diff options
Diffstat (limited to 'kernel/kthread.c')
-rw-r--r-- | kernel/kthread.c | 97 |
1 files changed, 41 insertions, 56 deletions
diff --git a/kernel/kthread.c b/kernel/kthread.c index 4ebaf8519ab..eb8751aa041 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -9,11 +9,12 @@ #include <linux/kthread.h> #include <linux/completion.h> #include <linux/err.h> +#include <linux/cpuset.h> #include <linux/unistd.h> #include <linux/file.h> #include <linux/module.h> #include <linux/mutex.h> -#include <trace/sched.h> +#include <trace/events/sched.h> #define KTHREAD_NICE_LEVEL (-5) @@ -21,15 +22,11 @@ static DEFINE_SPINLOCK(kthread_create_lock); static LIST_HEAD(kthread_create_list); struct task_struct *kthreadd_task; -DEFINE_TRACE(sched_kthread_stop); -DEFINE_TRACE(sched_kthread_stop_ret); - struct kthread_create_info { /* Information passed to kthread() from kthreadd. */ int (*threadfn)(void *data); void *data; - struct completion started; /* Result passed back to kthread_create() from kthreadd. */ struct task_struct *result; @@ -38,17 +35,13 @@ struct kthread_create_info 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? @@ -59,36 +52,35 @@ static struct kthread_stop_info kthread_stop_info; */ 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); create->result = current; - complete(&create->started); + 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) @@ -97,11 +89,10 @@ static void create_kthread(struct kthread_create_info *create) /* We want our own signal handler (we take no signals by default). */ pid = kernel_thread(kthread, create, CLONE_FS | CLONE_FILES | SIGCHLD); - if (pid < 0) + if (pid < 0) { create->result = ERR_PTR(pid); - else - wait_for_completion(&create->started); - complete(&create->done); + complete(&create->done); + } } /** @@ -132,7 +123,6 @@ struct task_struct *kthread_create(int (*threadfn)(void *data), create.threadfn = threadfn; create.data = data; - init_completion(&create.started); init_completion(&create.done); spin_lock(&kthread_create_lock); @@ -190,40 +180,34 @@ 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; @@ -239,6 +223,7 @@ int kthreadd(void *unused) 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; |