X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=kernel%2Fkthread.c;h=dcfe724300eb3cd32c46c2d06de4fc92c7de070b;hb=b00296fb781acfafa93687000cdef72b8922bb40;hp=24be714b04c775bb23fd47baaec588ca92e8c6ba;hpb=c0bc8721b8d0380ec69fa97578c91201201b05a9;p=linux-2.6 diff --git a/kernel/kthread.c b/kernel/kthread.c index 24be714b04..dcfe724300 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -1,7 +1,7 @@ /* Kernel thread helper functions. * Copyright (C) 2004 IBM Corporation, Rusty Russell. * - * Creation is done via keventd, so that we get a clean environment + * Creation is done via kthreadd, so that we get a clean environment * even if we're invoked from userspace (think modprobe, hotplug cpu, * etc.). */ @@ -15,22 +15,22 @@ #include #include -/* - * We dont want to execute off keventd since it might - * hold a semaphore our callers hold too: - */ -static struct workqueue_struct *helper_wq; +static DEFINE_SPINLOCK(kthread_create_lock); +static LIST_HEAD(kthread_create_list); +struct task_struct *kthreadd_task; struct kthread_create_info { - /* Information passed to kthread() from keventd. */ + /* Information passed to kthread() from kthreadd. */ int (*threadfn)(void *data); void *data; struct completion started; - /* Result passed back to kthread_create() from keventd. */ + /* Result passed back to kthread_create() from kthreadd. */ struct task_struct *result; struct completion done; + + struct list_head list; }; struct kthread_stop_info @@ -48,7 +48,7 @@ static struct kthread_stop_info kthread_stop_info; /** * kthread_should_stop - should this kthread return now? * - * When someone calls kthread_stop on your kthread, it will be woken + * 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(). */ @@ -58,44 +58,19 @@ int kthread_should_stop(void) } EXPORT_SYMBOL(kthread_should_stop); -static void kthread_exit_files(void) -{ - struct fs_struct *fs; - struct task_struct *tsk = current; - - exit_fs(tsk); /* current->fs->count--; */ - fs = init_task.fs; - tsk->fs = fs; - atomic_inc(&fs->count); - exit_files(tsk); - current->files = init_task.files; - atomic_inc(&tsk->files->count); -} - static int kthread(void *_create) { struct kthread_create_info *create = _create; int (*threadfn)(void *data); void *data; - sigset_t blocked; int ret = -EINTR; - kthread_exit_files(); - - /* Copy data: it's on keventd's stack */ + /* Copy data: it's on kthread's stack */ threadfn = create->threadfn; data = create->data; - /* Block and flush all signals (in case we're not from keventd). */ - sigfillset(&blocked); - sigprocmask(SIG_BLOCK, &blocked, NULL); - flush_signals(current); - - /* By default we can run anywhere, unlike keventd. */ - set_cpus_allowed(current, CPU_MASK_ALL); - /* OK, tell user we're spawned, wait for stop or wakeup */ - __set_current_state(TASK_INTERRUPTIBLE); + __set_current_state(TASK_UNINTERRUPTIBLE); complete(&create->started); schedule(); @@ -110,10 +85,8 @@ static int kthread(void *_create) return 0; } -/* We are keventd: create a thread. */ -static void keventd_create_kthread(void *_create) +static void create_kthread(struct kthread_create_info *create) { - struct kthread_create_info *create = _create; int pid; /* We want our own signal handler (we take no signals by default). */ @@ -140,7 +113,7 @@ static void keventd_create_kthread(void *_create) * 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 + * 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 @@ -154,22 +127,19 @@ struct task_struct *kthread_create(int (*threadfn)(void *data), ...) { struct kthread_create_info create; - DECLARE_WORK(work, keventd_create_kthread, &create); create.threadfn = threadfn; create.data = data; init_completion(&create.started); init_completion(&create.done); - /* - * The workqueue needs to start up first: - */ - if (!helper_wq) - work.func(work.data); - else { - queue_work(helper_wq, &work); - wait_for_completion(&create.done); - } + spin_lock(&kthread_create_lock); + list_add_tail(&create.list, &kthread_create_list); + wake_up_process(kthreadd_task); + spin_unlock(&kthread_create_lock); + + wait_for_completion(&create.done); + if (!IS_ERR(create.result)) { va_list args; va_start(args, namefmt); @@ -177,7 +147,6 @@ struct task_struct *kthread_create(int (*threadfn)(void *data), namefmt, args); va_end(args); } - return create.result; } EXPORT_SYMBOL(kthread_create); @@ -189,11 +158,14 @@ EXPORT_SYMBOL(kthread_create); * * 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(). + * stopped (i.e., just returned from kthread_create()). */ void kthread_bind(struct task_struct *k, unsigned int cpu) { - BUG_ON(k->state != TASK_INTERRUPTIBLE); + if (k->state != TASK_UNINTERRUPTIBLE) { + WARN_ON(1); + return; + } /* Must have done schedule() in kthread() before we set_task_cpu */ wait_task_inactive(k); set_task_cpu(k, cpu); @@ -215,23 +187,6 @@ EXPORT_SYMBOL(kthread_bind); * was never called. */ int kthread_stop(struct task_struct *k) -{ - return kthread_stop_sem(k, NULL); -} -EXPORT_SYMBOL(kthread_stop); - -/** - * kthread_stop_sem - stop a thread created by kthread_create(). - * @k: thread created by kthread_create(). - * @s: semaphore that @k waits on while idle. - * - * Does essentially the same thing as kthread_stop() above, but wakes - * @k by calling up(@s). - * - * Returns the result of threadfn(), or %-EINTR if wake_up_process() - * was never called. - */ -int kthread_stop_sem(struct task_struct *k, struct semaphore *s) { int ret; @@ -246,10 +201,7 @@ int kthread_stop_sem(struct task_struct *k, struct semaphore *s) /* Now set kthread_should_stop() to true, and wake it up. */ kthread_stop_info.k = k; - if (s) - up(s); - else - wake_up_process(k); + wake_up_process(k); put_task_struct(k); /* Once it dies, reset stop ptr, gather result and we're done. */ @@ -260,14 +212,41 @@ int kthread_stop_sem(struct task_struct *k, struct semaphore *s) return ret; } -EXPORT_SYMBOL(kthread_stop_sem); +EXPORT_SYMBOL(kthread_stop); -static __init int helper_init(void) +int kthreadd(void *unused) { - helper_wq = create_singlethread_workqueue("kthread"); - BUG_ON(!helper_wq); + 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, -5); + set_cpus_allowed(tsk, CPU_MASK_ALL); + + 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; } - -core_initcall(helper_init);