mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-06 11:06:42 +07:00
72fd4a35a8
A variety of (mostly) innocuous fixes to the embedded kernel-doc content in source files, including: * make multi-line initial descriptions single line * denote some function names, constants and structs as such * change erroneous opening '/*' to '/**' in a few places * reword some text for clarity Signed-off-by: Robert P. J. Day <rpjday@mindspring.com> Cc: "Randy.Dunlap" <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
257 lines
6.8 KiB
C
257 lines
6.8 KiB
C
/* Kernel thread helper functions.
|
|
* Copyright (C) 2004 IBM Corporation, Rusty Russell.
|
|
*
|
|
* Creation is done via keventd, so that we get a clean environment
|
|
* even if we're invoked from userspace (think modprobe, hotplug cpu,
|
|
* etc.).
|
|
*/
|
|
#include <linux/sched.h>
|
|
#include <linux/kthread.h>
|
|
#include <linux/completion.h>
|
|
#include <linux/err.h>
|
|
#include <linux/unistd.h>
|
|
#include <linux/file.h>
|
|
#include <linux/module.h>
|
|
#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;
|
|
|
|
struct kthread_create_info
|
|
{
|
|
/* Information passed to kthread() from keventd. */
|
|
int (*threadfn)(void *data);
|
|
void *data;
|
|
struct completion started;
|
|
|
|
/* Result passed back to kthread_create() from keventd. */
|
|
struct task_struct *result;
|
|
struct completion done;
|
|
|
|
struct work_struct work;
|
|
};
|
|
|
|
struct kthread_stop_info
|
|
{
|
|
struct task_struct *k;
|
|
int err;
|
|
struct completion done;
|
|
};
|
|
|
|
/* 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;
|
|
|
|
/**
|
|
* kthread_should_stop - should this kthread return now?
|
|
*
|
|
* 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().
|
|
*/
|
|
int kthread_should_stop(void)
|
|
{
|
|
return (kthread_stop_info.k == current);
|
|
}
|
|
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 */
|
|
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);
|
|
schedule();
|
|
|
|
if (!kthread_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 are keventd: create a thread. */
|
|
static void keventd_create_kthread(struct work_struct *work)
|
|
{
|
|
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). */
|
|
pid = kernel_thread(kthread, create, CLONE_FS | CLONE_FILES | SIGCHLD);
|
|
if (pid < 0) {
|
|
create->result = ERR_PTR(pid);
|
|
} else {
|
|
wait_for_completion(&create->started);
|
|
read_lock(&tasklist_lock);
|
|
create->result = find_task_by_pid(pid);
|
|
read_unlock(&tasklist_lock);
|
|
}
|
|
complete(&create->done);
|
|
}
|
|
|
|
/**
|
|
* kthread_create - create a kthread.
|
|
* @threadfn: the function to run until signal_pending(current).
|
|
* @data: data ptr for @threadfn.
|
|
* @namefmt: printf-style name for the thread.
|
|
*
|
|
* Description: This helper function creates and names a kernel
|
|
* thread. The thread will be stopped: use wake_up_process() to start
|
|
* 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
|
|
* 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
|
|
* or a negative error number; it will be passed to kthread_stop().
|
|
*
|
|
* Returns a task_struct or ERR_PTR(-ENOMEM).
|
|
*/
|
|
struct task_struct *kthread_create(int (*threadfn)(void *data),
|
|
void *data,
|
|
const char namefmt[],
|
|
...)
|
|
{
|
|
struct kthread_create_info create;
|
|
|
|
create.threadfn = threadfn;
|
|
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);
|
|
}
|
|
if (!IS_ERR(create.result)) {
|
|
va_list args;
|
|
va_start(args, namefmt);
|
|
vsnprintf(create.result->comm, sizeof(create.result->comm),
|
|
namefmt, args);
|
|
va_end(args);
|
|
}
|
|
|
|
return create.result;
|
|
}
|
|
EXPORT_SYMBOL(kthread_create);
|
|
|
|
/**
|
|
* kthread_bind - bind a just-created kthread to a cpu.
|
|
* @k: thread created by kthread_create().
|
|
* @cpu: cpu (might not be online, must be possible) for @k to run on.
|
|
*
|
|
* 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()).
|
|
*/
|
|
void kthread_bind(struct task_struct *k, unsigned int cpu)
|
|
{
|
|
BUG_ON(k->state != TASK_INTERRUPTIBLE);
|
|
/* 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);
|
|
}
|
|
EXPORT_SYMBOL(kthread_bind);
|
|
|
|
/**
|
|
* kthread_stop - stop a thread created by kthread_create().
|
|
* @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().
|
|
*
|
|
* Returns the result of threadfn(), or %-EINTR if wake_up_process()
|
|
* was never called.
|
|
*/
|
|
int kthread_stop(struct task_struct *k)
|
|
{
|
|
int ret;
|
|
|
|
mutex_lock(&kthread_stop_lock);
|
|
|
|
/* It could exit after stop_info.k set, but before wake_up_process. */
|
|
get_task_struct(k);
|
|
|
|
/* Must init completion *before* thread sees kthread_stop_info.k */
|
|
init_completion(&kthread_stop_info.done);
|
|
smp_wmb();
|
|
|
|
/* 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);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(kthread_stop);
|
|
|
|
static __init int helper_init(void)
|
|
{
|
|
helper_wq = create_singlethread_workqueue("kthread");
|
|
BUG_ON(!helper_wq);
|
|
|
|
return 0;
|
|
}
|
|
|
|
core_initcall(helper_init);
|