On Sun, Sep 11, 2016 at 09:49:19PM -0700, Adit Ranadive wrote:
> +
> +static int pvrdma_poll_one(struct pvrdma_cq *cq, struct pvrdma_qp **cur_qp,
> + struct ib_wc *wc)
> +{
> + struct pvrdma_dev *dev = to_vdev(cq->ibcq.device);
> + int has_data;
> + unsigned int head;
> + bool tried = false;
> + struct pvrdma_cqe *cqe;
> +
> +retry:
> + has_data = pvrdma_idx_ring_has_data(&cq->ring_state->rx,
> + cq->ibcq.cqe, &head);
> + if (has_data == 0) {
> + if (tried)
> + return -EAGAIN;
> +
> + /* Pass down POLL to give physical HCA a chance to poll. */
> + pvrdma_write_uar_cq(dev, cq->cq_handle | PVRDMA_UAR_CQ_POLL);
> +
> + tried = true;
> + goto retry;
> + } else if (has_data == PVRDMA_INVALID_IDX) {
I didn't went throw the entire life cycle of RX-ring's head and tail but
you need to make sure that PVRDMA_INVALID_IDX error is recoverable one, i.e
there is probability that in the next call to pvrdma_poll_one it will be
fine. Otherwise it is an endless loop.
> + dev_err(&dev->pdev->dev, "CQ ring state invalid\n");
> + return -EAGAIN;
> + }
> +
> + cqe = get_cqe(cq, head);
> +
> + /* Ensure cqe is valid. */
> + rmb();
> + if (dev->qp_tbl[cqe->qp & 0xffff])
> + *cur_qp = (struct pvrdma_qp *)dev->qp_tbl[cqe->qp & 0xffff];
> + else
> + return -EAGAIN;
> +
> + wc->opcode = pvrdma_wc_opcode_to_ib(cqe->opcode);
> + wc->status = pvrdma_wc_status_to_ib(cqe->status);
> + wc->wr_id = cqe->wr_id;
> + wc->qp = &(*cur_qp)->ibqp;
> + wc->byte_len = cqe->byte_len;
> + wc->ex.imm_data = cqe->imm_data;
> + wc->src_qp = cqe->src_qp;
> + wc->wc_flags = pvrdma_wc_flags_to_ib(cqe->wc_flags);
> + wc->pkey_index = cqe->pkey_index;
> + wc->slid = cqe->slid;
> + wc->sl = cqe->sl;
> + wc->dlid_path_bits = cqe->dlid_path_bits;
> + wc->port_num = cqe->port_num;
> + wc->vendor_err = 0;
> +
> + /* Update shared ring state */
> + pvrdma_idx_ring_inc(&cq->ring_state->rx.cons_head, cq->ibcq.cqe);
> +
> + return 0;
> +}
> +
> +/**
> + * pvrdma_poll_cq - poll for work completion queue entries
> + * @ibcq: completion queue
> + * @num_entries: the maximum number of entries
> + * @entry: pointer to work completion array
> + *
> + * @return: number of polled completion entries
> + */
> +int pvrdma_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *wc)
> +{
> + struct pvrdma_cq *cq = to_vcq(ibcq);
> + struct pvrdma_qp *cur_qp = NULL;
> + unsigned long flags;
> + int npolled;
> +
> + if (num_entries < 1 || wc == NULL)
> + return 0;
> +
> + spin_lock_irqsave(&cq->cq_lock, flags);
> + for (npolled = 0; npolled < num_entries; ++npolled) {
> + if (pvrdma_poll_one(cq, &cur_qp, wc + npolled))
> + break;
> + }
> +
> + spin_unlock_irqrestore(&cq->cq_lock, flags);
> +
> + /* Ensure we do not return errors from poll_cq */
> + return npolled;
> +}
> +
> +/**
> + * pvrdma_resize_cq - resize CQ
> + * @ibcq: the completion queue
> + * @entries: CQ entries
> + * @udata: user data
> + *
> + * @return: -EOPNOTSUPP as CQ resize is not supported.
> + */
> +int pvrdma_resize_cq(struct ib_cq *ibcq, int entries, struct ib_udata *udata)
> +{
> + return -EOPNOTSUPP;
> +}
> --
> 2.7.4
>
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