IB/rdmavt: Add post receive to rdmavt

int rvt_post_recv(struct ib_qp *ibqp, struct ib_recv_wr *wr,

		  struct ib_recv_wr **bad_wr)

{

	/*

	 * When a packet arrives the driver needs to call up to rvt to process

	 * the packet. The UD, RC, UC processing will be done in rvt, however

	 * the driver should be able to override this if it so choses. Perhaps a

	 * set of function pointers set up at registration time.

	 */

	struct rvt_qp *qp = ibqp_to_rvtqp(ibqp);

	struct rvt_rwq *wq = qp->r_rq.wq;

	unsigned long flags;

	return -EOPNOTSUPP;

	/* Check that state is OK to post receive. */

	if (!(ib_rvt_state_ops[qp->state] & RVT_POST_RECV_OK) || !wq) {

		*bad_wr = wr;

		return -EINVAL;

	}

	for (; wr; wr = wr->next) {

		struct rvt_rwqe *wqe;

		u32 next;

		int i;

		if ((unsigned)wr->num_sge > qp->r_rq.max_sge) {

			*bad_wr = wr;

			return -EINVAL;

		}

		spin_lock_irqsave(&qp->r_rq.lock, flags);

		next = wq->head + 1;

		if (next >= qp->r_rq.size)

			next = 0;

		if (next == wq->tail) {

			spin_unlock_irqrestore(&qp->r_rq.lock, flags);

			*bad_wr = wr;

			return -ENOMEM;

		}

		wqe = rvt_get_rwqe_ptr(&qp->r_rq, wq->head);

		wqe->wr_id = wr->wr_id;

		wqe->num_sge = wr->num_sge;

		for (i = 0; i < wr->num_sge; i++)

			wqe->sg_list[i] = wr->sg_list[i];

		/* Make sure queue entry is written before the head index. */

		smp_wmb();

		wq->head = next;

		spin_unlock_irqrestore(&qp->r_rq.lock, flags);

	}

	return 0;

}

/**