net/sunrpc/xprtrdma/verbs.c

   1 /*
   2  * Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
   3  *
   4  * This software is available to you under a choice of one of two
   5  * licenses.  You may choose to be licensed under the terms of the GNU
   6  * General Public License (GPL) Version 2, available from the file
   7  * COPYING in the main directory of this source tree, or the BSD-type
   8  * license below:
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  *
  14  *      Redistributions of source code must retain the above copyright
  15  *      notice, this list of conditions and the following disclaimer.
  16  *
  17  *      Redistributions in binary form must reproduce the above
  18  *      copyright notice, this list of conditions and the following
  19  *      disclaimer in the documentation and/or other materials provided
  20  *      with the distribution.
  21  *
  22  *      Neither the name of the Network Appliance, Inc. nor the names of
  23  *      its contributors may be used to endorse or promote products
  24  *      derived from this software without specific prior written
  25  *      permission.
  26  *
  27  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  28  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  29  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  30  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  31  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  32  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  33  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  34  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  35  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  36  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  37  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  38  */
  39
  40 /*
  41  * verbs.c
  42  *
  43  * Encapsulates the major functions managing:
  44  *  o adapters
  45  *  o endpoints
  46  *  o connections
  47  *  o buffer memory
  48  */
  49
  50 #include <linux/interrupt.h>
  51 #include <linux/slab.h>
  52 #include <linux/prefetch.h>
  53 #include <linux/sunrpc/addr.h>
  54 #include <asm/bitops.h>
  55 #include <linux/module.h> /* try_module_get()/module_put() */
  56
  57 #include "xprt_rdma.h"
  58
  59 /*
  60  * Globals/Macros
  61  */
  62
  63 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
  64 # define RPCDBG_FACILITY        RPCDBG_TRANS
  65 #endif
  66
  67 /*
  68  * internal functions
  69  */
  70
  71 static struct workqueue_struct *rpcrdma_receive_wq;
  72
  73 int
  74 rpcrdma_alloc_wq(void)
  75 {
  76         struct workqueue_struct *recv_wq;
  77
  78         recv_wq = alloc_workqueue("xprtrdma_receive",
  79                                   WQ_MEM_RECLAIM | WQ_UNBOUND | WQ_HIGHPRI,
  80                                   0);
  81         if (!recv_wq)
  82                 return -ENOMEM;
  83
  84         rpcrdma_receive_wq = recv_wq;
  85         return 0;
  86 }
  87
  88 void
  89 rpcrdma_destroy_wq(void)
  90 {
  91         struct workqueue_struct *wq;
  92
  93         if (rpcrdma_receive_wq) {
  94                 wq = rpcrdma_receive_wq;
  95                 rpcrdma_receive_wq = NULL;
  96                 destroy_workqueue(wq);
  97         }
  98 }
  99
 100 static void
 101 rpcrdma_qp_async_error_upcall(struct ib_event *event, void *context)
 102 {
 103         struct rpcrdma_ep *ep = context;
 104
 105         pr_err("RPC:       %s: %s on device %s ep %p\n",
 106                __func__, ib_event_msg(event->event),
 107                 event->device->name, context);
 108         if (ep->rep_connected == 1) {
 109                 ep->rep_connected = -EIO;
 110                 rpcrdma_conn_func(ep);
 111                 wake_up_all(&ep->rep_connect_wait);
 112         }
 113 }
 114
 115 static void
 116 rpcrdma_cq_async_error_upcall(struct ib_event *event, void *context)
 117 {
 118         struct rpcrdma_ep *ep = context;
 119
 120         pr_err("RPC:       %s: %s on device %s ep %p\n",
 121                __func__, ib_event_msg(event->event),
 122                 event->device->name, context);
 123         if (ep->rep_connected == 1) {
 124                 ep->rep_connected = -EIO;
 125                 rpcrdma_conn_func(ep);
 126                 wake_up_all(&ep->rep_connect_wait);
 127         }
 128 }
 129
 130 static void
 131 rpcrdma_sendcq_process_wc(struct ib_wc *wc)
 132 {
 133         /* WARNING: Only wr_id and status are reliable at this point */
 134         if (wc->wr_id == RPCRDMA_IGNORE_COMPLETION) {
 135                 if (wc->status != IB_WC_SUCCESS &&
 136                     wc->status != IB_WC_WR_FLUSH_ERR)
 137                         pr_err("RPC:       %s: SEND: %s\n",
 138                                __func__, ib_wc_status_msg(wc->status));
 139         } else {
 140                 struct rpcrdma_mw *r;
 141
 142                 r = (struct rpcrdma_mw *)(unsigned long)wc->wr_id;
 143                 r->mw_sendcompletion(wc);
 144         }
 145 }
 146
 147 /* The common case is a single send completion is waiting. By
 148  * passing two WC entries to ib_poll_cq, a return code of 1
 149  * means there is exactly one WC waiting and no more. We don't
 150  * have to invoke ib_poll_cq again to know that the CQ has been
 151  * properly drained.
 152  */
 153 static void
 154 rpcrdma_sendcq_poll(struct ib_cq *cq)
 155 {
 156         struct ib_wc *pos, wcs[2];
 157         int count, rc;
 158
 159         do {
 160                 pos = wcs;
 161
 162                 rc = ib_poll_cq(cq, ARRAY_SIZE(wcs), pos);
 163                 if (rc < 0)
 164                         break;
 165
 166                 count = rc;
 167                 while (count-- > 0)
 168                         rpcrdma_sendcq_process_wc(pos++);
 169         } while (rc == ARRAY_SIZE(wcs));
 170         return;
 171 }
 172
 173 /* Handle provider send completion upcalls.
 174  */
 175 static void
 176 rpcrdma_sendcq_upcall(struct ib_cq *cq, void *cq_context)
 177 {
 178         do {
 179                 rpcrdma_sendcq_poll(cq);
 180         } while (ib_req_notify_cq(cq, IB_CQ_NEXT_COMP |
 181                                   IB_CQ_REPORT_MISSED_EVENTS) > 0);
 182 }
 183
 184 static void
 185 rpcrdma_receive_worker(struct work_struct *work)
 186 {
 187         struct rpcrdma_rep *rep =
 188                         container_of(work, struct rpcrdma_rep, rr_work);
 189
 190         rpcrdma_reply_handler(rep);
 191 }
 192
 193 static void
 194 rpcrdma_recvcq_process_wc(struct ib_wc *wc)
 195 {
 196         struct rpcrdma_rep *rep =
 197                         (struct rpcrdma_rep *)(unsigned long)wc->wr_id;
 198
 199         /* WARNING: Only wr_id and status are reliable at this point */
 200         if (wc->status != IB_WC_SUCCESS)
 201                 goto out_fail;
 202
 203         /* status == SUCCESS means all fields in wc are trustworthy */
 204         if (wc->opcode != IB_WC_RECV)
 205                 return;
 206
 207         dprintk("RPC:       %s: rep %p opcode 'recv', length %u: success\n",
 208                 __func__, rep, wc->byte_len);
 209
 210         rep->rr_len = wc->byte_len;
 211         ib_dma_sync_single_for_cpu(rep->rr_device,
 212                                    rdmab_addr(rep->rr_rdmabuf),
 213                                    rep->rr_len, DMA_FROM_DEVICE);
 214         prefetch(rdmab_to_msg(rep->rr_rdmabuf));
 215
 216 out_schedule:
 217         queue_work(rpcrdma_receive_wq, &rep->rr_work);
 218         return;
 219
 220 out_fail:
 221         if (wc->status != IB_WC_WR_FLUSH_ERR)
 222                 pr_err("RPC:       %s: rep %p: %s\n",
 223                        __func__, rep, ib_wc_status_msg(wc->status));
 224         rep->rr_len = RPCRDMA_BAD_LEN;
 225         goto out_schedule;
 226 }
 227
 228 /* The wc array is on stack: automatic memory is always CPU-local.
 229  *
 230  * struct ib_wc is 64 bytes, making the poll array potentially
 231  * large. But this is at the bottom of the call chain. Further
 232  * substantial work is done in another thread.
 233  */
 234 static void
 235 rpcrdma_recvcq_poll(struct ib_cq *cq)
 236 {
 237         struct ib_wc *pos, wcs[4];
 238         int count, rc;
 239
 240         do {
 241                 pos = wcs;
 242
 243                 rc = ib_poll_cq(cq, ARRAY_SIZE(wcs), pos);
 244                 if (rc < 0)
 245                         break;
 246
 247                 count = rc;
 248                 while (count-- > 0)
 249                         rpcrdma_recvcq_process_wc(pos++);
 250         } while (rc == ARRAY_SIZE(wcs));
 251 }
 252
 253 /* Handle provider receive completion upcalls.
 254  */
 255 static void
 256 rpcrdma_recvcq_upcall(struct ib_cq *cq, void *cq_context)
 257 {
 258         do {
 259                 rpcrdma_recvcq_poll(cq);
 260         } while (ib_req_notify_cq(cq, IB_CQ_NEXT_COMP |
 261                                   IB_CQ_REPORT_MISSED_EVENTS) > 0);
 262 }
 263
 264 static void
 265 rpcrdma_flush_cqs(struct rpcrdma_ep *ep)
 266 {
 267         struct ib_wc wc;
 268
 269         while (ib_poll_cq(ep->rep_attr.recv_cq, 1, &wc) > 0)
 270                 rpcrdma_recvcq_process_wc(&wc);
 271         while (ib_poll_cq(ep->rep_attr.send_cq, 1, &wc) > 0)
 272                 rpcrdma_sendcq_process_wc(&wc);
 273 }
 274
 275 static int
 276 rpcrdma_conn_upcall(struct rdma_cm_id *id, struct rdma_cm_event *event)
 277 {
 278         struct rpcrdma_xprt *xprt = id->context;
 279         struct rpcrdma_ia *ia = &xprt->rx_ia;
 280         struct rpcrdma_ep *ep = &xprt->rx_ep;
 281 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 282         struct sockaddr *sap = (struct sockaddr *)&ep->rep_remote_addr;
 283 #endif
 284         struct ib_qp_attr *attr = &ia->ri_qp_attr;
 285         struct ib_qp_init_attr *iattr = &ia->ri_qp_init_attr;
 286         int connstate = 0;
 287
 288         switch (event->event) {
 289         case RDMA_CM_EVENT_ADDR_RESOLVED:
 290         case RDMA_CM_EVENT_ROUTE_RESOLVED:
 291                 ia->ri_async_rc = 0;
 292                 complete(&ia->ri_done);
 293                 break;
 294         case RDMA_CM_EVENT_ADDR_ERROR:
 295                 ia->ri_async_rc = -EHOSTUNREACH;
 296                 dprintk("RPC:       %s: CM address resolution error, ep 0x%p\n",
 297                         __func__, ep);
 298                 complete(&ia->ri_done);
 299                 break;
 300         case RDMA_CM_EVENT_ROUTE_ERROR:
 301                 ia->ri_async_rc = -ENETUNREACH;
 302                 dprintk("RPC:       %s: CM route resolution error, ep 0x%p\n",
 303                         __func__, ep);
 304                 complete(&ia->ri_done);
 305                 break;
 306         case RDMA_CM_EVENT_ESTABLISHED:
 307                 connstate = 1;
 308                 ib_query_qp(ia->ri_id->qp, attr,
 309                             IB_QP_MAX_QP_RD_ATOMIC | IB_QP_MAX_DEST_RD_ATOMIC,
 310                             iattr);
 311                 dprintk("RPC:       %s: %d responder resources"
 312                         " (%d initiator)\n",
 313                         __func__, attr->max_dest_rd_atomic,
 314                         attr->max_rd_atomic);
 315                 goto connected;
 316         case RDMA_CM_EVENT_CONNECT_ERROR:
 317                 connstate = -ENOTCONN;
 318                 goto connected;
 319         case RDMA_CM_EVENT_UNREACHABLE:
 320                 connstate = -ENETDOWN;
 321                 goto connected;
 322         case RDMA_CM_EVENT_REJECTED:
 323                 connstate = -ECONNREFUSED;
 324                 goto connected;
 325         case RDMA_CM_EVENT_DISCONNECTED:
 326                 connstate = -ECONNABORTED;
 327                 goto connected;
 328         case RDMA_CM_EVENT_DEVICE_REMOVAL:
 329                 connstate = -ENODEV;
 330 connected:
 331                 dprintk("RPC:       %s: %sconnected\n",
 332                                         __func__, connstate > 0 ? "" : "dis");
 333                 ep->rep_connected = connstate;
 334                 rpcrdma_conn_func(ep);
 335                 wake_up_all(&ep->rep_connect_wait);
 336                 /*FALLTHROUGH*/
 337         default:
 338                 dprintk("RPC:       %s: %pIS:%u (ep 0x%p): %s\n",
 339                         __func__, sap, rpc_get_port(sap), ep,
 340                         rdma_event_msg(event->event));
 341                 break;
 342         }
 343
 344 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 345         if (connstate == 1) {
 346                 int ird = attr->max_dest_rd_atomic;
 347                 int tird = ep->rep_remote_cma.responder_resources;
 348
 349                 pr_info("rpcrdma: connection to %pIS:%u on %s, memreg '%s', %d credits, %d responders%s\n",
 350                         sap, rpc_get_port(sap),
 351                         ia->ri_device->name,
 352                         ia->ri_ops->ro_displayname,
 353                         xprt->rx_buf.rb_max_requests,
 354                         ird, ird < 4 && ird < tird / 2 ? " (low!)" : "");
 355         } else if (connstate < 0) {
 356                 pr_info("rpcrdma: connection to %pIS:%u closed (%d)\n",
 357                         sap, rpc_get_port(sap), connstate);
 358         }
 359 #endif
 360
 361         return 0;
 362 }
 363
 364 static void rpcrdma_destroy_id(struct rdma_cm_id *id)
 365 {
 366         if (id) {
 367                 module_put(id->device->owner);
 368                 rdma_destroy_id(id);
 369         }
 370 }
 371
 372 static struct rdma_cm_id *
 373 rpcrdma_create_id(struct rpcrdma_xprt *xprt,
 374                         struct rpcrdma_ia *ia, struct sockaddr *addr)
 375 {
 376         struct rdma_cm_id *id;
 377         int rc;
 378
 379         init_completion(&ia->ri_done);
 380
 381         id = rdma_create_id(&init_net, rpcrdma_conn_upcall, xprt, RDMA_PS_TCP,
 382                             IB_QPT_RC);
 383         if (IS_ERR(id)) {
 384                 rc = PTR_ERR(id);
 385                 dprintk("RPC:       %s: rdma_create_id() failed %i\n",
 386                         __func__, rc);
 387                 return id;
 388         }
 389
 390         ia->ri_async_rc = -ETIMEDOUT;
 391         rc = rdma_resolve_addr(id, NULL, addr, RDMA_RESOLVE_TIMEOUT);
 392         if (rc) {
 393                 dprintk("RPC:       %s: rdma_resolve_addr() failed %i\n",
 394                         __func__, rc);
 395                 goto out;
 396         }
 397         wait_for_completion_interruptible_timeout(&ia->ri_done,
 398                                 msecs_to_jiffies(RDMA_RESOLVE_TIMEOUT) + 1);
 399
 400         /* FIXME:
 401          * Until xprtrdma supports DEVICE_REMOVAL, the provider must
 402          * be pinned while there are active NFS/RDMA mounts to prevent
 403          * hangs and crashes at umount time.
 404          */
 405         if (!ia->ri_async_rc && !try_module_get(id->device->owner)) {
 406                 dprintk("RPC:       %s: Failed to get device module\n",
 407                         __func__);
 408                 ia->ri_async_rc = -ENODEV;
 409         }
 410         rc = ia->ri_async_rc;
 411         if (rc)
 412                 goto out;
 413
 414         ia->ri_async_rc = -ETIMEDOUT;
 415         rc = rdma_resolve_route(id, RDMA_RESOLVE_TIMEOUT);
 416         if (rc) {
 417                 dprintk("RPC:       %s: rdma_resolve_route() failed %i\n",
 418                         __func__, rc);
 419                 goto put;
 420         }
 421         wait_for_completion_interruptible_timeout(&ia->ri_done,
 422                                 msecs_to_jiffies(RDMA_RESOLVE_TIMEOUT) + 1);
 423         rc = ia->ri_async_rc;
 424         if (rc)
 425                 goto put;
 426
 427         return id;
 428 put:
 429         module_put(id->device->owner);
 430 out:
 431         rdma_destroy_id(id);
 432         return ERR_PTR(rc);
 433 }
 434
 435 /*
 436  * Drain any cq, prior to teardown.
 437  */
 438 static void
 439 rpcrdma_clean_cq(struct ib_cq *cq)
 440 {
 441         struct ib_wc wc;
 442         int count = 0;
 443
 444         while (1 == ib_poll_cq(cq, 1, &wc))
 445                 ++count;
 446
 447         if (count)
 448                 dprintk("RPC:       %s: flushed %d events (last 0x%x)\n",
 449                         __func__, count, wc.opcode);
 450 }
 451
 452 /*
 453  * Exported functions.
 454  */
 455
 456 /*
 457  * Open and initialize an Interface Adapter.
 458  *  o initializes fields of struct rpcrdma_ia, including
 459  *    interface and provider attributes and protection zone.
 460  */
 461 int
 462 rpcrdma_ia_open(struct rpcrdma_xprt *xprt, struct sockaddr *addr, int memreg)
 463 {
 464         struct rpcrdma_ia *ia = &xprt->rx_ia;
 465         struct ib_device_attr *devattr = &ia->ri_devattr;
 466         int rc;
 467
 468         ia->ri_dma_mr = NULL;
 469
 470         ia->ri_id = rpcrdma_create_id(xprt, ia, addr);
 471         if (IS_ERR(ia->ri_id)) {
 472                 rc = PTR_ERR(ia->ri_id);
 473                 goto out1;
 474         }
 475         ia->ri_device = ia->ri_id->device;
 476
 477         ia->ri_pd = ib_alloc_pd(ia->ri_device);
 478         if (IS_ERR(ia->ri_pd)) {
 479                 rc = PTR_ERR(ia->ri_pd);
 480                 dprintk("RPC:       %s: ib_alloc_pd() failed %i\n",
 481                         __func__, rc);
 482                 goto out2;
 483         }
 484
 485         rc = ib_query_device(ia->ri_device, devattr);
 486         if (rc) {
 487                 dprintk("RPC:       %s: ib_query_device failed %d\n",
 488                         __func__, rc);
 489                 goto out3;
 490         }
 491
 492         if (memreg == RPCRDMA_FRMR) {
 493                 if (!(devattr->device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS) ||
 494                     (devattr->max_fast_reg_page_list_len == 0)) {
 495                         dprintk("RPC:       %s: FRMR registration "
 496                                 "not supported by HCA\n", __func__);
 497                         memreg = RPCRDMA_MTHCAFMR;
 498                 }
 499         }
 500         if (memreg == RPCRDMA_MTHCAFMR) {
 501                 if (!ia->ri_device->alloc_fmr) {
 502                         dprintk("RPC:       %s: MTHCAFMR registration "
 503                                 "not supported by HCA\n", __func__);
 504                         rc = -EINVAL;
 505                         goto out3;
 506                 }
 507         }
 508
 509         switch (memreg) {
 510         case RPCRDMA_FRMR:
 511                 ia->ri_ops = &rpcrdma_frwr_memreg_ops;
 512                 break;
 513         case RPCRDMA_ALLPHYSICAL:
 514                 ia->ri_ops = &rpcrdma_physical_memreg_ops;
 515                 break;
 516         case RPCRDMA_MTHCAFMR:
 517                 ia->ri_ops = &rpcrdma_fmr_memreg_ops;
 518                 break;
 519         default:
 520                 printk(KERN_ERR "RPC: Unsupported memory "
 521                                 "registration mode: %d\n", memreg);
 522                 rc = -ENOMEM;
 523                 goto out3;
 524         }
 525         dprintk("RPC:       %s: memory registration strategy is '%s'\n",
 526                 __func__, ia->ri_ops->ro_displayname);
 527
 528         rwlock_init(&ia->ri_qplock);
 529         return 0;
 530
 531 out3:
 532         ib_dealloc_pd(ia->ri_pd);
 533         ia->ri_pd = NULL;
 534 out2:
 535         rpcrdma_destroy_id(ia->ri_id);
 536         ia->ri_id = NULL;
 537 out1:
 538         return rc;
 539 }
 540
 541 /*
 542  * Clean up/close an IA.
 543  *   o if event handles and PD have been initialized, free them.
 544  *   o close the IA
 545  */
 546 void
 547 rpcrdma_ia_close(struct rpcrdma_ia *ia)
 548 {
 549         dprintk("RPC:       %s: entering\n", __func__);
 550         if (ia->ri_id != NULL && !IS_ERR(ia->ri_id)) {
 551                 if (ia->ri_id->qp)
 552                         rdma_destroy_qp(ia->ri_id);
 553                 rpcrdma_destroy_id(ia->ri_id);
 554                 ia->ri_id = NULL;
 555         }
 556
 557         /* If the pd is still busy, xprtrdma missed freeing a resource */
 558         if (ia->ri_pd && !IS_ERR(ia->ri_pd))
 559                 ib_dealloc_pd(ia->ri_pd);
 560 }
 561
 562 /*
 563  * Create unconnected endpoint.
 564  */
 565 int
 566 rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
 567                                 struct rpcrdma_create_data_internal *cdata)
 568 {
 569         struct ib_device_attr *devattr = &ia->ri_devattr;
 570         struct ib_cq *sendcq, *recvcq;
 571         struct ib_cq_init_attr cq_attr = {};
 572         unsigned int max_qp_wr;
 573         int rc, err;
 574
 575         if (devattr->max_sge < RPCRDMA_MAX_IOVS) {
 576                 dprintk("RPC:       %s: insufficient sge's available\n",
 577                         __func__);
 578                 return -ENOMEM;
 579         }
 580
 581         if (devattr->max_qp_wr <= RPCRDMA_BACKWARD_WRS) {
 582                 dprintk("RPC:       %s: insufficient wqe's available\n",
 583                         __func__);
 584                 return -ENOMEM;
 585         }
 586         max_qp_wr = devattr->max_qp_wr - RPCRDMA_BACKWARD_WRS;
 587
 588         /* check provider's send/recv wr limits */
 589         if (cdata->max_requests > max_qp_wr)
 590                 cdata->max_requests = max_qp_wr;
 591
 592         ep->rep_attr.event_handler = rpcrdma_qp_async_error_upcall;
 593         ep->rep_attr.qp_context = ep;
 594         ep->rep_attr.srq = NULL;
 595         ep->rep_attr.cap.max_send_wr = cdata->max_requests;
 596         ep->rep_attr.cap.max_send_wr += RPCRDMA_BACKWARD_WRS;
 597         rc = ia->ri_ops->ro_open(ia, ep, cdata);
 598         if (rc)
 599                 return rc;
 600         ep->rep_attr.cap.max_recv_wr = cdata->max_requests;
 601         ep->rep_attr.cap.max_recv_wr += RPCRDMA_BACKWARD_WRS;
 602         ep->rep_attr.cap.max_send_sge = RPCRDMA_MAX_IOVS;
 603         ep->rep_attr.cap.max_recv_sge = 1;
 604         ep->rep_attr.cap.max_inline_data = 0;
 605         ep->rep_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
 606         ep->rep_attr.qp_type = IB_QPT_RC;
 607         ep->rep_attr.port_num = ~0;
 608
 609         dprintk("RPC:       %s: requested max: dtos: send %d recv %d; "
 610                 "iovs: send %d recv %d\n",
 611                 __func__,
 612                 ep->rep_attr.cap.max_send_wr,
 613                 ep->rep_attr.cap.max_recv_wr,
 614                 ep->rep_attr.cap.max_send_sge,
 615                 ep->rep_attr.cap.max_recv_sge);
 616
 617         /* set trigger for requesting send completion */
 618         ep->rep_cqinit = ep->rep_attr.cap.max_send_wr/2 - 1;
 619         if (ep->rep_cqinit > RPCRDMA_MAX_UNSIGNALED_SENDS)
 620                 ep->rep_cqinit = RPCRDMA_MAX_UNSIGNALED_SENDS;
 621         else if (ep->rep_cqinit <= 2)
 622                 ep->rep_cqinit = 0;
 623         INIT_CQCOUNT(ep);
 624         init_waitqueue_head(&ep->rep_connect_wait);
 625         INIT_DELAYED_WORK(&ep->rep_connect_worker, rpcrdma_connect_worker);
 626
 627         cq_attr.cqe = ep->rep_attr.cap.max_send_wr + 1;
 628         sendcq = ib_create_cq(ia->ri_device, rpcrdma_sendcq_upcall,
 629                               rpcrdma_cq_async_error_upcall, NULL, &cq_attr);
 630         if (IS_ERR(sendcq)) {
 631                 rc = PTR_ERR(sendcq);
 632                 dprintk("RPC:       %s: failed to create send CQ: %i\n",
 633                         __func__, rc);
 634                 goto out1;
 635         }
 636
 637         rc = ib_req_notify_cq(sendcq, IB_CQ_NEXT_COMP);
 638         if (rc) {
 639                 dprintk("RPC:       %s: ib_req_notify_cq failed: %i\n",
 640                         __func__, rc);
 641                 goto out2;
 642         }
 643
 644         cq_attr.cqe = ep->rep_attr.cap.max_recv_wr + 1;
 645         recvcq = ib_create_cq(ia->ri_device, rpcrdma_recvcq_upcall,
 646                               rpcrdma_cq_async_error_upcall, NULL, &cq_attr);
 647         if (IS_ERR(recvcq)) {
 648                 rc = PTR_ERR(recvcq);
 649                 dprintk("RPC:       %s: failed to create recv CQ: %i\n",
 650                         __func__, rc);
 651                 goto out2;
 652         }
 653
 654         rc = ib_req_notify_cq(recvcq, IB_CQ_NEXT_COMP);
 655         if (rc) {
 656                 dprintk("RPC:       %s: ib_req_notify_cq failed: %i\n",
 657                         __func__, rc);
 658                 ib_destroy_cq(recvcq);
 659                 goto out2;
 660         }
 661
 662         ep->rep_attr.send_cq = sendcq;
 663         ep->rep_attr.recv_cq = recvcq;
 664
 665         /* Initialize cma parameters */
 666
 667         /* RPC/RDMA does not use private data */
 668         ep->rep_remote_cma.private_data = NULL;
 669         ep->rep_remote_cma.private_data_len = 0;
 670
 671         /* Client offers RDMA Read but does not initiate */
 672         ep->rep_remote_cma.initiator_depth = 0;
 673         if (devattr->max_qp_rd_atom > 32)       /* arbitrary but <= 255 */
 674                 ep->rep_remote_cma.responder_resources = 32;
 675         else
 676                 ep->rep_remote_cma.responder_resources =
 677                                                 devattr->max_qp_rd_atom;
 678
 679         ep->rep_remote_cma.retry_count = 7;
 680         ep->rep_remote_cma.flow_control = 0;
 681         ep->rep_remote_cma.rnr_retry_count = 0;
 682
 683         return 0;
 684
 685 out2:
 686         err = ib_destroy_cq(sendcq);
 687         if (err)
 688                 dprintk("RPC:       %s: ib_destroy_cq returned %i\n",
 689                         __func__, err);
 690 out1:
 691         if (ia->ri_dma_mr)
 692                 ib_dereg_mr(ia->ri_dma_mr);
 693         return rc;
 694 }
 695
 696 /*
 697  * rpcrdma_ep_destroy
 698  *
 699  * Disconnect and destroy endpoint. After this, the only
 700  * valid operations on the ep are to free it (if dynamically
 701  * allocated) or re-create it.
 702  */
 703 void
 704 rpcrdma_ep_destroy(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
 705 {
 706         int rc;
 707
 708         dprintk("RPC:       %s: entering, connected is %d\n",
 709                 __func__, ep->rep_connected);
 710
 711         cancel_delayed_work_sync(&ep->rep_connect_worker);
 712
 713         if (ia->ri_id->qp)
 714                 rpcrdma_ep_disconnect(ep, ia);
 715
 716         rpcrdma_clean_cq(ep->rep_attr.recv_cq);
 717         rpcrdma_clean_cq(ep->rep_attr.send_cq);
 718
 719         if (ia->ri_id->qp) {
 720                 rdma_destroy_qp(ia->ri_id);
 721                 ia->ri_id->qp = NULL;
 722         }
 723
 724         rc = ib_destroy_cq(ep->rep_attr.recv_cq);
 725         if (rc)
 726                 dprintk("RPC:       %s: ib_destroy_cq returned %i\n",
 727                         __func__, rc);
 728
 729         rc = ib_destroy_cq(ep->rep_attr.send_cq);
 730         if (rc)
 731                 dprintk("RPC:       %s: ib_destroy_cq returned %i\n",
 732                         __func__, rc);
 733
 734         if (ia->ri_dma_mr) {
 735                 rc = ib_dereg_mr(ia->ri_dma_mr);
 736                 dprintk("RPC:       %s: ib_dereg_mr returned %i\n",
 737                         __func__, rc);
 738         }
 739 }
 740
 741 /*
 742  * Connect unconnected endpoint.
 743  */
 744 int
 745 rpcrdma_ep_connect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
 746 {
 747         struct rdma_cm_id *id, *old;
 748         int rc = 0;
 749         int retry_count = 0;
 750
 751         if (ep->rep_connected != 0) {
 752                 struct rpcrdma_xprt *xprt;
 753 retry:
 754                 dprintk("RPC:       %s: reconnecting...\n", __func__);
 755
 756                 rpcrdma_ep_disconnect(ep, ia);
 757                 rpcrdma_flush_cqs(ep);
 758
 759                 xprt = container_of(ia, struct rpcrdma_xprt, rx_ia);
 760                 id = rpcrdma_create_id(xprt, ia,
 761                                 (struct sockaddr *)&xprt->rx_data.addr);
 762                 if (IS_ERR(id)) {
 763                         rc = -EHOSTUNREACH;
 764                         goto out;
 765                 }
 766                 /* TEMP TEMP TEMP - fail if new device:
 767                  * Deregister/remarshal *all* requests!
 768                  * Close and recreate adapter, pd, etc!
 769                  * Re-determine all attributes still sane!
 770                  * More stuff I haven't thought of!
 771                  * Rrrgh!
 772                  */
 773                 if (ia->ri_device != id->device) {
 774                         printk("RPC:       %s: can't reconnect on "
 775                                 "different device!\n", __func__);
 776                         rpcrdma_destroy_id(id);
 777                         rc = -ENETUNREACH;
 778                         goto out;
 779                 }
 780                 /* END TEMP */
 781                 rc = rdma_create_qp(id, ia->ri_pd, &ep->rep_attr);
 782                 if (rc) {
 783                         dprintk("RPC:       %s: rdma_create_qp failed %i\n",
 784                                 __func__, rc);
 785                         rpcrdma_destroy_id(id);
 786                         rc = -ENETUNREACH;
 787                         goto out;
 788                 }
 789
 790                 write_lock(&ia->ri_qplock);
 791                 old = ia->ri_id;
 792                 ia->ri_id = id;
 793                 write_unlock(&ia->ri_qplock);
 794
 795                 rdma_destroy_qp(old);
 796                 rpcrdma_destroy_id(old);
 797         } else {
 798                 dprintk("RPC:       %s: connecting...\n", __func__);
 799                 rc = rdma_create_qp(ia->ri_id, ia->ri_pd, &ep->rep_attr);
 800                 if (rc) {
 801                         dprintk("RPC:       %s: rdma_create_qp failed %i\n",
 802                                 __func__, rc);
 803                         /* do not update ep->rep_connected */
 804                         return -ENETUNREACH;
 805                 }
 806         }
 807
 808         ep->rep_connected = 0;
 809
 810         rc = rdma_connect(ia->ri_id, &ep->rep_remote_cma);
 811         if (rc) {
 812                 dprintk("RPC:       %s: rdma_connect() failed with %i\n",
 813                                 __func__, rc);
 814                 goto out;
 815         }
 816
 817         wait_event_interruptible(ep->rep_connect_wait, ep->rep_connected != 0);
 818
 819         /*
 820          * Check state. A non-peer reject indicates no listener
 821          * (ECONNREFUSED), which may be a transient state. All
 822          * others indicate a transport condition which has already
 823          * undergone a best-effort.
 824          */
 825         if (ep->rep_connected == -ECONNREFUSED &&
 826             ++retry_count <= RDMA_CONNECT_RETRY_MAX) {
 827                 dprintk("RPC:       %s: non-peer_reject, retry\n", __func__);
 828                 goto retry;
 829         }
 830         if (ep->rep_connected <= 0) {
 831                 /* Sometimes, the only way to reliably connect to remote
 832                  * CMs is to use same nonzero values for ORD and IRD. */
 833                 if (retry_count++ <= RDMA_CONNECT_RETRY_MAX + 1 &&
 834                     (ep->rep_remote_cma.responder_resources == 0 ||
 835                      ep->rep_remote_cma.initiator_depth !=
 836                                 ep->rep_remote_cma.responder_resources)) {
 837                         if (ep->rep_remote_cma.responder_resources == 0)
 838                                 ep->rep_remote_cma.responder_resources = 1;
 839                         ep->rep_remote_cma.initiator_depth =
 840                                 ep->rep_remote_cma.responder_resources;
 841                         goto retry;
 842                 }
 843                 rc = ep->rep_connected;
 844         } else {
 845                 struct rpcrdma_xprt *r_xprt;
 846                 unsigned int extras;
 847
 848                 dprintk("RPC:       %s: connected\n", __func__);
 849
 850                 r_xprt = container_of(ia, struct rpcrdma_xprt, rx_ia);
 851                 extras = r_xprt->rx_buf.rb_bc_srv_max_requests;
 852
 853                 if (extras) {
 854                         rc = rpcrdma_ep_post_extra_recv(r_xprt, extras);
 855                         if (rc)
 856                                 pr_warn("%s: rpcrdma_ep_post_extra_recv: %i\n",
 857                                         __func__, rc);
 858                                 rc = 0;
 859                 }
 860         }
 861
 862 out:
 863         if (rc)
 864                 ep->rep_connected = rc;
 865         return rc;
 866 }
 867
 868 /*
 869  * rpcrdma_ep_disconnect
 870  *
 871  * This is separate from destroy to facilitate the ability
 872  * to reconnect without recreating the endpoint.
 873  *
 874  * This call is not reentrant, and must not be made in parallel
 875  * on the same endpoint.
 876  */
 877 void
 878 rpcrdma_ep_disconnect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
 879 {
 880         int rc;
 881
 882         rpcrdma_flush_cqs(ep);
 883         rc = rdma_disconnect(ia->ri_id);
 884         if (!rc) {
 885                 /* returns without wait if not connected */
 886                 wait_event_interruptible(ep->rep_connect_wait,
 887                                                         ep->rep_connected != 1);
 888                 dprintk("RPC:       %s: after wait, %sconnected\n", __func__,
 889                         (ep->rep_connected == 1) ? "still " : "dis");
 890         } else {
 891                 dprintk("RPC:       %s: rdma_disconnect %i\n", __func__, rc);
 892                 ep->rep_connected = rc;
 893         }
 894 }
 895
 896 struct rpcrdma_req *
 897 rpcrdma_create_req(struct rpcrdma_xprt *r_xprt)
 898 {
 899         struct rpcrdma_buffer *buffer = &r_xprt->rx_buf;
 900         struct rpcrdma_req *req;
 901
 902         req = kzalloc(sizeof(*req), GFP_KERNEL);
 903         if (req == NULL)
 904                 return ERR_PTR(-ENOMEM);
 905
 906         INIT_LIST_HEAD(&req->rl_free);
 907         spin_lock(&buffer->rb_reqslock);
 908         list_add(&req->rl_all, &buffer->rb_allreqs);
 909         spin_unlock(&buffer->rb_reqslock);
 910         req->rl_buffer = &r_xprt->rx_buf;
 911         return req;
 912 }
 913
 914 /**
 915  * rpcrdma_create_rep - Allocate an rpcrdma_rep object
 916  * @r_xprt: controlling transport
 917  *
 918  * Returns 0 on success or a negative errno on failure.
 919  */
 920 int
 921  rpcrdma_create_rep(struct rpcrdma_xprt *r_xprt)
 922 {
 923         struct rpcrdma_create_data_internal *cdata = &r_xprt->rx_data;
 924         struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
 925         struct rpcrdma_ia *ia = &r_xprt->rx_ia;
 926         struct rpcrdma_rep *rep;
 927         int rc;
 928
 929         rc = -ENOMEM;
 930         rep = kzalloc(sizeof(*rep), GFP_KERNEL);
 931         if (rep == NULL)
 932                 goto out;
 933
 934         rep->rr_rdmabuf = rpcrdma_alloc_regbuf(ia, cdata->inline_rsize,
 935                                                GFP_KERNEL);
 936         if (IS_ERR(rep->rr_rdmabuf)) {
 937                 rc = PTR_ERR(rep->rr_rdmabuf);
 938                 goto out_free;
 939         }
 940
 941         rep->rr_device = ia->ri_device;
 942         rep->rr_rxprt = r_xprt;
 943         INIT_WORK(&rep->rr_work, rpcrdma_receive_worker);
 944
 945         spin_lock(&buf->rb_lock);
 946         list_add(&rep->rr_list, &buf->rb_recv_bufs);
 947         spin_unlock(&buf->rb_lock);
 948         return 0;
 949
 950 out_free:
 951         kfree(rep);
 952 out:
 953         dprintk("RPC:       %s: reply buffer %d alloc failed\n",
 954                 __func__, rc);
 955         return rc;
 956 }
 957
 958 int
 959 rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt)
 960 {
 961         struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
 962         struct rpcrdma_ia *ia = &r_xprt->rx_ia;
 963         int i, rc;
 964
 965         buf->rb_max_requests = r_xprt->rx_data.max_requests;
 966         buf->rb_bc_srv_max_requests = 0;
 967         spin_lock_init(&buf->rb_lock);
 968
 969         rc = ia->ri_ops->ro_init(r_xprt);
 970         if (rc)
 971                 goto out;
 972
 973         INIT_LIST_HEAD(&buf->rb_send_bufs);
 974         INIT_LIST_HEAD(&buf->rb_allreqs);
 975         spin_lock_init(&buf->rb_reqslock);
 976         for (i = 0; i < buf->rb_max_requests; i++) {
 977                 struct rpcrdma_req *req;
 978
 979                 req = rpcrdma_create_req(r_xprt);
 980                 if (IS_ERR(req)) {
 981                         dprintk("RPC:       %s: request buffer %d alloc"
 982                                 " failed\n", __func__, i);
 983                         rc = PTR_ERR(req);
 984                         goto out;
 985                 }
 986                 req->rl_backchannel = false;
 987                 list_add(&req->rl_free, &buf->rb_send_bufs);
 988         }
 989
 990         INIT_LIST_HEAD(&buf->rb_recv_bufs);
 991         for (i = 0; i <= buf->rb_max_requests; i++) {
 992                 rc = rpcrdma_create_rep(r_xprt);
 993                 if (rc)
 994                         goto out;
 995         }
 996
 997         return 0;
 998 out:
 999         rpcrdma_buffer_destroy(buf);
1000         return rc;
1001 }
1002
1003 static struct rpcrdma_req *
1004 rpcrdma_buffer_get_req_locked(struct rpcrdma_buffer *buf)
1005 {
1006         struct rpcrdma_req *req;
1007
1008         req = list_first_entry(&buf->rb_send_bufs,
1009                                struct rpcrdma_req, rl_free);
1010         list_del(&req->rl_free);
1011         return req;
1012 }
1013
1014 static struct rpcrdma_rep *
1015 rpcrdma_buffer_get_rep_locked(struct rpcrdma_buffer *buf)
1016 {
1017         struct rpcrdma_rep *rep;
1018
1019         rep = list_first_entry(&buf->rb_recv_bufs,
1020                                struct rpcrdma_rep, rr_list);
1021         list_del(&rep->rr_list);
1022         return rep;
1023 }
1024
1025 static void
1026 rpcrdma_destroy_rep(struct rpcrdma_ia *ia, struct rpcrdma_rep *rep)
1027 {
1028         rpcrdma_free_regbuf(ia, rep->rr_rdmabuf);
1029         kfree(rep);
1030 }
1031
1032 void
1033 rpcrdma_destroy_req(struct rpcrdma_ia *ia, struct rpcrdma_req *req)
1034 {
1035         rpcrdma_free_regbuf(ia, req->rl_sendbuf);
1036         rpcrdma_free_regbuf(ia, req->rl_rdmabuf);
1037         kfree(req);
1038 }
1039
1040 void
1041 rpcrdma_buffer_destroy(struct rpcrdma_buffer *buf)
1042 {
1043         struct rpcrdma_ia *ia = rdmab_to_ia(buf);
1044
1045         while (!list_empty(&buf->rb_recv_bufs)) {
1046                 struct rpcrdma_rep *rep;
1047
1048                 rep = rpcrdma_buffer_get_rep_locked(buf);
1049                 rpcrdma_destroy_rep(ia, rep);
1050         }
1051
1052         spin_lock(&buf->rb_reqslock);
1053         while (!list_empty(&buf->rb_allreqs)) {
1054                 struct rpcrdma_req *req;
1055
1056                 req = list_first_entry(&buf->rb_allreqs,
1057                                        struct rpcrdma_req, rl_all);
1058                 list_del(&req->rl_all);
1059
1060                 spin_unlock(&buf->rb_reqslock);
1061                 rpcrdma_destroy_req(ia, req);
1062                 spin_lock(&buf->rb_reqslock);
1063         }
1064         spin_unlock(&buf->rb_reqslock);
1065
1066         ia->ri_ops->ro_destroy(buf);
1067 }
1068
1069 struct rpcrdma_mw *
1070 rpcrdma_get_mw(struct rpcrdma_xprt *r_xprt)
1071 {
1072         struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
1073         struct rpcrdma_mw *mw = NULL;
1074
1075         spin_lock(&buf->rb_mwlock);
1076         if (!list_empty(&buf->rb_mws)) {
1077                 mw = list_first_entry(&buf->rb_mws,
1078                                       struct rpcrdma_mw, mw_list);
1079                 list_del_init(&mw->mw_list);
1080         }
1081         spin_unlock(&buf->rb_mwlock);
1082
1083         if (!mw)
1084                 pr_err("RPC:       %s: no MWs available\n", __func__);
1085         return mw;
1086 }
1087
1088 void
1089 rpcrdma_put_mw(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mw *mw)
1090 {
1091         struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
1092
1093         spin_lock(&buf->rb_mwlock);
1094         list_add_tail(&mw->mw_list, &buf->rb_mws);
1095         spin_unlock(&buf->rb_mwlock);
1096 }
1097
1098 /*
1099  * Get a set of request/reply buffers.
1100  *
1101  * Reply buffer (if available) is attached to send buffer upon return.
1102  */
1103 struct rpcrdma_req *
1104 rpcrdma_buffer_get(struct rpcrdma_buffer *buffers)
1105 {
1106         struct rpcrdma_req *req;
1107
1108         spin_lock(&buffers->rb_lock);
1109         if (list_empty(&buffers->rb_send_bufs))
1110                 goto out_reqbuf;
1111         req = rpcrdma_buffer_get_req_locked(buffers);
1112         if (list_empty(&buffers->rb_recv_bufs))
1113                 goto out_repbuf;
1114         req->rl_reply = rpcrdma_buffer_get_rep_locked(buffers);
1115         spin_unlock(&buffers->rb_lock);
1116         return req;
1117
1118 out_reqbuf:
1119         spin_unlock(&buffers->rb_lock);
1120         pr_warn("RPC:       %s: out of request buffers\n", __func__);
1121         return NULL;
1122 out_repbuf:
1123         spin_unlock(&buffers->rb_lock);
1124         pr_warn("RPC:       %s: out of reply buffers\n", __func__);
1125         req->rl_reply = NULL;
1126         return req;
1127 }
1128
1129 /*
1130  * Put request/reply buffers back into pool.
1131  * Pre-decrement counter/array index.
1132  */
1133 void
1134 rpcrdma_buffer_put(struct rpcrdma_req *req)
1135 {
1136         struct rpcrdma_buffer *buffers = req->rl_buffer;
1137         struct rpcrdma_rep *rep = req->rl_reply;
1138
1139         req->rl_niovs = 0;
1140         req->rl_reply = NULL;
1141
1142         spin_lock(&buffers->rb_lock);
1143         list_add_tail(&req->rl_free, &buffers->rb_send_bufs);
1144         if (rep)
1145                 list_add_tail(&rep->rr_list, &buffers->rb_recv_bufs);
1146         spin_unlock(&buffers->rb_lock);
1147 }
1148
1149 /*
1150  * Recover reply buffers from pool.
1151  * This happens when recovering from disconnect.
1152  */
1153 void
1154 rpcrdma_recv_buffer_get(struct rpcrdma_req *req)
1155 {
1156         struct rpcrdma_buffer *buffers = req->rl_buffer;
1157
1158         spin_lock(&buffers->rb_lock);
1159         if (!list_empty(&buffers->rb_recv_bufs))
1160                 req->rl_reply = rpcrdma_buffer_get_rep_locked(buffers);
1161         spin_unlock(&buffers->rb_lock);
1162 }
1163
1164 /*
1165  * Put reply buffers back into pool when not attached to
1166  * request. This happens in error conditions.
1167  */
1168 void
1169 rpcrdma_recv_buffer_put(struct rpcrdma_rep *rep)
1170 {
1171         struct rpcrdma_buffer *buffers = &rep->rr_rxprt->rx_buf;
1172
1173         spin_lock(&buffers->rb_lock);
1174         list_add_tail(&rep->rr_list, &buffers->rb_recv_bufs);
1175         spin_unlock(&buffers->rb_lock);
1176 }
1177
1178 /*
1179  * Wrappers for internal-use kmalloc memory registration, used by buffer code.
1180  */
1181
1182 void
1183 rpcrdma_mapping_error(struct rpcrdma_mr_seg *seg)
1184 {
1185         dprintk("RPC:       map_one: offset %p iova %llx len %zu\n",
1186                 seg->mr_offset,
1187                 (unsigned long long)seg->mr_dma, seg->mr_dmalen);
1188 }
1189
1190 /**
1191  * rpcrdma_alloc_regbuf - kmalloc and register memory for SEND/RECV buffers
1192  * @ia: controlling rpcrdma_ia
1193  * @size: size of buffer to be allocated, in bytes
1194  * @flags: GFP flags
1195  *
1196  * Returns pointer to private header of an area of internally
1197  * registered memory, or an ERR_PTR. The registered buffer follows
1198  * the end of the private header.
1199  *
1200  * xprtrdma uses a regbuf for posting an outgoing RDMA SEND, or for
1201  * receiving the payload of RDMA RECV operations. regbufs are not
1202  * used for RDMA READ/WRITE operations, thus are registered only for
1203  * LOCAL access.
1204  */
1205 struct rpcrdma_regbuf *
1206 rpcrdma_alloc_regbuf(struct rpcrdma_ia *ia, size_t size, gfp_t flags)
1207 {
1208         struct rpcrdma_regbuf *rb;
1209         struct ib_sge *iov;
1210
1211         rb = kmalloc(sizeof(*rb) + size, flags);
1212         if (rb == NULL)
1213                 goto out;
1214
1215         iov = &rb->rg_iov;
1216         iov->addr = ib_dma_map_single(ia->ri_device,
1217                                       (void *)rb->rg_base, size,
1218                                       DMA_BIDIRECTIONAL);
1219         if (ib_dma_mapping_error(ia->ri_device, iov->addr))
1220                 goto out_free;
1221
1222         iov->length = size;
1223         iov->lkey = ia->ri_pd->local_dma_lkey;
1224         rb->rg_size = size;
1225         rb->rg_owner = NULL;
1226         return rb;
1227
1228 out_free:
1229         kfree(rb);
1230 out:
1231         return ERR_PTR(-ENOMEM);
1232 }
1233
1234 /**
1235  * rpcrdma_free_regbuf - deregister and free registered buffer
1236  * @ia: controlling rpcrdma_ia
1237  * @rb: regbuf to be deregistered and freed
1238  */
1239 void
1240 rpcrdma_free_regbuf(struct rpcrdma_ia *ia, struct rpcrdma_regbuf *rb)
1241 {
1242         struct ib_sge *iov;
1243
1244         if (!rb)
1245                 return;
1246
1247         iov = &rb->rg_iov;
1248         ib_dma_unmap_single(ia->ri_device,
1249                             iov->addr, iov->length, DMA_BIDIRECTIONAL);
1250         kfree(rb);
1251 }
1252
1253 /*
1254  * Prepost any receive buffer, then post send.
1255  *
1256  * Receive buffer is donated to hardware, reclaimed upon recv completion.
1257  */
1258 int
1259 rpcrdma_ep_post(struct rpcrdma_ia *ia,
1260                 struct rpcrdma_ep *ep,
1261                 struct rpcrdma_req *req)
1262 {
1263         struct ib_device *device = ia->ri_device;
1264         struct ib_send_wr send_wr, *send_wr_fail;
1265         struct rpcrdma_rep *rep = req->rl_reply;
1266         struct ib_sge *iov = req->rl_send_iov;
1267         int i, rc;
1268
1269         if (rep) {
1270                 rc = rpcrdma_ep_post_recv(ia, ep, rep);
1271                 if (rc)
1272                         goto out;
1273                 req->rl_reply = NULL;
1274         }
1275
1276         send_wr.next = NULL;
1277         send_wr.wr_id = RPCRDMA_IGNORE_COMPLETION;
1278         send_wr.sg_list = iov;
1279         send_wr.num_sge = req->rl_niovs;
1280         send_wr.opcode = IB_WR_SEND;
1281
1282         for (i = 0; i < send_wr.num_sge; i++)
1283                 ib_dma_sync_single_for_device(device, iov[i].addr,
1284                                               iov[i].length, DMA_TO_DEVICE);
1285         dprintk("RPC:       %s: posting %d s/g entries\n",
1286                 __func__, send_wr.num_sge);
1287
1288         if (DECR_CQCOUNT(ep) > 0)
1289                 send_wr.send_flags = 0;
1290         else { /* Provider must take a send completion every now and then */
1291                 INIT_CQCOUNT(ep);
1292                 send_wr.send_flags = IB_SEND_SIGNALED;
1293         }
1294
1295         rc = ib_post_send(ia->ri_id->qp, &send_wr, &send_wr_fail);
1296         if (rc)
1297                 dprintk("RPC:       %s: ib_post_send returned %i\n", __func__,
1298                         rc);
1299 out:
1300         return rc;
1301 }
1302
1303 /*
1304  * (Re)post a receive buffer.
1305  */
1306 int
1307 rpcrdma_ep_post_recv(struct rpcrdma_ia *ia,
1308                      struct rpcrdma_ep *ep,
1309                      struct rpcrdma_rep *rep)
1310 {
1311         struct ib_recv_wr recv_wr, *recv_wr_fail;
1312         int rc;
1313
1314         recv_wr.next = NULL;
1315         recv_wr.wr_id = (u64) (unsigned long) rep;
1316         recv_wr.sg_list = &rep->rr_rdmabuf->rg_iov;
1317         recv_wr.num_sge = 1;
1318
1319         ib_dma_sync_single_for_cpu(ia->ri_device,
1320                                    rdmab_addr(rep->rr_rdmabuf),
1321                                    rdmab_length(rep->rr_rdmabuf),
1322                                    DMA_BIDIRECTIONAL);
1323
1324         rc = ib_post_recv(ia->ri_id->qp, &recv_wr, &recv_wr_fail);
1325
1326         if (rc)
1327                 dprintk("RPC:       %s: ib_post_recv returned %i\n", __func__,
1328                         rc);
1329         return rc;
1330 }
1331
1332 /**
1333  * rpcrdma_ep_post_extra_recv - Post buffers for incoming backchannel requests
1334  * @r_xprt: transport associated with these backchannel resources
1335  * @min_reqs: minimum number of incoming requests expected
1336  *
1337  * Returns zero if all requested buffers were posted, or a negative errno.
1338  */
1339 int
1340 rpcrdma_ep_post_extra_recv(struct rpcrdma_xprt *r_xprt, unsigned int count)
1341 {
1342         struct rpcrdma_buffer *buffers = &r_xprt->rx_buf;
1343         struct rpcrdma_ia *ia = &r_xprt->rx_ia;
1344         struct rpcrdma_ep *ep = &r_xprt->rx_ep;
1345         struct rpcrdma_rep *rep;
1346         int rc;
1347
1348         while (count--) {
1349                 spin_lock(&buffers->rb_lock);
1350                 if (list_empty(&buffers->rb_recv_bufs))
1351                         goto out_reqbuf;
1352                 rep = rpcrdma_buffer_get_rep_locked(buffers);
1353                 spin_unlock(&buffers->rb_lock);
1354
1355                 rc = rpcrdma_ep_post_recv(ia, ep, rep);
1356                 if (rc)
1357                         goto out_rc;
1358         }
1359
1360         return 0;
1361
1362 out_reqbuf:
1363         spin_unlock(&buffers->rb_lock);
1364         pr_warn("%s: no extra receive buffers\n", __func__);
1365         return -ENOMEM;
1366
1367 out_rc:
1368         rpcrdma_recv_buffer_put(rep);
1369         return rc;
1370 }
1371
1372 /* How many chunk list items fit within our inline buffers?
1373  */
1374 unsigned int
1375 rpcrdma_max_segments(struct rpcrdma_xprt *r_xprt)
1376 {
1377         struct rpcrdma_create_data_internal *cdata = &r_xprt->rx_data;
1378         int bytes, segments;
1379
1380         bytes = min_t(unsigned int, cdata->inline_wsize, cdata->inline_rsize);
1381         bytes -= RPCRDMA_HDRLEN_MIN;
1382         if (bytes < sizeof(struct rpcrdma_segment) * 2) {
1383                 pr_warn("RPC:       %s: inline threshold too small\n",
1384                         __func__);
1385                 return 0;
1386         }
1387
1388         segments = 1 << (fls(bytes / sizeof(struct rpcrdma_segment)) - 1);
1389         dprintk("RPC:       %s: max chunk list size = %d segments\n",
1390                 __func__, segments);
1391         return segments;
1392 }