git.oblomov.eu Git - linux-2.6/blob - 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_page(xprt->sc_cm_id->device, page, 0,
 132                                           PAGE_SIZE, DMA_TO_DEVICE);
 133                 if (ib_dma_mapping_error(xprt->sc_cm_id->device,
 134                                          frmr->page_list->page_list[page_no]))
 135                         goto fatal_err;
 136
 137                 atomic_inc(&xprt->sc_dma_used);
 138                 page_off = 0; /* reset for next time through loop */
 139                 frmr->map_len += PAGE_SIZE;
 140                 frmr->page_list_len++;
 141         }
 142         vec->count++;
 143
 144  encode_tail:
 145         /* Map tail */
 146         if (0 == xdr->tail[0].iov_len)
 147                 goto done;
 148
 149         vec->count++;
 150         vec->sge[sge_no].iov_len = xdr->tail[0].iov_len;
 151
 152         if (((unsigned long)xdr->tail[0].iov_base & PAGE_MASK) ==
 153             ((unsigned long)xdr->head[0].iov_base & PAGE_MASK)) {
 154                 /*
 155                  * If head and tail use the same page, we don't need
 156                  * to map it again.
 157                  */
 158                 vec->sge[sge_no].iov_base = xdr->tail[0].iov_base;
 159         } else {
 160                 void *va;
 161
 162                 /* Map another page for the tail */
 163                 page_off = (unsigned long)xdr->tail[0].iov_base & ~PAGE_MASK;
 164                 va = (void *)((unsigned long)xdr->tail[0].iov_base & PAGE_MASK);
 165                 vec->sge[sge_no].iov_base = frva + frmr->map_len + page_off;
 166
 167                 frmr->page_list->page_list[page_no] =
 168                         ib_dma_map_single(xprt->sc_cm_id->device, va, PAGE_SIZE,
 169                                           DMA_TO_DEVICE);
 170                 if (ib_dma_mapping_error(xprt->sc_cm_id->device,
 171                                          frmr->page_list->page_list[page_no]))
 172                         goto fatal_err;
 173                 atomic_inc(&xprt->sc_dma_used);
 174                 frmr->map_len += PAGE_SIZE;
 175                 frmr->page_list_len++;
 176         }
 177
 178  done:
 179         if (svc_rdma_fastreg(xprt, frmr))
 180                 goto fatal_err;
 181
 182         return 0;
 183
 184  fatal_err:
 185         printk("svcrdma: Error fast registering memory for xprt %p\n", xprt);
 186         svc_rdma_put_frmr(xprt, frmr);
 187         return -EIO;
 188 }
 189
 190 static int map_xdr(struct svcxprt_rdma *xprt,
 191                    struct xdr_buf *xdr,
 192                    struct svc_rdma_req_map *vec)
 193 {
 194         int sge_no;
 195         u32 sge_bytes;
 196         u32 page_bytes;
 197         u32 page_off;
 198         int page_no;
 199
 200         BUG_ON(xdr->len !=
 201                (xdr->head[0].iov_len + xdr->page_len + xdr->tail[0].iov_len));
 202
 203         if (xprt->sc_frmr_pg_list_len)
 204                 return fast_reg_xdr(xprt, xdr, vec);
 205
 206         /* Skip the first sge, this is for the RPCRDMA header */
 207         sge_no = 1;
 208
 209         /* Head SGE */
 210         vec->sge[sge_no].iov_base = xdr->head[0].iov_base;
 211         vec->sge[sge_no].iov_len = xdr->head[0].iov_len;
 212         sge_no++;
 213
 214         /* pages SGE */
 215         page_no = 0;
 216         page_bytes = xdr->page_len;
 217         page_off = xdr->page_base;
 218         while (page_bytes) {
 219                 vec->sge[sge_no].iov_base =
 220                         page_address(xdr->pages[page_no]) + page_off;
 221                 sge_bytes = min_t(u32, page_bytes, (PAGE_SIZE - page_off));
 222                 page_bytes -= sge_bytes;
 223                 vec->sge[sge_no].iov_len = sge_bytes;
 224
 225                 sge_no++;
 226                 page_no++;
 227                 page_off = 0; /* reset for next time through loop */
 228         }
 229
 230         /* Tail SGE */
 231         if (xdr->tail[0].iov_len) {
 232                 vec->sge[sge_no].iov_base = xdr->tail[0].iov_base;
 233                 vec->sge[sge_no].iov_len = xdr->tail[0].iov_len;
 234                 sge_no++;
 235         }
 236
 237         dprintk("svcrdma: map_xdr: sge_no %d page_no %d "
 238                 "page_base %u page_len %u head_len %zu tail_len %zu\n",
 239                 sge_no, page_no, xdr->page_base, xdr->page_len,
 240                 xdr->head[0].iov_len, xdr->tail[0].iov_len);
 241
 242         vec->count = sge_no;
 243         return 0;
 244 }
 245
 246 /* Assumptions:
 247  * - We are using FRMR
 248  *     - or -
 249  * - The specified write_len can be represented in sc_max_sge * PAGE_SIZE
 250  */
 251 static int send_write(struct svcxprt_rdma *xprt, struct svc_rqst *rqstp,
 252                       u32 rmr, u64 to,
 253                       u32 xdr_off, int write_len,
 254                       struct svc_rdma_req_map *vec)
 255 {
 256         struct ib_send_wr write_wr;
 257         struct ib_sge *sge;
 258         int xdr_sge_no;
 259         int sge_no;
 260         int sge_bytes;
 261         int sge_off;
 262         int bc;
 263         struct svc_rdma_op_ctxt *ctxt;
 264
 265         BUG_ON(vec->count > RPCSVC_MAXPAGES);
 266         dprintk("svcrdma: RDMA_WRITE rmr=%x, to=%llx, xdr_off=%d, "
 267                 "write_len=%d, vec->sge=%p, vec->count=%lu\n",
 268                 rmr, (unsigned long long)to, xdr_off,
 269                 write_len, vec->sge, vec->count);
 270
 271         ctxt = svc_rdma_get_context(xprt);
 272         ctxt->direction = DMA_TO_DEVICE;
 273         sge = ctxt->sge;
 274
 275         /* Find the SGE associated with xdr_off */
 276         for (bc = xdr_off, xdr_sge_no = 1; bc && xdr_sge_no < vec->count;
 277              xdr_sge_no++) {
 278                 if (vec->sge[xdr_sge_no].iov_len > bc)
 279                         break;
 280                 bc -= vec->sge[xdr_sge_no].iov_len;
 281         }
 282
 283         sge_off = bc;
 284         bc = write_len;
 285         sge_no = 0;
 286
 287         /* Copy the remaining SGE */
 288         while (bc != 0) {
 289                 sge_bytes = min_t(size_t,
 290                           bc, vec->sge[xdr_sge_no].iov_len-sge_off);
 291                 sge[sge_no].length = sge_bytes;
 292                 if (!vec->frmr) {
 293                         sge[sge_no].addr =
 294                                 ib_dma_map_single(xprt->sc_cm_id->device,
 295                                                   (void *)
 296                                                   vec->sge[xdr_sge_no].iov_base + sge_off,
 297                                                   sge_bytes, DMA_TO_DEVICE);
 298                         if (ib_dma_mapping_error(xprt->sc_cm_id->device,
 299                                                  sge[sge_no].addr))
 300                                 goto err;
 301                         atomic_inc(&xprt->sc_dma_used);
 302                         sge[sge_no].lkey = xprt->sc_dma_lkey;
 303                 } else {
 304                         sge[sge_no].addr = (unsigned long)
 305                                 vec->sge[xdr_sge_no].iov_base + sge_off;
 306                         sge[sge_no].lkey = vec->frmr->mr->lkey;
 307                 }
 308                 ctxt->count++;
 309                 ctxt->frmr = vec->frmr;
 310                 sge_off = 0;
 311                 sge_no++;
 312                 xdr_sge_no++;
 313                 BUG_ON(xdr_sge_no > vec->count);
 314                 bc -= sge_bytes;
 315         }
 316
 317         /* Prepare WRITE WR */
 318         memset(&write_wr, 0, sizeof write_wr);
 319         ctxt->wr_op = IB_WR_RDMA_WRITE;
 320         write_wr.wr_id = (unsigned long)ctxt;
 321         write_wr.sg_list = &sge[0];
 322         write_wr.num_sge = sge_no;
 323         write_wr.opcode = IB_WR_RDMA_WRITE;
 324         write_wr.send_flags = IB_SEND_SIGNALED;
 325         write_wr.wr.rdma.rkey = rmr;
 326         write_wr.wr.rdma.remote_addr = to;
 327
 328         /* Post It */
 329         atomic_inc(&rdma_stat_write);
 330         if (svc_rdma_send(xprt, &write_wr))
 331                 goto err;
 332         return 0;
 333  err:
 334         svc_rdma_put_context(ctxt, 0);
 335         /* Fatal error, close transport */
 336         return -EIO;
 337 }
 338
 339 static int send_write_chunks(struct svcxprt_rdma *xprt,
 340                              struct rpcrdma_msg *rdma_argp,
 341                              struct rpcrdma_msg *rdma_resp,
 342                              struct svc_rqst *rqstp,
 343                              struct svc_rdma_req_map *vec)
 344 {
 345         u32 xfer_len = rqstp->rq_res.page_len + rqstp->rq_res.tail[0].iov_len;
 346         int write_len;
 347         int max_write;
 348         u32 xdr_off;
 349         int chunk_off;
 350         int chunk_no;
 351         struct rpcrdma_write_array *arg_ary;
 352         struct rpcrdma_write_array *res_ary;
 353         int ret;
 354
 355         arg_ary = svc_rdma_get_write_array(rdma_argp);
 356         if (!arg_ary)
 357                 return 0;
 358         res_ary = (struct rpcrdma_write_array *)
 359                 &rdma_resp->rm_body.rm_chunks[1];
 360
 361         if (vec->frmr)
 362                 max_write = vec->frmr->map_len;
 363         else
 364                 max_write = xprt->sc_max_sge * PAGE_SIZE;
 365
 366         /* Write chunks start at the pagelist */
 367         for (xdr_off = rqstp->rq_res.head[0].iov_len, chunk_no = 0;
 368              xfer_len && chunk_no < arg_ary->wc_nchunks;
 369              chunk_no++) {
 370                 struct rpcrdma_segment *arg_ch;
 371                 u64 rs_offset;
 372
 373                 arg_ch = &arg_ary->wc_array[chunk_no].wc_target;
 374                 write_len = min(xfer_len, arg_ch->rs_length);
 375
 376                 /* Prepare the response chunk given the length actually
 377                  * written */
 378                 rs_offset = get_unaligned(&(arg_ch->rs_offset));
 379                 svc_rdma_xdr_encode_array_chunk(res_ary, chunk_no,
 380                                             arg_ch->rs_handle,
 381                                             rs_offset,
 382                                             write_len);
 383                 chunk_off = 0;
 384                 while (write_len) {
 385                         int this_write;
 386                         this_write = min(write_len, max_write);
 387                         ret = send_write(xprt, rqstp,
 388                                          arg_ch->rs_handle,
 389                                          rs_offset + chunk_off,
 390                                          xdr_off,
 391                                          this_write,
 392                                          vec);
 393                         if (ret) {
 394                                 dprintk("svcrdma: RDMA_WRITE failed, ret=%d\n",
 395                                         ret);
 396                                 return -EIO;
 397                         }
 398                         chunk_off += this_write;
 399                         xdr_off += this_write;
 400                         xfer_len -= this_write;
 401                         write_len -= this_write;
 402                 }
 403         }
 404         /* Update the req with the number of chunks actually used */
 405         svc_rdma_xdr_encode_write_list(rdma_resp, chunk_no);
 406
 407         return rqstp->rq_res.page_len + rqstp->rq_res.tail[0].iov_len;
 408 }
 409
 410 static int send_reply_chunks(struct svcxprt_rdma *xprt,
 411                              struct rpcrdma_msg *rdma_argp,
 412                              struct rpcrdma_msg *rdma_resp,
 413                              struct svc_rqst *rqstp,
 414                              struct svc_rdma_req_map *vec)
 415 {
 416         u32 xfer_len = rqstp->rq_res.len;
 417         int write_len;
 418         int max_write;
 419         u32 xdr_off;
 420         int chunk_no;
 421         int chunk_off;
 422         struct rpcrdma_segment *ch;
 423         struct rpcrdma_write_array *arg_ary;
 424         struct rpcrdma_write_array *res_ary;
 425         int ret;
 426
 427         arg_ary = svc_rdma_get_reply_array(rdma_argp);
 428         if (!arg_ary)
 429                 return 0;
 430         /* XXX: need to fix when reply lists occur with read-list and or
 431          * write-list */
 432         res_ary = (struct rpcrdma_write_array *)
 433                 &rdma_resp->rm_body.rm_chunks[2];
 434
 435         if (vec->frmr)
 436                 max_write = vec->frmr->map_len;
 437         else
 438                 max_write = xprt->sc_max_sge * PAGE_SIZE;
 439
 440         /* xdr offset starts at RPC message */
 441         for (xdr_off = 0, chunk_no = 0;
 442              xfer_len && chunk_no < arg_ary->wc_nchunks;
 443              chunk_no++) {
 444                 u64 rs_offset;
 445                 ch = &arg_ary->wc_array[chunk_no].wc_target;
 446                 write_len = min(xfer_len, ch->rs_length);
 447
 448                 /* Prepare the reply chunk given the length actually
 449                  * written */
 450                 rs_offset = get_unaligned(&(ch->rs_offset));
 451                 svc_rdma_xdr_encode_array_chunk(res_ary, chunk_no,
 452                                             ch->rs_handle, rs_offset,
 453                                             write_len);
 454                 chunk_off = 0;
 455                 while (write_len) {
 456                         int this_write;
 457
 458                         this_write = min(write_len, max_write);
 459                         ret = send_write(xprt, rqstp,
 460                                          ch->rs_handle,
 461                                          rs_offset + chunk_off,
 462                                          xdr_off,
 463                                          this_write,
 464                                          vec);
 465                         if (ret) {
 466                                 dprintk("svcrdma: RDMA_WRITE failed, ret=%d\n",
 467                                         ret);
 468                                 return -EIO;
 469                         }
 470                         chunk_off += this_write;
 471                         xdr_off += this_write;
 472                         xfer_len -= this_write;
 473                         write_len -= this_write;
 474                 }
 475         }
 476         /* Update the req with the number of chunks actually used */
 477         svc_rdma_xdr_encode_reply_array(res_ary, chunk_no);
 478
 479         return rqstp->rq_res.len;
 480 }
 481
 482 /* This function prepares the portion of the RPCRDMA message to be
 483  * sent in the RDMA_SEND. This function is called after data sent via
 484  * RDMA has already been transmitted. There are three cases:
 485  * - The RPCRDMA header, RPC header, and payload are all sent in a
 486  *   single RDMA_SEND. This is the "inline" case.
 487  * - The RPCRDMA header and some portion of the RPC header and data
 488  *   are sent via this RDMA_SEND and another portion of the data is
 489  *   sent via RDMA.
 490  * - The RPCRDMA header [NOMSG] is sent in this RDMA_SEND and the RPC
 491  *   header and data are all transmitted via RDMA.
 492  * In all three cases, this function prepares the RPCRDMA header in
 493  * sge[0], the 'type' parameter indicates the type to place in the
 494  * RPCRDMA header, and the 'byte_count' field indicates how much of
 495  * the XDR to include in this RDMA_SEND.
 496  */
 497 static int send_reply(struct svcxprt_rdma *rdma,
 498                       struct svc_rqst *rqstp,
 499                       struct page *page,
 500                       struct rpcrdma_msg *rdma_resp,
 501                       struct svc_rdma_op_ctxt *ctxt,
 502                       struct svc_rdma_req_map *vec,
 503                       int byte_count)
 504 {
 505         struct ib_send_wr send_wr;
 506         struct ib_send_wr inv_wr;
 507         int sge_no;
 508         int sge_bytes;
 509         int page_no;
 510         int ret;
 511
 512         /* Post a recv buffer to handle another request. */
 513         ret = svc_rdma_post_recv(rdma);
 514         if (ret) {
 515                 printk(KERN_INFO
 516                        "svcrdma: could not post a receive buffer, err=%d."
 517                        "Closing transport %p.\n", ret, rdma);
 518                 set_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags);
 519                 svc_rdma_put_context(ctxt, 0);
 520                 return -ENOTCONN;
 521         }
 522
 523         /* Prepare the context */
 524         ctxt->pages[0] = page;
 525         ctxt->count = 1;
 526         ctxt->frmr = vec->frmr;
 527         if (vec->frmr)
 528                 set_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags);
 529         else
 530                 clear_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags);
 531
 532         /* Prepare the SGE for the RPCRDMA Header */
 533         ctxt->sge[0].addr =
 534                 ib_dma_map_page(rdma->sc_cm_id->device,
 535                                 page, 0, PAGE_SIZE, DMA_TO_DEVICE);
 536         if (ib_dma_mapping_error(rdma->sc_cm_id->device, ctxt->sge[0].addr))
 537                 goto err;
 538         atomic_inc(&rdma->sc_dma_used);
 539
 540         ctxt->direction = DMA_TO_DEVICE;
 541
 542         ctxt->sge[0].length = svc_rdma_xdr_get_reply_hdr_len(rdma_resp);
 543         ctxt->sge[0].lkey = rdma->sc_dma_lkey;
 544
 545         /* Determine how many of our SGE are to be transmitted */
 546         for (sge_no = 1; byte_count && sge_no < vec->count; sge_no++) {
 547                 sge_bytes = min_t(size_t, vec->sge[sge_no].iov_len, byte_count);
 548                 byte_count -= sge_bytes;
 549                 if (!vec->frmr) {
 550                         ctxt->sge[sge_no].addr =
 551                                 ib_dma_map_single(rdma->sc_cm_id->device,
 552                                                   vec->sge[sge_no].iov_base,
 553                                                   sge_bytes, DMA_TO_DEVICE);
 554                         if (ib_dma_mapping_error(rdma->sc_cm_id->device,
 555                                                  ctxt->sge[sge_no].addr))
 556                                 goto err;
 557                         atomic_inc(&rdma->sc_dma_used);
 558                         ctxt->sge[sge_no].lkey = rdma->sc_dma_lkey;
 559                 } else {
 560                         ctxt->sge[sge_no].addr = (unsigned long)
 561                                 vec->sge[sge_no].iov_base;
 562                         ctxt->sge[sge_no].lkey = vec->frmr->mr->lkey;
 563                 }
 564                 ctxt->sge[sge_no].length = sge_bytes;
 565         }
 566         BUG_ON(byte_count != 0);
 567
 568         /* Save all respages in the ctxt and remove them from the
 569          * respages array. They are our pages until the I/O
 570          * completes.
 571          */
 572         for (page_no = 0; page_no < rqstp->rq_resused; page_no++) {
 573                 ctxt->pages[page_no+1] = rqstp->rq_respages[page_no];
 574                 ctxt->count++;
 575                 rqstp->rq_respages[page_no] = NULL;
 576                 /*
 577                  * If there are more pages than SGE, terminate SGE
 578                  * list so that svc_rdma_unmap_dma doesn't attempt to
 579                  * unmap garbage.
 580                  */
 581                 if (page_no+1 >= sge_no)
 582                         ctxt->sge[page_no+1].length = 0;
 583         }
 584         BUG_ON(sge_no > rdma->sc_max_sge);
 585         memset(&send_wr, 0, sizeof send_wr);
 586         ctxt->wr_op = IB_WR_SEND;
 587         send_wr.wr_id = (unsigned long)ctxt;
 588         send_wr.sg_list = ctxt->sge;
 589         send_wr.num_sge = sge_no;
 590         send_wr.opcode = IB_WR_SEND;
 591         send_wr.send_flags =  IB_SEND_SIGNALED;
 592         if (vec->frmr) {
 593                 /* Prepare INVALIDATE WR */
 594                 memset(&inv_wr, 0, sizeof inv_wr);
 595                 inv_wr.opcode = IB_WR_LOCAL_INV;
 596                 inv_wr.send_flags = IB_SEND_SIGNALED;
 597                 inv_wr.ex.invalidate_rkey =
 598                         vec->frmr->mr->lkey;
 599                 send_wr.next = &inv_wr;
 600         }
 601
 602         ret = svc_rdma_send(rdma, &send_wr);
 603         if (ret)
 604                 goto err;
 605
 606         return 0;
 607
 608  err:
 609         svc_rdma_put_frmr(rdma, vec->frmr);
 610         svc_rdma_put_context(ctxt, 1);
 611         return -EIO;
 612 }
 613
 614 void svc_rdma_prep_reply_hdr(struct svc_rqst *rqstp)
 615 {
 616 }
 617
 618 /*
 619  * Return the start of an xdr buffer.
 620  */
 621 static void *xdr_start(struct xdr_buf *xdr)
 622 {
 623         return xdr->head[0].iov_base -
 624                 (xdr->len -
 625                  xdr->page_len -
 626                  xdr->tail[0].iov_len -
 627                  xdr->head[0].iov_len);
 628 }
 629
 630 int svc_rdma_sendto(struct svc_rqst *rqstp)
 631 {
 632         struct svc_xprt *xprt = rqstp->rq_xprt;
 633         struct svcxprt_rdma *rdma =
 634                 container_of(xprt, struct svcxprt_rdma, sc_xprt);
 635         struct rpcrdma_msg *rdma_argp;
 636         struct rpcrdma_msg *rdma_resp;
 637         struct rpcrdma_write_array *reply_ary;
 638         enum rpcrdma_proc reply_type;
 639         int ret;
 640         int inline_bytes;
 641         struct page *res_page;
 642         struct svc_rdma_op_ctxt *ctxt;
 643         struct svc_rdma_req_map *vec;
 644
 645         dprintk("svcrdma: sending response for rqstp=%p\n", rqstp);
 646
 647         /* Get the RDMA request header. */
 648         rdma_argp = xdr_start(&rqstp->rq_arg);
 649
 650         /* Build an req vec for the XDR */
 651         ctxt = svc_rdma_get_context(rdma);
 652         ctxt->direction = DMA_TO_DEVICE;
 653         vec = svc_rdma_get_req_map();
 654         ret = map_xdr(rdma, &rqstp->rq_res, vec);
 655         if (ret)
 656                 goto err0;
 657         inline_bytes = rqstp->rq_res.len;
 658
 659         /* Create the RDMA response header */
 660         res_page = svc_rdma_get_page();
 661         rdma_resp = page_address(res_page);
 662         reply_ary = svc_rdma_get_reply_array(rdma_argp);
 663         if (reply_ary)
 664                 reply_type = RDMA_NOMSG;
 665         else
 666                 reply_type = RDMA_MSG;
 667         svc_rdma_xdr_encode_reply_header(rdma, rdma_argp,
 668                                          rdma_resp, reply_type);
 669
 670         /* Send any write-chunk data and build resp write-list */
 671         ret = send_write_chunks(rdma, rdma_argp, rdma_resp,
 672                                 rqstp, vec);
 673         if (ret < 0) {
 674                 printk(KERN_ERR "svcrdma: failed to send write chunks, rc=%d\n",
 675                        ret);
 676                 goto err1;
 677         }
 678         inline_bytes -= ret;
 679
 680         /* Send any reply-list data and update resp reply-list */
 681         ret = send_reply_chunks(rdma, rdma_argp, rdma_resp,
 682                                 rqstp, vec);
 683         if (ret < 0) {
 684                 printk(KERN_ERR "svcrdma: failed to send reply chunks, rc=%d\n",
 685                        ret);
 686                 goto err1;
 687         }
 688         inline_bytes -= ret;
 689
 690         ret = send_reply(rdma, rqstp, res_page, rdma_resp, ctxt, vec,
 691                          inline_bytes);
 692         svc_rdma_put_req_map(vec);
 693         dprintk("svcrdma: send_reply returns %d\n", ret);
 694         return ret;
 695
 696  err1:
 697         put_page(res_page);
 698  err0:
 699         svc_rdma_put_req_map(vec);
 700         svc_rdma_put_context(ctxt, 0);
 701         return ret;
 702 }