X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fkthread.c;h=92cf6930ab51a74e034ae9db30d72b21e9a84e9d;hb=1da8a77bdc294acdc37e8504926383b86f72d6be;hp=1db8c72d0d380c637b18e3951df45f32291ceeda;hpb=65f27f38446e1976cc98fd3004b110fedcddd189;p=safe%2Fjmp%2Flinux-2.6 diff --git a/kernel/kthread.c b/kernel/kthread.c index 1db8c72..92cf693 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.). */ @@ -13,26 +13,25 @@ #include #include #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; +#define KTHREAD_NICE_LEVEL (-5) + +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 work_struct work; + struct list_head list; }; struct kthread_stop_info @@ -50,7 +49,7 @@ 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(). */ @@ -60,44 +59,19 @@ 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(); @@ -112,11 +86,8 @@ static int kthread(void *_create) return 0; } -/* We are keventd: create a thread. */ -static void keventd_create_kthread(struct work_struct *work) +static void create_kthread(struct kthread_create_info *create) { - struct kthread_create_info *create = - container_of(work, struct kthread_create_info, work); int pid; /* We want our own signal handler (we take no signals by default). */ @@ -124,10 +95,18 @@ static void keventd_create_kthread(struct work_struct *work) if (pid < 0) { create->result = ERR_PTR(pid); } else { + struct sched_param param = { .sched_priority = 0 }; wait_for_completion(&create->started); read_lock(&tasklist_lock); create->result = find_task_by_pid(pid); read_unlock(&tasklist_lock); + /* + * root may have changed our (kthreadd's) priority or CPU mask. + * The kernel thread should not inherit these properties. + */ + sched_setscheduler(create->result, SCHED_NORMAL, ¶m); + set_user_nice(create->result, KTHREAD_NICE_LEVEL); + set_cpus_allowed(create->result, CPU_MASK_ALL); } complete(&create->done); } @@ -143,7 +122,7 @@ static void keventd_create_kthread(struct work_struct *work) * 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 @@ -162,17 +141,14 @@ struct task_struct *kthread_create(int (*threadfn)(void *data), create.data = data; init_completion(&create.started); init_completion(&create.done); - INIT_WORK(&create.work, keventd_create_kthread); - - /* - * The workqueue needs to start up first: - */ - if (!helper_wq) - create.work.func(&create.work); - else { - queue_work(helper_wq, &create.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); @@ -180,7 +156,6 @@ struct task_struct *kthread_create(int (*threadfn)(void *data), namefmt, args); va_end(args); } - return create.result; } EXPORT_SYMBOL(kthread_create); @@ -192,15 +167,19 @@ 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); k->cpus_allowed = cpumask_of_cpu(cpu); + k->rt.nr_cpus_allowed = 1; } EXPORT_SYMBOL(kthread_bind); @@ -245,12 +224,39 @@ int kthread_stop(struct task_struct *k) } 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, KTHREAD_NICE_LEVEL); + 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);