Beispiel #1
0
/**
 * qib_get_rwqe - copy the next RWQE into the QP's RWQE
 * @qp: the QP
 * @wr_id_only: update qp->r_wr_id only, not qp->r_sge
 *
 * Return -1 if there is a local error, 0 if no RWQE is available,
 * otherwise return 1.
 *
 * Can be called from interrupt level.
 */
int qib_get_rwqe(struct rvt_qp *qp, int wr_id_only)
{
	unsigned long flags;
	struct rvt_rq *rq;
	struct rvt_rwq *wq;
	struct rvt_srq *srq;
	struct rvt_rwqe *wqe;
	void (*handler)(struct ib_event *, void *);
	u32 tail;
	int ret;

	if (qp->ibqp.srq) {
		srq = ibsrq_to_rvtsrq(qp->ibqp.srq);
		handler = srq->ibsrq.event_handler;
		rq = &srq->rq;
	} else {
		srq = NULL;
		handler = NULL;
		rq = &qp->r_rq;
	}

	spin_lock_irqsave(&rq->lock, flags);
	if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK)) {
		ret = 0;
		goto unlock;
	}

	wq = rq->wq;
	tail = wq->tail;
	/* Validate tail before using it since it is user writable. */
	if (tail >= rq->size)
		tail = 0;
	if (unlikely(tail == wq->head)) {
		ret = 0;
		goto unlock;
	}
	/* Make sure entry is read after head index is read. */
	smp_rmb();
	wqe = rvt_get_rwqe_ptr(rq, tail);
	/*
	 * Even though we update the tail index in memory, the verbs
	 * consumer is not supposed to post more entries until a
	 * completion is generated.
	 */
	if (++tail >= rq->size)
		tail = 0;
	wq->tail = tail;
	if (!wr_id_only && !qib_init_sge(qp, wqe)) {
		ret = -1;
		goto unlock;
	}
	qp->r_wr_id = wqe->wr_id;

	ret = 1;
	set_bit(RVT_R_WRID_VALID, &qp->r_aflags);
	if (handler) {
		u32 n;

		/*
		 * Validate head pointer value and compute
		 * the number of remaining WQEs.
		 */
		n = wq->head;
		if (n >= rq->size)
			n = 0;
		if (n < tail)
			n += rq->size - tail;
		else
			n -= tail;
		if (n < srq->limit) {
			struct ib_event ev;

			srq->limit = 0;
			spin_unlock_irqrestore(&rq->lock, flags);
			ev.device = qp->ibqp.device;
			ev.element.srq = qp->ibqp.srq;
			ev.event = IB_EVENT_SRQ_LIMIT_REACHED;
			handler(&ev, srq->ibsrq.srq_context);
			goto bail;
		}
	}
unlock:
	spin_unlock_irqrestore(&rq->lock, flags);
bail:
	return ret;
}
int qib_get_rwqe(struct qib_qp *qp, int wr_id_only)
{
	unsigned long flags;
	struct qib_rq *rq;
	struct qib_rwq *wq;
	struct qib_srq *srq;
	struct qib_rwqe *wqe;
	void (*handler)(struct ib_event *, void *);
	u32 tail;
	int ret;

	if (qp->ibqp.srq) {
		srq = to_isrq(qp->ibqp.srq);
		handler = srq->ibsrq.event_handler;
		rq = &srq->rq;
	} else {
		srq = NULL;
		handler = NULL;
		rq = &qp->r_rq;
	}

	spin_lock_irqsave(&rq->lock, flags);
	if (!(ib_qib_state_ops[qp->state] & QIB_PROCESS_RECV_OK)) {
		ret = 0;
		goto unlock;
	}

	wq = rq->wq;
	tail = wq->tail;
	
	if (tail >= rq->size)
		tail = 0;
	if (unlikely(tail == wq->head)) {
		ret = 0;
		goto unlock;
	}
	
	smp_rmb();
	wqe = get_rwqe_ptr(rq, tail);
	if (++tail >= rq->size)
		tail = 0;
	wq->tail = tail;
	if (!wr_id_only && !qib_init_sge(qp, wqe)) {
		ret = -1;
		goto unlock;
	}
	qp->r_wr_id = wqe->wr_id;

	ret = 1;
	set_bit(QIB_R_WRID_VALID, &qp->r_aflags);
	if (handler) {
		u32 n;

		n = wq->head;
		if (n >= rq->size)
			n = 0;
		if (n < tail)
			n += rq->size - tail;
		else
			n -= tail;
		if (n < srq->limit) {
			struct ib_event ev;

			srq->limit = 0;
			spin_unlock_irqrestore(&rq->lock, flags);
			ev.device = qp->ibqp.device;
			ev.element.srq = qp->ibqp.srq;
			ev.event = IB_EVENT_SRQ_LIMIT_REACHED;
			handler(&ev, srq->ibsrq.srq_context);
			goto bail;
		}
	}
unlock:
	spin_unlock_irqrestore(&rq->lock, flags);
bail:
	return ret;
}