static int io_iopoll_check(struct io_ring_ctx *ctx, long min)
{
	unsigned int nr_events = 0;
	int iters = 0, ret = 0;

	/*
	 * We disallow the app entering submit/complete with polling, but we
	 * still need to lock the ring to prevent racing with polled issue
	 * that got punted to a workqueue.
	 */
	mutex_lock(&ctx->uring_lock);
	do {
		/*
		 * Don't enter poll loop if we already have events pending.
		 * If we do, we can potentially be spinning for commands that
		 * already triggered a CQE (eg in error).
		 */
		if (io_cqring_events(ctx, false))
			break;

		/*
		 * If a submit got punted to a workqueue, we can have the
		 * application entering polling for a command before it gets
		 * issued. That app will hold the uring_lock for the duration
		 * of the poll right here, so we need to take a breather every
		 * now and then to ensure that the issue has a chance to add
		 * the poll to the issued list. Otherwise we can spin here
		 * forever, while the workqueue is stuck trying to acquire the
		 * very same mutex.
		 */
		if (!(++iters & 7)) {
			mutex_unlock(&ctx->uring_lock);
			io_run_task_work();
			mutex_lock(&ctx->uring_lock);
		}

		ret = io_iopoll_getevents(ctx, &nr_events, min);
		if (ret <= 0)
			break;
		ret = 0;
	} while (min && !nr_events && !need_resched());

	mutex_unlock(&ctx->uring_lock);
	return ret;
}
static int io_iopoll_check(struct io_ring_ctx *ctx, long min)
{
	unsigned int nr_events = 0;
	int iters = 0, ret = 0;

	 
	mutex_lock(&ctx->uring_lock);
	do {
		 
		if (io_cqring_events(ctx, false))
			break;

		 
		if (!(++iters & 7)) {
			mutex_unlock(&ctx->uring_lock);
			io_run_task_work();
			mutex_lock(&ctx->uring_lock);
		}

		ret = io_iopoll_getevents(ctx, &nr_events, min);
		if (ret <= 0)
			break;
		ret = 0;
	} while (min && !nr_events && !need_resched());

	mutex_unlock(&ctx->uring_lock);
	return ret;
}