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 contiguous 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         /* Map the XDR head */
 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         page_off = (unsigned long)xdr->head[0].iov_base & ~PAGE_MASK;
 106         frmr->page_list->page_list[page_no] =
 107                 ib_dma_map_page(xprt->sc_cm_id->device,
 108                                 virt_to_page(xdr->head[0].iov_base),
 109                                 page_off,
 110                                 PAGE_SIZE - page_off,
 111                                 DMA_TO_DEVICE);
 112         if (ib_dma_mapping_error(xprt->sc_cm_id->device,
 113                                  frmr->page_list->page_list[page_no]))
 114                 goto fatal_err;
 115         atomic_inc(&xprt->sc_dma_used);
 116
 117         /* Map the XDR page list */
 118         page_off = xdr->page_base;
 119         page_bytes = xdr->page_len + page_off;
 120         if (!page_bytes)
 121                 goto encode_tail;
 122
 123         /* Map the pages */
 124         vec->sge[sge_no].iov_base = frva + frmr->map_len + page_off;
 125         vec->sge[sge_no].iov_len = page_bytes;
 126         sge_no++;
 127         while (page_bytes) {
 128                 struct page *page;
 129
 130                 page = xdr->pages[page_no++];
 131                 sge_bytes = min_t(u32, page_bytes, (PAGE_SIZE - page_off));
 132                 page_bytes -= sge_bytes;
 133
 134                 frmr->page_list->page_list[page_no] =
 135                         ib_dma_map_page(xprt->sc_cm_id->device,
 136                                         page, page_off,
 137                                         sge_bytes, DMA_TO_DEVICE);
 138                 if (ib_dma_mapping_error(xprt->sc_cm_id->device,
 139                                          frmr->page_list->page_list[page_no]))
 140                         goto fatal_err;
 141
 142                 atomic_inc(&xprt->sc_dma_used);
 143                 page_off = 0; /* reset for next time through loop */
 144                 frmr->map_len += PAGE_SIZE;
 145                 frmr->page_list_len++;
 146         }
 147         vec->count++;
 148
 149  encode_tail:
 150         /* Map tail */
 151         if (0 == xdr->tail[0].iov_len)
 152                 goto done;
 153
 154         vec->count++;
 155         vec->sge[sge_no].iov_len = xdr->tail[0].iov_len;
 156
 157         if (((unsigned long)xdr->tail[0].iov_base & PAGE_MASK) ==
 158             ((unsigned long)xdr->head[0].iov_base & PAGE_MASK)) {
 159                 /*
 160                  * If head and tail use the same page, we don't need
 161                  * to map it again.
 162                  */
 163                 vec->sge[sge_no].iov_base = xdr->tail[0].iov_base;
 164         } else {
 165                 void *va;
 166
 167                 /* Map another page for the tail */
 168                 page_off = (unsigned long)xdr->tail[0].iov_base & ~PAGE_MASK;
 169                 va = (void *)((unsigned long)xdr->tail[0].iov_base & PAGE_MASK);
 170                 vec->sge[sge_no].iov_base = frva + frmr->map_len + page_off;
 171
 172                 frmr->page_list->page_list[page_no] =
 173                     ib_dma_map_page(xprt->sc_cm_id->device, virt_to_page(va),
 174                                     page_off,
 175                                     PAGE_SIZE,
 176                                     DMA_TO_DEVICE);
 177                 if (ib_dma_mapping_error(xprt->sc_cm_id->device,
 178                                          frmr->page_list->page_list[page_no]))
 179                         goto fatal_err;
 180                 atomic_inc(&xprt->sc_dma_used);
 181                 frmr->map_len += PAGE_SIZE;
 182                 frmr->page_list_len++;
 183         }
 184
 185  done:
 186         if (svc_rdma_fastreg(xprt, frmr))
 187                 goto fatal_err;
 188
 189         return 0;
 190
 191  fatal_err:
 192         printk("svcrdma: Error fast registering memory for xprt %p\n", xprt);
 193         vec->frmr = NULL;
 194         svc_rdma_put_frmr(xprt, frmr);
 195         return -EIO;
 196 }
 197
 198 static int map_xdr(struct svcxprt_rdma *xprt,
 199                    struct xdr_buf *xdr,
 200                    struct svc_rdma_req_map *vec)
 201 {
 202         int sge_no;
 203         u32 sge_bytes;
 204         u32 page_bytes;
 205         u32 page_off;
 206         int page_no;
 207
 208         BUG_ON(xdr->len !=
 209                (xdr->head[0].iov_len + xdr->page_len + xdr->tail[0].iov_len));
 210
 211         if (xprt->sc_frmr_pg_list_len)
 212                 return fast_reg_xdr(xprt, xdr, vec);
 213
 214         /* Skip the first sge, this is for the RPCRDMA header */
 215         sge_no = 1;
 216
 217         /* Head SGE */
 218         vec->sge[sge_no].iov_base = xdr->head[0].iov_base;
 219         vec->sge[sge_no].iov_len = xdr->head[0].iov_len;
 220         sge_no++;
 221
 222         /* pages SGE */
 223         page_no = 0;
 224         page_bytes = xdr->page_len;
 225         page_off = xdr->page_base;
 226         while (page_bytes) {
 227                 vec->sge[sge_no].iov_base =
 228                         page_address(xdr->pages[page_no]) + page_off;
 229                 sge_bytes = min_t(u32, page_bytes, (PAGE_SIZE - page_off));
 230                 page_bytes -= sge_bytes;
 231                 vec->sge[sge_no].iov_len = sge_bytes;
 232
 233                 sge_no++;
 234                 page_no++;
 235                 page_off = 0; /* reset for next time through loop */
 236         }
 237
 238         /* Tail SGE */
 239         if (xdr->tail[0].iov_len) {
 240                 vec->sge[sge_no].iov_base = xdr->tail[0].iov_base;
 241                 vec->sge[sge_no].iov_len = xdr->tail[0].iov_len;
 242                 sge_no++;
 243         }
 244
 245         dprintk("svcrdma: map_xdr: sge_no %d page_no %d "
 246                 "page_base %u page_len %u head_len %zu tail_len %zu\n",
 247                 sge_no, page_no, xdr->page_base, xdr->page_len,
 248                 xdr->head[0].iov_len, xdr->tail[0].iov_len);
 249
 250         vec->count = sge_no;
 251         return 0;
 252 }
 253
 254 static dma_addr_t dma_map_xdr(struct svcxprt_rdma *xprt,
 255                               struct xdr_buf *xdr,
 256                               u32 xdr_off, size_t len, int dir)
 257 {
 258         struct page *page;
 259         dma_addr_t dma_addr;
 260         if (xdr_off < xdr->head[0].iov_len) {
 261                 /* This offset is in the head */
 262                 xdr_off += (unsigned long)xdr->head[0].iov_base & ~PAGE_MASK;
 263                 page = virt_to_page(xdr->head[0].iov_base);
 264         } else {
 265                 xdr_off -= xdr->head[0].iov_len;
 266                 if (xdr_off < xdr->page_len) {
 267                         /* This offset is in the page list */
 268                         xdr_off += xdr->page_base;
 269                         page = xdr->pages[xdr_off >> PAGE_SHIFT];
 270                         xdr_off &= ~PAGE_MASK;
 271                 } else {
 272                         /* This offset is in the tail */
 273                         xdr_off -= xdr->page_len;
 274                         xdr_off += (unsigned long)
 275                                 xdr->tail[0].iov_base & ~PAGE_MASK;
 276                         page = virt_to_page(xdr->tail[0].iov_base);
 277                 }
 278         }
 279         dma_addr = ib_dma_map_page(xprt->sc_cm_id->device, page, xdr_off,
 280                                    min_t(size_t, PAGE_SIZE, len), dir);
 281         return dma_addr;
 282 }
 283
 284 /* Assumptions:
 285  * - We are using FRMR
 286  *     - or -
 287  * - The specified write_len can be represented in sc_max_sge * PAGE_SIZE
 288  */
 289 static int send_write(struct svcxprt_rdma *xprt, struct svc_rqst *rqstp,
 290                       u32 rmr, u64 to,
 291                       u32 xdr_off, int write_len,
 292                       struct svc_rdma_req_map *vec)
 293 {
 294         struct ib_send_wr write_wr;
 295         struct ib_sge *sge;
 296         int xdr_sge_no;
 297         int sge_no;
 298         int sge_bytes;
 299         int sge_off;
 300         int bc;
 301         struct svc_rdma_op_ctxt *ctxt;
 302
 303         BUG_ON(vec->count > RPCSVC_MAXPAGES);
 304         dprintk("svcrdma: RDMA_WRITE rmr=%x, to=%llx, xdr_off=%d, "
 305                 "write_len=%d, vec->sge=%p, vec->count=%lu\n",
 306                 rmr, (unsigned long long)to, xdr_off,
 307                 write_len, vec->sge, vec->count);
 308
 309         ctxt = svc_rdma_get_context(xprt);
 310         ctxt->direction = DMA_TO_DEVICE;
 311         sge = ctxt->sge;
 312
 313         /* Find the SGE associated with xdr_off */
 314         for (bc = xdr_off, xdr_sge_no = 1; bc && xdr_sge_no < vec->count;
 315              xdr_sge_no++) {
 316                 if (vec->sge[xdr_sge_no].iov_len > bc)
 317                         break;
 318                 bc -= vec->sge[xdr_sge_no].iov_len;
 319         }
 320
 321         sge_off = bc;
 322         bc = write_len;
 323         sge_no = 0;
 324
 325         /* Copy the remaining SGE */
 326         while (bc != 0) {
 327                 sge_bytes = min_t(size_t,
 328                           bc, vec->sge[xdr_sge_no].iov_len-sge_off);
 329                 sge[sge_no].length = sge_bytes;
 330                 if (!vec->frmr) {
 331                         sge[sge_no].addr =
 332                                 dma_map_xdr(xprt, &rqstp->rq_res, xdr_off,
 333                                             sge_bytes, DMA_TO_DEVICE);
 334                         xdr_off += sge_bytes;
 335                         if (ib_dma_mapping_error(xprt->sc_cm_id->device,
 336                                                  sge[sge_no].addr))
 337                                 goto err;
 338                         atomic_inc(&xprt->sc_dma_used);
 339                         sge[sge_no].lkey = xprt->sc_dma_lkey;
 340                 } else {
 341                         sge[sge_no].addr = (unsigned long)
 342                                 vec->sge[xdr_sge_no].iov_base + sge_off;
 343                         sge[sge_no].lkey = vec->frmr->mr->lkey;
 344                 }
 345                 ctxt->count++;
 346                 ctxt->frmr = vec->frmr;
 347                 sge_off = 0;
 348                 sge_no++;
 349                 xdr_sge_no++;
 350                 BUG_ON(xdr_sge_no > vec->count);
 351                 bc -= sge_bytes;
 352         }
 353
 354         /* Prepare WRITE WR */
 355         memset(&write_wr, 0, sizeof write_wr);
 356         ctxt->wr_op = IB_WR_RDMA_WRITE;
 357         write_wr.wr_id = (unsigned long)ctxt;
 358         write_wr.sg_list = &sge[0];
 359         write_wr.num_sge = sge_no;
 360         write_wr.opcode = IB_WR_RDMA_WRITE;
 361         write_wr.send_flags = IB_SEND_SIGNALED;
 362         write_wr.wr.rdma.rkey = rmr;
 363         write_wr.wr.rdma.remote_addr = to;
 364
 365         /* Post It */
 366         atomic_inc(&rdma_stat_write);
 367         if (svc_rdma_send(xprt, &write_wr))
 368                 goto err;
 369         return 0;
 370  err:
 371         svc_rdma_unmap_dma(ctxt);
 372         svc_rdma_put_frmr(xprt, vec->frmr);
 373         svc_rdma_put_context(ctxt, 0);
 374         /* Fatal error, close transport */
 375         return -EIO;
 376 }
 377
 378 static int send_write_chunks(struct svcxprt_rdma *xprt,
 379                              struct rpcrdma_msg *rdma_argp,
 380                              struct rpcrdma_msg *rdma_resp,
 381                              struct svc_rqst *rqstp,
 382                              struct svc_rdma_req_map *vec)
 383 {
 384         u32 xfer_len = rqstp->rq_res.page_len + rqstp->rq_res.tail[0].iov_len;
 385         int write_len;
 386         int max_write;
 387         u32 xdr_off;
 388         int chunk_off;
 389         int chunk_no;
 390         struct rpcrdma_write_array *arg_ary;
 391         struct rpcrdma_write_array *res_ary;
 392         int ret;
 393
 394         arg_ary = svc_rdma_get_write_array(rdma_argp);
 395         if (!arg_ary)
 396                 return 0;
 397         res_ary = (struct rpcrdma_write_array *)
 398                 &rdma_resp->rm_body.rm_chunks[1];
 399
 400         if (vec->frmr)
 401                 max_write = vec->frmr->map_len;
 402         else
 403                 max_write = xprt->sc_max_sge * PAGE_SIZE;
 404
 405         /* Write chunks start at the pagelist */
 406         for (xdr_off = rqstp->rq_res.head[0].iov_len, chunk_no = 0;
 407              xfer_len && chunk_no < arg_ary->wc_nchunks;
 408              chunk_no++) {
 409                 struct rpcrdma_segment *arg_ch;
 410                 u64 rs_offset;
 411
 412                 arg_ch = &arg_ary->wc_array[chunk_no].wc_target;
 413                 write_len = min(xfer_len, ntohl(arg_ch->rs_length));
 414
 415                 /* Prepare the response chunk given the length actually
 416                  * written */
 417                 xdr_decode_hyper((__be32 *)&arg_ch->rs_offset, &rs_offset);
 418                 svc_rdma_xdr_encode_array_chunk(res_ary, chunk_no,
 419                                                 arg_ch->rs_handle,
 420                                                 arg_ch->rs_offset,
 421                                                 write_len);
 422                 chunk_off = 0;
 423                 while (write_len) {
 424                         int this_write;
 425                         this_write = min(write_len, max_write);
 426                         ret = send_write(xprt, rqstp,
 427                                          ntohl(arg_ch->rs_handle),
 428                                          rs_offset + chunk_off,
 429                                          xdr_off,
 430                                          this_write,
 431                                          vec);
 432                         if (ret) {
 433                                 dprintk("svcrdma: RDMA_WRITE failed, ret=%d\n",
 434                                         ret);
 435                                 return -EIO;
 436                         }
 437                         chunk_off += this_write;
 438                         xdr_off += this_write;
 439                         xfer_len -= this_write;
 440                         write_len -= this_write;
 441                 }
 442         }
 443         /* Update the req with the number of chunks actually used */
 444         svc_rdma_xdr_encode_write_list(rdma_resp, chunk_no);
 445
 446         return rqstp->rq_res.page_len + rqstp->rq_res.tail[0].iov_len;
 447 }
 448
 449 static int send_reply_chunks(struct svcxprt_rdma *xprt,
 450                              struct rpcrdma_msg *rdma_argp,
 451                              struct rpcrdma_msg *rdma_resp,
 452                              struct svc_rqst *rqstp,
 453                              struct svc_rdma_req_map *vec)
 454 {
 455         u32 xfer_len = rqstp->rq_res.len;
 456         int write_len;
 457         int max_write;
 458         u32 xdr_off;
 459         int chunk_no;
 460         int chunk_off;
 461         int nchunks;
 462         struct rpcrdma_segment *ch;
 463         struct rpcrdma_write_array *arg_ary;
 464         struct rpcrdma_write_array *res_ary;
 465         int ret;
 466
 467         arg_ary = svc_rdma_get_reply_array(rdma_argp);
 468         if (!arg_ary)
 469                 return 0;
 470         /* XXX: need to fix when reply lists occur with read-list and or
 471          * write-list */
 472         res_ary = (struct rpcrdma_write_array *)
 473                 &rdma_resp->rm_body.rm_chunks[2];
 474
 475         if (vec->frmr)
 476                 max_write = vec->frmr->map_len;
 477         else
 478                 max_write = xprt->sc_max_sge * PAGE_SIZE;
 479
 480         /* xdr offset starts at RPC message */
 481         nchunks = ntohl(arg_ary->wc_nchunks);
 482         for (xdr_off = 0, chunk_no = 0;
 483              xfer_len && chunk_no < nchunks;
 484              chunk_no++) {
 485                 u64 rs_offset;
 486                 ch = &arg_ary->wc_array[chunk_no].wc_target;
 487                 write_len = min(xfer_len, htonl(ch->rs_length));
 488
 489                 /* Prepare the reply chunk given the length actually
 490                  * written */
 491                 xdr_decode_hyper((__be32 *)&ch->rs_offset, &rs_offset);
 492                 svc_rdma_xdr_encode_array_chunk(res_ary, chunk_no,
 493                                                 ch->rs_handle, ch->rs_offset,
 494                                                 write_len);
 495                 chunk_off = 0;
 496                 while (write_len) {
 497                         int this_write;
 498
 499                         this_write = min(write_len, max_write);
 500                         ret = send_write(xprt, rqstp,
 501                                          ntohl(ch->rs_handle),
 502                                          rs_offset + chunk_off,
 503                                          xdr_off,
 504                                          this_write,
 505                                          vec);
 506                         if (ret) {
 507                                 dprintk("svcrdma: RDMA_WRITE failed, ret=%d\n",
 508                                         ret);
 509                                 return -EIO;
 510                         }
 511                         chunk_off += this_write;
 512                         xdr_off += this_write;
 513                         xfer_len -= this_write;
 514                         write_len -= this_write;
 515                 }
 516         }
 517         /* Update the req with the number of chunks actually used */
 518         svc_rdma_xdr_encode_reply_array(res_ary, chunk_no);
 519
 520         return rqstp->rq_res.len;
 521 }
 522
 523 /* This function prepares the portion of the RPCRDMA message to be
 524  * sent in the RDMA_SEND. This function is called after data sent via
 525  * RDMA has already been transmitted. There are three cases:
 526  * - The RPCRDMA header, RPC header, and payload are all sent in a
 527  *   single RDMA_SEND. This is the "inline" case.
 528  * - The RPCRDMA header and some portion of the RPC header and data
 529  *   are sent via this RDMA_SEND and another portion of the data is
 530  *   sent via RDMA.
 531  * - The RPCRDMA header [NOMSG] is sent in this RDMA_SEND and the RPC
 532  *   header and data are all transmitted via RDMA.
 533  * In all three cases, this function prepares the RPCRDMA header in
 534  * sge[0], the 'type' parameter indicates the type to place in the
 535  * RPCRDMA header, and the 'byte_count' field indicates how much of
 536  * the XDR to include in this RDMA_SEND. NB: The offset of the payload
 537  * to send is zero in the XDR.
 538  */
 539 static int send_reply(struct svcxprt_rdma *rdma,
 540                       struct svc_rqst *rqstp,
 541                       struct page *page,
 542                       struct rpcrdma_msg *rdma_resp,
 543                       struct svc_rdma_op_ctxt *ctxt,
 544                       struct svc_rdma_req_map *vec,
 545                       int byte_count)
 546 {
 547         struct ib_send_wr send_wr;
 548         struct ib_send_wr inv_wr;
 549         int sge_no;
 550         int sge_bytes;
 551         int page_no;
 552         int pages;
 553         int ret;
 554
 555         /* Post a recv buffer to handle another request. */
 556         ret = svc_rdma_post_recv(rdma);
 557         if (ret) {
 558                 printk(KERN_INFO
 559                        "svcrdma: could not post a receive buffer, err=%d."
 560                        "Closing transport %p.\n", ret, rdma);
 561                 set_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags);
 562                 svc_rdma_put_frmr(rdma, vec->frmr);
 563                 svc_rdma_put_context(ctxt, 0);
 564                 return -ENOTCONN;
 565         }
 566
 567         /* Prepare the context */
 568         ctxt->pages[0] = page;
 569         ctxt->count = 1;
 570         ctxt->frmr = vec->frmr;
 571         if (vec->frmr)
 572                 set_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags);
 573         else
 574                 clear_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags);
 575
 576         /* Prepare the SGE for the RPCRDMA Header */
 577         ctxt->sge[0].lkey = rdma->sc_dma_lkey;
 578         ctxt->sge[0].length = svc_rdma_xdr_get_reply_hdr_len(rdma_resp);
 579         ctxt->sge[0].addr =
 580             ib_dma_map_page(rdma->sc_cm_id->device, page, 0,
 581                             ctxt->sge[0].length, DMA_TO_DEVICE);
 582         if (ib_dma_mapping_error(rdma->sc_cm_id->device, ctxt->sge[0].addr))
 583                 goto err;
 584         atomic_inc(&rdma->sc_dma_used);
 585
 586         ctxt->direction = DMA_TO_DEVICE;
 587
 588         /* Map the payload indicated by 'byte_count' */
 589         for (sge_no = 1; byte_count && sge_no < vec->count; sge_no++) {
 590                 int xdr_off = 0;
 591                 sge_bytes = min_t(size_t, vec->sge[sge_no].iov_len, byte_count);
 592                 byte_count -= sge_bytes;
 593                 if (!vec->frmr) {
 594                         ctxt->sge[sge_no].addr =
 595                                 dma_map_xdr(rdma, &rqstp->rq_res, xdr_off,
 596                                             sge_bytes, DMA_TO_DEVICE);
 597                         xdr_off += sge_bytes;
 598                         if (ib_dma_mapping_error(rdma->sc_cm_id->device,
 599                                                  ctxt->sge[sge_no].addr))
 600                                 goto err;
 601                         atomic_inc(&rdma->sc_dma_used);
 602                         ctxt->sge[sge_no].lkey = rdma->sc_dma_lkey;
 603                 } else {
 604                         ctxt->sge[sge_no].addr = (unsigned long)
 605                                 vec->sge[sge_no].iov_base;
 606                         ctxt->sge[sge_no].lkey = vec->frmr->mr->lkey;
 607                 }
 608                 ctxt->sge[sge_no].length = sge_bytes;
 609         }
 610         BUG_ON(byte_count != 0);
 611
 612         /* Save all respages in the ctxt and remove them from the
 613          * respages array. They are our pages until the I/O
 614          * completes.
 615          */
 616         pages = rqstp->rq_next_page - rqstp->rq_respages;
 617         for (page_no = 0; page_no < pages; page_no++) {
 618                 ctxt->pages[page_no+1] = rqstp->rq_respages[page_no];
 619                 ctxt->count++;
 620                 rqstp->rq_respages[page_no] = NULL;
 621                 /*
 622                  * If there are more pages than SGE, terminate SGE
 623                  * list so that svc_rdma_unmap_dma doesn't attempt to
 624                  * unmap garbage.
 625                  */
 626                 if (page_no+1 >= sge_no)
 627                         ctxt->sge[page_no+1].length = 0;
 628         }
 629         rqstp->rq_next_page = rqstp->rq_respages + 1;
 630         BUG_ON(sge_no > rdma->sc_max_sge);
 631         memset(&send_wr, 0, sizeof send_wr);
 632         ctxt->wr_op = IB_WR_SEND;
 633         send_wr.wr_id = (unsigned long)ctxt;
 634         send_wr.sg_list = ctxt->sge;
 635         send_wr.num_sge = sge_no;
 636         send_wr.opcode = IB_WR_SEND;
 637         send_wr.send_flags =  IB_SEND_SIGNALED;
 638         if (vec->frmr) {
 639                 /* Prepare INVALIDATE WR */
 640                 memset(&inv_wr, 0, sizeof inv_wr);
 641                 inv_wr.opcode = IB_WR_LOCAL_INV;
 642                 inv_wr.send_flags = IB_SEND_SIGNALED;
 643                 inv_wr.ex.invalidate_rkey =
 644                         vec->frmr->mr->lkey;
 645                 send_wr.next = &inv_wr;
 646         }
 647
 648         ret = svc_rdma_send(rdma, &send_wr);
 649         if (ret)
 650                 goto err;
 651
 652         return 0;
 653
 654  err:
 655         svc_rdma_unmap_dma(ctxt);
 656         svc_rdma_put_frmr(rdma, vec->frmr);
 657         svc_rdma_put_context(ctxt, 1);
 658         return -EIO;
 659 }
 660
 661 void svc_rdma_prep_reply_hdr(struct svc_rqst *rqstp)
 662 {
 663 }
 664
 665 /*
 666  * Return the start of an xdr buffer.
 667  */
 668 static void *xdr_start(struct xdr_buf *xdr)
 669 {
 670         return xdr->head[0].iov_base -
 671                 (xdr->len -
 672                  xdr->page_len -
 673                  xdr->tail[0].iov_len -
 674                  xdr->head[0].iov_len);
 675 }
 676
 677 int svc_rdma_sendto(struct svc_rqst *rqstp)
 678 {
 679         struct svc_xprt *xprt = rqstp->rq_xprt;
 680         struct svcxprt_rdma *rdma =
 681                 container_of(xprt, struct svcxprt_rdma, sc_xprt);
 682         struct rpcrdma_msg *rdma_argp;
 683         struct rpcrdma_msg *rdma_resp;
 684         struct rpcrdma_write_array *reply_ary;
 685         enum rpcrdma_proc reply_type;
 686         int ret;
 687         int inline_bytes;
 688         struct page *res_page;
 689         struct svc_rdma_op_ctxt *ctxt;
 690         struct svc_rdma_req_map *vec;
 691
 692         dprintk("svcrdma: sending response for rqstp=%p\n", rqstp);
 693
 694         /* Get the RDMA request header. */
 695         rdma_argp = xdr_start(&rqstp->rq_arg);
 696
 697         /* Build an req vec for the XDR */
 698         ctxt = svc_rdma_get_context(rdma);
 699         ctxt->direction = DMA_TO_DEVICE;
 700         vec = svc_rdma_get_req_map();
 701         ret = map_xdr(rdma, &rqstp->rq_res, vec);
 702         if (ret)
 703                 goto err0;
 704         inline_bytes = rqstp->rq_res.len;
 705
 706         /* Create the RDMA response header */
 707         res_page = svc_rdma_get_page();
 708         rdma_resp = page_address(res_page);
 709         reply_ary = svc_rdma_get_reply_array(rdma_argp);
 710         if (reply_ary)
 711                 reply_type = RDMA_NOMSG;
 712         else
 713                 reply_type = RDMA_MSG;
 714         svc_rdma_xdr_encode_reply_header(rdma, rdma_argp,
 715                                          rdma_resp, reply_type);
 716
 717         /* Send any write-chunk data and build resp write-list */
 718         ret = send_write_chunks(rdma, rdma_argp, rdma_resp,
 719                                 rqstp, vec);
 720         if (ret < 0) {
 721                 printk(KERN_ERR "svcrdma: failed to send write chunks, rc=%d\n",
 722                        ret);
 723                 goto err1;
 724         }
 725         inline_bytes -= ret;
 726
 727         /* Send any reply-list data and update resp reply-list */
 728         ret = send_reply_chunks(rdma, rdma_argp, rdma_resp,
 729                                 rqstp, vec);
 730         if (ret < 0) {
 731                 printk(KERN_ERR "svcrdma: failed to send reply chunks, rc=%d\n",
 732                        ret);
 733                 goto err1;
 734         }
 735         inline_bytes -= ret;
 736
 737         ret = send_reply(rdma, rqstp, res_page, rdma_resp, ctxt, vec,
 738                          inline_bytes);
 739         svc_rdma_put_req_map(vec);
 740         dprintk("svcrdma: send_reply returns %d\n", ret);
 741         return ret;
 742
 743  err1:
 744         put_page(res_page);
 745  err0:
 746         svc_rdma_put_req_map(vec);
 747         svc_rdma_put_context(ctxt, 0);
 748         return ret;
 749 }