userfaultfd: non-cooperative: Split the find_userfault() routine

}

/* fault_pending_wqh.lock must be hold by the caller */

static inline struct userfaultfd_wait_queue *find_userfault(

	struct userfaultfd_ctx *ctx)

static inline struct userfaultfd_wait_queue *find_userfault_in(

		wait_queue_head_t *wqh)

{

	wait_queue_t *wq;

	struct userfaultfd_wait_queue *uwq;

	VM_BUG_ON(!spin_is_locked(&ctx->fault_pending_wqh.lock));

	VM_BUG_ON(!spin_is_locked(&wqh->lock));

	uwq = NULL;

	if (!waitqueue_active(&ctx->fault_pending_wqh))

	if (!waitqueue_active(wqh))

		goto out;

	/* walk in reverse to provide FIFO behavior to read userfaults */

	wq = list_last_entry(&ctx->fault_pending_wqh.task_list,

			     typeof(*wq), task_list);

	wq = list_last_entry(&wqh->task_list, typeof(*wq), task_list);

	uwq = container_of(wq, struct userfaultfd_wait_queue, wq);

out:

	return uwq;

}

static inline struct userfaultfd_wait_queue *find_userfault(

		struct userfaultfd_ctx *ctx)

{

	return find_userfault_in(&ctx->fault_pending_wqh);

}

static unsigned int userfaultfd_poll(struct file *file, poll_table *wait)

{

	struct userfaultfd_ctx *ctx = file->private_data;