drbd: try hard to max out the updates per AL transaction

			break;

		wait_event(mdev->al_wait, prepare_al_transaction_nonblock(mdev, &incoming, &pending));

		/* Maybe more was queued, while we prepared the transaction?

		 * Try to stuff them into this transaction as well.

		 * Be strictly non-blocking here, no wait_event, we already

		 * have something to commit.

		 * Stop if we don't make any more progres.

		 */

		for (;;) {

			LIST_HEAD(more_pending);

			LIST_HEAD(more_incoming);

			bool made_progress;

			/* It is ok to look outside the lock,

			 * it's only an optimization anyways */

			if (list_empty(&mdev->submit.writes))

				break;

			spin_lock(&mdev->submit.lock);

			list_splice_tail_init(&mdev->submit.writes, &more_incoming);

			spin_unlock(&mdev->submit.lock);

			if (list_empty(&more_incoming))

				break;

			made_progress = prepare_al_transaction_nonblock(mdev, &more_incoming, &more_pending);

			list_splice_tail_init(&more_pending, &pending);

			list_splice_tail_init(&more_incoming, &incoming);

			if (!made_progress)

				break;

		}

		drbd_al_begin_io_commit(mdev, false);

		list_for_each_entry_safe(req, tmp, &pending, tl_requests) {