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ipath_ud.c

/*
 * Copyright (c) 2006, 2007 QLogic Corporation. All rights reserved.
 * Copyright (c) 2005, 2006 PathScale, Inc. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <rdma/ib_smi.h>

#include "ipath_verbs.h"
#include "ipath_kernel.h"

/**
 * ipath_ud_loopback - handle send on loopback QPs
 * @sqp: the sending QP
 * @swqe: the send work request
 *
 * This is called from ipath_make_ud_req() to forward a WQE addressed
 * to the same HCA.
 * Note that the receive interrupt handler may be calling ipath_ud_rcv()
 * while this is being called.
 */
static void ipath_ud_loopback(struct ipath_qp *sqp, struct ipath_swqe *swqe)
{
      struct ipath_ibdev *dev = to_idev(sqp->ibqp.device);
      struct ipath_qp *qp;
      struct ib_ah_attr *ah_attr;
      unsigned long flags;
      struct ipath_rq *rq;
      struct ipath_srq *srq;
      struct ipath_sge_state rsge;
      struct ipath_sge *sge;
      struct ipath_rwq *wq;
      struct ipath_rwqe *wqe;
      void (*handler)(struct ib_event *, void *);
      struct ib_wc wc;
      u32 tail;
      u32 rlen;
      u32 length;

      qp = ipath_lookup_qpn(&dev->qp_table, swqe->wr.wr.ud.remote_qpn);
      if (!qp) {
            dev->n_pkt_drops++;
            goto send_comp;
      }

      rsge.sg_list = NULL;

      /*
       * Check that the qkey matches (except for QP0, see 9.6.1.4.1).
       * Qkeys with the high order bit set mean use the
       * qkey from the QP context instead of the WR (see 10.2.5).
       */
      if (unlikely(qp->ibqp.qp_num &&
                 ((int) swqe->wr.wr.ud.remote_qkey < 0 ?
                  sqp->qkey : swqe->wr.wr.ud.remote_qkey) != qp->qkey)) {
            /* XXX OK to lose a count once in a while. */
            dev->qkey_violations++;
            dev->n_pkt_drops++;
            goto drop;
      }

      /*
       * A GRH is expected to preceed the data even if not
       * present on the wire.
       */
      length = swqe->length;
      wc.byte_len = length + sizeof(struct ib_grh);

      if (swqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
            wc.wc_flags = IB_WC_WITH_IMM;
            wc.imm_data = swqe->wr.imm_data;
      } else {
            wc.wc_flags = 0;
            wc.imm_data = 0;
      }

      /*
       * This would be a lot simpler if we could call ipath_get_rwqe()
       * but that uses state that the receive interrupt handler uses
       * so we would need to lock out receive interrupts while doing
       * local loopback.
       */
      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;
      }

      if (rq->max_sge > 1) {
            /*
             * XXX We could use GFP_KERNEL if ipath_do_send()
             * was always called from the tasklet instead of
             * from ipath_post_send().
             */
            rsge.sg_list = kmalloc((rq->max_sge - 1) *
                              sizeof(struct ipath_sge),
                               GFP_ATOMIC);
            if (!rsge.sg_list) {
                  dev->n_pkt_drops++;
                  goto drop;
            }
      }

      /*
       * Get the next work request entry to find where to put the data.
       * Note that it is safe to drop the lock after changing rq->tail
       * since ipath_post_receive() won't fill the empty slot.
       */
      spin_lock_irqsave(&rq->lock, flags);
      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)) {
            spin_unlock_irqrestore(&rq->lock, flags);
            dev->n_pkt_drops++;
            goto drop;
      }
      wqe = get_rwqe_ptr(rq, tail);
      if (!ipath_init_sge(qp, wqe, &rlen, &rsge)) {
            spin_unlock_irqrestore(&rq->lock, flags);
            dev->n_pkt_drops++;
            goto drop;
      }
      /* Silently drop packets which are too big. */
      if (wc.byte_len > rlen) {
            spin_unlock_irqrestore(&rq->lock, flags);
            dev->n_pkt_drops++;
            goto drop;
      }
      if (++tail >= rq->size)
            tail = 0;
      wq->tail = tail;
      wc.wr_id = wqe->wr_id;
      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);
            } else
                  spin_unlock_irqrestore(&rq->lock, flags);
      } else
            spin_unlock_irqrestore(&rq->lock, flags);

      ah_attr = &to_iah(swqe->wr.wr.ud.ah)->attr;
      if (ah_attr->ah_flags & IB_AH_GRH) {
            ipath_copy_sge(&rsge, &ah_attr->grh, sizeof(struct ib_grh));
            wc.wc_flags |= IB_WC_GRH;
      } else
            ipath_skip_sge(&rsge, sizeof(struct ib_grh));
      sge = swqe->sg_list;
      while (length) {
            u32 len = sge->length;

            if (len > length)
                  len = length;
            if (len > sge->sge_length)
                  len = sge->sge_length;
            BUG_ON(len == 0);
            ipath_copy_sge(&rsge, sge->vaddr, len);
            sge->vaddr += len;
            sge->length -= len;
            sge->sge_length -= len;
            if (sge->sge_length == 0) {
                  if (--swqe->wr.num_sge)
                        sge++;
            } else if (sge->length == 0 && sge->mr != NULL) {
                  if (++sge->n >= IPATH_SEGSZ) {
                        if (++sge->m >= sge->mr->mapsz)
                              break;
                        sge->n = 0;
                  }
                  sge->vaddr =
                        sge->mr->map[sge->m]->segs[sge->n].vaddr;
                  sge->length =
                        sge->mr->map[sge->m]->segs[sge->n].length;
            }
            length -= len;
      }
      wc.status = IB_WC_SUCCESS;
      wc.opcode = IB_WC_RECV;
      wc.vendor_err = 0;
      wc.qp = &qp->ibqp;
      wc.src_qp = sqp->ibqp.qp_num;
      /* XXX do we know which pkey matched? Only needed for GSI. */
      wc.pkey_index = 0;
      wc.slid = dev->dd->ipath_lid |
            (ah_attr->src_path_bits &
             ((1 << dev->dd->ipath_lmc) - 1));
      wc.sl = ah_attr->sl;
      wc.dlid_path_bits =
            ah_attr->dlid & ((1 << dev->dd->ipath_lmc) - 1);
      wc.port_num = 1;
      /* Signal completion event if the solicited bit is set. */
      ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
                   swqe->wr.send_flags & IB_SEND_SOLICITED);
drop:
      kfree(rsge.sg_list);
      if (atomic_dec_and_test(&qp->refcount))
            wake_up(&qp->wait);
send_comp:
      ipath_send_complete(sqp, swqe, IB_WC_SUCCESS);
}

/**
 * ipath_make_ud_req - construct a UD request packet
 * @qp: the QP
 *
 * Return 1 if constructed; otherwise, return 0.
 */
int ipath_make_ud_req(struct ipath_qp *qp)
{
      struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
      struct ipath_other_headers *ohdr;
      struct ib_ah_attr *ah_attr;
      struct ipath_swqe *wqe;
      u32 nwords;
      u32 extra_bytes;
      u32 bth0;
      u16 lrh0;
      u16 lid;
      int ret = 0;

      if (unlikely(!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_SEND_OK)))
            goto bail;

      if (qp->s_cur == qp->s_head)
            goto bail;

      wqe = get_swqe_ptr(qp, qp->s_cur);

      /* Construct the header. */
      ah_attr = &to_iah(wqe->wr.wr.ud.ah)->attr;
      if (ah_attr->dlid >= IPATH_MULTICAST_LID_BASE) {
            if (ah_attr->dlid != IPATH_PERMISSIVE_LID)
                  dev->n_multicast_xmit++;
            else
                  dev->n_unicast_xmit++;
      } else {
            dev->n_unicast_xmit++;
            lid = ah_attr->dlid &
                  ~((1 << dev->dd->ipath_lmc) - 1);
            if (unlikely(lid == dev->dd->ipath_lid)) {
                  ipath_ud_loopback(qp, wqe);
                  goto done;
            }
      }

      extra_bytes = -wqe->length & 3;
      nwords = (wqe->length + extra_bytes) >> 2;

      /* header size in 32-bit words LRH+BTH+DETH = (8+12+8)/4. */
      qp->s_hdrwords = 7;
      if (wqe->wr.opcode == IB_WR_SEND_WITH_IMM)
            qp->s_hdrwords++;
      qp->s_cur_size = wqe->length;
      qp->s_cur_sge = &qp->s_sge;
      qp->s_wqe = wqe;
      qp->s_sge.sge = wqe->sg_list[0];
      qp->s_sge.sg_list = wqe->sg_list + 1;
      qp->s_sge.num_sge = wqe->wr.num_sge;

      if (ah_attr->ah_flags & IB_AH_GRH) {
            /* Header size in 32-bit words. */
            qp->s_hdrwords += ipath_make_grh(dev, &qp->s_hdr.u.l.grh,
                                     &ah_attr->grh,
                                     qp->s_hdrwords, nwords);
            lrh0 = IPATH_LRH_GRH;
            ohdr = &qp->s_hdr.u.l.oth;
            /*
             * Don't worry about sending to locally attached multicast
             * QPs.  It is unspecified by the spec. what happens.
             */
      } else {
            /* Header size in 32-bit words. */
            lrh0 = IPATH_LRH_BTH;
            ohdr = &qp->s_hdr.u.oth;
      }
      if (wqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
            ohdr->u.ud.imm_data = wqe->wr.imm_data;
            bth0 = IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE << 24;
      } else
            bth0 = IB_OPCODE_UD_SEND_ONLY << 24;
      lrh0 |= ah_attr->sl << 4;
      if (qp->ibqp.qp_type == IB_QPT_SMI)
            lrh0 |= 0xF000;   /* Set VL (see ch. 13.5.3.1) */
      qp->s_hdr.lrh[0] = cpu_to_be16(lrh0);
      qp->s_hdr.lrh[1] = cpu_to_be16(ah_attr->dlid);  /* DEST LID */
      qp->s_hdr.lrh[2] = cpu_to_be16(qp->s_hdrwords + nwords +
                                 SIZE_OF_CRC);
      lid = dev->dd->ipath_lid;
      if (lid) {
            lid |= ah_attr->src_path_bits &
                  ((1 << dev->dd->ipath_lmc) - 1);
            qp->s_hdr.lrh[3] = cpu_to_be16(lid);
      } else
            qp->s_hdr.lrh[3] = IB_LID_PERMISSIVE;
      if (wqe->wr.send_flags & IB_SEND_SOLICITED)
            bth0 |= 1 << 23;
      bth0 |= extra_bytes << 20;
      bth0 |= qp->ibqp.qp_type == IB_QPT_SMI ? IPATH_DEFAULT_P_KEY :
            ipath_get_pkey(dev->dd, qp->s_pkey_index);
      ohdr->bth[0] = cpu_to_be32(bth0);
      /*
       * Use the multicast QP if the destination LID is a multicast LID.
       */
      ohdr->bth[1] = ah_attr->dlid >= IPATH_MULTICAST_LID_BASE &&
            ah_attr->dlid != IPATH_PERMISSIVE_LID ?
            __constant_cpu_to_be32(IPATH_MULTICAST_QPN) :
            cpu_to_be32(wqe->wr.wr.ud.remote_qpn);
      ohdr->bth[2] = cpu_to_be32(qp->s_next_psn++ & IPATH_PSN_MASK);
      /*
       * Qkeys with the high order bit set mean use the
       * qkey from the QP context instead of the WR (see 10.2.5).
       */
      ohdr->u.ud.deth[0] = cpu_to_be32((int)wqe->wr.wr.ud.remote_qkey < 0 ?
                               qp->qkey : wqe->wr.wr.ud.remote_qkey);
      ohdr->u.ud.deth[1] = cpu_to_be32(qp->ibqp.qp_num);

done:
      if (++qp->s_cur >= qp->s_size)
            qp->s_cur = 0;
      ret = 1;

bail:
      return ret;
}

/**
 * ipath_ud_rcv - receive an incoming UD packet
 * @dev: the device the packet came in on
 * @hdr: the packet header
 * @has_grh: true if the packet has a GRH
 * @data: the packet data
 * @tlen: the packet length
 * @qp: the QP the packet came on
 *
 * This is called from ipath_qp_rcv() to process an incoming UD packet
 * for the given QP.
 * Called at interrupt level.
 */
void ipath_ud_rcv(struct ipath_ibdev *dev, struct ipath_ib_header *hdr,
              int has_grh, void *data, u32 tlen, struct ipath_qp *qp)
{
      struct ipath_other_headers *ohdr;
      int opcode;
      u32 hdrsize;
      u32 pad;
      struct ib_wc wc;
      u32 qkey;
      u32 src_qp;
      u16 dlid;
      int header_in_data;

      /* Check for GRH */
      if (!has_grh) {
            ohdr = &hdr->u.oth;
            hdrsize = 8 + 12 + 8;   /* LRH + BTH + DETH */
            qkey = be32_to_cpu(ohdr->u.ud.deth[0]);
            src_qp = be32_to_cpu(ohdr->u.ud.deth[1]);
            header_in_data = 0;
      } else {
            ohdr = &hdr->u.l.oth;
            hdrsize = 8 + 40 + 12 + 8; /* LRH + GRH + BTH + DETH */
            /*
             * The header with GRH is 68 bytes and the core driver sets
             * the eager header buffer size to 56 bytes so the last 12
             * bytes of the IB header is in the data buffer.
             */
            header_in_data = dev->dd->ipath_rcvhdrentsize == 16;
            if (header_in_data) {
                  qkey = be32_to_cpu(((__be32 *) data)[1]);
                  src_qp = be32_to_cpu(((__be32 *) data)[2]);
                  data += 12;
            } else {
                  qkey = be32_to_cpu(ohdr->u.ud.deth[0]);
                  src_qp = be32_to_cpu(ohdr->u.ud.deth[1]);
            }
      }
      src_qp &= IPATH_QPN_MASK;

      /*
       * Check that the permissive LID is only used on QP0
       * and the QKEY matches (see 9.6.1.4.1 and 9.6.1.5.1).
       */
      if (qp->ibqp.qp_num) {
            if (unlikely(hdr->lrh[1] == IB_LID_PERMISSIVE ||
                       hdr->lrh[3] == IB_LID_PERMISSIVE)) {
                  dev->n_pkt_drops++;
                  goto bail;
            }
            if (unlikely(qkey != qp->qkey)) {
                  /* XXX OK to lose a count once in a while. */
                  dev->qkey_violations++;
                  dev->n_pkt_drops++;
                  goto bail;
            }
      } else if (hdr->lrh[1] == IB_LID_PERMISSIVE ||
               hdr->lrh[3] == IB_LID_PERMISSIVE) {
            struct ib_smp *smp = (struct ib_smp *) data;

            if (smp->mgmt_class != IB_MGMT_CLASS_SUBN_DIRECTED_ROUTE) {
                  dev->n_pkt_drops++;
                  goto bail;
            }
      }

      /*
       * The opcode is in the low byte when its in network order
       * (top byte when in host order).
       */
      opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
      if (qp->ibqp.qp_num > 1 &&
          opcode == IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE) {
            if (header_in_data) {
                  wc.imm_data = *(__be32 *) data;
                  data += sizeof(__be32);
            } else
                  wc.imm_data = ohdr->u.ud.imm_data;
            wc.wc_flags = IB_WC_WITH_IMM;
            hdrsize += sizeof(u32);
      } else if (opcode == IB_OPCODE_UD_SEND_ONLY) {
            wc.imm_data = 0;
            wc.wc_flags = 0;
      } else {
            dev->n_pkt_drops++;
            goto bail;
      }

      /* Get the number of bytes the message was padded by. */
      pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
      if (unlikely(tlen < (hdrsize + pad + 4))) {
            /* Drop incomplete packets. */
            dev->n_pkt_drops++;
            goto bail;
      }
      tlen -= hdrsize + pad + 4;

      /* Drop invalid MAD packets (see 13.5.3.1). */
      if (unlikely((qp->ibqp.qp_num == 0 &&
                  (tlen != 256 ||
                   (be16_to_cpu(hdr->lrh[0]) >> 12) != 15)) ||
                 (qp->ibqp.qp_num == 1 &&
                  (tlen != 256 ||
                   (be16_to_cpu(hdr->lrh[0]) >> 12) == 15)))) {
            dev->n_pkt_drops++;
            goto bail;
      }

      /*
       * A GRH is expected to preceed the data even if not
       * present on the wire.
       */
      wc.byte_len = tlen + sizeof(struct ib_grh);

      /*
       * Get the next work request entry to find where to put the data.
       */
      if (qp->r_reuse_sge)
            qp->r_reuse_sge = 0;
      else if (!ipath_get_rwqe(qp, 0)) {
            /*
             * Count VL15 packets dropped due to no receive buffer.
             * Otherwise, count them as buffer overruns since usually,
             * the HW will be able to receive packets even if there are
             * no QPs with posted receive buffers.
             */
            if (qp->ibqp.qp_num == 0)
                  dev->n_vl15_dropped++;
            else
                  dev->rcv_errors++;
            goto bail;
      }
      /* Silently drop packets which are too big. */
      if (wc.byte_len > qp->r_len) {
            qp->r_reuse_sge = 1;
            dev->n_pkt_drops++;
            goto bail;
      }
      if (has_grh) {
            ipath_copy_sge(&qp->r_sge, &hdr->u.l.grh,
                         sizeof(struct ib_grh));
            wc.wc_flags |= IB_WC_GRH;
      } else
            ipath_skip_sge(&qp->r_sge, sizeof(struct ib_grh));
      ipath_copy_sge(&qp->r_sge, data,
                   wc.byte_len - sizeof(struct ib_grh));
      qp->r_wrid_valid = 0;
      wc.wr_id = qp->r_wr_id;
      wc.status = IB_WC_SUCCESS;
      wc.opcode = IB_WC_RECV;
      wc.vendor_err = 0;
      wc.qp = &qp->ibqp;
      wc.src_qp = src_qp;
      /* XXX do we know which pkey matched? Only needed for GSI. */
      wc.pkey_index = 0;
      wc.slid = be16_to_cpu(hdr->lrh[3]);
      wc.sl = (be16_to_cpu(hdr->lrh[0]) >> 4) & 0xF;
      dlid = be16_to_cpu(hdr->lrh[1]);
      /*
       * Save the LMC lower bits if the destination LID is a unicast LID.
       */
      wc.dlid_path_bits = dlid >= IPATH_MULTICAST_LID_BASE ? 0 :
            dlid & ((1 << dev->dd->ipath_lmc) - 1);
      wc.port_num = 1;
      /* Signal completion event if the solicited bit is set. */
      ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
                   (ohdr->bth[0] &
                  __constant_cpu_to_be32(1 << 23)) != 0);

bail:;
}

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