if (!wait_task_inactive(p, 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;
+
+ p->cpus_allowed = cpumask_of_cpu(cpu);
+ p->rt.nr_cpus_allowed = 1;
+ p->flags |= PF_THREAD_BOUND;
}
EXPORT_SYMBOL(kthread_bind);
* @k: thread created by kthread_create().
*
* Sets kthread_should_stop() for @k to return true, wakes it, and
- * waits for it to exit. Your threadfn() must not call do_exit()
- * itself if you use this function! This can also be called after
- * kthread_create() instead of calling wake_up_process(): the thread
- * will exit without calling threadfn().
+ * 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;
- mutex_lock(&kthread_stop_lock);
-
- /* It could exit after stop_info.k set, but before wake_up_process. */
- get_task_struct(k);
-
trace_sched_kthread_stop(k);
+ get_task_struct(k);
- /* Must init completion *before* thread sees kthread_stop_info.k */
- init_completion(&kthread_stop_info.done);
- smp_wmb();
+ 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;
- /* Now set kthread_should_stop() to true, and wake it up. */
- kthread_stop_info.k = k;
- wake_up_process(k);
put_task_struct(k);
-
- /* Once it dies, reset stop ptr, gather result and we're done. */
- wait_for_completion(&kthread_stop_info.done);
- kthread_stop_info.k = NULL;
- ret = kthread_stop_info.err;
- mutex_unlock(&kthread_stop_lock);
-
trace_sched_kthread_stop_ret(ret);
return ret;
/* 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);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff