diff options
| -rw-r--r-- | include/linux/kthread.h | 3 | ||||
| -rw-r--r-- | init/main.c | 5 | ||||
| -rw-r--r-- | kernel/kthread.c | 124 |
3 files changed, 76 insertions, 56 deletions
diff --git a/include/linux/kthread.h b/include/linux/kthread.h index 1c65e7a9f186..00dd957e245b 100644 --- a/include/linux/kthread.h +++ b/include/linux/kthread.h @@ -30,4 +30,7 @@ void kthread_bind(struct task_struct *k, unsigned int cpu); int kthread_stop(struct task_struct *k); int kthread_should_stop(void); +int kthreadd(void *unused); +extern struct task_struct *kthreadd_task; + #endif /* _LINUX_KTHREAD_H */ diff --git a/init/main.c b/init/main.c index c1537e0ddceb..e8d080cab443 100644 --- a/init/main.c +++ b/init/main.c @@ -54,6 +54,7 @@ #include <linux/lockdep.h> #include <linux/pid_namespace.h> #include <linux/device.h> +#include <linux/kthread.h> #include <asm/io.h> #include <asm/bugs.h> @@ -425,8 +426,12 @@ static void __init setup_command_line(char *command_line) static void noinline rest_init(void) __releases(kernel_lock) { + int pid; + kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND); numa_default_policy(); + pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES); + kthreadd_task = find_task_by_pid(pid); unlock_kernel(); /* diff --git a/kernel/kthread.c b/kernel/kthread.c index 87c50ccd1d4e..0eb0070a3c57 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.). */ @@ -15,24 +15,22 @@ #include <linux/mutex.h> #include <asm/semaphore.h> -/* - * 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 work_struct work; + struct list_head list; }; struct kthread_stop_info @@ -60,42 +58,17 @@ 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); complete(&create->started); @@ -112,11 +85,8 @@ 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). */ @@ -162,17 +132,14 @@ 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 +147,6 @@ struct task_struct *kthread_create(int (*threadfn)(void *data), namefmt, args); va_end(args); } - return create.result; } EXPORT_SYMBOL(kthread_create); @@ -245,12 +211,58 @@ int kthread_stop(struct task_struct *k) } EXPORT_SYMBOL(kthread_stop); -static __init int helper_init(void) + +static __init void kthreadd_setup(void) { - helper_wq = create_singlethread_workqueue("kthread"); - BUG_ON(!helper_wq); + struct task_struct *tsk = current; + struct k_sigaction sa; + sigset_t blocked; - return 0; + set_task_comm(tsk, "kthreadd"); + + /* Block and flush all signals */ + sigfillset(&blocked); + sigprocmask(SIG_BLOCK, &blocked, NULL); + flush_signals(tsk); + + /* SIG_IGN makes children autoreap: see do_notify_parent(). */ + sa.sa.sa_handler = SIG_IGN; + sa.sa.sa_flags = 0; + siginitset(&sa.sa.sa_mask, sigmask(SIGCHLD)); + do_sigaction(SIGCHLD, &sa, (struct k_sigaction *)0); + + set_user_nice(current, -5); + set_cpus_allowed(current, CPU_MASK_ALL); } -core_initcall(helper_init); +int kthreadd(void *unused) +{ + /* Setup a clean context for our children to inherit. */ + kthreadd_setup(); + + 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; +} |