net/sunrpc/xprtrdma/svc_rdma_sendto.c

   1 /*
   2  * Copyright (c) 2005-2006 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  * Author: Tom Tucker <tom@opengridcomputing.com>
  40  */
  41
  42 #include <linux/sunrpc/debug.h>
  43 #include <linux/sunrpc/rpc_rdma.h>
  44 #include <linux/spinlock.h>
  45 #include <asm/unaligned.h>
  46 #include <rdma/ib_verbs.h>
  47 #include <rdma/rdma_cm.h>
  48 #include <linux/sunrpc/svc_rdma.h>
  49
  50 #define RPCDBG_FACILITY RPCDBG_SVCXPRT
  51
  52 /* Encode an XDR as an array of IB SGE
  53  *
  54  * Assumptions:
  55  * - head[0] is physically contiguous.
  56  * - tail[0] is physically contiguous.
  57  * - pages[] is not physically or virtually contigous and consists of
  58  *   PAGE_SIZE elements.
  59  *
  60  * Output:
  61  * SGE[0]              reserved for RCPRDMA header
  62  * SGE[1]              data from xdr->head[]
  63  * SGE[2..sge_count-2] data from xdr->pages[]
  64  * SGE[sge_count-1]    data from xdr->tail.
  65  *
  66  * The max SGE we need is the length of the XDR / pagesize + one for
  67  * head + one for tail + one for RPCRDMA header. Since RPCSVC_MAXPAGES
  68  * reserves a page for both the request and the reply header, and this
  69  * array is only concerned with the reply we are assured that we have
  70  * on extra page for the RPCRMDA header.
  71  */
  72 static int fast_reg_xdr(struct svcxprt_rdma *xprt,
  73                  struct xdr_buf *xdr,
  74                  struct svc_rdma_req_map *vec)
  75 {
  76         int sge_no;
  77         u32 sge_bytes;
  78         u32 page_bytes;
  79         u32 page_off;
  80         int page_no = 0;
  81         u8 *frva;
  82         struct svc_rdma_fastreg_mr *frmr;
  83
  84         frmr = svc_rdma_get_frmr(xprt);
  85         if (IS_ERR(frmr))
  86                 return -ENOMEM;
  87         vec->frmr = frmr;
  88
  89         /* Skip the RPCRDMA header */
  90         sge_no = 1;
  91
  92         /* Map the head. */
  93         frva = (void *)((unsigned long)(xdr->head[0].iov_base) & PAGE_MASK);
  94         vec->sge[sge_no].iov_base = xdr->head[0].iov_base;
  95         vec->sge[sge_no].iov_len = xdr->head[0].iov_len;
  96         vec->count = 2;
  97         sge_no++;
  98
  99         /* Build the FRMR */
 100         frmr->kva = frva;
 101         frmr->direction = DMA_TO_DEVICE;
 102         frmr->access_flags = 0;
 103         frmr->map_len = PAGE_SIZE;
 104         frmr->page_list_len = 1;
 105         frmr->page_list->page_list[page_no] =
 106                 ib_dma_map_single(xprt->sc_cm_id->device,
 107                                   (void *)xdr->head[0].iov_base,
 108                                   PAGE_SIZE, DMA_TO_DEVICE);
 109         if (ib_dma_mapping_error(xprt->sc_cm_id->device,
 110                                  frmr->page_list->page_list[page_no]))
 111                 goto fatal_err;
 112         atomic_inc(&xprt->sc_dma_used);
 113
 114         page_off = xdr->page_base;
 115         page_bytes = xdr->page_len + page_off;
 116         if (!page_bytes)
 117                 goto encode_tail;
 118
 119         /* Map the pages */
 120         vec->sge[sge_no].iov_base = frva + frmr->map_len + page_off;
 121         vec->sge[sge_no].iov_len = page_bytes;
 122         sge_no++;
 123         while (page_bytes) {
 124                 struct page *page;
 125
 126                 page = xdr->pages[page_no++];
 127                 sge_bytes = min_t(u32, page_bytes, (PAGE_SIZE - page_off));
 128                 page_bytes -= sge_bytes;
 129
 130                 frmr->page_list->page_list[page_no] =
 131                         ib_dma_map_single(xprt->sc_cm_id->device,
 132                                           page_address(page),
 133                                           PAGE_SIZE, DMA_TO_DEVICE);
 134                 if (ib_dma_mapping_error(xprt->sc_cm_id->device,
 135                                          frmr->page_list->page_list[page_no]))
 136                         goto fatal_err;
 137
 138                 atomic_inc(&xprt->sc_dma_used);
 139                 page_off = 0; /* reset for next time through loop */
 140                 frmr->map_len += PAGE_SIZE;
 141                 frmr->page_list_len++;
 142         }
 143         vec->count++;
 144
 145  encode_tail:
 146         /* Map tail */
 147         if (0 == xdr->tail[0].iov_len)
 148                 goto done;
 149
 150         vec->count++;
 151         vec->sge[sge_no].iov_len = xdr->tail[0].iov_len;
 152
 153         if (((unsigned long)xdr->tail[0].iov_base & PAGE_MASK) ==
 154             ((unsigned long)xdr->head[0].iov_base & PAGE_MASK)) {
 155                 /*
 156                  * If head and tail use the same page, we don't need
 157                  * to map it again.
 158                  */
 159                 vec->sge[sge_no].iov_base = xdr->tail[0].iov_base;
 160         } else {
 161                 void *va;
 162
 163                 /* Map another page for the tail */
 164                 page_off = (unsigned long)xdr->tail[0].iov_base & ~PAGE_MASK;
 165                 va = (void *)((unsigned long)xdr->tail[0].iov_base & PAGE_MASK);
 166                 vec->sge[sge_no].iov_base = frva + frmr->map_len + page_off;
 167
 168                 frmr->page_list->page_list[page_no] =
 169                         ib_dma_map_single(xprt->sc_cm_id->device, va, PAGE_SIZE,
 170                                           DMA_TO_DEVICE);
 171                 if (ib_dma_mapping_error(xprt->sc_cm_id->device,
 172                                          frmr->page_list->page_list[page_no]))
 173                         goto fatal_err;
 174                 atomic_inc(&xprt->sc_dma_used);
 175                 frmr->map_len += PAGE_SIZE;
 176                 frmr->page_list_len++;
 177         }
 178
 179  done:
 180         if (svc_rdma_fastreg(xprt, frmr))
 181                 goto fatal_err;
 182
 183         return 0;
 184
 185  fatal_err:
 186         printk("svcrdma: Error fast registering memory for xprt %p\n", xprt);
 187         vec->frmr = NULL;
 188         svc_rdma_put_frmr(xprt, frmr);
 189         return -EIO;
 190 }
 191
 192 static int map_xdr(struct svcxprt_rdma *xprt,
 193                    struct xdr_buf *xdr,
 194                    struct svc_rdma_req_map *vec)
 195 {
 196         int sge_no;
 197         u32 sge_bytes;
 198         u32 page_bytes;
 199         u32 page_off;
 200         int page_no;
 201
 202         BUG_ON(xdr->len !=
 203                (xdr->head[0].iov_len + xdr->page_len + xdr->tail[0].iov_len));
 204
 205         if (xprt->sc_frmr_pg_list_len)
 206                 return fast_reg_xdr(xprt, xdr, vec);
 207
 208         /* Skip the first sge, this is for the RPCRDMA header */
 209         sge_no = 1;
 210
 211         /* Head SGE */
 212         vec->sge[sge_no].iov_base = xdr->head[0].iov_base;
 213         vec->sge[sge_no].iov_len = xdr->head[0].iov_len;
 214         sge_no++;
 215
 216         /* pages SGE */
 217         page_no = 0;
 218         page_bytes = xdr->page_len;
 219         page_off = xdr->page_base;
 220         while (page_bytes) {
 221                 vec->sge[sge_no].iov_base =
 222                         page_address(xdr->pages[page_no]) + page_off;
 223                 sge_bytes = min_t(u32, page_bytes, (PAGE_SIZE - page_off));
 224                 page_bytes -= sge_bytes;
 225                 vec->sge[sge_no].iov_len = sge_bytes;
 226
 227                 sge_no++;
 228                 page_no++;
 229                 page_off = 0; /* reset for next time through loop */
 230         }
 231
 232         /* Tail SGE */
 233         if (xdr->tail[0].iov_len) {
 234                 vec->sge[sge_no].iov_base = xdr->tail[0].iov_base;
 235                 vec->sge[sge_no].iov_len = xdr->tail[0].iov_len;
 236                 sge_no++;
 237         }
 238
 239         dprintk("svcrdma: map_xdr: sge_no %d page_no %d "
 240                 "page_base %u page_len %u head_len %zu tail_len %zu\n",
 241                 sge_no, page_no, xdr->page_base, xdr->page_len,
 242                 xdr->head[0].iov_len, xdr->tail[0].iov_len);
 243
 244         vec->count = sge_no;
 245         return 0;
 246 }
 247
 248 /* Assumptions:
 249  * - We are using FRMR
 250  *     - or -
 251  * - The specified write_len can be represented in sc_max_sge * PAGE_SIZE
 252  */
 253 static int send_write(struct svcxprt_rdma *xprt, struct svc_rqst *rqstp,
 254                       u32 rmr, u64 to,
 255                       u32 xdr_off, int write_len,
 256                       struct svc_rdma_req_map *vec)
 257 {
 258         struct ib_send_wr write_wr;
 259         struct ib_sge *sge;
 260         int xdr_sge_no;
 261         int sge_no;
 262         int sge_bytes;
 263         int sge_off;
 264         int bc;
 265         struct svc_rdma_op_ctxt *ctxt;
 266
 267         BUG_ON(vec->count > RPCSVC_MAXPAGES);
 268         dprintk("svcrdma: RDMA_WRITE rmr=%x, to=%llx, xdr_off=%d, "
 269                 "write_len=%d, vec->sge=%p, vec->count=%lu\n",
 270                 rmr, (unsigned long long)to, xdr_off,
 271                 write_len, vec->sge, vec->count);
 272
 273         ctxt = svc_rdma_get_context(xprt);
 274         ctxt->direction = DMA_TO_DEVICE;
 275         sge = ctxt->sge;
 276
 277         /* Find the SGE associated with xdr_off */
 278         for (bc = xdr_off, xdr_sge_no = 1; bc && xdr_sge_no < vec->count;
 279              xdr_sge_no++) {
 280                 if (vec->sge[xdr_sge_no].iov_len > bc)
 281                         break;
 282                 bc -= vec->sge[xdr_sge_no].iov_len;
 283         }
 284
 285         sge_off = bc;
 286         bc = write_len;
 287         sge_no = 0;
 288
 289         /* Copy the remaining SGE */
 290         while (bc != 0) {
 291                 sge_bytes = min_t(size_t,
 292                           bc, vec->sge[xdr_sge_no].iov_len-sge_off);
 293                 sge[sge_no].length = sge_bytes;
 294                 if (!vec->frmr) {
 295                         sge[sge_no].addr =
 296                                 ib_dma_map_single(xprt->sc_cm_id->device,
 297                                                   (void *)
 298                                                   vec->sge[xdr_sge_no].iov_base + sge_off,
 299                                                   sge_bytes, DMA_TO_DEVICE);
 300                         if (ib_dma_mapping_error(xprt->sc_cm_id->device,
 301                                                  sge[sge_no].addr))
 302                                 goto err;
 303                         atomic_inc(&xprt->sc_dma_used);
 304                         sge[sge_no].lkey = xprt->sc_dma_lkey;
 305                 } else {
 306                         sge[sge_no].addr = (unsigned long)
 307                                 vec->sge[xdr_sge_no].iov_base + sge_off;
 308                         sge[sge_no].lkey = vec->frmr->mr->lkey;
 309                 }
 310                 ctxt->count++;
 311                 ctxt->frmr = vec->frmr;
 312                 sge_off = 0;
 313                 sge_no++;
 314                 xdr_sge_no++;
 315                 BUG_ON(xdr_sge_no > vec->count);
 316                 bc -= sge_bytes;
 317         }
 318
 319         /* Prepare WRITE WR */
 320         memset(&write_wr, 0, sizeof write_wr);
 321         ctxt->wr_op = IB_WR_RDMA_WRITE;
 322         write_wr.wr_id = (unsigned long)ctxt;
 323         write_wr.sg_list = &sge[0];
 324         write_wr.num_sge = sge_no;
 325         write_wr.opcode = IB_WR_RDMA_WRITE;
 326         write_wr.send_flags = IB_SEND_SIGNALED;
 327         write_wr.wr.rdma.rkey = rmr;
 328         write_wr.wr.rdma.remote_addr = to;
 329
 330         /* Post It */
 331         atomic_inc(&rdma_stat_write);
 332         if (svc_rdma_send(xprt, &write_wr))
 333                 goto err;
 334         return 0;
 335  err:
 336         svc_rdma_put_context(ctxt, 0);
 337         /* Fatal error, close transport */
 338         return -EIO;
 339 }
 340
 341 static int send_write_chunks(struct svcxprt_rdma *xprt,
 342                              struct rpcrdma_msg *rdma_argp,
 343                              struct rpcrdma_msg *rdma_resp,
 344                              struct svc_rqst *rqstp,
 345                              struct svc_rdma_req_map *vec)
 346 {
 347         u32 xfer_len = rqstp->rq_res.page_len + rqstp->rq_res.tail[0].iov_len;
 348         int write_len;
 349         int max_write;
 350         u32 xdr_off;
 351         int chunk_off;
 352         int chunk_no;
 353         struct rpcrdma_write_array *arg_ary;
 354         struct rpcrdma_write_array *res_ary;
 355         int ret;
 356
 357         arg_ary = svc_rdma_get_write_array(rdma_argp);
 358         if (!arg_ary)
 359                 return 0;
 360         res_ary = (struct rpcrdma_write_array *)
 361                 &rdma_resp->rm_body.rm_chunks[1];
 362
 363         if (vec->frmr)
 364                 max_write = vec->frmr->map_len;
 365         else
 366                 max_write = xprt->sc_max_sge * PAGE_SIZE;
 367
 368         /* Write chunks start at the pagelist */
 369         for (xdr_off = rqstp->rq_res.head[0].iov_len, chunk_no = 0;
 370              xfer_len && chunk_no < arg_ary->wc_nchunks;
 371              chunk_no++) {
 372                 struct rpcrdma_segment *arg_ch;
 373                 u64 rs_offset;
 374
 375                 arg_ch = &arg_ary->wc_array[chunk_no].wc_target;
 376                 write_len = min(xfer_len, arg_ch->rs_length);
 377
 378                 /* Prepare the response chunk given the length actually
 379                  * written */
 380                 rs_offset = get_unaligned(&(arg_ch->rs_offset));
 381                 svc_rdma_xdr_encode_array_chunk(res_ary, chunk_no,
 382                                             arg_ch->rs_handle,
 383                                             rs_offset,
 384                                             write_len);
 385                 chunk_off = 0;
 386                 while (write_len) {
 387                         int this_write;
 388                         this_write = min(write_len, max_write);
 389                         ret = send_write(xprt, rqstp,
 390                                          arg_ch->rs_handle,
 391                                          rs_offset + chunk_off,
 392                                          xdr_off,
 393                                          this_write,
 394                                          vec);
 395                         if (ret) {
 396                                 dprintk("svcrdma: RDMA_WRITE failed, ret=%d\n",
 397                                         ret);
 398                                 return -EIO;
 399                         }
 400                         chunk_off += this_write;
 401                         xdr_off += this_write;
 402                         xfer_len -= this_write;
 403                         write_len -= this_write;
 404                 }
 405         }
 406         /* Update the req with the number of chunks actually used */
 407         svc_rdma_xdr_encode_write_list(rdma_resp, chunk_no);
 408
 409         return rqstp->rq_res.page_len + rqstp->rq_res.tail[0].iov_len;
 410 }
 411
 412 static int send_reply_chunks(struct svcxprt_rdma *xprt,
 413                              struct rpcrdma_msg *rdma_argp,
 414                              struct rpcrdma_msg *rdma_resp,
 415                              struct svc_rqst *rqstp,
 416                              struct svc_rdma_req_map *vec)
 417 {
 418         u32 xfer_len = rqstp->rq_res.len;
 419         int write_len;
 420         int max_write;
 421         u32 xdr_off;
 422         int chunk_no;
 423         int chunk_off;
 424         struct rpcrdma_segment *ch;
 425         struct rpcrdma_write_array *arg_ary;
 426         struct rpcrdma_write_array *res_ary;
 427         int ret;
 428
 429         arg_ary = svc_rdma_get_reply_array(rdma_argp);
 430         if (!arg_ary)
 431                 return 0;
 432         /* XXX: need to fix when reply lists occur with read-list and or
 433          * write-list */
 434         res_ary = (struct rpcrdma_write_array *)
 435                 &rdma_resp->rm_body.rm_chunks[2];
 436
 437         if (vec->frmr)
 438                 max_write = vec->frmr->map_len;
 439         else
 440                 max_write = xprt->sc_max_sge * PAGE_SIZE;
 441
 442         /* xdr offset starts at RPC message */
 443         for (xdr_off = 0, chunk_no = 0;
 444              xfer_len && chunk_no < arg_ary->wc_nchunks;
 445              chunk_no++) {
 446                 u64 rs_offset;
 447                 ch = &arg_ary->wc_array[chunk_no].wc_target;
 448                 write_len = min(xfer_len, ch->rs_length);
 449
 450                 /* Prepare the reply chunk given the length actually
 451                  * written */
 452                 rs_offset = get_unaligned(&(ch->rs_offset));
 453                 svc_rdma_xdr_encode_array_chunk(res_ary, chunk_no,
 454                                             ch->rs_handle, rs_offset,
 455                                             write_len);
 456                 chunk_off = 0;
 457                 while (write_len) {
 458                         int this_write;
 459
 460                         this_write = min(write_len, max_write);
 461                         ret = send_write(xprt, rqstp,
 462                                          ch->rs_handle,
 463                                          rs_offset + chunk_off,
 464                                          xdr_off,
 465                                          this_write,
 466                                          vec);
 467                         if (ret) {
 468                                 dprintk("svcrdma: RDMA_WRITE failed, ret=%d\n",
 469                                         ret);
 470                                 return -EIO;
 471                         }
 472                         chunk_off += this_write;
 473                         xdr_off += this_write;
 474                         xfer_len -= this_write;
 475                         write_len -= this_write;
 476                 }
 477         }
 478         /* Update the req with the number of chunks actually used */
 479         svc_rdma_xdr_encode_reply_array(res_ary, chunk_no);
 480
 481         return rqstp->rq_res.len;
 482 }
 483
 484 /* This function prepares the portion of the RPCRDMA message to be
 485  * sent in the RDMA_SEND. This function is called after data sent via
 486  * RDMA has already been transmitted. There are three cases:
 487  * - The RPCRDMA header, RPC header, and payload are all sent in a
 488  *   single RDMA_SEND. This is the "inline" case.
 489  * - The RPCRDMA header and some portion of the RPC header and data
 490  *   are sent via this RDMA_SEND and another portion of the data is
 491  *   sent via RDMA.
 492  * - The RPCRDMA header [NOMSG] is sent in this RDMA_SEND and the RPC
 493  *   header and data are all transmitted via RDMA.
 494  * In all three cases, this function prepares the RPCRDMA header in
 495  * sge[0], the 'type' parameter indicates the type to place in the
 496  * RPCRDMA header, and the 'byte_count' field indicates how much of
 497  * the XDR to include in this RDMA_SEND.
 498  */
 499 static int send_reply(struct svcxprt_rdma *rdma,
 500                       struct svc_rqst *rqstp,
 501                       struct page *page,
 502                       struct rpcrdma_msg *rdma_resp,
 503                       struct svc_rdma_op_ctxt *ctxt,
 504                       struct svc_rdma_req_map *vec,
 505                       int byte_count)
 506 {
 507         struct ib_send_wr send_wr;
 508         struct ib_send_wr inv_wr;
 509         int sge_no;
 510         int sge_bytes;
 511         int page_no;
 512         int ret;
 513
 514         /* Post a recv buffer to handle another request. */
 515         ret = svc_rdma_post_recv(rdma);
 516         if (ret) {
 517                 printk(KERN_INFO
 518                        "svcrdma: could not post a receive buffer, err=%d."
 519                        "Closing transport %p.\n", ret, rdma);
 520                 set_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags);
 521                 svc_rdma_put_frmr(rdma, vec->frmr);
 522                 svc_rdma_put_context(ctxt, 0);
 523                 return -ENOTCONN;
 524         }
 525
 526         /* Prepare the context */
 527         ctxt->pages[0] = page;
 528         ctxt->count = 1;
 529         ctxt->frmr = vec->frmr;
 530         if (vec->frmr)
 531                 set_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags);
 532         else
 533                 clear_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags);
 534
 535         /* Prepare the SGE for the RPCRDMA Header */
 536         ctxt->sge[0].lkey = rdma->sc_dma_lkey;
 537         ctxt->sge[0].length = svc_rdma_xdr_get_reply_hdr_len(rdma_resp);
 538         ctxt->sge[0].addr =
 539                 ib_dma_map_single(rdma->sc_cm_id->device, page_address(page),
 540                                   ctxt->sge[0].length, DMA_TO_DEVICE);
 541         if (ib_dma_mapping_error(rdma->sc_cm_id->device, ctxt->sge[0].addr))
 542                 goto err;
 543         atomic_inc(&rdma->sc_dma_used);
 544
 545         ctxt->direction = DMA_TO_DEVICE;
 546
 547         /* Determine how many of our SGE are to be transmitted */
 548         for (sge_no = 1; byte_count && sge_no < vec->count; sge_no++) {
 549                 sge_bytes = min_t(size_t, vec->sge[sge_no].iov_len, byte_count);
 550                 byte_count -= sge_bytes;
 551                 if (!vec->frmr) {
 552                         ctxt->sge[sge_no].addr =
 553                                 ib_dma_map_single(rdma->sc_cm_id->device,
 554                                                   vec->sge[sge_no].iov_base,
 555                                                   sge_bytes, DMA_TO_DEVICE);
 556                         if (ib_dma_mapping_error(rdma->sc_cm_id->device,
 557                                                  ctxt->sge[sge_no].addr))
 558                                 goto err;
 559                         atomic_inc(&rdma->sc_dma_used);
 560                         ctxt->sge[sge_no].lkey = rdma->sc_dma_lkey;
 561                 } else {
 562                         ctxt->sge[sge_no].addr = (unsigned long)
 563                                 vec->sge[sge_no].iov_base;
 564                         ctxt->sge[sge_no].lkey = vec->frmr->mr->lkey;
 565                 }
 566                 ctxt->sge[sge_no].length = sge_bytes;
 567         }
 568         BUG_ON(byte_count != 0);
 569
 570         /* Save all respages in the ctxt and remove them from the
 571          * respages array. They are our pages until the I/O
 572          * completes.
 573          */
 574         for (page_no = 0; page_no < rqstp->rq_resused; page_no++) {
 575                 ctxt->pages[page_no+1] = rqstp->rq_respages[page_no];
 576                 ctxt->count++;
 577                 rqstp->rq_respages[page_no] = NULL;
 578                 /*
 579                  * If there are more pages than SGE, terminate SGE
 580                  * list so that svc_rdma_unmap_dma doesn't attempt to
 581                  * unmap garbage.
 582                  */
 583                 if (page_no+1 >= sge_no)
 584                         ctxt->sge[page_no+1].length = 0;
 585         }
 586         BUG_ON(sge_no > rdma->sc_max_sge);
 587         memset(&send_wr, 0, sizeof send_wr);
 588         ctxt->wr_op = IB_WR_SEND;
 589         send_wr.wr_id = (unsigned long)ctxt;
 590         send_wr.sg_list = ctxt->sge;
 591         send_wr.num_sge = sge_no;
 592         send_wr.opcode = IB_WR_SEND;
 593         send_wr.send_flags =  IB_SEND_SIGNALED;
 594         if (vec->frmr) {
 595                 /* Prepare INVALIDATE WR */
 596                 memset(&inv_wr, 0, sizeof inv_wr);
 597                 inv_wr.opcode = IB_WR_LOCAL_INV;
 598                 inv_wr.send_flags = IB_SEND_SIGNALED;
 599                 inv_wr.ex.invalidate_rkey =
 600                         vec->frmr->mr->lkey;
 601                 send_wr.next = &inv_wr;
 602         }
 603
 604         ret = svc_rdma_send(rdma, &send_wr);
 605         if (ret)
 606                 goto err;
 607
 608         return 0;
 609
 610  err:
 611         svc_rdma_unmap_dma(ctxt);
 612         svc_rdma_put_frmr(rdma, vec->frmr);
 613         svc_rdma_put_context(ctxt, 1);
 614         return -EIO;
 615 }
 616
 617 void svc_rdma_prep_reply_hdr(struct svc_rqst *rqstp)
 618 {
 619 }
 620
 621 /*
 622  * Return the start of an xdr buffer.
 623  */
 624 static void *xdr_start(struct xdr_buf *xdr)
 625 {
 626         return xdr->head[0].iov_base -
 627                 (xdr->len -
 628                  xdr->page_len -
 629                  xdr->tail[0].iov_len -
 630                  xdr->head[0].iov_len);
 631 }
 632
 633 int svc_rdma_sendto(struct svc_rqst *rqstp)
 634 {
 635         struct svc_xprt *xprt = rqstp->rq_xprt;
 636         struct svcxprt_rdma *rdma =
 637                 container_of(xprt, struct svcxprt_rdma, sc_xprt);
 638         struct rpcrdma_msg *rdma_argp;
 639         struct rpcrdma_msg *rdma_resp;
 640         struct rpcrdma_write_array *reply_ary;
 641         enum rpcrdma_proc reply_type;
 642         int ret;
 643         int inline_bytes;
 644         struct page *res_page;
 645         struct svc_rdma_op_ctxt *ctxt;
 646         struct svc_rdma_req_map *vec;
 647
 648         dprintk("svcrdma: sending response for rqstp=%p\n", rqstp);
 649
 650         /* Get the RDMA request header. */
 651         rdma_argp = xdr_start(&rqstp->rq_arg);
 652
 653         /* Build an req vec for the XDR */
 654         ctxt = svc_rdma_get_context(rdma);
 655         ctxt->direction = DMA_TO_DEVICE;
 656         vec = svc_rdma_get_req_map();
 657         ret = map_xdr(rdma, &rqstp->rq_res, vec);
 658         if (ret)
 659                 goto err0;
 660         inline_bytes = rqstp->rq_res.len;
 661
 662         /* Create the RDMA response header */
 663         res_page = svc_rdma_get_page();
 664         rdma_resp = page_address(res_page);
 665         reply_ary = svc_rdma_get_reply_array(rdma_argp);
 666         if (reply_ary)
 667                 reply_type = RDMA_NOMSG;
 668         else
 669                 reply_type = RDMA_MSG;
 670         svc_rdma_xdr_encode_reply_header(rdma, rdma_argp,
 671                                          rdma_resp, reply_type);
 672
 673         /* Send any write-chunk data and build resp write-list */
 674         ret = send_write_chunks(rdma, rdma_argp, rdma_resp,
 675                                 rqstp, vec);
 676         if (ret < 0) {
 677                 printk(KERN_ERR "svcrdma: failed to send write chunks, rc=%d\n",
 678                        ret);
 679                 goto err1;
 680         }
 681         inline_bytes -= ret;
 682
 683         /* Send any reply-list data and update resp reply-list */
 684         ret = send_reply_chunks(rdma, rdma_argp, rdma_resp,
 685                                 rqstp, vec);
 686         if (ret < 0) {
 687                 printk(KERN_ERR "svcrdma: failed to send reply chunks, rc=%d\n",
 688                        ret);
 689                 goto err1;
 690         }
 691         inline_bytes -= ret;
 692
 693         ret = send_reply(rdma, rqstp, res_page, rdma_resp, ctxt, vec,
 694                          inline_bytes);
 695         svc_rdma_put_req_map(vec);
 696         dprintk("svcrdma: send_reply returns %d\n", ret);
 697         return ret;
 698
 699  err1:
 700         put_page(res_page);
 701  err0:
 702         svc_rdma_put_req_map(vec);
 703         svc_rdma_put_context(ctxt, 0);
 704         return ret;
 705 }