binder驱动中binder_ioctl方法会先获取一个thread，为啥根据binder_thread->pid在红黑树寻找thread？难道同一个进程的不同线程的pid不一样吗？

[zhuzhibin1991]

`static struct binder_thread *binder_get_thread_ilocked(
struct binder_proc *proc, struct binder_thread *new_thread)
{
struct binder_thread *thread = NULL;
struct rb_node *parent = NULL;
struct rb_node **p = &proc->threads.rb_node;

while (*p) {
	parent = *p;
	thread = rb_entry(parent, struct binder_thread, rb_node);

	if (current->pid < thread->pid)
		p = &(*p)->rb_left;
	else if (current->pid > thread->pid)
		p = &(*p)->rb_right;
	else
		return thread;
}
if (!new_thread)
	return NULL;
thread = new_thread;
binder_stats_created(BINDER_STAT_THREAD);
thread->proc = proc;
thread->pid = current->pid;
get_task_struct(current);
thread->task = current;
atomic_set(&thread->tmp_ref, 0);
init_waitqueue_head(&thread->wait);
INIT_LIST_HEAD(&thread->todo);
rb_link_node(&thread->rb_node, parent, p);
rb_insert_color(&thread->rb_node, &proc->threads);
thread->looper_need_return = true;
thread->return_error.work.type = BINDER_WORK_RETURN_ERROR;
thread->return_error.cmd = BR_OK;
thread->reply_error.work.type = BINDER_WORK_RETURN_ERROR;
thread->reply_error.cmd = BR_OK;
spin_lock_init(&thread->prio_lock);
thread->prio_state = BINDER_PRIO_SET;
INIT_LIST_HEAD(&new_thread->waiting_thread_node);
return thread;

}`
以上代码中可以看到赋值语句thread->pid = current->pid;
#define get_current() (current_thread_info()->task)
#define current get_current()
thread->pid拿到的其实是当前线程对应的 task_struct中的pid，这个pid其实是线程id，不同线程的id是不同的

[yuandaimaahao]

主线程pid 和进程 pid 相同