QP request logic.

Signed-off-by: Kamal Heib <kam...@mellanox.com>
Signed-off-by: Amir Vadai <am...@mellanox.com>
---
 drivers/staging/rxe/rxe_req.c | 679 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 679 insertions(+)
 create mode 100644 drivers/staging/rxe/rxe_req.c

diff --git a/drivers/staging/rxe/rxe_req.c b/drivers/staging/rxe/rxe_req.c
new file mode 100644
index 0000000..41d13a5
--- /dev/null
+++ b/drivers/staging/rxe/rxe_req.c
@@ -0,0 +1,679 @@
+/*
+ * Copyright (c) 2015 Mellanox Technologies Ltd. All rights reserved.
+ * Copyright (c) 2015 System Fabric Works, 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 <linux/skbuff.h>
+
+#include "rxe.h"
+#include "rxe_loc.h"
+#include "rxe_queue.h"
+
+static int next_opcode(struct rxe_qp *qp, struct rxe_send_wqe *wqe,
+                      unsigned opcode);
+
+static inline void retry_first_write_send(struct rxe_qp *qp,
+                                         struct rxe_send_wqe *wqe,
+                                         unsigned mask, int npsn)
+{
+       int i;
+
+       for (i = 0; i < npsn; i++) {
+               int to_send = (wqe->dma.resid > qp->mtu) ?
+                               qp->mtu : wqe->dma.resid;
+
+               qp->req.opcode = next_opcode(qp, wqe,
+                                            wqe->wr.opcode);
+
+               if (wqe->wr.send_flags & IB_SEND_INLINE) {
+                       wqe->dma.resid -= to_send;
+                       wqe->dma.sge_offset += to_send;
+               } else {
+                       advance_dma_data(&wqe->dma, to_send);
+               }
+               if (mask & WR_WRITE_MASK)
+                       wqe->iova += qp->mtu;
+       }
+}
+
+static void req_retry(struct rxe_qp *qp)
+{
+       struct rxe_send_wqe *wqe;
+       unsigned int wqe_index;
+       unsigned int mask;
+       int npsn;
+       int first = 1;
+
+       wqe = queue_head(qp->sq.queue);
+       npsn = (qp->comp.psn - wqe->first_psn) & BTH_PSN_MASK;
+
+       qp->req.wqe_index       = consumer_index(qp->sq.queue);
+       qp->req.psn             = qp->comp.psn;
+       qp->req.opcode          = -1;
+
+       for (wqe_index = consumer_index(qp->sq.queue);
+               wqe_index != producer_index(qp->sq.queue);
+               wqe_index = next_index(qp->sq.queue, wqe_index)) {
+               wqe = addr_from_index(qp->sq.queue, wqe_index);
+               mask = wr_opcode_mask(wqe->wr.opcode, qp);
+
+               if (wqe->state == wqe_state_posted)
+                       break;
+
+               if (wqe->state == wqe_state_done)
+                       continue;
+
+               wqe->iova = (mask & WR_ATOMIC_MASK) ?
+                       wqe->wr.wr.atomic.remote_addr :
+                       wqe->wr.wr.rdma.remote_addr;
+
+               if (!first || (mask & WR_READ_MASK) == 0) {
+                       wqe->dma.resid = wqe->dma.length;
+                       wqe->dma.cur_sge = 0;
+                       wqe->dma.sge_offset = 0;
+               }
+
+               if (first) {
+                       first = 0;
+
+                       if (mask & WR_WRITE_OR_SEND_MASK)
+                               retry_first_write_send(qp, wqe, mask, npsn);
+
+                       if (mask & WR_READ_MASK)
+                               wqe->iova += npsn * qp->mtu;
+               }
+
+               wqe->state = wqe_state_posted;
+       }
+}
+
+void rnr_nak_timer(unsigned long data)
+{
+       struct rxe_qp *qp = (struct rxe_qp *)data;
+
+       pr_debug("rnr nak timer fired\n");
+       rxe_run_task(&qp->req.task, 1);
+}
+
+static struct rxe_send_wqe *req_next_wqe(struct rxe_qp *qp)
+{
+       struct rxe_send_wqe *wqe = queue_head(qp->sq.queue);
+       unsigned long flags;
+
+       if (unlikely(qp->req.state == QP_STATE_DRAIN)) {
+               /* check to see if we are drained;
+                * state_lock used by requester and completer
+                */
+               spin_lock_irqsave(&qp->state_lock, flags);
+               do {
+                       if (qp->req.state != QP_STATE_DRAIN) {
+                               /* comp just finished */
+                               spin_unlock_irqrestore(&qp->state_lock,
+                                                      flags);
+                               break;
+                       }
+
+                       if (wqe && ((qp->req.wqe_index !=
+                               consumer_index(qp->sq.queue)) ||
+                               (wqe->state != wqe_state_posted))) {
+                               /* comp not done yet */
+                               spin_unlock_irqrestore(&qp->state_lock,
+                                                      flags);
+                               break;
+                       }
+
+                       qp->req.state = QP_STATE_DRAINED;
+                       spin_unlock_irqrestore(&qp->state_lock, flags);
+
+                       if (qp->ibqp.event_handler) {
+                               struct ib_event ev;
+
+                               ev.device = qp->ibqp.device;
+                               ev.element.qp = &qp->ibqp;
+                               ev.event = IB_EVENT_SQ_DRAINED;
+                               qp->ibqp.event_handler(&ev,
+                                       qp->ibqp.qp_context);
+                       }
+               } while (0);
+       }
+
+       if (qp->req.wqe_index == producer_index(qp->sq.queue))
+               return NULL;
+
+       wqe = addr_from_index(qp->sq.queue, qp->req.wqe_index);
+
+       if (unlikely((qp->req.state == QP_STATE_DRAIN ||
+                     qp->req.state == QP_STATE_DRAINED) &&
+                    (wqe->state != wqe_state_processing)))
+               return NULL;
+
+       if (unlikely((wqe->wr.send_flags & IB_SEND_FENCE) &&
+                    (qp->req.wqe_index != consumer_index(qp->sq.queue)))) {
+               qp->req.wait_fence = 1;
+               return NULL;
+       }
+
+       wqe->mask = wr_opcode_mask(wqe->wr.opcode, qp);
+       return wqe;
+}
+
+static int next_opcode_rc(struct rxe_qp *qp, unsigned opcode, int fits)
+{
+       switch (opcode) {
+       case IB_WR_RDMA_WRITE:
+               if (qp->req.opcode == IB_OPCODE_RC_RDMA_WRITE_FIRST ||
+                   qp->req.opcode == IB_OPCODE_RC_RDMA_WRITE_MIDDLE)
+                       return fits ?
+                               IB_OPCODE_RC_RDMA_WRITE_LAST :
+                               IB_OPCODE_RC_RDMA_WRITE_MIDDLE;
+               else
+                       return fits ?
+                               IB_OPCODE_RC_RDMA_WRITE_ONLY :
+                               IB_OPCODE_RC_RDMA_WRITE_FIRST;
+
+       case IB_WR_RDMA_WRITE_WITH_IMM:
+               if (qp->req.opcode == IB_OPCODE_RC_RDMA_WRITE_FIRST ||
+                   qp->req.opcode == IB_OPCODE_RC_RDMA_WRITE_MIDDLE)
+                       return fits ?
+                               IB_OPCODE_RC_RDMA_WRITE_LAST_WITH_IMMEDIATE :
+                               IB_OPCODE_RC_RDMA_WRITE_MIDDLE;
+               else
+                       return fits ?
+                               IB_OPCODE_RC_RDMA_WRITE_ONLY_WITH_IMMEDIATE :
+                               IB_OPCODE_RC_RDMA_WRITE_FIRST;
+
+       case IB_WR_SEND:
+               if (qp->req.opcode == IB_OPCODE_RC_SEND_FIRST ||
+                   qp->req.opcode == IB_OPCODE_RC_SEND_MIDDLE)
+                       return fits ?
+                               IB_OPCODE_RC_SEND_LAST :
+                               IB_OPCODE_RC_SEND_MIDDLE;
+               else
+                       return fits ?
+                               IB_OPCODE_RC_SEND_ONLY :
+                               IB_OPCODE_RC_SEND_FIRST;
+
+       case IB_WR_SEND_WITH_IMM:
+               if (qp->req.opcode == IB_OPCODE_RC_SEND_FIRST ||
+                   qp->req.opcode == IB_OPCODE_RC_SEND_MIDDLE)
+                       return fits ?
+                               IB_OPCODE_RC_SEND_LAST_WITH_IMMEDIATE :
+                               IB_OPCODE_RC_SEND_MIDDLE;
+               else
+                       return fits ?
+                               IB_OPCODE_RC_SEND_ONLY_WITH_IMMEDIATE :
+                               IB_OPCODE_RC_SEND_FIRST;
+
+       case IB_WR_RDMA_READ:
+               return IB_OPCODE_RC_RDMA_READ_REQUEST;
+
+       case IB_WR_ATOMIC_CMP_AND_SWP:
+               return IB_OPCODE_RC_COMPARE_SWAP;
+
+       case IB_WR_ATOMIC_FETCH_AND_ADD:
+               return IB_OPCODE_RC_FETCH_ADD;
+
+       case IB_WR_SEND_WITH_INV:
+               if (qp->req.opcode == IB_OPCODE_RC_SEND_FIRST ||
+                   qp->req.opcode == IB_OPCODE_RC_SEND_MIDDLE)
+                       return fits ? IB_OPCODE_RC_SEND_LAST_INV :
+                               IB_OPCODE_RC_SEND_MIDDLE;
+               else
+                       return fits ? IB_OPCODE_RC_SEND_ONLY_INV :
+                               IB_OPCODE_RC_SEND_FIRST;
+       }
+
+       return -EINVAL;
+}
+
+static int next_opcode_uc(struct rxe_qp *qp, unsigned opcode, int fits)
+{
+       switch (opcode) {
+       case IB_WR_RDMA_WRITE:
+               if (qp->req.opcode == IB_OPCODE_UC_RDMA_WRITE_FIRST ||
+                   qp->req.opcode == IB_OPCODE_UC_RDMA_WRITE_MIDDLE)
+                       return fits ?
+                               IB_OPCODE_UC_RDMA_WRITE_LAST :
+                               IB_OPCODE_UC_RDMA_WRITE_MIDDLE;
+               else
+                       return fits ?
+                               IB_OPCODE_UC_RDMA_WRITE_ONLY :
+                               IB_OPCODE_UC_RDMA_WRITE_FIRST;
+
+       case IB_WR_RDMA_WRITE_WITH_IMM:
+               if (qp->req.opcode == IB_OPCODE_UC_RDMA_WRITE_FIRST ||
+                   qp->req.opcode == IB_OPCODE_UC_RDMA_WRITE_MIDDLE)
+                       return fits ?
+                               IB_OPCODE_UC_RDMA_WRITE_LAST_WITH_IMMEDIATE :
+                               IB_OPCODE_UC_RDMA_WRITE_MIDDLE;
+               else
+                       return fits ?
+                               IB_OPCODE_UC_RDMA_WRITE_ONLY_WITH_IMMEDIATE :
+                               IB_OPCODE_UC_RDMA_WRITE_FIRST;
+
+       case IB_WR_SEND:
+               if (qp->req.opcode == IB_OPCODE_UC_SEND_FIRST ||
+                   qp->req.opcode == IB_OPCODE_UC_SEND_MIDDLE)
+                       return fits ?
+                               IB_OPCODE_UC_SEND_LAST :
+                               IB_OPCODE_UC_SEND_MIDDLE;
+               else
+                       return fits ?
+                               IB_OPCODE_UC_SEND_ONLY :
+                               IB_OPCODE_UC_SEND_FIRST;
+
+       case IB_WR_SEND_WITH_IMM:
+               if (qp->req.opcode == IB_OPCODE_UC_SEND_FIRST ||
+                   qp->req.opcode == IB_OPCODE_UC_SEND_MIDDLE)
+                       return fits ?
+                               IB_OPCODE_UC_SEND_LAST_WITH_IMMEDIATE :
+                               IB_OPCODE_UC_SEND_MIDDLE;
+               else
+                       return fits ?
+                               IB_OPCODE_UC_SEND_ONLY_WITH_IMMEDIATE :
+                               IB_OPCODE_UC_SEND_FIRST;
+       }
+
+       return -EINVAL;
+}
+
+static int next_opcode(struct rxe_qp *qp, struct rxe_send_wqe *wqe,
+                      unsigned opcode)
+{
+       int fits = (wqe->dma.resid <= qp->mtu);
+
+       switch (qp_type(qp)) {
+       case IB_QPT_RC:
+               return next_opcode_rc(qp, opcode, fits);
+
+       case IB_QPT_UC:
+               return next_opcode_uc(qp, opcode, fits);
+
+       case IB_QPT_SMI:
+       case IB_QPT_UD:
+       case IB_QPT_GSI:
+               switch (opcode) {
+               case IB_WR_SEND:
+                       return IB_OPCODE_UD_SEND_ONLY;
+
+               case IB_WR_SEND_WITH_IMM:
+                       return IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE;
+               }
+               break;
+
+       default:
+               break;
+       }
+
+       return -EINVAL;
+}
+
+static inline int check_init_depth(struct rxe_qp *qp, struct rxe_send_wqe *wqe)
+{
+       int depth;
+
+       if (wqe->has_rd_atomic)
+               return 0;
+
+       qp->req.need_rd_atomic = 1;
+       depth = atomic_dec_return(&qp->req.rd_atomic);
+
+       if (depth >= 0) {
+               qp->req.need_rd_atomic = 0;
+               wqe->has_rd_atomic = 1;
+               return 0;
+       }
+
+       atomic_inc(&qp->req.rd_atomic);
+       return -EAGAIN;
+}
+
+static inline int get_mtu(struct rxe_qp *qp, struct rxe_send_wqe *wqe)
+{
+       struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
+       struct rxe_port *port;
+       struct rxe_av *av;
+
+       if ((qp_type(qp) == IB_QPT_RC) || (qp_type(qp) == IB_QPT_UC))
+               return qp->mtu;
+
+       av = &wqe->av;
+       port = &rxe->port[av->port_num - 1];
+
+       return port->mtu_cap;
+}
+
+static struct sk_buff *init_req_packet(struct rxe_qp *qp,
+                                      struct rxe_send_wqe *wqe,
+                                      int opcode, int payload,
+                                      struct rxe_pkt_info *pkt)
+{
+       struct rxe_dev          *rxe = to_rdev(qp->ibqp.device);
+       struct rxe_port         *port = &rxe->port[qp->attr.port_num - 1];
+       struct sk_buff          *skb;
+       struct rxe_send_wr      *ibwr = &wqe->wr;
+       struct rxe_av           *av;
+       int                     pad = (-payload) & 0x3;
+       int                     paylen;
+       int                     solicited;
+       u16                     pkey;
+       u32                     qp_num;
+       int                     ack_req;
+
+       /* length from start of bth to end of icrc */
+       paylen = rxe_opcode[opcode].length + payload + pad + RXE_ICRC_SIZE;
+
+       if (qp_type(qp) == IB_QPT_RC || qp_type(qp) == IB_QPT_UC)
+               av = &qp->pri_av;
+       else
+               av = &wqe->av;
+
+       /* init skb */
+       skb = rxe->ifc_ops->init_packet(rxe, av, paylen, pkt);
+       if (unlikely(!skb))
+               return NULL;
+
+       /* pkt->hdr, rxe, port_num, paylen and mask are initialized in ifc
+        * layer
+        */
+       pkt->opcode     = opcode;
+       pkt->qp         = qp;
+       pkt->psn        = qp->req.psn;
+       pkt->mask       |= rxe_opcode[opcode].mask;
+       pkt->paylen     = paylen;
+       pkt->offset     = 0;
+       pkt->wqe        = wqe;
+
+       /* init bth */
+       solicited = (ibwr->send_flags & IB_SEND_SOLICITED) &&
+                       (pkt->mask & RXE_END_MASK) &&
+                       ((pkt->mask & (RXE_SEND_MASK)) ||
+                       (pkt->mask & (RXE_WRITE_MASK | RXE_IMMDT_MASK)) ==
+                       (RXE_WRITE_MASK | RXE_IMMDT_MASK));
+
+       pkey = (qp_type(qp) == IB_QPT_GSI) ?
+                port->pkey_tbl[ibwr->wr.ud.pkey_index] :
+                port->pkey_tbl[qp->attr.pkey_index];
+
+       qp_num = (pkt->mask & RXE_DETH_MASK) ? ibwr->wr.ud.remote_qpn :
+                                        qp->attr.dest_qp_num;
+
+       ack_req = ((pkt->mask & RXE_END_MASK) ||
+               (qp->req.noack_pkts++ > RXE_MAX_PKT_PER_ACK));
+       if (ack_req)
+               qp->req.noack_pkts = 0;
+
+       bth_init(pkt, pkt->opcode, solicited, 0, pad, pkey, qp_num,
+                ack_req, pkt->psn);
+
+       /* init optional headers */
+       if (pkt->mask & RXE_RETH_MASK) {
+               reth_set_rkey(pkt, ibwr->wr.rdma.rkey);
+               reth_set_va(pkt, wqe->iova);
+               reth_set_len(pkt, wqe->dma.length);
+       }
+
+       if (pkt->mask & RXE_IMMDT_MASK)
+               immdt_set_imm(pkt, cpu_to_be32(ibwr->ex.imm_data));
+
+       if (pkt->mask & RXE_IETH_MASK)
+               ieth_set_rkey(pkt, ibwr->ex.invalidate_rkey);
+
+       if (pkt->mask & RXE_ATMETH_MASK) {
+               atmeth_set_va(pkt, wqe->iova);
+               if (opcode == IB_OPCODE_RC_COMPARE_SWAP ||
+                   opcode == IB_OPCODE_RD_COMPARE_SWAP) {
+                       atmeth_set_swap_add(pkt, ibwr->wr.atomic.swap);
+                       atmeth_set_comp(pkt, ibwr->wr.atomic.compare_add);
+               } else {
+                       atmeth_set_swap_add(pkt, ibwr->wr.atomic.compare_add);
+               }
+               atmeth_set_rkey(pkt, ibwr->wr.atomic.rkey);
+       }
+
+       if (pkt->mask & RXE_DETH_MASK) {
+               if (qp->ibqp.qp_num == 1)
+                       deth_set_qkey(pkt, GSI_QKEY);
+               else
+                       deth_set_qkey(pkt, ibwr->wr.ud.remote_qkey);
+               deth_set_sqp(pkt, qp->ibqp.qp_num);
+       }
+
+       return skb;
+}
+
+static int fill_packet(struct rxe_qp *qp, struct rxe_send_wqe *wqe,
+                      struct rxe_pkt_info *pkt, struct sk_buff *skb,
+                      int payload)
+{
+       struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
+       u32 crc = 0;
+       u32 *p;
+       int err;
+
+       err = rxe->ifc_ops->prepare(rxe, pkt, skb, &crc);
+       if (err)
+               return err;
+
+       if (pkt->mask & RXE_WRITE_OR_SEND) {
+               if (wqe->wr.send_flags & IB_SEND_INLINE) {
+                       u8 *tmp = &wqe->dma.inline_data[wqe->dma.sge_offset];
+
+                       crc = crc32_le(crc, tmp, payload);
+
+                       memcpy(payload_addr(pkt), tmp, payload);
+
+                       wqe->dma.resid -= payload;
+                       wqe->dma.sge_offset += payload;
+               } else {
+                       err = copy_data(rxe, qp->pd, 0, &wqe->dma,
+                                       payload_addr(pkt), payload,
+                                       from_mem_obj,
+                                       &crc);
+                       if (err)
+                               return err;
+               }
+       }
+       p = payload_addr(pkt) + payload;
+
+       *p = ~crc;
+
+       return 0;
+}
+
+static void update_state(struct rxe_qp *qp, struct rxe_send_wqe *wqe,
+                        struct rxe_pkt_info *pkt, int payload)
+{
+       /* number of packets left to send including current one */
+       int num_pkt = (wqe->dma.resid + payload + qp->mtu - 1) / qp->mtu;
+
+       /* handle zero length packet case */
+       if (num_pkt == 0)
+               num_pkt = 1;
+
+       if (pkt->mask & RXE_START_MASK) {
+               wqe->first_psn = qp->req.psn;
+               wqe->last_psn = (qp->req.psn + num_pkt - 1) & BTH_PSN_MASK;
+       }
+
+       if (pkt->mask & RXE_READ_MASK)
+               qp->req.psn = (wqe->first_psn + num_pkt) & BTH_PSN_MASK;
+       else
+               qp->req.psn = (qp->req.psn + 1) & BTH_PSN_MASK;
+
+       qp->req.opcode = pkt->opcode;
+
+       if (pkt->mask & RXE_END_MASK) {
+               if (qp_type(qp) == IB_QPT_RC)
+                       wqe->state = wqe_state_pending;
+
+               qp->req.wqe_index = next_index(qp->sq.queue,
+                                               qp->req.wqe_index);
+       } else {
+               wqe->state = wqe_state_processing;
+       }
+
+       qp->need_req_skb = 0;
+
+       if (qp->qp_timeout_jiffies && !timer_pending(&qp->retrans_timer))
+               mod_timer(&qp->retrans_timer,
+                         jiffies + qp->qp_timeout_jiffies);
+}
+
+int rxe_requester(void *arg)
+{
+       struct rxe_qp *qp = (struct rxe_qp *)arg;
+       struct rxe_pkt_info pkt;
+       struct sk_buff *skb;
+       struct rxe_send_wqe *wqe;
+       unsigned mask;
+       int payload;
+       int mtu;
+       int opcode;
+       int ret = 0;
+
+next_wqe:
+       if (unlikely(!qp->valid || qp->req.state == QP_STATE_ERROR))
+               goto exit;
+
+       if (unlikely(qp->req.state == QP_STATE_RESET)) {
+               qp->req.wqe_index = consumer_index(qp->sq.queue);
+               qp->req.opcode = -1;
+               qp->req.need_rd_atomic = 0;
+               qp->req.wait_psn = 0;
+               qp->req.need_retry = 0;
+               goto exit;
+       }
+
+       if (unlikely(qp->req.need_retry)) {
+               req_retry(qp);
+               qp->req.need_retry = 0;
+       }
+
+       wqe = req_next_wqe(qp);
+       if (unlikely(!wqe))
+               goto exit;
+
+       /* RC only, PSN window to prevent mixing new packets PSN
+        * with old ones. According to IB SPEC this number is
+        * half of the PSN range (2^24).
+        */
+       if (unlikely(qp_type(qp) == IB_QPT_RC &&
+                    qp->req.psn > (qp->comp.psn + RXE_MAX_UNACKED_PSNS))) {
+               qp->req.wait_psn = 1;
+               goto exit;
+       }
+
+       /* Limit the number of inflight SKBs per QP */
+       if (unlikely(atomic_read(&qp->skb_out) >
+                    RXE_INFLIGHT_SKBS_PER_QP_HIGH)) {
+               qp->need_req_skb = 1;
+               goto exit;
+       }
+
+       opcode = next_opcode(qp, wqe, wqe->wr.opcode);
+       if (unlikely(opcode < 0)) {
+               wqe->status = IB_WC_LOC_QP_OP_ERR;
+               goto exit;
+       }
+
+       mask = rxe_opcode[opcode].mask;
+       if (unlikely(mask & RXE_READ_OR_ATOMIC)) {
+               if (check_init_depth(qp, wqe))
+                       goto exit;
+       }
+
+       mtu = get_mtu(qp, wqe);
+       payload = (mask & RXE_WRITE_OR_SEND) ? wqe->dma.resid : 0;
+       if (payload > mtu) {
+               if (qp_type(qp) == IB_QPT_UD) {
+                       /* believe it or not this is what the spec says to do */
+
+                       /*
+                        * fake a successful UD send
+                        */
+                       wqe->first_psn = qp->req.psn;
+                       wqe->last_psn = qp->req.psn;
+                       qp->req.psn = (qp->req.psn + 1) & BTH_PSN_MASK;
+                       qp->req.opcode = IB_OPCODE_UD_SEND_ONLY;
+                       qp->req.wqe_index = next_index(qp->sq.queue,
+                                                      qp->req.wqe_index);
+                       wqe->state = wqe_state_done;
+                       wqe->status = IB_WC_SUCCESS;
+                       goto complete;
+               }
+               payload = mtu;
+       }
+
+       skb = init_req_packet(qp, wqe, opcode, payload, &pkt);
+       if (unlikely(!skb)) {
+               pr_err("Failed allocating skb\n");
+               goto err;
+       }
+
+       if (fill_packet(qp, wqe, &pkt, skb, payload)) {
+               pr_debug("Error during fill packet\n");
+               goto err;
+       }
+
+       ret = rxe_xmit_packet(to_rdev(qp->ibqp.device), qp, &pkt, skb);
+       if (ret) {
+               qp->need_req_skb = 1;
+               kfree_skb(skb);
+
+               if (-EAGAIN == ret) {
+                       rxe_run_task(&qp->req.task, 1);
+                       goto exit;
+               }
+
+               goto err;
+       }
+
+       update_state(qp, wqe, &pkt, payload);
+
+       goto next_wqe;
+
+err:
+       kfree_skb(skb);
+       wqe->status = IB_WC_LOC_PROT_ERR;
+       wqe->state = wqe_state_error;
+
+complete:
+       if (qp_type(qp) != IB_QPT_RC) {
+               while (rxe_completer(qp) == 0)
+                       ;
+       }
+
+       return 0;
+
+exit:
+       return -EAGAIN;
+}
-- 
1.8.3.1

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