aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
-rw-r--r--include/linux/kthread.h3
-rw-r--r--init/main.c5
-rw-r--r--kernel/kthread.c124
3 files changed, 76 insertions, 56 deletions
diff --git a/include/linux/kthread.h b/include/linux/kthread.h
index 1c65e7a9f18..00dd957e245 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 c1537e0ddce..e8d080cab44 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 87c50ccd1d4..0eb0070a3c5 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;
+}