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 <linux/sunrpc/svc_rdma.h>
  55 #include <asm/bitops.h>
  56 #include <linux/module.h> /* try_module_get()/module_put() */
  57 #include <rdma/ib_cm.h>
  58
  59 #include "xprt_rdma.h"
  60
  61 /*
  62  * Globals/Macros
  63  */
  64
  65 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
  66 # define RPCDBG_FACILITY        RPCDBG_TRANS
  67 #endif
  68
  69 /*
  70  * internal functions
  71  */
  72 static void rpcrdma_destroy_mrs(struct rpcrdma_buffer *buf);
  73 static void rpcrdma_dma_unmap_regbuf(struct rpcrdma_regbuf *rb);
  74
  75 static struct workqueue_struct *rpcrdma_receive_wq;
  76
  77 int
  78 rpcrdma_alloc_wq(void)
  79 {
  80         struct workqueue_struct *recv_wq;
  81
  82         recv_wq = alloc_workqueue("xprtrdma_receive",
  83                                   WQ_MEM_RECLAIM | WQ_UNBOUND | WQ_HIGHPRI,
  84                                   0);
  85         if (!recv_wq)
  86                 return -ENOMEM;
  87
  88         rpcrdma_receive_wq = recv_wq;
  89         return 0;
  90 }
  91
  92 void
  93 rpcrdma_destroy_wq(void)
  94 {
  95         struct workqueue_struct *wq;
  96
  97         if (rpcrdma_receive_wq) {
  98                 wq = rpcrdma_receive_wq;
  99                 rpcrdma_receive_wq = NULL;
 100                 destroy_workqueue(wq);
 101         }
 102 }
 103
 104 static void
 105 rpcrdma_qp_async_error_upcall(struct ib_event *event, void *context)
 106 {
 107         struct rpcrdma_ep *ep = context;
 108
 109         pr_err("rpcrdma: %s on device %s ep %p\n",
 110                ib_event_msg(event->event), event->device->name, context);
 111
 112         if (ep->rep_connected == 1) {
 113                 ep->rep_connected = -EIO;
 114                 rpcrdma_conn_func(ep);
 115                 wake_up_all(&ep->rep_connect_wait);
 116         }
 117 }
 118
 119 /**
 120  * rpcrdma_wc_send - Invoked by RDMA provider for each polled Send WC
 121  * @cq: completion queue (ignored)
 122  * @wc: completed WR
 123  *
 124  */
 125 static void
 126 rpcrdma_wc_send(struct ib_cq *cq, struct ib_wc *wc)
 127 {
 128         /* WARNING: Only wr_cqe and status are reliable at this point */
 129         if (wc->status != IB_WC_SUCCESS && wc->status != IB_WC_WR_FLUSH_ERR)
 130                 pr_err("rpcrdma: Send: %s (%u/0x%x)\n",
 131                        ib_wc_status_msg(wc->status),
 132                        wc->status, wc->vendor_err);
 133 }
 134
 135 /* Perform basic sanity checking to avoid using garbage
 136  * to update the credit grant value.
 137  */
 138 static void
 139 rpcrdma_update_granted_credits(struct rpcrdma_rep *rep)
 140 {
 141         struct rpcrdma_msg *rmsgp = rdmab_to_msg(rep->rr_rdmabuf);
 142         struct rpcrdma_buffer *buffer = &rep->rr_rxprt->rx_buf;
 143         u32 credits;
 144
 145         if (rep->rr_len < RPCRDMA_HDRLEN_ERR)
 146                 return;
 147
 148         credits = be32_to_cpu(rmsgp->rm_credit);
 149         if (credits == 0)
 150                 credits = 1;    /* don't deadlock */
 151         else if (credits > buffer->rb_max_requests)
 152                 credits = buffer->rb_max_requests;
 153
 154         atomic_set(&buffer->rb_credits, credits);
 155 }
 156
 157 /**
 158  * rpcrdma_wc_receive - Invoked by RDMA provider for each polled Receive WC
 159  * @cq: completion queue (ignored)
 160  * @wc: completed WR
 161  *
 162  */
 163 static void
 164 rpcrdma_wc_receive(struct ib_cq *cq, struct ib_wc *wc)
 165 {
 166         struct ib_cqe *cqe = wc->wr_cqe;
 167         struct rpcrdma_rep *rep = container_of(cqe, struct rpcrdma_rep,
 168                                                rr_cqe);
 169
 170         /* WARNING: Only wr_id and status are reliable at this point */
 171         if (wc->status != IB_WC_SUCCESS)
 172                 goto out_fail;
 173
 174         /* status == SUCCESS means all fields in wc are trustworthy */
 175         if (wc->opcode != IB_WC_RECV)
 176                 return;
 177
 178         dprintk("RPC:       %s: rep %p opcode 'recv', length %u: success\n",
 179                 __func__, rep, wc->byte_len);
 180
 181         rep->rr_len = wc->byte_len;
 182         rep->rr_wc_flags = wc->wc_flags;
 183         rep->rr_inv_rkey = wc->ex.invalidate_rkey;
 184
 185         ib_dma_sync_single_for_cpu(rdmab_device(rep->rr_rdmabuf),
 186                                    rdmab_addr(rep->rr_rdmabuf),
 187                                    rep->rr_len, DMA_FROM_DEVICE);
 188
 189         rpcrdma_update_granted_credits(rep);
 190
 191 out_schedule:
 192         queue_work(rpcrdma_receive_wq, &rep->rr_work);
 193         return;
 194
 195 out_fail:
 196         if (wc->status != IB_WC_WR_FLUSH_ERR)
 197                 pr_err("rpcrdma: Recv: %s (%u/0x%x)\n",
 198                        ib_wc_status_msg(wc->status),
 199                        wc->status, wc->vendor_err);
 200         rep->rr_len = RPCRDMA_BAD_LEN;
 201         goto out_schedule;
 202 }
 203
 204 static void
 205 rpcrdma_update_connect_private(struct rpcrdma_xprt *r_xprt,
 206                                struct rdma_conn_param *param)
 207 {
 208         struct rpcrdma_create_data_internal *cdata = &r_xprt->rx_data;
 209         const struct rpcrdma_connect_private *pmsg = param->private_data;
 210         unsigned int rsize, wsize;
 211
 212         /* Default settings for RPC-over-RDMA Version One */
 213         r_xprt->rx_ia.ri_reminv_expected = false;
 214         r_xprt->rx_ia.ri_implicit_roundup = xprt_rdma_pad_optimize;
 215         rsize = RPCRDMA_V1_DEF_INLINE_SIZE;
 216         wsize = RPCRDMA_V1_DEF_INLINE_SIZE;
 217
 218         if (pmsg &&
 219             pmsg->cp_magic == rpcrdma_cmp_magic &&
 220             pmsg->cp_version == RPCRDMA_CMP_VERSION) {
 221                 r_xprt->rx_ia.ri_reminv_expected = true;
 222                 r_xprt->rx_ia.ri_implicit_roundup = true;
 223                 rsize = rpcrdma_decode_buffer_size(pmsg->cp_send_size);
 224                 wsize = rpcrdma_decode_buffer_size(pmsg->cp_recv_size);
 225         }
 226
 227         if (rsize < cdata->inline_rsize)
 228                 cdata->inline_rsize = rsize;
 229         if (wsize < cdata->inline_wsize)
 230                 cdata->inline_wsize = wsize;
 231         dprintk("RPC:       %s: max send %u, max recv %u\n",
 232                 __func__, cdata->inline_wsize, cdata->inline_rsize);
 233         rpcrdma_set_max_header_sizes(r_xprt);
 234 }
 235
 236 static int
 237 rpcrdma_conn_upcall(struct rdma_cm_id *id, struct rdma_cm_event *event)
 238 {
 239         struct rpcrdma_xprt *xprt = id->context;
 240         struct rpcrdma_ia *ia = &xprt->rx_ia;
 241         struct rpcrdma_ep *ep = &xprt->rx_ep;
 242 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 243         struct sockaddr *sap = (struct sockaddr *)&ep->rep_remote_addr;
 244 #endif
 245         struct ib_qp_attr *attr = &ia->ri_qp_attr;
 246         struct ib_qp_init_attr *iattr = &ia->ri_qp_init_attr;
 247         int connstate = 0;
 248
 249         switch (event->event) {
 250         case RDMA_CM_EVENT_ADDR_RESOLVED:
 251         case RDMA_CM_EVENT_ROUTE_RESOLVED:
 252                 ia->ri_async_rc = 0;
 253                 complete(&ia->ri_done);
 254                 break;
 255         case RDMA_CM_EVENT_ADDR_ERROR:
 256                 ia->ri_async_rc = -EHOSTUNREACH;
 257                 dprintk("RPC:       %s: CM address resolution error, ep 0x%p\n",
 258                         __func__, ep);
 259                 complete(&ia->ri_done);
 260                 break;
 261         case RDMA_CM_EVENT_ROUTE_ERROR:
 262                 ia->ri_async_rc = -ENETUNREACH;
 263                 dprintk("RPC:       %s: CM route resolution error, ep 0x%p\n",
 264                         __func__, ep);
 265                 complete(&ia->ri_done);
 266                 break;
 267         case RDMA_CM_EVENT_DEVICE_REMOVAL:
 268 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 269                 pr_info("rpcrdma: removing device for %pIS:%u\n",
 270                         sap, rpc_get_port(sap));
 271 #endif
 272                 set_bit(RPCRDMA_IAF_REMOVING, &ia->ri_flags);
 273                 ep->rep_connected = -ENODEV;
 274                 xprt_force_disconnect(&xprt->rx_xprt);
 275                 wait_for_completion(&ia->ri_remove_done);
 276
 277                 ia->ri_id = NULL;
 278                 ia->ri_pd = NULL;
 279                 ia->ri_device = NULL;
 280                 /* Return 1 to ensure the core destroys the id. */
 281                 return 1;
 282         case RDMA_CM_EVENT_ESTABLISHED:
 283                 connstate = 1;
 284                 ib_query_qp(ia->ri_id->qp, attr,
 285                             IB_QP_MAX_QP_RD_ATOMIC | IB_QP_MAX_DEST_RD_ATOMIC,
 286                             iattr);
 287                 dprintk("RPC:       %s: %d responder resources"
 288                         " (%d initiator)\n",
 289                         __func__, attr->max_dest_rd_atomic,
 290                         attr->max_rd_atomic);
 291                 rpcrdma_update_connect_private(xprt, &event->param.conn);
 292                 goto connected;
 293         case RDMA_CM_EVENT_CONNECT_ERROR:
 294                 connstate = -ENOTCONN;
 295                 goto connected;
 296         case RDMA_CM_EVENT_UNREACHABLE:
 297                 connstate = -ENETDOWN;
 298                 goto connected;
 299         case RDMA_CM_EVENT_REJECTED:
 300 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 301                 pr_info("rpcrdma: connection to %pIS:%u on %s rejected: %s\n",
 302                         sap, rpc_get_port(sap), ia->ri_device->name,
 303                         rdma_reject_msg(id, event->status));
 304 #endif
 305                 connstate = -ECONNREFUSED;
 306                 if (event->status == IB_CM_REJ_STALE_CONN)
 307                         connstate = -EAGAIN;
 308                 goto connected;
 309         case RDMA_CM_EVENT_DISCONNECTED:
 310                 connstate = -ECONNABORTED;
 311 connected:
 312                 dprintk("RPC:       %s: %sconnected\n",
 313                                         __func__, connstate > 0 ? "" : "dis");
 314                 atomic_set(&xprt->rx_buf.rb_credits, 1);
 315                 ep->rep_connected = connstate;
 316                 rpcrdma_conn_func(ep);
 317                 wake_up_all(&ep->rep_connect_wait);
 318                 /*FALLTHROUGH*/
 319         default:
 320                 dprintk("RPC:       %s: %pIS:%u (ep 0x%p): %s\n",
 321                         __func__, sap, rpc_get_port(sap), ep,
 322                         rdma_event_msg(event->event));
 323                 break;
 324         }
 325
 326 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 327         if (connstate == 1) {
 328                 int ird = attr->max_dest_rd_atomic;
 329                 int tird = ep->rep_remote_cma.responder_resources;
 330
 331                 pr_info("rpcrdma: connection to %pIS:%u on %s, memreg '%s', %d credits, %d responders%s\n",
 332                         sap, rpc_get_port(sap),
 333                         ia->ri_device->name,
 334                         ia->ri_ops->ro_displayname,
 335                         xprt->rx_buf.rb_max_requests,
 336                         ird, ird < 4 && ird < tird / 2 ? " (low!)" : "");
 337         } else if (connstate < 0) {
 338                 pr_info("rpcrdma: connection to %pIS:%u closed (%d)\n",
 339                         sap, rpc_get_port(sap), connstate);
 340         }
 341 #endif
 342
 343         return 0;
 344 }
 345
 346 static void rpcrdma_destroy_id(struct rdma_cm_id *id)
 347 {
 348         if (id) {
 349                 module_put(id->device->owner);
 350                 rdma_destroy_id(id);
 351         }
 352 }
 353
 354 static struct rdma_cm_id *
 355 rpcrdma_create_id(struct rpcrdma_xprt *xprt,
 356                         struct rpcrdma_ia *ia, struct sockaddr *addr)
 357 {
 358         unsigned long wtimeout = msecs_to_jiffies(RDMA_RESOLVE_TIMEOUT) + 1;
 359         struct rdma_cm_id *id;
 360         int rc;
 361
 362         init_completion(&ia->ri_done);
 363         init_completion(&ia->ri_remove_done);
 364
 365         id = rdma_create_id(&init_net, rpcrdma_conn_upcall, xprt, RDMA_PS_TCP,
 366                             IB_QPT_RC);
 367         if (IS_ERR(id)) {
 368                 rc = PTR_ERR(id);
 369                 dprintk("RPC:       %s: rdma_create_id() failed %i\n",
 370                         __func__, rc);
 371                 return id;
 372         }
 373
 374         ia->ri_async_rc = -ETIMEDOUT;
 375         rc = rdma_resolve_addr(id, NULL, addr, RDMA_RESOLVE_TIMEOUT);
 376         if (rc) {
 377                 dprintk("RPC:       %s: rdma_resolve_addr() failed %i\n",
 378                         __func__, rc);
 379                 goto out;
 380         }
 381         rc = wait_for_completion_interruptible_timeout(&ia->ri_done, wtimeout);
 382         if (rc < 0) {
 383                 dprintk("RPC:       %s: wait() exited: %i\n",
 384                         __func__, rc);
 385                 goto out;
 386         }
 387
 388         /* FIXME:
 389          * Until xprtrdma supports DEVICE_REMOVAL, the provider must
 390          * be pinned while there are active NFS/RDMA mounts to prevent
 391          * hangs and crashes at umount time.
 392          */
 393         if (!ia->ri_async_rc && !try_module_get(id->device->owner)) {
 394                 dprintk("RPC:       %s: Failed to get device module\n",
 395                         __func__);
 396                 ia->ri_async_rc = -ENODEV;
 397         }
 398         rc = ia->ri_async_rc;
 399         if (rc)
 400                 goto out;
 401
 402         ia->ri_async_rc = -ETIMEDOUT;
 403         rc = rdma_resolve_route(id, RDMA_RESOLVE_TIMEOUT);
 404         if (rc) {
 405                 dprintk("RPC:       %s: rdma_resolve_route() failed %i\n",
 406                         __func__, rc);
 407                 goto put;
 408         }
 409         rc = wait_for_completion_interruptible_timeout(&ia->ri_done, wtimeout);
 410         if (rc < 0) {
 411                 dprintk("RPC:       %s: wait() exited: %i\n",
 412                         __func__, rc);
 413                 goto put;
 414         }
 415         rc = ia->ri_async_rc;
 416         if (rc)
 417                 goto put;
 418
 419         return id;
 420 put:
 421         module_put(id->device->owner);
 422 out:
 423         rdma_destroy_id(id);
 424         return ERR_PTR(rc);
 425 }
 426
 427 /*
 428  * Exported functions.
 429  */
 430
 431 /**
 432  * rpcrdma_ia_open - Open and initialize an Interface Adapter.
 433  * @xprt: controlling transport
 434  * @addr: IP address of remote peer
 435  *
 436  * Returns 0 on success, negative errno if an appropriate
 437  * Interface Adapter could not be found and opened.
 438  */
 439 int
 440 rpcrdma_ia_open(struct rpcrdma_xprt *xprt, struct sockaddr *addr)
 441 {
 442         struct rpcrdma_ia *ia = &xprt->rx_ia;
 443         int rc;
 444
 445         ia->ri_id = rpcrdma_create_id(xprt, ia, addr);
 446         if (IS_ERR(ia->ri_id)) {
 447                 rc = PTR_ERR(ia->ri_id);
 448                 goto out_err;
 449         }
 450         ia->ri_device = ia->ri_id->device;
 451
 452         ia->ri_pd = ib_alloc_pd(ia->ri_device, 0);
 453         if (IS_ERR(ia->ri_pd)) {
 454                 rc = PTR_ERR(ia->ri_pd);
 455                 pr_err("rpcrdma: ib_alloc_pd() returned %d\n", rc);
 456                 goto out_err;
 457         }
 458
 459         switch (xprt_rdma_memreg_strategy) {
 460         case RPCRDMA_FRMR:
 461                 if (frwr_is_supported(ia)) {
 462                         ia->ri_ops = &rpcrdma_frwr_memreg_ops;
 463                         break;
 464                 }
 465                 /*FALLTHROUGH*/
 466         case RPCRDMA_MTHCAFMR:
 467                 if (fmr_is_supported(ia)) {
 468                         ia->ri_ops = &rpcrdma_fmr_memreg_ops;
 469                         break;
 470                 }
 471                 /*FALLTHROUGH*/
 472         default:
 473                 pr_err("rpcrdma: Device %s does not support memreg mode %d\n",
 474                        ia->ri_device->name, xprt_rdma_memreg_strategy);
 475                 rc = -EINVAL;
 476                 goto out_err;
 477         }
 478
 479         return 0;
 480
 481 out_err:
 482         rpcrdma_ia_close(ia);
 483         return rc;
 484 }
 485
 486 /**
 487  * rpcrdma_ia_remove - Handle device driver unload
 488  * @ia: interface adapter being removed
 489  *
 490  * Divest transport H/W resources associated with this adapter,
 491  * but allow it to be restored later.
 492  */
 493 void
 494 rpcrdma_ia_remove(struct rpcrdma_ia *ia)
 495 {
 496         struct rpcrdma_xprt *r_xprt = container_of(ia, struct rpcrdma_xprt,
 497                                                    rx_ia);
 498         struct rpcrdma_ep *ep = &r_xprt->rx_ep;
 499         struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
 500         struct rpcrdma_req *req;
 501         struct rpcrdma_rep *rep;
 502
 503         cancel_delayed_work_sync(&buf->rb_refresh_worker);
 504
 505         /* This is similar to rpcrdma_ep_destroy, but:
 506          * - Don't cancel the connect worker.
 507          * - Don't call rpcrdma_ep_disconnect, which waits
 508          *   for another conn upcall, which will deadlock.
 509          * - rdma_disconnect is unneeded, the underlying
 510          *   connection is already gone.
 511          */
 512         if (ia->ri_id->qp) {
 513                 ib_drain_qp(ia->ri_id->qp);
 514                 rdma_destroy_qp(ia->ri_id);
 515                 ia->ri_id->qp = NULL;
 516         }
 517         ib_free_cq(ep->rep_attr.recv_cq);
 518         ib_free_cq(ep->rep_attr.send_cq);
 519
 520         /* The ULP is responsible for ensuring all DMA
 521          * mappings and MRs are gone.
 522          */
 523         list_for_each_entry(rep, &buf->rb_recv_bufs, rr_list)
 524                 rpcrdma_dma_unmap_regbuf(rep->rr_rdmabuf);
 525         list_for_each_entry(req, &buf->rb_allreqs, rl_all) {
 526                 rpcrdma_dma_unmap_regbuf(req->rl_rdmabuf);
 527                 rpcrdma_dma_unmap_regbuf(req->rl_sendbuf);
 528                 rpcrdma_dma_unmap_regbuf(req->rl_recvbuf);
 529         }
 530         rpcrdma_destroy_mrs(buf);
 531
 532         /* Allow waiters to continue */
 533         complete(&ia->ri_remove_done);
 534 }
 535
 536 /**
 537  * rpcrdma_ia_close - Clean up/close an IA.
 538  * @ia: interface adapter to close
 539  *
 540  */
 541 void
 542 rpcrdma_ia_close(struct rpcrdma_ia *ia)
 543 {
 544         dprintk("RPC:       %s: entering\n", __func__);
 545         if (ia->ri_id != NULL && !IS_ERR(ia->ri_id)) {
 546                 if (ia->ri_id->qp)
 547                         rdma_destroy_qp(ia->ri_id);
 548                 rpcrdma_destroy_id(ia->ri_id);
 549         }
 550         ia->ri_id = NULL;
 551         ia->ri_device = NULL;
 552
 553         /* If the pd is still busy, xprtrdma missed freeing a resource */
 554         if (ia->ri_pd && !IS_ERR(ia->ri_pd))
 555                 ib_dealloc_pd(ia->ri_pd);
 556         ia->ri_pd = NULL;
 557 }
 558
 559 /*
 560  * Create unconnected endpoint.
 561  */
 562 int
 563 rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
 564                   struct rpcrdma_create_data_internal *cdata)
 565 {
 566         struct rpcrdma_connect_private *pmsg = &ep->rep_cm_private;
 567         unsigned int max_qp_wr, max_sge;
 568         struct ib_cq *sendcq, *recvcq;
 569         int rc;
 570
 571         max_sge = min_t(unsigned int, ia->ri_device->attrs.max_sge,
 572                         RPCRDMA_MAX_SEND_SGES);
 573         if (max_sge < RPCRDMA_MIN_SEND_SGES) {
 574                 pr_warn("rpcrdma: HCA provides only %d send SGEs\n", max_sge);
 575                 return -ENOMEM;
 576         }
 577         ia->ri_max_send_sges = max_sge - RPCRDMA_MIN_SEND_SGES;
 578
 579         if (ia->ri_device->attrs.max_qp_wr <= RPCRDMA_BACKWARD_WRS) {
 580                 dprintk("RPC:       %s: insufficient wqe's available\n",
 581                         __func__);
 582                 return -ENOMEM;
 583         }
 584         max_qp_wr = ia->ri_device->attrs.max_qp_wr - RPCRDMA_BACKWARD_WRS - 1;
 585
 586         /* check provider's send/recv wr limits */
 587         if (cdata->max_requests > max_qp_wr)
 588                 cdata->max_requests = max_qp_wr;
 589
 590         ep->rep_attr.event_handler = rpcrdma_qp_async_error_upcall;
 591         ep->rep_attr.qp_context = ep;
 592         ep->rep_attr.srq = NULL;
 593         ep->rep_attr.cap.max_send_wr = cdata->max_requests;
 594         ep->rep_attr.cap.max_send_wr += RPCRDMA_BACKWARD_WRS;
 595         ep->rep_attr.cap.max_send_wr += 1;      /* drain cqe */
 596         rc = ia->ri_ops->ro_open(ia, ep, cdata);
 597         if (rc)
 598                 return rc;
 599         ep->rep_attr.cap.max_recv_wr = cdata->max_requests;
 600         ep->rep_attr.cap.max_recv_wr += RPCRDMA_BACKWARD_WRS;
 601         ep->rep_attr.cap.max_recv_wr += 1;      /* drain cqe */
 602         ep->rep_attr.cap.max_send_sge = max_sge;
 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 <= 2)
 620                 ep->rep_cqinit = 0;     /* always signal? */
 621         rpcrdma_init_cqcount(ep, 0);
 622         init_waitqueue_head(&ep->rep_connect_wait);
 623         INIT_DELAYED_WORK(&ep->rep_connect_worker, rpcrdma_connect_worker);
 624
 625         sendcq = ib_alloc_cq(ia->ri_device, NULL,
 626                              ep->rep_attr.cap.max_send_wr + 1,
 627                              0, IB_POLL_SOFTIRQ);
 628         if (IS_ERR(sendcq)) {
 629                 rc = PTR_ERR(sendcq);
 630                 dprintk("RPC:       %s: failed to create send CQ: %i\n",
 631                         __func__, rc);
 632                 goto out1;
 633         }
 634
 635         recvcq = ib_alloc_cq(ia->ri_device, NULL,
 636                              ep->rep_attr.cap.max_recv_wr + 1,
 637                              0, IB_POLL_SOFTIRQ);
 638         if (IS_ERR(recvcq)) {
 639                 rc = PTR_ERR(recvcq);
 640                 dprintk("RPC:       %s: failed to create recv CQ: %i\n",
 641                         __func__, rc);
 642                 goto out2;
 643         }
 644
 645         ep->rep_attr.send_cq = sendcq;
 646         ep->rep_attr.recv_cq = recvcq;
 647
 648         /* Initialize cma parameters */
 649         memset(&ep->rep_remote_cma, 0, sizeof(ep->rep_remote_cma));
 650
 651         /* Prepare RDMA-CM private message */
 652         pmsg->cp_magic = rpcrdma_cmp_magic;
 653         pmsg->cp_version = RPCRDMA_CMP_VERSION;
 654         pmsg->cp_flags |= ia->ri_ops->ro_send_w_inv_ok;
 655         pmsg->cp_send_size = rpcrdma_encode_buffer_size(cdata->inline_wsize);
 656         pmsg->cp_recv_size = rpcrdma_encode_buffer_size(cdata->inline_rsize);
 657         ep->rep_remote_cma.private_data = pmsg;
 658         ep->rep_remote_cma.private_data_len = sizeof(*pmsg);
 659
 660         /* Client offers RDMA Read but does not initiate */
 661         ep->rep_remote_cma.initiator_depth = 0;
 662         if (ia->ri_device->attrs.max_qp_rd_atom > 32)   /* arbitrary but <= 255 */
 663                 ep->rep_remote_cma.responder_resources = 32;
 664         else
 665                 ep->rep_remote_cma.responder_resources =
 666                                                 ia->ri_device->attrs.max_qp_rd_atom;
 667
 668         /* Limit transport retries so client can detect server
 669          * GID changes quickly. RPC layer handles re-establishing
 670          * transport connection and retransmission.
 671          */
 672         ep->rep_remote_cma.retry_count = 6;
 673
 674         /* RPC-over-RDMA handles its own flow control. In addition,
 675          * make all RNR NAKs visible so we know that RPC-over-RDMA
 676          * flow control is working correctly (no NAKs should be seen).
 677          */
 678         ep->rep_remote_cma.flow_control = 0;
 679         ep->rep_remote_cma.rnr_retry_count = 0;
 680
 681         return 0;
 682
 683 out2:
 684         ib_free_cq(sendcq);
 685 out1:
 686         return rc;
 687 }
 688
 689 /*
 690  * rpcrdma_ep_destroy
 691  *
 692  * Disconnect and destroy endpoint. After this, the only
 693  * valid operations on the ep are to free it (if dynamically
 694  * allocated) or re-create it.
 695  */
 696 void
 697 rpcrdma_ep_destroy(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
 698 {
 699         dprintk("RPC:       %s: entering, connected is %d\n",
 700                 __func__, ep->rep_connected);
 701
 702         cancel_delayed_work_sync(&ep->rep_connect_worker);
 703
 704         if (ia->ri_id->qp) {
 705                 rpcrdma_ep_disconnect(ep, ia);
 706                 rdma_destroy_qp(ia->ri_id);
 707                 ia->ri_id->qp = NULL;
 708         }
 709
 710         ib_free_cq(ep->rep_attr.recv_cq);
 711         ib_free_cq(ep->rep_attr.send_cq);
 712 }
 713
 714 static int
 715 rpcrdma_ep_reconnect(struct rpcrdma_xprt *r_xprt, struct rpcrdma_ep *ep,
 716                      struct rpcrdma_ia *ia)
 717 {
 718         struct sockaddr *sap = (struct sockaddr *)&r_xprt->rx_data.addr;
 719         struct rdma_cm_id *id, *old;
 720         int err, rc;
 721
 722         dprintk("RPC:       %s: reconnecting...\n", __func__);
 723
 724         rpcrdma_ep_disconnect(ep, ia);
 725
 726         rc = -EHOSTUNREACH;
 727         id = rpcrdma_create_id(r_xprt, ia, sap);
 728         if (IS_ERR(id))
 729                 goto out;
 730
 731         /* As long as the new ID points to the same device as the
 732          * old ID, we can reuse the transport's existing PD and all
 733          * previously allocated MRs. Also, the same device means
 734          * the transport's previous DMA mappings are still valid.
 735          *
 736          * This is a sanity check only. There should be no way these
 737          * point to two different devices here.
 738          */
 739         old = id;
 740         rc = -ENETUNREACH;
 741         if (ia->ri_device != id->device) {
 742                 pr_err("rpcrdma: can't reconnect on different device!\n");
 743                 goto out_destroy;
 744         }
 745
 746         err = rdma_create_qp(id, ia->ri_pd, &ep->rep_attr);
 747         if (err) {
 748                 dprintk("RPC:       %s: rdma_create_qp returned %d\n",
 749                         __func__, err);
 750                 goto out_destroy;
 751         }
 752
 753         /* Atomically replace the transport's ID and QP. */
 754         rc = 0;
 755         old = ia->ri_id;
 756         ia->ri_id = id;
 757         rdma_destroy_qp(old);
 758
 759 out_destroy:
 760         rpcrdma_destroy_id(old);
 761 out:
 762         return rc;
 763 }
 764
 765 /*
 766  * Connect unconnected endpoint.
 767  */
 768 int
 769 rpcrdma_ep_connect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
 770 {
 771         struct rpcrdma_xprt *r_xprt = container_of(ia, struct rpcrdma_xprt,
 772                                                    rx_ia);
 773         unsigned int extras;
 774         int rc;
 775
 776 retry:
 777         switch (ep->rep_connected) {
 778         case 0:
 779                 dprintk("RPC:       %s: connecting...\n", __func__);
 780                 rc = rdma_create_qp(ia->ri_id, ia->ri_pd, &ep->rep_attr);
 781                 if (rc) {
 782                         dprintk("RPC:       %s: rdma_create_qp failed %i\n",
 783                                 __func__, rc);
 784                         rc = -ENETUNREACH;
 785                         goto out_noupdate;
 786                 }
 787                 break;
 788         default:
 789                 rc = rpcrdma_ep_reconnect(r_xprt, ep, ia);
 790                 if (rc)
 791                         goto out;
 792         }
 793
 794         ep->rep_connected = 0;
 795
 796         rc = rdma_connect(ia->ri_id, &ep->rep_remote_cma);
 797         if (rc) {
 798                 dprintk("RPC:       %s: rdma_connect() failed with %i\n",
 799                                 __func__, rc);
 800                 goto out;
 801         }
 802
 803         wait_event_interruptible(ep->rep_connect_wait, ep->rep_connected != 0);
 804         if (ep->rep_connected <= 0) {
 805                 if (ep->rep_connected == -EAGAIN)
 806                         goto retry;
 807                 rc = ep->rep_connected;
 808                 goto out;
 809         }
 810
 811         dprintk("RPC:       %s: connected\n", __func__);
 812         extras = r_xprt->rx_buf.rb_bc_srv_max_requests;
 813         if (extras)
 814                 rpcrdma_ep_post_extra_recv(r_xprt, extras);
 815
 816 out:
 817         if (rc)
 818                 ep->rep_connected = rc;
 819
 820 out_noupdate:
 821         return rc;
 822 }
 823
 824 /*
 825  * rpcrdma_ep_disconnect
 826  *
 827  * This is separate from destroy to facilitate the ability
 828  * to reconnect without recreating the endpoint.
 829  *
 830  * This call is not reentrant, and must not be made in parallel
 831  * on the same endpoint.
 832  */
 833 void
 834 rpcrdma_ep_disconnect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
 835 {
 836         int rc;
 837
 838         rc = rdma_disconnect(ia->ri_id);
 839         if (!rc) {
 840                 /* returns without wait if not connected */
 841                 wait_event_interruptible(ep->rep_connect_wait,
 842                                                         ep->rep_connected != 1);
 843                 dprintk("RPC:       %s: after wait, %sconnected\n", __func__,
 844                         (ep->rep_connected == 1) ? "still " : "dis");
 845         } else {
 846                 dprintk("RPC:       %s: rdma_disconnect %i\n", __func__, rc);
 847                 ep->rep_connected = rc;
 848         }
 849
 850         ib_drain_qp(ia->ri_id->qp);
 851 }
 852
 853 static void
 854 rpcrdma_mr_recovery_worker(struct work_struct *work)
 855 {
 856         struct rpcrdma_buffer *buf = container_of(work, struct rpcrdma_buffer,
 857                                                   rb_recovery_worker.work);
 858         struct rpcrdma_mw *mw;
 859
 860         spin_lock(&buf->rb_recovery_lock);
 861         while (!list_empty(&buf->rb_stale_mrs)) {
 862                 mw = rpcrdma_pop_mw(&buf->rb_stale_mrs);
 863                 spin_unlock(&buf->rb_recovery_lock);
 864
 865                 dprintk("RPC:       %s: recovering MR %p\n", __func__, mw);
 866                 mw->mw_xprt->rx_ia.ri_ops->ro_recover_mr(mw);
 867
 868                 spin_lock(&buf->rb_recovery_lock);
 869         }
 870         spin_unlock(&buf->rb_recovery_lock);
 871 }
 872
 873 void
 874 rpcrdma_defer_mr_recovery(struct rpcrdma_mw *mw)
 875 {
 876         struct rpcrdma_xprt *r_xprt = mw->mw_xprt;
 877         struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
 878
 879         spin_lock(&buf->rb_recovery_lock);
 880         rpcrdma_push_mw(mw, &buf->rb_stale_mrs);
 881         spin_unlock(&buf->rb_recovery_lock);
 882
 883         schedule_delayed_work(&buf->rb_recovery_worker, 0);
 884 }
 885
 886 static void
 887 rpcrdma_create_mrs(struct rpcrdma_xprt *r_xprt)
 888 {
 889         struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
 890         struct rpcrdma_ia *ia = &r_xprt->rx_ia;
 891         unsigned int count;
 892         LIST_HEAD(free);
 893         LIST_HEAD(all);
 894
 895         for (count = 0; count < 32; count++) {
 896                 struct rpcrdma_mw *mw;
 897                 int rc;
 898
 899                 mw = kzalloc(sizeof(*mw), GFP_KERNEL);
 900                 if (!mw)
 901                         break;
 902
 903                 rc = ia->ri_ops->ro_init_mr(ia, mw);
 904                 if (rc) {
 905                         kfree(mw);
 906                         break;
 907                 }
 908
 909                 mw->mw_xprt = r_xprt;
 910
 911                 list_add(&mw->mw_list, &free);
 912                 list_add(&mw->mw_all, &all);
 913         }
 914
 915         spin_lock(&buf->rb_mwlock);
 916         list_splice(&free, &buf->rb_mws);
 917         list_splice(&all, &buf->rb_all);
 918         r_xprt->rx_stats.mrs_allocated += count;
 919         spin_unlock(&buf->rb_mwlock);
 920
 921         dprintk("RPC:       %s: created %u MRs\n", __func__, count);
 922 }
 923
 924 static void
 925 rpcrdma_mr_refresh_worker(struct work_struct *work)
 926 {
 927         struct rpcrdma_buffer *buf = container_of(work, struct rpcrdma_buffer,
 928                                                   rb_refresh_worker.work);
 929         struct rpcrdma_xprt *r_xprt = container_of(buf, struct rpcrdma_xprt,
 930                                                    rx_buf);
 931
 932         rpcrdma_create_mrs(r_xprt);
 933 }
 934
 935 struct rpcrdma_req *
 936 rpcrdma_create_req(struct rpcrdma_xprt *r_xprt)
 937 {
 938         struct rpcrdma_buffer *buffer = &r_xprt->rx_buf;
 939         struct rpcrdma_req *req;
 940
 941         req = kzalloc(sizeof(*req), GFP_KERNEL);
 942         if (req == NULL)
 943                 return ERR_PTR(-ENOMEM);
 944
 945         INIT_LIST_HEAD(&req->rl_free);
 946         spin_lock(&buffer->rb_reqslock);
 947         list_add(&req->rl_all, &buffer->rb_allreqs);
 948         spin_unlock(&buffer->rb_reqslock);
 949         req->rl_cqe.done = rpcrdma_wc_send;
 950         req->rl_buffer = &r_xprt->rx_buf;
 951         INIT_LIST_HEAD(&req->rl_registered);
 952         req->rl_send_wr.next = NULL;
 953         req->rl_send_wr.wr_cqe = &req->rl_cqe;
 954         req->rl_send_wr.sg_list = req->rl_send_sge;
 955         req->rl_send_wr.opcode = IB_WR_SEND;
 956         return req;
 957 }
 958
 959 struct rpcrdma_rep *
 960 rpcrdma_create_rep(struct rpcrdma_xprt *r_xprt)
 961 {
 962         struct rpcrdma_create_data_internal *cdata = &r_xprt->rx_data;
 963         struct rpcrdma_rep *rep;
 964         int rc;
 965
 966         rc = -ENOMEM;
 967         rep = kzalloc(sizeof(*rep), GFP_KERNEL);
 968         if (rep == NULL)
 969                 goto out;
 970
 971         rep->rr_rdmabuf = rpcrdma_alloc_regbuf(cdata->inline_rsize,
 972                                                DMA_FROM_DEVICE, GFP_KERNEL);
 973         if (IS_ERR(rep->rr_rdmabuf)) {
 974                 rc = PTR_ERR(rep->rr_rdmabuf);
 975                 goto out_free;
 976         }
 977
 978         rep->rr_cqe.done = rpcrdma_wc_receive;
 979         rep->rr_rxprt = r_xprt;
 980         INIT_WORK(&rep->rr_work, rpcrdma_reply_handler);
 981         rep->rr_recv_wr.next = NULL;
 982         rep->rr_recv_wr.wr_cqe = &rep->rr_cqe;
 983         rep->rr_recv_wr.sg_list = &rep->rr_rdmabuf->rg_iov;
 984         rep->rr_recv_wr.num_sge = 1;
 985         return rep;
 986
 987 out_free:
 988         kfree(rep);
 989 out:
 990         return ERR_PTR(rc);
 991 }
 992
 993 int
 994 rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt)
 995 {
 996         struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
 997         int i, rc;
 998
 999         buf->rb_max_requests = r_xprt->rx_data.max_requests;
1000         buf->rb_bc_srv_max_requests = 0;
1001         atomic_set(&buf->rb_credits, 1);
1002         spin_lock_init(&buf->rb_mwlock);
1003         spin_lock_init(&buf->rb_lock);
1004         spin_lock_init(&buf->rb_recovery_lock);
1005         INIT_LIST_HEAD(&buf->rb_mws);
1006         INIT_LIST_HEAD(&buf->rb_all);
1007         INIT_LIST_HEAD(&buf->rb_stale_mrs);
1008         INIT_DELAYED_WORK(&buf->rb_refresh_worker,
1009                           rpcrdma_mr_refresh_worker);
1010         INIT_DELAYED_WORK(&buf->rb_recovery_worker,
1011                           rpcrdma_mr_recovery_worker);
1012
1013         rpcrdma_create_mrs(r_xprt);
1014
1015         INIT_LIST_HEAD(&buf->rb_send_bufs);
1016         INIT_LIST_HEAD(&buf->rb_allreqs);
1017         spin_lock_init(&buf->rb_reqslock);
1018         for (i = 0; i < buf->rb_max_requests; i++) {
1019                 struct rpcrdma_req *req;
1020
1021                 req = rpcrdma_create_req(r_xprt);
1022                 if (IS_ERR(req)) {
1023                         dprintk("RPC:       %s: request buffer %d alloc"
1024                                 " failed\n", __func__, i);
1025                         rc = PTR_ERR(req);
1026                         goto out;
1027                 }
1028                 req->rl_backchannel = false;
1029                 list_add(&req->rl_free, &buf->rb_send_bufs);
1030         }
1031
1032         INIT_LIST_HEAD(&buf->rb_recv_bufs);
1033         for (i = 0; i < buf->rb_max_requests + RPCRDMA_MAX_BC_REQUESTS; i++) {
1034                 struct rpcrdma_rep *rep;
1035
1036                 rep = rpcrdma_create_rep(r_xprt);
1037                 if (IS_ERR(rep)) {
1038                         dprintk("RPC:       %s: reply buffer %d alloc failed\n",
1039                                 __func__, i);
1040                         rc = PTR_ERR(rep);
1041                         goto out;
1042                 }
1043                 list_add(&rep->rr_list, &buf->rb_recv_bufs);
1044         }
1045
1046         return 0;
1047 out:
1048         rpcrdma_buffer_destroy(buf);
1049         return rc;
1050 }
1051
1052 static struct rpcrdma_req *
1053 rpcrdma_buffer_get_req_locked(struct rpcrdma_buffer *buf)
1054 {
1055         struct rpcrdma_req *req;
1056
1057         req = list_first_entry(&buf->rb_send_bufs,
1058                                struct rpcrdma_req, rl_free);
1059         list_del(&req->rl_free);
1060         return req;
1061 }
1062
1063 static struct rpcrdma_rep *
1064 rpcrdma_buffer_get_rep_locked(struct rpcrdma_buffer *buf)
1065 {
1066         struct rpcrdma_rep *rep;
1067
1068         rep = list_first_entry(&buf->rb_recv_bufs,
1069                                struct rpcrdma_rep, rr_list);
1070         list_del(&rep->rr_list);
1071         return rep;
1072 }
1073
1074 static void
1075 rpcrdma_destroy_rep(struct rpcrdma_rep *rep)
1076 {
1077         rpcrdma_free_regbuf(rep->rr_rdmabuf);
1078         kfree(rep);
1079 }
1080
1081 void
1082 rpcrdma_destroy_req(struct rpcrdma_req *req)
1083 {
1084         rpcrdma_free_regbuf(req->rl_recvbuf);
1085         rpcrdma_free_regbuf(req->rl_sendbuf);
1086         rpcrdma_free_regbuf(req->rl_rdmabuf);
1087         kfree(req);
1088 }
1089
1090 static void
1091 rpcrdma_destroy_mrs(struct rpcrdma_buffer *buf)
1092 {
1093         struct rpcrdma_xprt *r_xprt = container_of(buf, struct rpcrdma_xprt,
1094                                                    rx_buf);
1095         struct rpcrdma_ia *ia = rdmab_to_ia(buf);
1096         struct rpcrdma_mw *mw;
1097         unsigned int count;
1098
1099         count = 0;
1100         spin_lock(&buf->rb_mwlock);
1101         while (!list_empty(&buf->rb_all)) {
1102                 mw = list_entry(buf->rb_all.next, struct rpcrdma_mw, mw_all);
1103                 list_del(&mw->mw_all);
1104
1105                 spin_unlock(&buf->rb_mwlock);
1106                 ia->ri_ops->ro_release_mr(mw);
1107                 count++;
1108                 spin_lock(&buf->rb_mwlock);
1109         }
1110         spin_unlock(&buf->rb_mwlock);
1111         r_xprt->rx_stats.mrs_allocated = 0;
1112
1113         dprintk("RPC:       %s: released %u MRs\n", __func__, count);
1114 }
1115
1116 void
1117 rpcrdma_buffer_destroy(struct rpcrdma_buffer *buf)
1118 {
1119         cancel_delayed_work_sync(&buf->rb_recovery_worker);
1120         cancel_delayed_work_sync(&buf->rb_refresh_worker);
1121
1122         while (!list_empty(&buf->rb_recv_bufs)) {
1123                 struct rpcrdma_rep *rep;
1124
1125                 rep = rpcrdma_buffer_get_rep_locked(buf);
1126                 rpcrdma_destroy_rep(rep);
1127         }
1128         buf->rb_send_count = 0;
1129
1130         spin_lock(&buf->rb_reqslock);
1131         while (!list_empty(&buf->rb_allreqs)) {
1132                 struct rpcrdma_req *req;
1133
1134                 req = list_first_entry(&buf->rb_allreqs,
1135                                        struct rpcrdma_req, rl_all);
1136                 list_del(&req->rl_all);
1137
1138                 spin_unlock(&buf->rb_reqslock);
1139                 rpcrdma_destroy_req(req);
1140                 spin_lock(&buf->rb_reqslock);
1141         }
1142         spin_unlock(&buf->rb_reqslock);
1143         buf->rb_recv_count = 0;
1144
1145         rpcrdma_destroy_mrs(buf);
1146 }
1147
1148 struct rpcrdma_mw *
1149 rpcrdma_get_mw(struct rpcrdma_xprt *r_xprt)
1150 {
1151         struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
1152         struct rpcrdma_mw *mw = NULL;
1153
1154         spin_lock(&buf->rb_mwlock);
1155         if (!list_empty(&buf->rb_mws))
1156                 mw = rpcrdma_pop_mw(&buf->rb_mws);
1157         spin_unlock(&buf->rb_mwlock);
1158
1159         if (!mw)
1160                 goto out_nomws;
1161         return mw;
1162
1163 out_nomws:
1164         dprintk("RPC:       %s: no MWs available\n", __func__);
1165         if (r_xprt->rx_ep.rep_connected != -ENODEV)
1166                 schedule_delayed_work(&buf->rb_refresh_worker, 0);
1167
1168         /* Allow the reply handler and refresh worker to run */
1169         cond_resched();
1170
1171         return NULL;
1172 }
1173
1174 void
1175 rpcrdma_put_mw(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mw *mw)
1176 {
1177         struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
1178
1179         spin_lock(&buf->rb_mwlock);
1180         rpcrdma_push_mw(mw, &buf->rb_mws);
1181         spin_unlock(&buf->rb_mwlock);
1182 }
1183
1184 static struct rpcrdma_rep *
1185 rpcrdma_buffer_get_rep(struct rpcrdma_buffer *buffers)
1186 {
1187         /* If an RPC previously completed without a reply (say, a
1188          * credential problem or a soft timeout occurs) then hold off
1189          * on supplying more Receive buffers until the number of new
1190          * pending RPCs catches up to the number of posted Receives.
1191          */
1192         if (unlikely(buffers->rb_send_count < buffers->rb_recv_count))
1193                 return NULL;
1194
1195         if (unlikely(list_empty(&buffers->rb_recv_bufs)))
1196                 return NULL;
1197         buffers->rb_recv_count++;
1198         return rpcrdma_buffer_get_rep_locked(buffers);
1199 }
1200
1201 /*
1202  * Get a set of request/reply buffers.
1203  *
1204  * Reply buffer (if available) is attached to send buffer upon return.
1205  */
1206 struct rpcrdma_req *
1207 rpcrdma_buffer_get(struct rpcrdma_buffer *buffers)
1208 {
1209         struct rpcrdma_req *req;
1210
1211         spin_lock(&buffers->rb_lock);
1212         if (list_empty(&buffers->rb_send_bufs))
1213                 goto out_reqbuf;
1214         buffers->rb_send_count++;
1215         req = rpcrdma_buffer_get_req_locked(buffers);
1216         req->rl_reply = rpcrdma_buffer_get_rep(buffers);
1217         spin_unlock(&buffers->rb_lock);
1218         return req;
1219
1220 out_reqbuf:
1221         spin_unlock(&buffers->rb_lock);
1222         pr_warn("RPC:       %s: out of request buffers\n", __func__);
1223         return NULL;
1224 }
1225
1226 /*
1227  * Put request/reply buffers back into pool.
1228  * Pre-decrement counter/array index.
1229  */
1230 void
1231 rpcrdma_buffer_put(struct rpcrdma_req *req)
1232 {
1233         struct rpcrdma_buffer *buffers = req->rl_buffer;
1234         struct rpcrdma_rep *rep = req->rl_reply;
1235
1236         req->rl_send_wr.num_sge = 0;
1237         req->rl_reply = NULL;
1238
1239         spin_lock(&buffers->rb_lock);
1240         buffers->rb_send_count--;
1241         list_add_tail(&req->rl_free, &buffers->rb_send_bufs);
1242         if (rep) {
1243                 buffers->rb_recv_count--;
1244                 list_add_tail(&rep->rr_list, &buffers->rb_recv_bufs);
1245         }
1246         spin_unlock(&buffers->rb_lock);
1247 }
1248
1249 /*
1250  * Recover reply buffers from pool.
1251  * This happens when recovering from disconnect.
1252  */
1253 void
1254 rpcrdma_recv_buffer_get(struct rpcrdma_req *req)
1255 {
1256         struct rpcrdma_buffer *buffers = req->rl_buffer;
1257
1258         spin_lock(&buffers->rb_lock);
1259         req->rl_reply = rpcrdma_buffer_get_rep(buffers);
1260         spin_unlock(&buffers->rb_lock);
1261 }
1262
1263 /*
1264  * Put reply buffers back into pool when not attached to
1265  * request. This happens in error conditions.
1266  */
1267 void
1268 rpcrdma_recv_buffer_put(struct rpcrdma_rep *rep)
1269 {
1270         struct rpcrdma_buffer *buffers = &rep->rr_rxprt->rx_buf;
1271
1272         spin_lock(&buffers->rb_lock);
1273         buffers->rb_recv_count--;
1274         list_add_tail(&rep->rr_list, &buffers->rb_recv_bufs);
1275         spin_unlock(&buffers->rb_lock);
1276 }
1277
1278 /**
1279  * rpcrdma_alloc_regbuf - allocate and DMA-map memory for SEND/RECV buffers
1280  * @size: size of buffer to be allocated, in bytes
1281  * @direction: direction of data movement
1282  * @flags: GFP flags
1283  *
1284  * Returns an ERR_PTR, or a pointer to a regbuf, a buffer that
1285  * can be persistently DMA-mapped for I/O.
1286  *
1287  * xprtrdma uses a regbuf for posting an outgoing RDMA SEND, or for
1288  * receiving the payload of RDMA RECV operations. During Long Calls
1289  * or Replies they may be registered externally via ro_map.
1290  */
1291 struct rpcrdma_regbuf *
1292 rpcrdma_alloc_regbuf(size_t size, enum dma_data_direction direction,
1293                      gfp_t flags)
1294 {
1295         struct rpcrdma_regbuf *rb;
1296
1297         rb = kmalloc(sizeof(*rb) + size, flags);
1298         if (rb == NULL)
1299                 return ERR_PTR(-ENOMEM);
1300
1301         rb->rg_device = NULL;
1302         rb->rg_direction = direction;
1303         rb->rg_iov.length = size;
1304
1305         return rb;
1306 }
1307
1308 /**
1309  * __rpcrdma_map_regbuf - DMA-map a regbuf
1310  * @ia: controlling rpcrdma_ia
1311  * @rb: regbuf to be mapped
1312  */
1313 bool
1314 __rpcrdma_dma_map_regbuf(struct rpcrdma_ia *ia, struct rpcrdma_regbuf *rb)
1315 {
1316         struct ib_device *device = ia->ri_device;
1317
1318         if (rb->rg_direction == DMA_NONE)
1319                 return false;
1320
1321         rb->rg_iov.addr = ib_dma_map_single(device,
1322                                             (void *)rb->rg_base,
1323                                             rdmab_length(rb),
1324                                             rb->rg_direction);
1325         if (ib_dma_mapping_error(device, rdmab_addr(rb)))
1326                 return false;
1327
1328         rb->rg_device = device;
1329         rb->rg_iov.lkey = ia->ri_pd->local_dma_lkey;
1330         return true;
1331 }
1332
1333 static void
1334 rpcrdma_dma_unmap_regbuf(struct rpcrdma_regbuf *rb)
1335 {
1336         if (!rpcrdma_regbuf_is_mapped(rb))
1337                 return;
1338
1339         ib_dma_unmap_single(rb->rg_device, rdmab_addr(rb),
1340                             rdmab_length(rb), rb->rg_direction);
1341         rb->rg_device = NULL;
1342 }
1343
1344 /**
1345  * rpcrdma_free_regbuf - deregister and free registered buffer
1346  * @rb: regbuf to be deregistered and freed
1347  */
1348 void
1349 rpcrdma_free_regbuf(struct rpcrdma_regbuf *rb)
1350 {
1351         if (!rb)
1352                 return;
1353
1354         rpcrdma_dma_unmap_regbuf(rb);
1355         kfree(rb);
1356 }
1357
1358 /*
1359  * Prepost any receive buffer, then post send.
1360  *
1361  * Receive buffer is donated to hardware, reclaimed upon recv completion.
1362  */
1363 int
1364 rpcrdma_ep_post(struct rpcrdma_ia *ia,
1365                 struct rpcrdma_ep *ep,
1366                 struct rpcrdma_req *req)
1367 {
1368         struct ib_send_wr *send_wr = &req->rl_send_wr;
1369         struct ib_send_wr *send_wr_fail;
1370         int rc;
1371
1372         if (req->rl_reply) {
1373                 rc = rpcrdma_ep_post_recv(ia, req->rl_reply);
1374                 if (rc)
1375                         return rc;
1376                 req->rl_reply = NULL;
1377         }
1378
1379         dprintk("RPC:       %s: posting %d s/g entries\n",
1380                 __func__, send_wr->num_sge);
1381
1382         rpcrdma_set_signaled(ep, send_wr);
1383         rc = ib_post_send(ia->ri_id->qp, send_wr, &send_wr_fail);
1384         if (rc)
1385                 goto out_postsend_err;
1386         return 0;
1387
1388 out_postsend_err:
1389         pr_err("rpcrdma: RDMA Send ib_post_send returned %i\n", rc);
1390         return -ENOTCONN;
1391 }
1392
1393 int
1394 rpcrdma_ep_post_recv(struct rpcrdma_ia *ia,
1395                      struct rpcrdma_rep *rep)
1396 {
1397         struct ib_recv_wr *recv_wr_fail;
1398         int rc;
1399
1400         if (!rpcrdma_dma_map_regbuf(ia, rep->rr_rdmabuf))
1401                 goto out_map;
1402         rc = ib_post_recv(ia->ri_id->qp, &rep->rr_recv_wr, &recv_wr_fail);
1403         if (rc)
1404                 goto out_postrecv;
1405         return 0;
1406
1407 out_map:
1408         pr_err("rpcrdma: failed to DMA map the Receive buffer\n");
1409         return -EIO;
1410
1411 out_postrecv:
1412         pr_err("rpcrdma: ib_post_recv returned %i\n", rc);
1413         return -ENOTCONN;
1414 }
1415
1416 /**
1417  * rpcrdma_ep_post_extra_recv - Post buffers for incoming backchannel requests
1418  * @r_xprt: transport associated with these backchannel resources
1419  * @min_reqs: minimum number of incoming requests expected
1420  *
1421  * Returns zero if all requested buffers were posted, or a negative errno.
1422  */
1423 int
1424 rpcrdma_ep_post_extra_recv(struct rpcrdma_xprt *r_xprt, unsigned int count)
1425 {
1426         struct rpcrdma_buffer *buffers = &r_xprt->rx_buf;
1427         struct rpcrdma_ia *ia = &r_xprt->rx_ia;
1428         struct rpcrdma_rep *rep;
1429         int rc;
1430
1431         while (count--) {
1432                 spin_lock(&buffers->rb_lock);
1433                 if (list_empty(&buffers->rb_recv_bufs))
1434                         goto out_reqbuf;
1435                 rep = rpcrdma_buffer_get_rep_locked(buffers);
1436                 spin_unlock(&buffers->rb_lock);
1437
1438                 rc = rpcrdma_ep_post_recv(ia, rep);
1439                 if (rc)
1440                         goto out_rc;
1441         }
1442
1443         return 0;
1444
1445 out_reqbuf:
1446         spin_unlock(&buffers->rb_lock);
1447         pr_warn("%s: no extra receive buffers\n", __func__);
1448         return -ENOMEM;
1449
1450 out_rc:
1451         rpcrdma_recv_buffer_put(rep);
1452         return rc;
1453 }