]> err.no Git - linux-2.6/commitdiff
IB/ipath: infiniband UC and UD protocol support
authorBryan O'Sullivan <bos@pathscale.com>
Wed, 29 Mar 2006 23:23:34 +0000 (15:23 -0800)
committerRoland Dreier <rolandd@cisco.com>
Fri, 31 Mar 2006 21:14:20 +0000 (13:14 -0800)
These files implement the Infiniband UC ("unreliable connection") and UD
("unreliable datagram") protocols.

Signed-off-by: Bryan O'Sullivan <bos@pathscale.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
drivers/infiniband/hw/ipath/ipath_uc.c [new file with mode: 0644]
drivers/infiniband/hw/ipath/ipath_ud.c [new file with mode: 0644]

diff --git a/drivers/infiniband/hw/ipath/ipath_uc.c b/drivers/infiniband/hw/ipath/ipath_uc.c
new file mode 100644 (file)
index 0000000..0d6dbc0
--- /dev/null
@@ -0,0 +1,645 @@
+/*
+ * 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 "ipath_verbs.h"
+#include "ips_common.h"
+
+/* cut down ridiculously long IB macro names */
+#define OP(x) IB_OPCODE_UC_##x
+
+static void complete_last_send(struct ipath_qp *qp, struct ipath_swqe *wqe,
+                              struct ib_wc *wc)
+{
+       if (++qp->s_last == qp->s_size)
+               qp->s_last = 0;
+       if (!test_bit(IPATH_S_SIGNAL_REQ_WR, &qp->s_flags) ||
+           (wqe->wr.send_flags & IB_SEND_SIGNALED)) {
+               wc->wr_id = wqe->wr.wr_id;
+               wc->status = IB_WC_SUCCESS;
+               wc->opcode = ib_ipath_wc_opcode[wqe->wr.opcode];
+               wc->vendor_err = 0;
+               wc->byte_len = wqe->length;
+               wc->qp_num = qp->ibqp.qp_num;
+               wc->src_qp = qp->remote_qpn;
+               wc->pkey_index = 0;
+               wc->slid = qp->remote_ah_attr.dlid;
+               wc->sl = qp->remote_ah_attr.sl;
+               wc->dlid_path_bits = 0;
+               wc->port_num = 0;
+               ipath_cq_enter(to_icq(qp->ibqp.send_cq), wc, 0);
+       }
+       wqe = get_swqe_ptr(qp, qp->s_last);
+}
+
+/**
+ * ipath_do_uc_send - do a send on a UC queue
+ * @data: contains a pointer to the QP to send on
+ *
+ * Process entries in the send work queue until the queue is exhausted.
+ * Only allow one CPU to send a packet per QP (tasklet).
+ * Otherwise, after we drop the QP lock, two threads could send
+ * packets out of order.
+ * This is similar to ipath_do_rc_send() below except we don't have
+ * timeouts or resends.
+ */
+void ipath_do_uc_send(unsigned long data)
+{
+       struct ipath_qp *qp = (struct ipath_qp *)data;
+       struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
+       struct ipath_swqe *wqe;
+       unsigned long flags;
+       u16 lrh0;
+       u32 hwords;
+       u32 nwords;
+       u32 extra_bytes;
+       u32 bth0;
+       u32 bth2;
+       u32 pmtu = ib_mtu_enum_to_int(qp->path_mtu);
+       u32 len;
+       struct ipath_other_headers *ohdr;
+       struct ib_wc wc;
+
+       if (test_and_set_bit(IPATH_S_BUSY, &qp->s_flags))
+               goto bail;
+
+       if (unlikely(qp->remote_ah_attr.dlid ==
+                    ipath_layer_get_lid(dev->dd))) {
+               /* Pass in an uninitialized ib_wc to save stack space. */
+               ipath_ruc_loopback(qp, &wc);
+               clear_bit(IPATH_S_BUSY, &qp->s_flags);
+               goto bail;
+       }
+
+       ohdr = &qp->s_hdr.u.oth;
+       if (qp->remote_ah_attr.ah_flags & IB_AH_GRH)
+               ohdr = &qp->s_hdr.u.l.oth;
+
+again:
+       /* Check for a constructed packet to be sent. */
+       if (qp->s_hdrwords != 0) {
+                       /*
+                        * If no PIO bufs are available, return.
+                        * An interrupt will call ipath_ib_piobufavail()
+                        * when one is available.
+                        */
+                       if (ipath_verbs_send(dev->dd, qp->s_hdrwords,
+                                            (u32 *) &qp->s_hdr,
+                                            qp->s_cur_size,
+                                            qp->s_cur_sge)) {
+                               ipath_no_bufs_available(qp, dev);
+                               goto bail;
+                       }
+                       dev->n_unicast_xmit++;
+               /* Record that we sent the packet and s_hdr is empty. */
+               qp->s_hdrwords = 0;
+       }
+
+       lrh0 = IPS_LRH_BTH;
+       /* header size in 32-bit words LRH+BTH = (8+12)/4. */
+       hwords = 5;
+
+       /*
+        * The lock is needed to synchronize between
+        * setting qp->s_ack_state and post_send().
+        */
+       spin_lock_irqsave(&qp->s_lock, flags);
+
+       if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_SEND_OK))
+               goto done;
+
+       bth0 = ipath_layer_get_pkey(dev->dd, qp->s_pkey_index);
+
+       /* Send a request. */
+       wqe = get_swqe_ptr(qp, qp->s_last);
+       switch (qp->s_state) {
+       default:
+               /*
+                * Signal the completion of the last send (if there is
+                * one).
+                */
+               if (qp->s_last != qp->s_tail)
+                       complete_last_send(qp, wqe, &wc);
+
+               /* Check if send work queue is empty. */
+               if (qp->s_tail == qp->s_head)
+                       goto done;
+               /*
+                * Start a new request.
+                */
+               qp->s_psn = wqe->psn = qp->s_next_psn;
+               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;
+               qp->s_len = len = wqe->length;
+               switch (wqe->wr.opcode) {
+               case IB_WR_SEND:
+               case IB_WR_SEND_WITH_IMM:
+                       if (len > pmtu) {
+                               qp->s_state = OP(SEND_FIRST);
+                               len = pmtu;
+                               break;
+                       }
+                       if (wqe->wr.opcode == IB_WR_SEND)
+                               qp->s_state = OP(SEND_ONLY);
+                       else {
+                               qp->s_state =
+                                       OP(SEND_ONLY_WITH_IMMEDIATE);
+                               /* Immediate data comes after the BTH */
+                               ohdr->u.imm_data = wqe->wr.imm_data;
+                               hwords += 1;
+                       }
+                       if (wqe->wr.send_flags & IB_SEND_SOLICITED)
+                               bth0 |= 1 << 23;
+                       break;
+
+               case IB_WR_RDMA_WRITE:
+               case IB_WR_RDMA_WRITE_WITH_IMM:
+                       ohdr->u.rc.reth.vaddr =
+                               cpu_to_be64(wqe->wr.wr.rdma.remote_addr);
+                       ohdr->u.rc.reth.rkey =
+                               cpu_to_be32(wqe->wr.wr.rdma.rkey);
+                       ohdr->u.rc.reth.length = cpu_to_be32(len);
+                       hwords += sizeof(struct ib_reth) / 4;
+                       if (len > pmtu) {
+                               qp->s_state = OP(RDMA_WRITE_FIRST);
+                               len = pmtu;
+                               break;
+                       }
+                       if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
+                               qp->s_state = OP(RDMA_WRITE_ONLY);
+                       else {
+                               qp->s_state =
+                                       OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE);
+                               /* Immediate data comes after the RETH */
+                               ohdr->u.rc.imm_data = wqe->wr.imm_data;
+                               hwords += 1;
+                               if (wqe->wr.send_flags & IB_SEND_SOLICITED)
+                                       bth0 |= 1 << 23;
+                       }
+                       break;
+
+               default:
+                       goto done;
+               }
+               if (++qp->s_tail >= qp->s_size)
+                       qp->s_tail = 0;
+               break;
+
+       case OP(SEND_FIRST):
+               qp->s_state = OP(SEND_MIDDLE);
+               /* FALLTHROUGH */
+       case OP(SEND_MIDDLE):
+               len = qp->s_len;
+               if (len > pmtu) {
+                       len = pmtu;
+                       break;
+               }
+               if (wqe->wr.opcode == IB_WR_SEND)
+                       qp->s_state = OP(SEND_LAST);
+               else {
+                       qp->s_state = OP(SEND_LAST_WITH_IMMEDIATE);
+                       /* Immediate data comes after the BTH */
+                       ohdr->u.imm_data = wqe->wr.imm_data;
+                       hwords += 1;
+               }
+               if (wqe->wr.send_flags & IB_SEND_SOLICITED)
+                       bth0 |= 1 << 23;
+               break;
+
+       case OP(RDMA_WRITE_FIRST):
+               qp->s_state = OP(RDMA_WRITE_MIDDLE);
+               /* FALLTHROUGH */
+       case OP(RDMA_WRITE_MIDDLE):
+               len = qp->s_len;
+               if (len > pmtu) {
+                       len = pmtu;
+                       break;
+               }
+               if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
+                       qp->s_state = OP(RDMA_WRITE_LAST);
+               else {
+                       qp->s_state =
+                               OP(RDMA_WRITE_LAST_WITH_IMMEDIATE);
+                       /* Immediate data comes after the BTH */
+                       ohdr->u.imm_data = wqe->wr.imm_data;
+                       hwords += 1;
+                       if (wqe->wr.send_flags & IB_SEND_SOLICITED)
+                               bth0 |= 1 << 23;
+               }
+               break;
+       }
+       bth2 = qp->s_next_psn++ & IPS_PSN_MASK;
+       qp->s_len -= len;
+       bth0 |= qp->s_state << 24;
+
+       spin_unlock_irqrestore(&qp->s_lock, flags);
+
+       /* Construct the header. */
+       extra_bytes = (4 - len) & 3;
+       nwords = (len + extra_bytes) >> 2;
+       if (unlikely(qp->remote_ah_attr.ah_flags & IB_AH_GRH)) {
+               /* Header size in 32-bit words. */
+               hwords += 10;
+               lrh0 = IPS_LRH_GRH;
+               qp->s_hdr.u.l.grh.version_tclass_flow =
+                       cpu_to_be32((6 << 28) |
+                                   (qp->remote_ah_attr.grh.traffic_class
+                                    << 20) |
+                                   qp->remote_ah_attr.grh.flow_label);
+               qp->s_hdr.u.l.grh.paylen =
+                       cpu_to_be16(((hwords - 12) + nwords +
+                                    SIZE_OF_CRC) << 2);
+               /* next_hdr is defined by C8-7 in ch. 8.4.1 */
+               qp->s_hdr.u.l.grh.next_hdr = 0x1B;
+               qp->s_hdr.u.l.grh.hop_limit =
+                       qp->remote_ah_attr.grh.hop_limit;
+               /* The SGID is 32-bit aligned. */
+               qp->s_hdr.u.l.grh.sgid.global.subnet_prefix =
+                       dev->gid_prefix;
+               qp->s_hdr.u.l.grh.sgid.global.interface_id =
+                       ipath_layer_get_guid(dev->dd);
+               qp->s_hdr.u.l.grh.dgid = qp->remote_ah_attr.grh.dgid;
+       }
+       qp->s_hdrwords = hwords;
+       qp->s_cur_sge = &qp->s_sge;
+       qp->s_cur_size = len;
+       lrh0 |= qp->remote_ah_attr.sl << 4;
+       qp->s_hdr.lrh[0] = cpu_to_be16(lrh0);
+       /* DEST LID */
+       qp->s_hdr.lrh[1] = cpu_to_be16(qp->remote_ah_attr.dlid);
+       qp->s_hdr.lrh[2] = cpu_to_be16(hwords + nwords + SIZE_OF_CRC);
+       qp->s_hdr.lrh[3] = cpu_to_be16(ipath_layer_get_lid(dev->dd));
+       bth0 |= extra_bytes << 20;
+       ohdr->bth[0] = cpu_to_be32(bth0);
+       ohdr->bth[1] = cpu_to_be32(qp->remote_qpn);
+       ohdr->bth[2] = cpu_to_be32(bth2);
+
+       /* Check for more work to do. */
+       goto again;
+
+done:
+       spin_unlock_irqrestore(&qp->s_lock, flags);
+       clear_bit(IPATH_S_BUSY, &qp->s_flags);
+
+bail:
+       return;
+}
+
+/**
+ * ipath_uc_rcv - handle an incoming UC packet
+ * @dev: the device the packet came in on
+ * @hdr: the header of the packet
+ * @has_grh: true if the packet has a GRH
+ * @data: the packet data
+ * @tlen: the length of the packet
+ * @qp: the QP for this packet.
+ *
+ * This is called from ipath_qp_rcv() to process an incoming UC packet
+ * for the given QP.
+ * Called at interrupt level.
+ */
+void ipath_uc_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 psn;
+       u32 pad;
+       unsigned long flags;
+       struct ib_wc wc;
+       u32 pmtu = ib_mtu_enum_to_int(qp->path_mtu);
+       struct ib_reth *reth;
+       int header_in_data;
+
+       /* Check for GRH */
+       if (!has_grh) {
+               ohdr = &hdr->u.oth;
+               hdrsize = 8 + 12;       /* LRH + BTH */
+               psn = be32_to_cpu(ohdr->bth[2]);
+               header_in_data = 0;
+       } else {
+               ohdr = &hdr->u.l.oth;
+               hdrsize = 8 + 40 + 12;  /* LRH + GRH + BTH */
+               /*
+                * The header with GRH is 60 bytes and the
+                * core driver sets the eager header buffer
+                * size to 56 bytes so the last 4 bytes of
+                * the BTH header (PSN) is in the data buffer.
+                */
+               header_in_data =
+                       ipath_layer_get_rcvhdrentsize(dev->dd) == 16;
+               if (header_in_data) {
+                       psn = be32_to_cpu(((__be32 *) data)[0]);
+                       data += sizeof(__be32);
+               } else
+                       psn = be32_to_cpu(ohdr->bth[2]);
+       }
+       /*
+        * 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;
+
+       wc.imm_data = 0;
+       wc.wc_flags = 0;
+
+       spin_lock_irqsave(&qp->r_rq.lock, flags);
+
+       /* Compare the PSN verses the expected PSN. */
+       if (unlikely(ipath_cmp24(psn, qp->r_psn) != 0)) {
+               /*
+                * Handle a sequence error.
+                * Silently drop any current message.
+                */
+               qp->r_psn = psn;
+       inv:
+               qp->r_state = OP(SEND_LAST);
+               switch (opcode) {
+               case OP(SEND_FIRST):
+               case OP(SEND_ONLY):
+               case OP(SEND_ONLY_WITH_IMMEDIATE):
+                       goto send_first;
+
+               case OP(RDMA_WRITE_FIRST):
+               case OP(RDMA_WRITE_ONLY):
+               case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE):
+                       goto rdma_first;
+
+               default:
+                       dev->n_pkt_drops++;
+                       goto done;
+               }
+       }
+
+       /* Check for opcode sequence errors. */
+       switch (qp->r_state) {
+       case OP(SEND_FIRST):
+       case OP(SEND_MIDDLE):
+               if (opcode == OP(SEND_MIDDLE) ||
+                   opcode == OP(SEND_LAST) ||
+                   opcode == OP(SEND_LAST_WITH_IMMEDIATE))
+                       break;
+               goto inv;
+
+       case OP(RDMA_WRITE_FIRST):
+       case OP(RDMA_WRITE_MIDDLE):
+               if (opcode == OP(RDMA_WRITE_MIDDLE) ||
+                   opcode == OP(RDMA_WRITE_LAST) ||
+                   opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
+                       break;
+               goto inv;
+
+       default:
+               if (opcode == OP(SEND_FIRST) ||
+                   opcode == OP(SEND_ONLY) ||
+                   opcode == OP(SEND_ONLY_WITH_IMMEDIATE) ||
+                   opcode == OP(RDMA_WRITE_FIRST) ||
+                   opcode == OP(RDMA_WRITE_ONLY) ||
+                   opcode == OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE))
+                       break;
+               goto inv;
+       }
+
+       /* OK, process the packet. */
+       switch (opcode) {
+       case OP(SEND_FIRST):
+       case OP(SEND_ONLY):
+       case OP(SEND_ONLY_WITH_IMMEDIATE):
+       send_first:
+               if (qp->r_reuse_sge) {
+                       qp->r_reuse_sge = 0;
+                       qp->r_sge = qp->s_rdma_sge;
+               } else if (!ipath_get_rwqe(qp, 0)) {
+                       dev->n_pkt_drops++;
+                       goto done;
+               }
+               /* Save the WQE so we can reuse it in case of an error. */
+               qp->s_rdma_sge = qp->r_sge;
+               qp->r_rcv_len = 0;
+               if (opcode == OP(SEND_ONLY))
+                       goto send_last;
+               else if (opcode == OP(SEND_ONLY_WITH_IMMEDIATE))
+                       goto send_last_imm;
+               /* FALLTHROUGH */
+       case OP(SEND_MIDDLE):
+               /* Check for invalid length PMTU or posted rwqe len. */
+               if (unlikely(tlen != (hdrsize + pmtu + 4))) {
+                       qp->r_reuse_sge = 1;
+                       dev->n_pkt_drops++;
+                       goto done;
+               }
+               qp->r_rcv_len += pmtu;
+               if (unlikely(qp->r_rcv_len > qp->r_len)) {
+                       qp->r_reuse_sge = 1;
+                       dev->n_pkt_drops++;
+                       goto done;
+               }
+               ipath_copy_sge(&qp->r_sge, data, pmtu);
+               break;
+
+       case OP(SEND_LAST_WITH_IMMEDIATE):
+       send_last_imm:
+               if (header_in_data) {
+                       wc.imm_data = *(__be32 *) data;
+                       data += sizeof(__be32);
+               } else {
+                       /* Immediate data comes after BTH */
+                       wc.imm_data = ohdr->u.imm_data;
+               }
+               hdrsize += 4;
+               wc.wc_flags = IB_WC_WITH_IMM;
+               /* FALLTHROUGH */
+       case OP(SEND_LAST):
+       send_last:
+               /* Get the number of bytes the message was padded by. */
+               pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
+               /* Check for invalid length. */
+               /* XXX LAST len should be >= 1 */
+               if (unlikely(tlen < (hdrsize + pad + 4))) {
+                       qp->r_reuse_sge = 1;
+                       dev->n_pkt_drops++;
+                       goto done;
+               }
+               /* Don't count the CRC. */
+               tlen -= (hdrsize + pad + 4);
+               wc.byte_len = tlen + qp->r_rcv_len;
+               if (unlikely(wc.byte_len > qp->r_len)) {
+                       qp->r_reuse_sge = 1;
+                       dev->n_pkt_drops++;
+                       goto done;
+               }
+               /* XXX Need to free SGEs */
+       last_imm:
+               ipath_copy_sge(&qp->r_sge, data, tlen);
+               wc.wr_id = qp->r_wr_id;
+               wc.status = IB_WC_SUCCESS;
+               wc.opcode = IB_WC_RECV;
+               wc.vendor_err = 0;
+               wc.qp_num = qp->ibqp.qp_num;
+               wc.src_qp = qp->remote_qpn;
+               wc.pkey_index = 0;
+               wc.slid = qp->remote_ah_attr.dlid;
+               wc.sl = qp->remote_ah_attr.sl;
+               wc.dlid_path_bits = 0;
+               wc.port_num = 0;
+               /* 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);
+               break;
+
+       case OP(RDMA_WRITE_FIRST):
+       case OP(RDMA_WRITE_ONLY):
+       case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE): /* consume RWQE */
+       rdma_first:
+               /* RETH comes after BTH */
+               if (!header_in_data)
+                       reth = &ohdr->u.rc.reth;
+               else {
+                       reth = (struct ib_reth *)data;
+                       data += sizeof(*reth);
+               }
+               hdrsize += sizeof(*reth);
+               qp->r_len = be32_to_cpu(reth->length);
+               qp->r_rcv_len = 0;
+               if (qp->r_len != 0) {
+                       u32 rkey = be32_to_cpu(reth->rkey);
+                       u64 vaddr = be64_to_cpu(reth->vaddr);
+
+                       /* Check rkey */
+                       if (unlikely(!ipath_rkey_ok(
+                                            dev, &qp->r_sge, qp->r_len,
+                                            vaddr, rkey,
+                                            IB_ACCESS_REMOTE_WRITE))) {
+                               dev->n_pkt_drops++;
+                               goto done;
+                       }
+               } else {
+                       qp->r_sge.sg_list = NULL;
+                       qp->r_sge.sge.mr = NULL;
+                       qp->r_sge.sge.vaddr = NULL;
+                       qp->r_sge.sge.length = 0;
+                       qp->r_sge.sge.sge_length = 0;
+               }
+               if (unlikely(!(qp->qp_access_flags &
+                              IB_ACCESS_REMOTE_WRITE))) {
+                       dev->n_pkt_drops++;
+                       goto done;
+               }
+               if (opcode == OP(RDMA_WRITE_ONLY))
+                       goto rdma_last;
+               else if (opcode ==
+                        OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE))
+                       goto rdma_last_imm;
+               /* FALLTHROUGH */
+       case OP(RDMA_WRITE_MIDDLE):
+               /* Check for invalid length PMTU or posted rwqe len. */
+               if (unlikely(tlen != (hdrsize + pmtu + 4))) {
+                       dev->n_pkt_drops++;
+                       goto done;
+               }
+               qp->r_rcv_len += pmtu;
+               if (unlikely(qp->r_rcv_len > qp->r_len)) {
+                       dev->n_pkt_drops++;
+                       goto done;
+               }
+               ipath_copy_sge(&qp->r_sge, data, pmtu);
+               break;
+
+       case OP(RDMA_WRITE_LAST_WITH_IMMEDIATE):
+       rdma_last_imm:
+               /* Get the number of bytes the message was padded by. */
+               pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
+               /* Check for invalid length. */
+               /* XXX LAST len should be >= 1 */
+               if (unlikely(tlen < (hdrsize + pad + 4))) {
+                       dev->n_pkt_drops++;
+                       goto done;
+               }
+               /* Don't count the CRC. */
+               tlen -= (hdrsize + pad + 4);
+               if (unlikely(tlen + qp->r_rcv_len != qp->r_len)) {
+                       dev->n_pkt_drops++;
+                       goto done;
+               }
+               if (qp->r_reuse_sge) {
+                       qp->r_reuse_sge = 0;
+               } else if (!ipath_get_rwqe(qp, 1)) {
+                       dev->n_pkt_drops++;
+                       goto done;
+               }
+               if (header_in_data) {
+                       wc.imm_data = *(__be32 *) data;
+                       data += sizeof(__be32);
+               } else {
+                       /* Immediate data comes after BTH */
+                       wc.imm_data = ohdr->u.imm_data;
+               }
+               hdrsize += 4;
+               wc.wc_flags = IB_WC_WITH_IMM;
+               wc.byte_len = 0;
+               goto last_imm;
+
+       case OP(RDMA_WRITE_LAST):
+       rdma_last:
+               /* Get the number of bytes the message was padded by. */
+               pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
+               /* Check for invalid length. */
+               /* XXX LAST len should be >= 1 */
+               if (unlikely(tlen < (hdrsize + pad + 4))) {
+                       dev->n_pkt_drops++;
+                       goto done;
+               }
+               /* Don't count the CRC. */
+               tlen -= (hdrsize + pad + 4);
+               if (unlikely(tlen + qp->r_rcv_len != qp->r_len)) {
+                       dev->n_pkt_drops++;
+                       goto done;
+               }
+               ipath_copy_sge(&qp->r_sge, data, tlen);
+               break;
+
+       default:
+               /* Drop packet for unknown opcodes. */
+               spin_unlock_irqrestore(&qp->r_rq.lock, flags);
+               dev->n_pkt_drops++;
+               goto bail;
+       }
+       qp->r_psn++;
+       qp->r_state = opcode;
+done:
+       spin_unlock_irqrestore(&qp->r_rq.lock, flags);
+
+bail:
+       return;
+}
diff --git a/drivers/infiniband/hw/ipath/ipath_ud.c b/drivers/infiniband/hw/ipath/ipath_ud.c
new file mode 100644 (file)
index 0000000..5ff3de6
--- /dev/null
@@ -0,0 +1,621 @@
+/*
+ * 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 "ips_common.h"
+
+/**
+ * ipath_ud_loopback - handle send on loopback QPs
+ * @sqp: the QP
+ * @ss: the SGE state
+ * @length: the length of the data to send
+ * @wr: the work request
+ * @wc: the work completion entry
+ *
+ * This is called from ipath_post_ud_send() to forward a WQE addressed
+ * to the same HCA.
+ */
+void ipath_ud_loopback(struct ipath_qp *sqp, struct ipath_sge_state *ss,
+                      u32 length, struct ib_send_wr *wr, struct ib_wc *wc)
+{
+       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_rwqe *wqe;
+
+       qp = ipath_lookup_qpn(&dev->qp_table, wr->wr.ud.remote_qpn);
+       if (!qp)
+               return;
+
+       /*
+        * 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) wr->wr.ud.remote_qkey < 0
+                     ? qp->qkey : 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 done;
+       }
+
+       /*
+        * A GRH is expected to preceed the data even if not
+        * present on the wire.
+        */
+       wc->byte_len = length + sizeof(struct ib_grh);
+
+       if (wr->opcode == IB_WR_SEND_WITH_IMM) {
+               wc->wc_flags = IB_WC_WITH_IMM;
+               wc->imm_data = wr->imm_data;
+       } else {
+               wc->wc_flags = 0;
+               wc->imm_data = 0;
+       }
+
+       /*
+        * 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.
+        */
+       if (qp->ibqp.srq) {
+               srq = to_isrq(qp->ibqp.srq);
+               rq = &srq->rq;
+       } else {
+               srq = NULL;
+               rq = &qp->r_rq;
+       }
+       spin_lock_irqsave(&rq->lock, flags);
+       if (rq->tail == rq->head) {
+               spin_unlock_irqrestore(&rq->lock, flags);
+               dev->n_pkt_drops++;
+               goto done;
+       }
+       /* Silently drop packets which are too big. */
+       wqe = get_rwqe_ptr(rq, rq->tail);
+       if (wc->byte_len > wqe->length) {
+               spin_unlock_irqrestore(&rq->lock, flags);
+               dev->n_pkt_drops++;
+               goto done;
+       }
+       wc->wr_id = wqe->wr_id;
+       rsge.sge = wqe->sg_list[0];
+       rsge.sg_list = wqe->sg_list + 1;
+       rsge.num_sge = wqe->num_sge;
+       if (++rq->tail >= rq->size)
+               rq->tail = 0;
+       if (srq && srq->ibsrq.event_handler) {
+               u32 n;
+
+               if (rq->head < rq->tail)
+                       n = rq->size + rq->head - rq->tail;
+               else
+                       n = rq->head - rq->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;
+                       srq->ibsrq.event_handler(&ev,
+                                                srq->ibsrq.srq_context);
+               } else
+                       spin_unlock_irqrestore(&rq->lock, flags);
+       } else
+               spin_unlock_irqrestore(&rq->lock, flags);
+       ah_attr = &to_iah(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 = &ss->sge;
+       while (length) {
+               u32 len = sge->length;
+
+               if (len > length)
+                       len = 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 (--ss->num_sge)
+                               *sge = *ss->sg_list++;
+               } 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_num = qp->ibqp.qp_num;
+       wc->src_qp = sqp->ibqp.qp_num;
+       /* XXX do we know which pkey matched? Only needed for GSI. */
+       wc->pkey_index = 0;
+       wc->slid = ipath_layer_get_lid(dev->dd) |
+               (ah_attr->src_path_bits &
+                ((1 << (dev->mkeyprot_resv_lmc & 7)) - 1));
+       wc->sl = ah_attr->sl;
+       wc->dlid_path_bits =
+               ah_attr->dlid & ((1 << (dev->mkeyprot_resv_lmc & 7)) - 1);
+       /* Signal completion event if the solicited bit is set. */
+       ipath_cq_enter(to_icq(qp->ibqp.recv_cq), wc,
+                      wr->send_flags & IB_SEND_SOLICITED);
+
+done:
+       if (atomic_dec_and_test(&qp->refcount))
+               wake_up(&qp->wait);
+}
+
+/**
+ * ipath_post_ud_send - post a UD send on QP
+ * @qp: the QP
+ * @wr: the work request
+ *
+ * Note that we actually send the data as it is posted instead of putting
+ * the request into a ring buffer.  If we wanted to use a ring buffer,
+ * we would need to save a reference to the destination address in the SWQE.
+ */
+int ipath_post_ud_send(struct ipath_qp *qp, struct ib_send_wr *wr)
+{
+       struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
+       struct ipath_other_headers *ohdr;
+       struct ib_ah_attr *ah_attr;
+       struct ipath_sge_state ss;
+       struct ipath_sge *sg_list;
+       struct ib_wc wc;
+       u32 hwords;
+       u32 nwords;
+       u32 len;
+       u32 extra_bytes;
+       u32 bth0;
+       u16 lrh0;
+       u16 lid;
+       int i;
+       int ret;
+
+       if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_SEND_OK)) {
+               ret = 0;
+               goto bail;
+       }
+
+       /* IB spec says that num_sge == 0 is OK. */
+       if (wr->num_sge > qp->s_max_sge) {
+               ret = -EINVAL;
+               goto bail;
+       }
+
+       if (wr->num_sge > 1) {
+               sg_list = kmalloc((qp->s_max_sge - 1) * sizeof(*sg_list),
+                                 GFP_ATOMIC);
+               if (!sg_list) {
+                       ret = -ENOMEM;
+                       goto bail;
+               }
+       } else
+               sg_list = NULL;
+
+       /* Check the buffer to send. */
+       ss.sg_list = sg_list;
+       ss.sge.mr = NULL;
+       ss.sge.vaddr = NULL;
+       ss.sge.length = 0;
+       ss.sge.sge_length = 0;
+       ss.num_sge = 0;
+       len = 0;
+       for (i = 0; i < wr->num_sge; i++) {
+               /* Check LKEY */
+               if (to_ipd(qp->ibqp.pd)->user && wr->sg_list[i].lkey == 0) {
+                       ret = -EINVAL;
+                       goto bail;
+               }
+
+               if (wr->sg_list[i].length == 0)
+                       continue;
+               if (!ipath_lkey_ok(&dev->lk_table, ss.num_sge ?
+                                  sg_list + ss.num_sge - 1 : &ss.sge,
+                                  &wr->sg_list[i], 0)) {
+                       ret = -EINVAL;
+                       goto bail;
+               }
+               len += wr->sg_list[i].length;
+               ss.num_sge++;
+       }
+       extra_bytes = (4 - len) & 3;
+       nwords = (len + extra_bytes) >> 2;
+
+       /* Construct the header. */
+       ah_attr = &to_iah(wr->wr.ud.ah)->attr;
+       if (ah_attr->dlid == 0) {
+               ret = -EINVAL;
+               goto bail;
+       }
+       if (ah_attr->dlid >= IPS_MULTICAST_LID_BASE) {
+               if (ah_attr->dlid != IPS_PERMISSIVE_LID)
+                       dev->n_multicast_xmit++;
+               else
+                       dev->n_unicast_xmit++;
+       } else {
+               dev->n_unicast_xmit++;
+               lid = ah_attr->dlid &
+                       ~((1 << (dev->mkeyprot_resv_lmc & 7)) - 1);
+               if (unlikely(lid == ipath_layer_get_lid(dev->dd))) {
+                       /*
+                        * Pass in an uninitialized ib_wc to save stack
+                        * space.
+                        */
+                       ipath_ud_loopback(qp, &ss, len, wr, &wc);
+                       goto done;
+               }
+       }
+       if (ah_attr->ah_flags & IB_AH_GRH) {
+               /* Header size in 32-bit words. */
+               hwords = 17;
+               lrh0 = IPS_LRH_GRH;
+               ohdr = &qp->s_hdr.u.l.oth;
+               qp->s_hdr.u.l.grh.version_tclass_flow =
+                       cpu_to_be32((6 << 28) |
+                                   (ah_attr->grh.traffic_class << 20) |
+                                   ah_attr->grh.flow_label);
+               qp->s_hdr.u.l.grh.paylen =
+                       cpu_to_be16(((wr->opcode ==
+                                     IB_WR_SEND_WITH_IMM ? 6 : 5) +
+                                    nwords + SIZE_OF_CRC) << 2);
+               /* next_hdr is defined by C8-7 in ch. 8.4.1 */
+               qp->s_hdr.u.l.grh.next_hdr = 0x1B;
+               qp->s_hdr.u.l.grh.hop_limit = ah_attr->grh.hop_limit;
+               /* The SGID is 32-bit aligned. */
+               qp->s_hdr.u.l.grh.sgid.global.subnet_prefix =
+                       dev->gid_prefix;
+               qp->s_hdr.u.l.grh.sgid.global.interface_id =
+                       ipath_layer_get_guid(dev->dd);
+               qp->s_hdr.u.l.grh.dgid = ah_attr->grh.dgid;
+               /*
+                * 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. */
+               hwords = 7;
+               lrh0 = IPS_LRH_BTH;
+               ohdr = &qp->s_hdr.u.oth;
+       }
+       if (wr->opcode == IB_WR_SEND_WITH_IMM) {
+               ohdr->u.ud.imm_data = wr->imm_data;
+               wc.imm_data = wr->imm_data;
+               hwords += 1;
+               bth0 = IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE << 24;
+       } else if (wr->opcode == IB_WR_SEND) {
+               wc.imm_data = 0;
+               bth0 = IB_OPCODE_UD_SEND_ONLY << 24;
+       } else {
+               ret = -EINVAL;
+               goto bail;
+       }
+       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(hwords + nwords + SIZE_OF_CRC);
+       lid = ipath_layer_get_lid(dev->dd);
+       if (lid) {
+               lid |= ah_attr->src_path_bits &
+                       ((1 << (dev->mkeyprot_resv_lmc & 7)) - 1);
+               qp->s_hdr.lrh[3] = cpu_to_be16(lid);
+       } else
+               qp->s_hdr.lrh[3] = IB_LID_PERMISSIVE;
+       if (wr->send_flags & IB_SEND_SOLICITED)
+               bth0 |= 1 << 23;
+       bth0 |= extra_bytes << 20;
+       bth0 |= qp->ibqp.qp_type == IB_QPT_SMI ? IPS_DEFAULT_P_KEY :
+               ipath_layer_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 >= IPS_MULTICAST_LID_BASE &&
+               ah_attr->dlid != IPS_PERMISSIVE_LID ?
+               __constant_cpu_to_be32(IPS_MULTICAST_QPN) :
+               cpu_to_be32(wr->wr.ud.remote_qpn);
+       /* XXX Could lose a PSN count but not worth locking */
+       ohdr->bth[2] = cpu_to_be32(qp->s_next_psn++ & IPS_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)wr->wr.ud.remote_qkey < 0 ?
+                                        qp->qkey : wr->wr.ud.remote_qkey);
+       ohdr->u.ud.deth[1] = cpu_to_be32(qp->ibqp.qp_num);
+       if (ipath_verbs_send(dev->dd, hwords, (u32 *) &qp->s_hdr,
+                            len, &ss))
+               dev->n_no_piobuf++;
+
+done:
+       /* Queue the completion status entry. */
+       if (!test_bit(IPATH_S_SIGNAL_REQ_WR, &qp->s_flags) ||
+           (wr->send_flags & IB_SEND_SIGNALED)) {
+               wc.wr_id = wr->wr_id;
+               wc.status = IB_WC_SUCCESS;
+               wc.vendor_err = 0;
+               wc.opcode = IB_WC_SEND;
+               wc.byte_len = len;
+               wc.qp_num = qp->ibqp.qp_num;
+               wc.src_qp = 0;
+               wc.wc_flags = 0;
+               /* XXX initialize other fields? */
+               ipath_cq_enter(to_icq(qp->ibqp.send_cq), &wc, 0);
+       }
+       kfree(sg_list);
+
+       ret = 0;
+
+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;
+       unsigned long flags;
+       struct ib_wc wc;
+       u32 qkey;
+       u32 src_qp;
+       struct ipath_rq *rq;
+       struct ipath_srq *srq;
+       struct ipath_rwqe *wqe;
+       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 =
+                       ipath_layer_get_rcvhdrentsize(dev->dd) == 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 &= IPS_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;
+               }
+       }
+
+       /* 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);
+
+       /*
+        * 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 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.
+        */
+       if (qp->ibqp.srq) {
+               srq = to_isrq(qp->ibqp.srq);
+               rq = &srq->rq;
+       } else {
+               srq = NULL;
+               rq = &qp->r_rq;
+       }
+       spin_lock_irqsave(&rq->lock, flags);
+       if (rq->tail == rq->head) {
+               spin_unlock_irqrestore(&rq->lock, flags);
+               dev->n_pkt_drops++;
+               goto bail;
+       }
+       /* Silently drop packets which are too big. */
+       wqe = get_rwqe_ptr(rq, rq->tail);
+       if (wc.byte_len > wqe->length) {
+               spin_unlock_irqrestore(&rq->lock, flags);
+               dev->n_pkt_drops++;
+               goto bail;
+       }
+       wc.wr_id = wqe->wr_id;
+       qp->r_sge.sge = wqe->sg_list[0];
+       qp->r_sge.sg_list = wqe->sg_list + 1;
+       qp->r_sge.num_sge = wqe->num_sge;
+       if (++rq->tail >= rq->size)
+               rq->tail = 0;
+       if (srq && srq->ibsrq.event_handler) {
+               u32 n;
+
+               if (rq->head < rq->tail)
+                       n = rq->size + rq->head - rq->tail;
+               else
+                       n = rq->head - rq->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;
+                       srq->ibsrq.event_handler(&ev,
+                                                srq->ibsrq.srq_context);
+               } else
+                       spin_unlock_irqrestore(&rq->lock, flags);
+       } else
+               spin_unlock_irqrestore(&rq->lock, flags);
+       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));
+       wc.status = IB_WC_SUCCESS;
+       wc.opcode = IB_WC_RECV;
+       wc.vendor_err = 0;
+       wc.qp_num = qp->ibqp.qp_num;
+       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 >= IPS_MULTICAST_LID_BASE ? 0 :
+               dlid & ((1 << (dev->mkeyprot_resv_lmc & 7)) - 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:;
+}