[sheepdog] [PATCH v2 1/7] sheep: make requests with new epoch sleep until epoch is updated

[Christoph Hellwig]

> +void resume_wait_epoch_requests(void)
> +{
> +	struct request *req, *t;
> +
> +	/* Request must have result SD_RES_OLD_NODE_VER
> +	 * or SD_RES_NEW_NODE_VER in sys->wait_epoch_queue. */
> +	list_for_each_entry_safe(req, t, &sys->wait_rw_queue,
> +				 request_list) {
> +
> +		list_del(&req->request_list);
> +		list_add_tail(&req->request_list, &sys->request_queue);
> +		process_request_event_queues();
> +	}

I think this should simply use list_splice_tail_init (which still needs
to be ported from the Linux Kernel) to move all entries efficiently in
one go, and then just call process_request_event_queues once.