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