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   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 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_max = (xdr->len+PAGE_SIZE-1) / PAGE_SIZE + 3;
 195         int sge_no;
 196         u32 sge_bytes;
 197         u32 page_bytes;
 198         u32 page_off;
 199         int page_no;
 200
 201         BUG_ON(xdr->len !=
 202                (xdr->head[0].iov_len + xdr->page_len + xdr->tail[0].iov_len));
 203
 204         if (xprt->sc_frmr_pg_list_len)
 205                 return fast_reg_xdr(xprt, xdr, vec);
 206
 207         /* Skip the first sge, this is for the RPCRDMA header */
 208         sge_no = 1;
 209
 210         /* Head SGE */
 211         vec->sge[sge_no].iov_base = xdr->head[0].iov_base;
 212         vec->sge[sge_no].iov_len = xdr->head[0].iov_len;
 213         sge_no++;
 214
 215         /* pages SGE */
 216         page_no = 0;
 217         page_bytes = xdr->page_len;
 218         page_off = xdr->page_base;
 219         while (page_bytes) {
 220                 vec->sge[sge_no].iov_base =
 221                         page_address(xdr->pages[page_no]) + page_off;
 222                 sge_bytes = min_t(u32, page_bytes, (PAGE_SIZE - page_off));
 223                 page_bytes -= sge_bytes;
 224                 vec->sge[sge_no].iov_len = sge_bytes;
 225
 226                 sge_no++;
 227                 page_no++;
 228                 page_off = 0; /* reset for next time through loop */
 229         }
 230
 231         /* Tail SGE */
 232         if (xdr->tail[0].iov_len) {
 233                 vec->sge[sge_no].iov_base = xdr->tail[0].iov_base;
 234                 vec->sge[sge_no].iov_len = xdr->tail[0].iov_len;
 235                 sge_no++;
 236         }
 237
 238         BUG_ON(sge_no > sge_max);
 239         vec->count = sge_no;
 240         return 0;
 241 }
 242
 243 /* Assumptions:
 244  * - We are using FRMR
 245  *     - or -
 246  * - The specified write_len can be represented in sc_max_sge * PAGE_SIZE
 247  */
 248 static int send_write(struct svcxprt_rdma *xprt, struct svc_rqst *rqstp,
 249                       u32 rmr, u64 to,
 250                       u32 xdr_off, int write_len,
 251                       struct svc_rdma_req_map *vec)
 252 {
 253         struct ib_send_wr write_wr;
 254         struct ib_sge *sge;
 255         int xdr_sge_no;
 256         int sge_no;
 257         int sge_bytes;
 258         int sge_off;
 259         int bc;
 260         struct svc_rdma_op_ctxt *ctxt;
 261
 262         BUG_ON(vec->count > RPCSVC_MAXPAGES);
 263         dprintk("svcrdma: RDMA_WRITE rmr=%x, to=%llx, xdr_off=%d, "
 264                 "write_len=%d, vec->sge=%p, vec->count=%lu\n",
 265                 rmr, (unsigned long long)to, xdr_off,
 266                 write_len, vec->sge, vec->count);
 267
 268         ctxt = svc_rdma_get_context(xprt);
 269         ctxt->direction = DMA_TO_DEVICE;
 270         sge = ctxt->sge;
 271
 272         /* Find the SGE associated with xdr_off */
 273         for (bc = xdr_off, xdr_sge_no = 1; bc && xdr_sge_no < vec->count;
 274              xdr_sge_no++) {
 275                 if (vec->sge[xdr_sge_no].iov_len > bc)
 276                         break;
 277                 bc -= vec->sge[xdr_sge_no].iov_len;
 278         }
 279
 280         sge_off = bc;
 281         bc = write_len;
 282         sge_no = 0;
 283
 284         /* Copy the remaining SGE */
 285         while (bc != 0) {
 286                 sge_bytes = min_t(size_t,
 287                           bc, vec->sge[xdr_sge_no].iov_len-sge_off);
 288                 sge[sge_no].length = sge_bytes;
 289                 if (!vec->frmr) {
 290                         sge[sge_no].addr =
 291                                 ib_dma_map_single(xprt->sc_cm_id->device,
 292                                                   (void *)
 293                                                   vec->sge[xdr_sge_no].iov_base + sge_off,
 294                                                   sge_bytes, DMA_TO_DEVICE);
 295                         if (ib_dma_mapping_error(xprt->sc_cm_id->device,
 296                                                  sge[sge_no].addr))
 297                                 goto err;
 298                         atomic_inc(&xprt->sc_dma_used);
 299                         sge[sge_no].lkey = xprt->sc_dma_lkey;
 300                 } else {
 301                         sge[sge_no].addr = (unsigned long)
 302                                 vec->sge[xdr_sge_no].iov_base + sge_off;
 303                         sge[sge_no].lkey = vec->frmr->mr->lkey;
 304                 }
 305                 ctxt->count++;
 306                 ctxt->frmr = vec->frmr;
 307                 sge_off = 0;
 308                 sge_no++;
 309                 xdr_sge_no++;
 310                 BUG_ON(xdr_sge_no > vec->count);
 311                 bc -= sge_bytes;
 312         }
 313
 314         /* Prepare WRITE WR */
 315         memset(&write_wr, 0, sizeof write_wr);
 316         ctxt->wr_op = IB_WR_RDMA_WRITE;
 317         write_wr.wr_id = (unsigned long)ctxt;
 318         write_wr.sg_list = &sge[0];
 319         write_wr.num_sge = sge_no;
 320         write_wr.opcode = IB_WR_RDMA_WRITE;
 321         write_wr.send_flags = IB_SEND_SIGNALED;
 322         write_wr.wr.rdma.rkey = rmr;
 323         write_wr.wr.rdma.remote_addr = to;
 324
 325         /* Post It */
 326         atomic_inc(&rdma_stat_write);
 327         if (svc_rdma_send(xprt, &write_wr))
 328                 goto err;
 329         return 0;
 330  err:
 331         svc_rdma_put_context(ctxt, 0);
 332         /* Fatal error, close transport */
 333         return -EIO;
 334 }
 335
 336 static int send_write_chunks(struct svcxprt_rdma *xprt,
 337                              struct rpcrdma_msg *rdma_argp,
 338                              struct rpcrdma_msg *rdma_resp,
 339                              struct svc_rqst *rqstp,
 340                              struct svc_rdma_req_map *vec)
 341 {
 342         u32 xfer_len = rqstp->rq_res.page_len + rqstp->rq_res.tail[0].iov_len;
 343         int write_len;
 344         int max_write;
 345         u32 xdr_off;
 346         int chunk_off;
 347         int chunk_no;
 348         struct rpcrdma_write_array *arg_ary;
 349         struct rpcrdma_write_array *res_ary;
 350         int ret;
 351
 352         arg_ary = svc_rdma_get_write_array(rdma_argp);
 353         if (!arg_ary)
 354                 return 0;
 355         res_ary = (struct rpcrdma_write_array *)
 356                 &rdma_resp->rm_body.rm_chunks[1];
 357
 358         if (vec->frmr)
 359                 max_write = vec->frmr->map_len;
 360         else
 361                 max_write = xprt->sc_max_sge * PAGE_SIZE;
 362
 363         /* Write chunks start at the pagelist */
 364         for (xdr_off = rqstp->rq_res.head[0].iov_len, chunk_no = 0;
 365              xfer_len && chunk_no < arg_ary->wc_nchunks;
 366              chunk_no++) {
 367                 struct rpcrdma_segment *arg_ch;
 368                 u64 rs_offset;
 369
 370                 arg_ch = &arg_ary->wc_array[chunk_no].wc_target;
 371                 write_len = min(xfer_len, arg_ch->rs_length);
 372
 373                 /* Prepare the response chunk given the length actually
 374                  * written */
 375                 rs_offset = get_unaligned(&(arg_ch->rs_offset));
 376                 svc_rdma_xdr_encode_array_chunk(res_ary, chunk_no,
 377                                             arg_ch->rs_handle,
 378                                             rs_offset,
 379                                             write_len);
 380                 chunk_off = 0;
 381                 while (write_len) {
 382                         int this_write;
 383                         this_write = min(write_len, max_write);
 384                         ret = send_write(xprt, rqstp,
 385                                          arg_ch->rs_handle,
 386                                          rs_offset + chunk_off,
 387                                          xdr_off,
 388                                          this_write,
 389                                          vec);
 390                         if (ret) {
 391                                 dprintk("svcrdma: RDMA_WRITE failed, ret=%d\n",
 392                                         ret);
 393                                 return -EIO;
 394                         }
 395                         chunk_off += this_write;
 396                         xdr_off += this_write;
 397                         xfer_len -= this_write;
 398                         write_len -= this_write;
 399                 }
 400         }
 401         /* Update the req with the number of chunks actually used */
 402         svc_rdma_xdr_encode_write_list(rdma_resp, chunk_no);
 403
 404         return rqstp->rq_res.page_len + rqstp->rq_res.tail[0].iov_len;
 405 }
 406
 407 static int send_reply_chunks(struct svcxprt_rdma *xprt,
 408                              struct rpcrdma_msg *rdma_argp,
 409                              struct rpcrdma_msg *rdma_resp,
 410                              struct svc_rqst *rqstp,
 411                              struct svc_rdma_req_map *vec)
 412 {
 413         u32 xfer_len = rqstp->rq_res.len;
 414         int write_len;
 415         int max_write;
 416         u32 xdr_off;
 417         int chunk_no;
 418         int chunk_off;
 419         struct rpcrdma_segment *ch;
 420         struct rpcrdma_write_array *arg_ary;
 421         struct rpcrdma_write_array *res_ary;
 422         int ret;
 423
 424         arg_ary = svc_rdma_get_reply_array(rdma_argp);
 425         if (!arg_ary)
 426                 return 0;
 427         /* XXX: need to fix when reply lists occur with read-list and or
 428          * write-list */
 429         res_ary = (struct rpcrdma_write_array *)
 430                 &rdma_resp->rm_body.rm_chunks[2];
 431
 432         if (vec->frmr)
 433                 max_write = vec->frmr->map_len;
 434         else
 435                 max_write = xprt->sc_max_sge * PAGE_SIZE;
 436
 437         /* xdr offset starts at RPC message */
 438         for (xdr_off = 0, chunk_no = 0;
 439              xfer_len && chunk_no < arg_ary->wc_nchunks;
 440              chunk_no++) {
 441                 u64 rs_offset;
 442                 ch = &arg_ary->wc_array[chunk_no].wc_target;
 443                 write_len = min(xfer_len, ch->rs_length);
 444
 445                 /* Prepare the reply chunk given the length actually
 446                  * written */
 447                 rs_offset = get_unaligned(&(ch->rs_offset));
 448                 svc_rdma_xdr_encode_array_chunk(res_ary, chunk_no,
 449                                             ch->rs_handle, rs_offset,
 450                                             write_len);
 451                 chunk_off = 0;
 452                 while (write_len) {
 453                         int this_write;
 454
 455                         this_write = min(write_len, max_write);
 456                         ret = send_write(xprt, rqstp,
 457                                          ch->rs_handle,
 458                                          rs_offset + chunk_off,
 459                                          xdr_off,
 460                                          this_write,
 461                                          vec);
 462                         if (ret) {
 463                                 dprintk("svcrdma: RDMA_WRITE failed, ret=%d\n",
 464                                         ret);
 465                                 return -EIO;
 466                         }
 467                         chunk_off += this_write;
 468                         xdr_off += this_write;
 469                         xfer_len -= this_write;
 470                         write_len -= this_write;
 471                 }
 472         }
 473         /* Update the req with the number of chunks actually used */
 474         svc_rdma_xdr_encode_reply_array(res_ary, chunk_no);
 475
 476         return rqstp->rq_res.len;
 477 }
 478
 479 /* This function prepares the portion of the RPCRDMA message to be
 480  * sent in the RDMA_SEND. This function is called after data sent via
 481  * RDMA has already been transmitted. There are three cases:
 482  * - The RPCRDMA header, RPC header, and payload are all sent in a
 483  *   single RDMA_SEND. This is the "inline" case.
 484  * - The RPCRDMA header and some portion of the RPC header and data
 485  *   are sent via this RDMA_SEND and another portion of the data is
 486  *   sent via RDMA.
 487  * - The RPCRDMA header [NOMSG] is sent in this RDMA_SEND and the RPC
 488  *   header and data are all transmitted via RDMA.
 489  * In all three cases, this function prepares the RPCRDMA header in
 490  * sge[0], the 'type' parameter indicates the type to place in the
 491  * RPCRDMA header, and the 'byte_count' field indicates how much of
 492  * the XDR to include in this RDMA_SEND.
 493  */
 494 static int send_reply(struct svcxprt_rdma *rdma,
 495                       struct svc_rqst *rqstp,
 496                       struct page *page,
 497                       struct rpcrdma_msg *rdma_resp,
 498                       struct svc_rdma_op_ctxt *ctxt,
 499                       struct svc_rdma_req_map *vec,
 500                       int byte_count)
 501 {
 502         struct ib_send_wr send_wr;
 503         struct ib_send_wr inv_wr;
 504         int sge_no;
 505         int sge_bytes;
 506         int page_no;
 507         int ret;
 508
 509         /* Post a recv buffer to handle another request. */
 510         ret = svc_rdma_post_recv(rdma);
 511         if (ret) {
 512                 printk(KERN_INFO
 513                        "svcrdma: could not post a receive buffer, err=%d."
 514                        "Closing transport %p.\n", ret, rdma);
 515                 set_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags);
 516                 svc_rdma_put_context(ctxt, 0);
 517                 return -ENOTCONN;
 518         }
 519
 520         /* Prepare the context */
 521         ctxt->pages[0] = page;
 522         ctxt->count = 1;
 523         ctxt->frmr = vec->frmr;
 524         if (vec->frmr)
 525                 set_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags);
 526         else
 527                 clear_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags);
 528
 529         /* Prepare the SGE for the RPCRDMA Header */
 530         ctxt->sge[0].addr =
 531                 ib_dma_map_page(rdma->sc_cm_id->device,
 532                                 page, 0, PAGE_SIZE, DMA_TO_DEVICE);
 533         if (ib_dma_mapping_error(rdma->sc_cm_id->device, ctxt->sge[0].addr))
 534                 goto err;
 535         atomic_inc(&rdma->sc_dma_used);
 536
 537         ctxt->direction = DMA_TO_DEVICE;
 538
 539         ctxt->sge[0].length = svc_rdma_xdr_get_reply_hdr_len(rdma_resp);
 540         ctxt->sge[0].lkey = rdma->sc_dma_lkey;
 541
 542         /* Determine how many of our SGE are to be transmitted */
 543         for (sge_no = 1; byte_count && sge_no < vec->count; sge_no++) {
 544                 sge_bytes = min_t(size_t, vec->sge[sge_no].iov_len, byte_count);
 545                 byte_count -= sge_bytes;
 546                 if (!vec->frmr) {
 547                         ctxt->sge[sge_no].addr =
 548                                 ib_dma_map_single(rdma->sc_cm_id->device,
 549                                                   vec->sge[sge_no].iov_base,
 550                                                   sge_bytes, DMA_TO_DEVICE);
 551                         if (ib_dma_mapping_error(rdma->sc_cm_id->device,
 552                                                  ctxt->sge[sge_no].addr))
 553                                 goto err;
 554                         atomic_inc(&rdma->sc_dma_used);
 555                         ctxt->sge[sge_no].lkey = rdma->sc_dma_lkey;
 556                 } else {
 557                         ctxt->sge[sge_no].addr = (unsigned long)
 558                                 vec->sge[sge_no].iov_base;
 559                         ctxt->sge[sge_no].lkey = vec->frmr->mr->lkey;
 560                 }
 561                 ctxt->sge[sge_no].length = sge_bytes;
 562         }
 563         BUG_ON(byte_count != 0);
 564
 565         /* Save all respages in the ctxt and remove them from the
 566          * respages array. They are our pages until the I/O
 567          * completes.
 568          */
 569         for (page_no = 0; page_no < rqstp->rq_resused; page_no++) {
 570                 ctxt->pages[page_no+1] = rqstp->rq_respages[page_no];
 571                 ctxt->count++;
 572                 rqstp->rq_respages[page_no] = NULL;
 573                 /*
 574                  * If there are more pages than SGE, terminate SGE
 575                  * list so that svc_rdma_unmap_dma doesn't attempt to
 576                  * unmap garbage.
 577                  */
 578                 if (page_no+1 >= sge_no)
 579                         ctxt->sge[page_no+1].length = 0;
 580         }
 581         BUG_ON(sge_no > rdma->sc_max_sge);
 582         BUG_ON(sge_no > ctxt->count);
 583         memset(&send_wr, 0, sizeof send_wr);
 584         ctxt->wr_op = IB_WR_SEND;
 585         send_wr.wr_id = (unsigned long)ctxt;
 586         send_wr.sg_list = ctxt->sge;
 587         send_wr.num_sge = sge_no;
 588         send_wr.opcode = IB_WR_SEND;
 589         send_wr.send_flags =  IB_SEND_SIGNALED;
 590         if (vec->frmr) {
 591                 /* Prepare INVALIDATE WR */
 592                 memset(&inv_wr, 0, sizeof inv_wr);
 593                 inv_wr.opcode = IB_WR_LOCAL_INV;
 594                 inv_wr.send_flags = IB_SEND_SIGNALED;
 595                 inv_wr.ex.invalidate_rkey =
 596                         vec->frmr->mr->lkey;
 597                 send_wr.next = &inv_wr;
 598         }
 599
 600         ret = svc_rdma_send(rdma, &send_wr);
 601         if (ret)
 602                 goto err;
 603
 604         return 0;
 605
 606  err:
 607         svc_rdma_put_frmr(rdma, vec->frmr);
 608         svc_rdma_put_context(ctxt, 1);
 609         return -EIO;
 610 }
 611
 612 void svc_rdma_prep_reply_hdr(struct svc_rqst *rqstp)
 613 {
 614 }
 615
 616 /*
 617  * Return the start of an xdr buffer.
 618  */
 619 static void *xdr_start(struct xdr_buf *xdr)
 620 {
 621         return xdr->head[0].iov_base -
 622                 (xdr->len -
 623                  xdr->page_len -
 624                  xdr->tail[0].iov_len -
 625                  xdr->head[0].iov_len);
 626 }
 627
 628 int svc_rdma_sendto(struct svc_rqst *rqstp)
 629 {
 630         struct svc_xprt *xprt = rqstp->rq_xprt;
 631         struct svcxprt_rdma *rdma =
 632                 container_of(xprt, struct svcxprt_rdma, sc_xprt);
 633         struct rpcrdma_msg *rdma_argp;
 634         struct rpcrdma_msg *rdma_resp;
 635         struct rpcrdma_write_array *reply_ary;
 636         enum rpcrdma_proc reply_type;
 637         int ret;
 638         int inline_bytes;
 639         struct page *res_page;
 640         struct svc_rdma_op_ctxt *ctxt;
 641         struct svc_rdma_req_map *vec;
 642
 643         dprintk("svcrdma: sending response for rqstp=%p\n", rqstp);
 644
 645         /* Get the RDMA request header. */
 646         rdma_argp = xdr_start(&rqstp->rq_arg);
 647
 648         /* Build an req vec for the XDR */
 649         ctxt = svc_rdma_get_context(rdma);
 650         ctxt->direction = DMA_TO_DEVICE;
 651         vec = svc_rdma_get_req_map();
 652         ret = map_xdr(rdma, &rqstp->rq_res, vec);
 653         if (ret)
 654                 goto err0;
 655         inline_bytes = rqstp->rq_res.len;
 656
 657         /* Create the RDMA response header */
 658         res_page = svc_rdma_get_page();
 659         rdma_resp = page_address(res_page);
 660         reply_ary = svc_rdma_get_reply_array(rdma_argp);
 661         if (reply_ary)
 662                 reply_type = RDMA_NOMSG;
 663         else
 664                 reply_type = RDMA_MSG;
 665         svc_rdma_xdr_encode_reply_header(rdma, rdma_argp,
 666                                          rdma_resp, reply_type);
 667
 668         /* Send any write-chunk data and build resp write-list */
 669         ret = send_write_chunks(rdma, rdma_argp, rdma_resp,
 670                                 rqstp, vec);
 671         if (ret < 0) {
 672                 printk(KERN_ERR "svcrdma: failed to send write chunks, rc=%d\n",
 673                        ret);
 674                 goto err1;
 675         }
 676         inline_bytes -= ret;
 677
 678         /* Send any reply-list data and update resp reply-list */
 679         ret = send_reply_chunks(rdma, rdma_argp, rdma_resp,
 680                                 rqstp, vec);
 681         if (ret < 0) {
 682                 printk(KERN_ERR "svcrdma: failed to send reply chunks, rc=%d\n",
 683                        ret);
 684                 goto err1;
 685         }
 686         inline_bytes -= ret;
 687
 688         ret = send_reply(rdma, rqstp, res_page, rdma_resp, ctxt, vec,
 689                          inline_bytes);
 690         svc_rdma_put_req_map(vec);
 691         dprintk("svcrdma: send_reply returns %d\n", ret);
 692         return ret;
 693
 694  err1:
 695         put_page(res_page);
 696  err0:
 697         svc_rdma_put_req_map(vec);
 698         svc_rdma_put_context(ctxt, 0);
 699         return ret;
 700 }