drivers/infiniband/hw/ipath/ipath_ruc.c

   1 /*
   2  * Copyright (c) 2006 QLogic, Inc. All rights reserved.
   3  * Copyright (c) 2005, 2006 PathScale, Inc. All rights reserved.
   4  *
   5  * This software is available to you under a choice of one of two
   6  * licenses.  You may choose to be licensed under the terms of the GNU
   7  * General Public License (GPL) Version 2, available from the file
   8  * COPYING in the main directory of this source tree, or the
   9  * OpenIB.org BSD license below:
  10  *
  11  *     Redistribution and use in source and binary forms, with or
  12  *     without modification, are permitted provided that the following
  13  *     conditions are met:
  14  *
  15  *      - Redistributions of source code must retain the above
  16  *        copyright notice, this list of conditions and the following
  17  *        disclaimer.
  18  *
  19  *      - Redistributions in binary form must reproduce the above
  20  *        copyright notice, this list of conditions and the following
  21  *        disclaimer in the documentation and/or other materials
  22  *        provided with the distribution.
  23  *
  24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  25  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  26  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  27  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  28  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  29  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  30  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  31  * SOFTWARE.
  32  */
  33
  34 #include "ipath_verbs.h"
  35 #include "ipath_kernel.h"
  36
  37 /*
  38  * Convert the AETH RNR timeout code into the number of milliseconds.
  39  */
  40 const u32 ib_ipath_rnr_table[32] = {
  41         656,                    /* 0 */
  42         1,                      /* 1 */
  43         1,                      /* 2 */
  44         1,                      /* 3 */
  45         1,                      /* 4 */
  46         1,                      /* 5 */
  47         1,                      /* 6 */
  48         1,                      /* 7 */
  49         1,                      /* 8 */
  50         1,                      /* 9 */
  51         1,                      /* A */
  52         1,                      /* B */
  53         1,                      /* C */
  54         1,                      /* D */
  55         2,                      /* E */
  56         2,                      /* F */
  57         3,                      /* 10 */
  58         4,                      /* 11 */
  59         6,                      /* 12 */
  60         8,                      /* 13 */
  61         11,                     /* 14 */
  62         16,                     /* 15 */
  63         21,                     /* 16 */
  64         31,                     /* 17 */
  65         41,                     /* 18 */
  66         62,                     /* 19 */
  67         82,                     /* 1A */
  68         123,                    /* 1B */
  69         164,                    /* 1C */
  70         246,                    /* 1D */
  71         328,                    /* 1E */
  72         492                     /* 1F */
  73 };
  74
  75 /**
  76  * ipath_insert_rnr_queue - put QP on the RNR timeout list for the device
  77  * @qp: the QP
  78  *
  79  * XXX Use a simple list for now.  We might need a priority
  80  * queue if we have lots of QPs waiting for RNR timeouts
  81  * but that should be rare.
  82  */
  83 void ipath_insert_rnr_queue(struct ipath_qp *qp)
  84 {
  85         struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
  86         unsigned long flags;
  87
  88         spin_lock_irqsave(&dev->pending_lock, flags);
  89         if (list_empty(&dev->rnrwait))
  90                 list_add(&qp->timerwait, &dev->rnrwait);
  91         else {
  92                 struct list_head *l = &dev->rnrwait;
  93                 struct ipath_qp *nqp = list_entry(l->next, struct ipath_qp,
  94                                                   timerwait);
  95
  96                 while (qp->s_rnr_timeout >= nqp->s_rnr_timeout) {
  97                         qp->s_rnr_timeout -= nqp->s_rnr_timeout;
  98                         l = l->next;
  99                         if (l->next == &dev->rnrwait)
 100                                 break;
 101                         nqp = list_entry(l->next, struct ipath_qp,
 102                                          timerwait);
 103                 }
 104                 list_add(&qp->timerwait, l);
 105         }
 106         spin_unlock_irqrestore(&dev->pending_lock, flags);
 107 }
 108
 109 static int init_sge(struct ipath_qp *qp, struct ipath_rwqe *wqe)
 110 {
 111         struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
 112         int user = to_ipd(qp->ibqp.pd)->user;
 113         int i, j, ret;
 114         struct ib_wc wc;
 115
 116         qp->r_len = 0;
 117         for (i = j = 0; i < wqe->num_sge; i++) {
 118                 if (wqe->sg_list[i].length == 0)
 119                         continue;
 120                 /* Check LKEY */
 121                 if ((user && wqe->sg_list[i].lkey == 0) ||
 122                     !ipath_lkey_ok(&dev->lk_table,
 123                                    &qp->r_sg_list[j], &wqe->sg_list[i],
 124                                    IB_ACCESS_LOCAL_WRITE))
 125                         goto bad_lkey;
 126                 qp->r_len += wqe->sg_list[i].length;
 127                 j++;
 128         }
 129         qp->r_sge.sge = qp->r_sg_list[0];
 130         qp->r_sge.sg_list = qp->r_sg_list + 1;
 131         qp->r_sge.num_sge = j;
 132         ret = 1;
 133         goto bail;
 134
 135 bad_lkey:
 136         wc.wr_id = wqe->wr_id;
 137         wc.status = IB_WC_LOC_PROT_ERR;
 138         wc.opcode = IB_WC_RECV;
 139         wc.vendor_err = 0;
 140         wc.byte_len = 0;
 141         wc.imm_data = 0;
 142         wc.qp_num = qp->ibqp.qp_num;
 143         wc.src_qp = 0;
 144         wc.wc_flags = 0;
 145         wc.pkey_index = 0;
 146         wc.slid = 0;
 147         wc.sl = 0;
 148         wc.dlid_path_bits = 0;
 149         wc.port_num = 0;
 150         /* Signal solicited completion event. */
 151         ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc, 1);
 152         ret = 0;
 153 bail:
 154         return ret;
 155 }
 156
 157 /**
 158  * ipath_get_rwqe - copy the next RWQE into the QP's RWQE
 159  * @qp: the QP
 160  * @wr_id_only: update wr_id only, not SGEs
 161  *
 162  * Return 0 if no RWQE is available, otherwise return 1.
 163  *
 164  * Can be called from interrupt level.
 165  */
 166 int ipath_get_rwqe(struct ipath_qp *qp, int wr_id_only)
 167 {
 168         unsigned long flags;
 169         struct ipath_rq *rq;
 170         struct ipath_rwq *wq;
 171         struct ipath_srq *srq;
 172         struct ipath_rwqe *wqe;
 173         void (*handler)(struct ib_event *, void *);
 174         u32 tail;
 175         int ret;
 176
 177         if (qp->ibqp.srq) {
 178                 srq = to_isrq(qp->ibqp.srq);
 179                 handler = srq->ibsrq.event_handler;
 180                 rq = &srq->rq;
 181         } else {
 182                 srq = NULL;
 183                 handler = NULL;
 184                 rq = &qp->r_rq;
 185         }
 186
 187         spin_lock_irqsave(&rq->lock, flags);
 188         wq = rq->wq;
 189         tail = wq->tail;
 190         /* Validate tail before using it since it is user writable. */
 191         if (tail >= rq->size)
 192                 tail = 0;
 193         do {
 194                 if (unlikely(tail == wq->head)) {
 195                         spin_unlock_irqrestore(&rq->lock, flags);
 196                         ret = 0;
 197                         goto bail;
 198                 }
 199                 wqe = get_rwqe_ptr(rq, tail);
 200                 if (++tail >= rq->size)
 201                         tail = 0;
 202         } while (!wr_id_only && !init_sge(qp, wqe));
 203         qp->r_wr_id = wqe->wr_id;
 204         wq->tail = tail;
 205
 206         ret = 1;
 207         if (handler) {
 208                 u32 n;
 209
 210                 /*
 211                  * validate head pointer value and compute
 212                  * the number of remaining WQEs.
 213                  */
 214                 n = wq->head;
 215                 if (n >= rq->size)
 216                         n = 0;
 217                 if (n < tail)
 218                         n += rq->size - tail;
 219                 else
 220                         n -= tail;
 221                 if (n < srq->limit) {
 222                         struct ib_event ev;
 223
 224                         srq->limit = 0;
 225                         spin_unlock_irqrestore(&rq->lock, flags);
 226                         ev.device = qp->ibqp.device;
 227                         ev.element.srq = qp->ibqp.srq;
 228                         ev.event = IB_EVENT_SRQ_LIMIT_REACHED;
 229                         handler(&ev, srq->ibsrq.srq_context);
 230                         goto bail;
 231                 }
 232         }
 233         spin_unlock_irqrestore(&rq->lock, flags);
 234
 235 bail:
 236         return ret;
 237 }
 238
 239 /**
 240  * ipath_ruc_loopback - handle UC and RC lookback requests
 241  * @sqp: the loopback QP
 242  *
 243  * This is called from ipath_do_uc_send() or ipath_do_rc_send() to
 244  * forward a WQE addressed to the same HCA.
 245  * Note that although we are single threaded due to the tasklet, we still
 246  * have to protect against post_send().  We don't have to worry about
 247  * receive interrupts since this is a connected protocol and all packets
 248  * will pass through here.
 249  */
 250 static void ipath_ruc_loopback(struct ipath_qp *sqp)
 251 {
 252         struct ipath_ibdev *dev = to_idev(sqp->ibqp.device);
 253         struct ipath_qp *qp;
 254         struct ipath_swqe *wqe;
 255         struct ipath_sge *sge;
 256         unsigned long flags;
 257         struct ib_wc wc;
 258         u64 sdata;
 259
 260         qp = ipath_lookup_qpn(&dev->qp_table, sqp->remote_qpn);
 261         if (!qp) {
 262                 dev->n_pkt_drops++;
 263                 return;
 264         }
 265
 266 again:
 267         spin_lock_irqsave(&sqp->s_lock, flags);
 268
 269         if (!(ib_ipath_state_ops[sqp->state] & IPATH_PROCESS_SEND_OK)) {
 270                 spin_unlock_irqrestore(&sqp->s_lock, flags);
 271                 goto done;
 272         }
 273
 274         /* Get the next send request. */
 275         if (sqp->s_last == sqp->s_head) {
 276                 /* Send work queue is empty. */
 277                 spin_unlock_irqrestore(&sqp->s_lock, flags);
 278                 goto done;
 279         }
 280
 281         /*
 282          * We can rely on the entry not changing without the s_lock
 283          * being held until we update s_last.
 284          */
 285         wqe = get_swqe_ptr(sqp, sqp->s_last);
 286         spin_unlock_irqrestore(&sqp->s_lock, flags);
 287
 288         wc.wc_flags = 0;
 289         wc.imm_data = 0;
 290
 291         sqp->s_sge.sge = wqe->sg_list[0];
 292         sqp->s_sge.sg_list = wqe->sg_list + 1;
 293         sqp->s_sge.num_sge = wqe->wr.num_sge;
 294         sqp->s_len = wqe->length;
 295         switch (wqe->wr.opcode) {
 296         case IB_WR_SEND_WITH_IMM:
 297                 wc.wc_flags = IB_WC_WITH_IMM;
 298                 wc.imm_data = wqe->wr.imm_data;
 299                 /* FALLTHROUGH */
 300         case IB_WR_SEND:
 301                 if (!ipath_get_rwqe(qp, 0)) {
 302                 rnr_nak:
 303                         /* Handle RNR NAK */
 304                         if (qp->ibqp.qp_type == IB_QPT_UC)
 305                                 goto send_comp;
 306                         if (sqp->s_rnr_retry == 0) {
 307                                 wc.status = IB_WC_RNR_RETRY_EXC_ERR;
 308                                 goto err;
 309                         }
 310                         if (sqp->s_rnr_retry_cnt < 7)
 311                                 sqp->s_rnr_retry--;
 312                         dev->n_rnr_naks++;
 313                         sqp->s_rnr_timeout =
 314                                 ib_ipath_rnr_table[sqp->r_min_rnr_timer];
 315                         ipath_insert_rnr_queue(sqp);
 316                         goto done;
 317                 }
 318                 break;
 319
 320         case IB_WR_RDMA_WRITE_WITH_IMM:
 321                 wc.wc_flags = IB_WC_WITH_IMM;
 322                 wc.imm_data = wqe->wr.imm_data;
 323                 if (!ipath_get_rwqe(qp, 1))
 324                         goto rnr_nak;
 325                 /* FALLTHROUGH */
 326         case IB_WR_RDMA_WRITE:
 327                 if (wqe->length == 0)
 328                         break;
 329                 if (unlikely(!ipath_rkey_ok(dev, &qp->r_sge, wqe->length,
 330                                             wqe->wr.wr.rdma.remote_addr,
 331                                             wqe->wr.wr.rdma.rkey,
 332                                             IB_ACCESS_REMOTE_WRITE))) {
 333                 acc_err:
 334                         wc.status = IB_WC_REM_ACCESS_ERR;
 335                 err:
 336                         wc.wr_id = wqe->wr.wr_id;
 337                         wc.opcode = ib_ipath_wc_opcode[wqe->wr.opcode];
 338                         wc.vendor_err = 0;
 339                         wc.byte_len = 0;
 340                         wc.qp_num = sqp->ibqp.qp_num;
 341                         wc.src_qp = sqp->remote_qpn;
 342                         wc.pkey_index = 0;
 343                         wc.slid = sqp->remote_ah_attr.dlid;
 344                         wc.sl = sqp->remote_ah_attr.sl;
 345                         wc.dlid_path_bits = 0;
 346                         wc.port_num = 0;
 347                         ipath_sqerror_qp(sqp, &wc);
 348                         goto done;
 349                 }
 350                 break;
 351
 352         case IB_WR_RDMA_READ:
 353                 if (unlikely(!ipath_rkey_ok(dev, &sqp->s_sge, wqe->length,
 354                                             wqe->wr.wr.rdma.remote_addr,
 355                                             wqe->wr.wr.rdma.rkey,
 356                                             IB_ACCESS_REMOTE_READ)))
 357                         goto acc_err;
 358                 if (unlikely(!(qp->qp_access_flags &
 359                                IB_ACCESS_REMOTE_READ)))
 360                         goto acc_err;
 361                 qp->r_sge.sge = wqe->sg_list[0];
 362                 qp->r_sge.sg_list = wqe->sg_list + 1;
 363                 qp->r_sge.num_sge = wqe->wr.num_sge;
 364                 break;
 365
 366         case IB_WR_ATOMIC_CMP_AND_SWP:
 367         case IB_WR_ATOMIC_FETCH_AND_ADD:
 368                 if (unlikely(!ipath_rkey_ok(dev, &qp->r_sge, sizeof(u64),
 369                                             wqe->wr.wr.rdma.remote_addr,
 370                                             wqe->wr.wr.rdma.rkey,
 371                                             IB_ACCESS_REMOTE_ATOMIC)))
 372                         goto acc_err;
 373                 /* Perform atomic OP and save result. */
 374                 sdata = wqe->wr.wr.atomic.swap;
 375                 spin_lock_irqsave(&dev->pending_lock, flags);
 376                 qp->r_atomic_data = *(u64 *) qp->r_sge.sge.vaddr;
 377                 if (wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)
 378                         *(u64 *) qp->r_sge.sge.vaddr =
 379                                 qp->r_atomic_data + sdata;
 380                 else if (qp->r_atomic_data == wqe->wr.wr.atomic.compare_add)
 381                         *(u64 *) qp->r_sge.sge.vaddr = sdata;
 382                 spin_unlock_irqrestore(&dev->pending_lock, flags);
 383                 *(u64 *) sqp->s_sge.sge.vaddr = qp->r_atomic_data;
 384                 goto send_comp;
 385
 386         default:
 387                 goto done;
 388         }
 389
 390         sge = &sqp->s_sge.sge;
 391         while (sqp->s_len) {
 392                 u32 len = sqp->s_len;
 393
 394                 if (len > sge->length)
 395                         len = sge->length;
 396                 BUG_ON(len == 0);
 397                 ipath_copy_sge(&qp->r_sge, sge->vaddr, len);
 398                 sge->vaddr += len;
 399                 sge->length -= len;
 400                 sge->sge_length -= len;
 401                 if (sge->sge_length == 0) {
 402                         if (--sqp->s_sge.num_sge)
 403                                 *sge = *sqp->s_sge.sg_list++;
 404                 } else if (sge->length == 0 && sge->mr != NULL) {
 405                         if (++sge->n >= IPATH_SEGSZ) {
 406                                 if (++sge->m >= sge->mr->mapsz)
 407                                         break;
 408                                 sge->n = 0;
 409                         }
 410                         sge->vaddr =
 411                                 sge->mr->map[sge->m]->segs[sge->n].vaddr;
 412                         sge->length =
 413                                 sge->mr->map[sge->m]->segs[sge->n].length;
 414                 }
 415                 sqp->s_len -= len;
 416         }
 417
 418         if (wqe->wr.opcode == IB_WR_RDMA_WRITE ||
 419             wqe->wr.opcode == IB_WR_RDMA_READ)
 420                 goto send_comp;
 421
 422         if (wqe->wr.opcode == IB_WR_RDMA_WRITE_WITH_IMM)
 423                 wc.opcode = IB_WC_RECV_RDMA_WITH_IMM;
 424         else
 425                 wc.opcode = IB_WC_RECV;
 426         wc.wr_id = qp->r_wr_id;
 427         wc.status = IB_WC_SUCCESS;
 428         wc.vendor_err = 0;
 429         wc.byte_len = wqe->length;
 430         wc.qp_num = qp->ibqp.qp_num;
 431         wc.src_qp = qp->remote_qpn;
 432         /* XXX do we know which pkey matched? Only needed for GSI. */
 433         wc.pkey_index = 0;
 434         wc.slid = qp->remote_ah_attr.dlid;
 435         wc.sl = qp->remote_ah_attr.sl;
 436         wc.dlid_path_bits = 0;
 437         /* Signal completion event if the solicited bit is set. */
 438         ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
 439                        wqe->wr.send_flags & IB_SEND_SOLICITED);
 440
 441 send_comp:
 442         sqp->s_rnr_retry = sqp->s_rnr_retry_cnt;
 443
 444         if (!test_bit(IPATH_S_SIGNAL_REQ_WR, &sqp->s_flags) ||
 445             (wqe->wr.send_flags & IB_SEND_SIGNALED)) {
 446                 wc.wr_id = wqe->wr.wr_id;
 447                 wc.status = IB_WC_SUCCESS;
 448                 wc.opcode = ib_ipath_wc_opcode[wqe->wr.opcode];
 449                 wc.vendor_err = 0;
 450                 wc.byte_len = wqe->length;
 451                 wc.qp_num = sqp->ibqp.qp_num;
 452                 wc.src_qp = 0;
 453                 wc.pkey_index = 0;
 454                 wc.slid = 0;
 455                 wc.sl = 0;
 456                 wc.dlid_path_bits = 0;
 457                 wc.port_num = 0;
 458                 ipath_cq_enter(to_icq(sqp->ibqp.send_cq), &wc, 0);
 459         }
 460
 461         /* Update s_last now that we are finished with the SWQE */
 462         spin_lock_irqsave(&sqp->s_lock, flags);
 463         if (++sqp->s_last >= sqp->s_size)
 464                 sqp->s_last = 0;
 465         spin_unlock_irqrestore(&sqp->s_lock, flags);
 466         goto again;
 467
 468 done:
 469         if (atomic_dec_and_test(&qp->refcount))
 470                 wake_up(&qp->wait);
 471 }
 472
 473 static int want_buffer(struct ipath_devdata *dd)
 474 {
 475         set_bit(IPATH_S_PIOINTBUFAVAIL, &dd->ipath_sendctrl);
 476         ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl,
 477                          dd->ipath_sendctrl);
 478
 479         return 0;
 480 }
 481
 482 /**
 483  * ipath_no_bufs_available - tell the layer driver we need buffers
 484  * @qp: the QP that caused the problem
 485  * @dev: the device we ran out of buffers on
 486  *
 487  * Called when we run out of PIO buffers.
 488  */
 489 void ipath_no_bufs_available(struct ipath_qp *qp, struct ipath_ibdev *dev)
 490 {
 491         unsigned long flags;
 492
 493         spin_lock_irqsave(&dev->pending_lock, flags);
 494         if (list_empty(&qp->piowait))
 495                 list_add_tail(&qp->piowait, &dev->piowait);
 496         spin_unlock_irqrestore(&dev->pending_lock, flags);
 497         /*
 498          * Note that as soon as want_buffer() is called and
 499          * possibly before it returns, ipath_ib_piobufavail()
 500          * could be called.  If we are still in the tasklet function,
 501          * tasklet_hi_schedule() will not call us until the next time
 502          * tasklet_hi_schedule() is called.
 503          * We clear the tasklet flag now since we are committing to return
 504          * from the tasklet function.
 505          */
 506         clear_bit(IPATH_S_BUSY, &qp->s_flags);
 507         tasklet_unlock(&qp->s_task);
 508         want_buffer(dev->dd);
 509         dev->n_piowait++;
 510 }
 511
 512 /**
 513  * ipath_post_ruc_send - post RC and UC sends
 514  * @qp: the QP to post on
 515  * @wr: the work request to send
 516  */
 517 int ipath_post_ruc_send(struct ipath_qp *qp, struct ib_send_wr *wr)
 518 {
 519         struct ipath_swqe *wqe;
 520         unsigned long flags;
 521         u32 next;
 522         int i, j;
 523         int acc;
 524         int ret;
 525
 526         /*
 527          * Don't allow RDMA reads or atomic operations on UC or
 528          * undefined operations.
 529          * Make sure buffer is large enough to hold the result for atomics.
 530          */
 531         if (qp->ibqp.qp_type == IB_QPT_UC) {
 532                 if ((unsigned) wr->opcode >= IB_WR_RDMA_READ) {
 533                         ret = -EINVAL;
 534                         goto bail;
 535                 }
 536         } else if ((unsigned) wr->opcode > IB_WR_ATOMIC_FETCH_AND_ADD) {
 537                 ret = -EINVAL;
 538                 goto bail;
 539         } else if (wr->opcode >= IB_WR_ATOMIC_CMP_AND_SWP &&
 540                    (wr->num_sge == 0 ||
 541                     wr->sg_list[0].length < sizeof(u64) ||
 542                     wr->sg_list[0].addr & (sizeof(u64) - 1))) {
 543                 ret = -EINVAL;
 544                 goto bail;
 545         }
 546         /* IB spec says that num_sge == 0 is OK. */
 547         if (wr->num_sge > qp->s_max_sge) {
 548                 ret = -ENOMEM;
 549                 goto bail;
 550         }
 551         spin_lock_irqsave(&qp->s_lock, flags);
 552         next = qp->s_head + 1;
 553         if (next >= qp->s_size)
 554                 next = 0;
 555         if (next == qp->s_last) {
 556                 spin_unlock_irqrestore(&qp->s_lock, flags);
 557                 ret = -EINVAL;
 558                 goto bail;
 559         }
 560
 561         wqe = get_swqe_ptr(qp, qp->s_head);
 562         wqe->wr = *wr;
 563         wqe->ssn = qp->s_ssn++;
 564         wqe->sg_list[0].mr = NULL;
 565         wqe->sg_list[0].vaddr = NULL;
 566         wqe->sg_list[0].length = 0;
 567         wqe->sg_list[0].sge_length = 0;
 568         wqe->length = 0;
 569         acc = wr->opcode >= IB_WR_RDMA_READ ? IB_ACCESS_LOCAL_WRITE : 0;
 570         for (i = 0, j = 0; i < wr->num_sge; i++) {
 571                 if (to_ipd(qp->ibqp.pd)->user && wr->sg_list[i].lkey == 0) {
 572                         spin_unlock_irqrestore(&qp->s_lock, flags);
 573                         ret = -EINVAL;
 574                         goto bail;
 575                 }
 576                 if (wr->sg_list[i].length == 0)
 577                         continue;
 578                 if (!ipath_lkey_ok(&to_idev(qp->ibqp.device)->lk_table,
 579                                    &wqe->sg_list[j], &wr->sg_list[i],
 580                                    acc)) {
 581                         spin_unlock_irqrestore(&qp->s_lock, flags);
 582                         ret = -EINVAL;
 583                         goto bail;
 584                 }
 585                 wqe->length += wr->sg_list[i].length;
 586                 j++;
 587         }
 588         wqe->wr.num_sge = j;
 589         qp->s_head = next;
 590         spin_unlock_irqrestore(&qp->s_lock, flags);
 591
 592         ipath_do_ruc_send((unsigned long) qp);
 593
 594         ret = 0;
 595
 596 bail:
 597         return ret;
 598 }
 599
 600 /**
 601  * ipath_make_grh - construct a GRH header
 602  * @dev: a pointer to the ipath device
 603  * @hdr: a pointer to the GRH header being constructed
 604  * @grh: the global route address to send to
 605  * @hwords: the number of 32 bit words of header being sent
 606  * @nwords: the number of 32 bit words of data being sent
 607  *
 608  * Return the size of the header in 32 bit words.
 609  */
 610 u32 ipath_make_grh(struct ipath_ibdev *dev, struct ib_grh *hdr,
 611                    struct ib_global_route *grh, u32 hwords, u32 nwords)
 612 {
 613         hdr->version_tclass_flow =
 614                 cpu_to_be32((6 << 28) |
 615                             (grh->traffic_class << 20) |
 616                             grh->flow_label);
 617         hdr->paylen = cpu_to_be16((hwords - 2 + nwords + SIZE_OF_CRC) << 2);
 618         /* next_hdr is defined by C8-7 in ch. 8.4.1 */
 619         hdr->next_hdr = 0x1B;
 620         hdr->hop_limit = grh->hop_limit;
 621         /* The SGID is 32-bit aligned. */
 622         hdr->sgid.global.subnet_prefix = dev->gid_prefix;
 623         hdr->sgid.global.interface_id = dev->dd->ipath_guid;
 624         hdr->dgid = grh->dgid;
 625
 626         /* GRH header size in 32-bit words. */
 627         return sizeof(struct ib_grh) / sizeof(u32);
 628 }
 629
 630 /**
 631  * ipath_do_ruc_send - perform a send on an RC or UC QP
 632  * @data: contains a pointer to the QP
 633  *
 634  * Process entries in the send work queue until credit or queue is
 635  * exhausted.  Only allow one CPU to send a packet per QP (tasklet).
 636  * Otherwise, after we drop the QP s_lock, two threads could send
 637  * packets out of order.
 638  */
 639 void ipath_do_ruc_send(unsigned long data)
 640 {
 641         struct ipath_qp *qp = (struct ipath_qp *)data;
 642         struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
 643         unsigned long flags;
 644         u16 lrh0;
 645         u32 nwords;
 646         u32 extra_bytes;
 647         u32 bth0;
 648         u32 bth2;
 649         u32 pmtu = ib_mtu_enum_to_int(qp->path_mtu);
 650         struct ipath_other_headers *ohdr;
 651
 652         if (test_and_set_bit(IPATH_S_BUSY, &qp->s_flags))
 653                 goto bail;
 654
 655         if (unlikely(qp->remote_ah_attr.dlid == dev->dd->ipath_lid)) {
 656                 ipath_ruc_loopback(qp);
 657                 goto clear;
 658         }
 659
 660         ohdr = &qp->s_hdr.u.oth;
 661         if (qp->remote_ah_attr.ah_flags & IB_AH_GRH)
 662                 ohdr = &qp->s_hdr.u.l.oth;
 663
 664 again:
 665         /* Check for a constructed packet to be sent. */
 666         if (qp->s_hdrwords != 0) {
 667                 /*
 668                  * If no PIO bufs are available, return.  An interrupt will
 669                  * call ipath_ib_piobufavail() when one is available.
 670                  */
 671                 if (ipath_verbs_send(dev->dd, qp->s_hdrwords,
 672                                      (u32 *) &qp->s_hdr, qp->s_cur_size,
 673                                      qp->s_cur_sge)) {
 674                         ipath_no_bufs_available(qp, dev);
 675                         goto bail;
 676                 }
 677                 dev->n_unicast_xmit++;
 678                 /* Record that we sent the packet and s_hdr is empty. */
 679                 qp->s_hdrwords = 0;
 680         }
 681
 682         /*
 683          * The lock is needed to synchronize between setting
 684          * qp->s_ack_state, resend timer, and post_send().
 685          */
 686         spin_lock_irqsave(&qp->s_lock, flags);
 687
 688         /* Sending responses has higher priority over sending requests. */
 689         if (qp->s_ack_state != IB_OPCODE_RC_ACKNOWLEDGE &&
 690             (bth0 = ipath_make_rc_ack(qp, ohdr, pmtu)) != 0)
 691                 bth2 = qp->s_ack_psn++ & IPATH_PSN_MASK;
 692         else if (!((qp->ibqp.qp_type == IB_QPT_RC) ?
 693                    ipath_make_rc_req(qp, ohdr, pmtu, &bth0, &bth2) :
 694                    ipath_make_uc_req(qp, ohdr, pmtu, &bth0, &bth2))) {
 695                 /*
 696                  * Clear the busy bit before unlocking to avoid races with
 697                  * adding new work queue items and then failing to process
 698                  * them.
 699                  */
 700                 clear_bit(IPATH_S_BUSY, &qp->s_flags);
 701                 spin_unlock_irqrestore(&qp->s_lock, flags);
 702                 goto bail;
 703         }
 704
 705         spin_unlock_irqrestore(&qp->s_lock, flags);
 706
 707         /* Construct the header. */
 708         extra_bytes = (4 - qp->s_cur_size) & 3;
 709         nwords = (qp->s_cur_size + extra_bytes) >> 2;
 710         lrh0 = IPATH_LRH_BTH;
 711         if (unlikely(qp->remote_ah_attr.ah_flags & IB_AH_GRH)) {
 712                 qp->s_hdrwords += ipath_make_grh(dev, &qp->s_hdr.u.l.grh,
 713                                                  &qp->remote_ah_attr.grh,
 714                                                  qp->s_hdrwords, nwords);
 715                 lrh0 = IPATH_LRH_GRH;
 716         }
 717         lrh0 |= qp->remote_ah_attr.sl << 4;
 718         qp->s_hdr.lrh[0] = cpu_to_be16(lrh0);
 719         qp->s_hdr.lrh[1] = cpu_to_be16(qp->remote_ah_attr.dlid);
 720         qp->s_hdr.lrh[2] = cpu_to_be16(qp->s_hdrwords + nwords +
 721                                        SIZE_OF_CRC);
 722         qp->s_hdr.lrh[3] = cpu_to_be16(dev->dd->ipath_lid);
 723         bth0 |= ipath_get_pkey(dev->dd, qp->s_pkey_index);
 724         bth0 |= extra_bytes << 20;
 725         ohdr->bth[0] = cpu_to_be32(bth0);
 726         ohdr->bth[1] = cpu_to_be32(qp->remote_qpn);
 727         ohdr->bth[2] = cpu_to_be32(bth2);
 728
 729         /* Check for more work to do. */
 730         goto again;
 731
 732 clear:
 733         clear_bit(IPATH_S_BUSY, &qp->s_flags);
 734 bail:
 735         return;
 736 }