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#include <linux-thread.h>
/*
* Thread interfaces
*/
typedef struct thread_priv_s {
unsigned long tp_magic; /* Magic */
void (*tp_func)(void *); /* Registered function */
void *tp_args; /* Args to be passed to function */
size_t tp_len; /* Len to be passed to function */
int tp_state; /* State to start thread at */
pri_t tp_pri; /* Priority to start threat at */
volatile kthread_t *tp_task; /* Task pointer for new thread */
spinlock_t tp_lock; /* Syncronization lock */
wait_queue_head_t tp_waitq; /* Syncronization wait queue */
} thread_priv_t;
static int
thread_generic_wrapper(void *arg)
{
thread_priv_t *tp = (thread_priv_t *)arg;
void (*func)(void *);
void *args;
char name[16];
/* Use the truncated function name as thread name */
snprintf(name, sizeof(name), "%s", "kthread");
daemonize(name);
spin_lock(&tp->tp_lock);
BUG_ON(tp->tp_magic != TP_MAGIC);
func = tp->tp_func;
args = tp->tp_args;
tp->tp_task = get_current();
set_current_state(tp->tp_state);
set_user_nice((kthread_t *)tp->tp_task, PRIO_TO_NICE(tp->tp_pri));
spin_unlock(&tp->tp_lock);
wake_up(&tp->tp_waitq);
/* DO NOT USE 'ARG' AFTER THIS POINT, EVER, EVER, EVER!
* Local variables are used here because after the calling thread
* has been woken up it will exit and this memory will no longer
* be safe to access since it was declared on the callers stack. */
if (func)
func(args);
return 0;
}
void
__thread_exit(void)
{
return;
}
EXPORT_SYMBOL(__thread_exit);
/* thread_create() may block forever if it cannot create a thread or
* allocate memory. This is preferable to returning a NULL which Solaris
* style callers likely never check for... since it can't fail. */
kthread_t *
__thread_create(caddr_t stk, size_t stksize, void (*proc)(void *),
void *args, size_t len, proc_t *pp, int state, pri_t pri)
{
thread_priv_t tp;
DEFINE_WAIT(wait);
long pid;
/* Option pp is simply ignored */
/* Variable stack size unsupported */
BUG_ON(stk != NULL);
BUG_ON(stk != 0);
/* Variable tp is located on the stack and not the heap because I want
* to minimize any chance of a failure, since the Solaris code is designed
* such that this function cannot fail. This is a little dangerous since
* we're passing a stack address to a new thread but correct locking was
* added to ensure the callee can use the data safely until wake_up(). */
tp.tp_magic = TP_MAGIC;
tp.tp_func = proc;
tp.tp_args = args;
tp.tp_len = len;
tp.tp_state = state;
tp.tp_pri = pri;
tp.tp_task = NULL;
spin_lock_init(&tp.tp_lock);
init_waitqueue_head(&tp.tp_waitq);
spin_lock(&tp.tp_lock);
/* Solaris says this must never fail so we try forever */
while ((pid = kernel_thread(thread_generic_wrapper, (void *)&tp, 0)) < 0)
printk(KERN_ERR "linux-thread: Unable to create thread; "
"pid = %ld\n", pid);
/* All signals are ignored due to sleeping TASK_UNINTERRUPTIBLE */
for (;;) {
prepare_to_wait(&tp.tp_waitq, &wait, TASK_UNINTERRUPTIBLE);
if (tp.tp_task != NULL)
break;
spin_unlock(&tp.tp_lock);
schedule();
spin_lock(&tp.tp_lock);
}
/* Verify the pid retunred matches the pid in the task struct */
BUG_ON(pid != (tp.tp_task)->pid);
spin_unlock(&tp.tp_lock);
return (kthread_t *)tp.tp_task;
}
EXPORT_SYMBOL(__thread_create);
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