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  */
  67 static struct ib_sge *xdr_to_sge(struct svcxprt_rdma *xprt,
  68                                  struct xdr_buf *xdr,
  69                                  struct ib_sge *sge,
  70                                  int *sge_count)
  71 {
  72         /* Max we need is the length of the XDR / pagesize + one for
  73          * head + one for tail + one for RPCRDMA header
  74          */
  75         int sge_max = (xdr->len+PAGE_SIZE-1) / PAGE_SIZE + 3;
  76         int sge_no;
  77         u32 byte_count = xdr->len;
  78         u32 sge_bytes;
  79         u32 page_bytes;
  80         int page_off;
  81         int page_no;
  82
  83         /* Skip the first sge, this is for the RPCRDMA header */
  84         sge_no = 1;
  85
  86         /* Head SGE */
  87         sge[sge_no].addr = ib_dma_map_single(xprt->sc_cm_id->device,
  88                                              xdr->head[0].iov_base,
  89                                              xdr->head[0].iov_len,
  90                                              DMA_TO_DEVICE);
  91         sge_bytes = min_t(u32, byte_count, xdr->head[0].iov_len);
  92         byte_count -= sge_bytes;
  93         sge[sge_no].length = sge_bytes;
  94         sge[sge_no].lkey = xprt->sc_phys_mr->lkey;
  95         sge_no++;
  96
  97         /* pages SGE */
  98         page_no = 0;
  99         page_bytes = xdr->page_len;
 100         page_off = xdr->page_base;
 101         while (byte_count && page_bytes) {
 102                 sge_bytes = min_t(u32, byte_count, (PAGE_SIZE-page_off));
 103                 sge[sge_no].addr =
 104                         ib_dma_map_page(xprt->sc_cm_id->device,
 105                                         xdr->pages[page_no], page_off,
 106                                         sge_bytes, DMA_TO_DEVICE);
 107                 sge_bytes = min(sge_bytes, page_bytes);
 108                 byte_count -= sge_bytes;
 109                 page_bytes -= sge_bytes;
 110                 sge[sge_no].length = sge_bytes;
 111                 sge[sge_no].lkey = xprt->sc_phys_mr->lkey;
 112
 113                 sge_no++;
 114                 page_no++;
 115                 page_off = 0; /* reset for next time through loop */
 116         }
 117
 118         /* Tail SGE */
 119         if (byte_count && xdr->tail[0].iov_len) {
 120                 sge[sge_no].addr =
 121                         ib_dma_map_single(xprt->sc_cm_id->device,
 122                                           xdr->tail[0].iov_base,
 123                                           xdr->tail[0].iov_len,
 124                                           DMA_TO_DEVICE);
 125                 sge_bytes = min_t(u32, byte_count, xdr->tail[0].iov_len);
 126                 byte_count -= sge_bytes;
 127                 sge[sge_no].length = sge_bytes;
 128                 sge[sge_no].lkey = xprt->sc_phys_mr->lkey;
 129                 sge_no++;
 130         }
 131
 132         BUG_ON(sge_no > sge_max);
 133         BUG_ON(byte_count != 0);
 134
 135         *sge_count = sge_no;
 136         return sge;
 137 }
 138
 139
 140 /* Assumptions:
 141  * - The specified write_len can be represented in sc_max_sge * PAGE_SIZE
 142  */
 143 static int send_write(struct svcxprt_rdma *xprt, struct svc_rqst *rqstp,
 144                       u32 rmr, u64 to,
 145                       u32 xdr_off, int write_len,
 146                       struct ib_sge *xdr_sge, int sge_count)
 147 {
 148         struct svc_rdma_op_ctxt *tmp_sge_ctxt;
 149         struct ib_send_wr write_wr;
 150         struct ib_sge *sge;
 151         int xdr_sge_no;
 152         int sge_no;
 153         int sge_bytes;
 154         int sge_off;
 155         int bc;
 156         struct svc_rdma_op_ctxt *ctxt;
 157         int ret = 0;
 158
 159         BUG_ON(sge_count >= 32);
 160         dprintk("svcrdma: RDMA_WRITE rmr=%x, to=%llx, xdr_off=%d, "
 161                 "write_len=%d, xdr_sge=%p, sge_count=%d\n",
 162                 rmr, (unsigned long long)to, xdr_off,
 163                 write_len, xdr_sge, sge_count);
 164
 165         ctxt = svc_rdma_get_context(xprt);
 166         ctxt->count = 0;
 167         tmp_sge_ctxt = svc_rdma_get_context(xprt);
 168         sge = tmp_sge_ctxt->sge;
 169
 170         /* Find the SGE associated with xdr_off */
 171         for (bc = xdr_off, xdr_sge_no = 1; bc && xdr_sge_no < sge_count;
 172              xdr_sge_no++) {
 173                 if (xdr_sge[xdr_sge_no].length > bc)
 174                         break;
 175                 bc -= xdr_sge[xdr_sge_no].length;
 176         }
 177
 178         sge_off = bc;
 179         bc = write_len;
 180         sge_no = 0;
 181
 182         /* Copy the remaining SGE */
 183         while (bc != 0 && xdr_sge_no < sge_count) {
 184                 sge[sge_no].addr = xdr_sge[xdr_sge_no].addr + sge_off;
 185                 sge[sge_no].lkey = xdr_sge[xdr_sge_no].lkey;
 186                 sge_bytes = min((size_t)bc,
 187                                 (size_t)(xdr_sge[xdr_sge_no].length-sge_off));
 188                 sge[sge_no].length = sge_bytes;
 189
 190                 sge_off = 0;
 191                 sge_no++;
 192                 xdr_sge_no++;
 193                 bc -= sge_bytes;
 194         }
 195
 196         BUG_ON(bc != 0);
 197         BUG_ON(xdr_sge_no > sge_count);
 198
 199         /* Prepare WRITE WR */
 200         memset(&write_wr, 0, sizeof write_wr);
 201         ctxt->wr_op = IB_WR_RDMA_WRITE;
 202         write_wr.wr_id = (unsigned long)ctxt;
 203         write_wr.sg_list = &sge[0];
 204         write_wr.num_sge = sge_no;
 205         write_wr.opcode = IB_WR_RDMA_WRITE;
 206         write_wr.send_flags = IB_SEND_SIGNALED;
 207         write_wr.wr.rdma.rkey = rmr;
 208         write_wr.wr.rdma.remote_addr = to;
 209
 210         /* Post It */
 211         atomic_inc(&rdma_stat_write);
 212         if (svc_rdma_send(xprt, &write_wr)) {
 213                 svc_rdma_put_context(ctxt, 1);
 214                 /* Fatal error, close transport */
 215                 ret = -EIO;
 216         }
 217         svc_rdma_put_context(tmp_sge_ctxt, 0);
 218         return ret;
 219 }
 220
 221 static int send_write_chunks(struct svcxprt_rdma *xprt,
 222                              struct rpcrdma_msg *rdma_argp,
 223                              struct rpcrdma_msg *rdma_resp,
 224                              struct svc_rqst *rqstp,
 225                              struct ib_sge *sge,
 226                              int sge_count)
 227 {
 228         u32 xfer_len = rqstp->rq_res.page_len + rqstp->rq_res.tail[0].iov_len;
 229         int write_len;
 230         int max_write;
 231         u32 xdr_off;
 232         int chunk_off;
 233         int chunk_no;
 234         struct rpcrdma_write_array *arg_ary;
 235         struct rpcrdma_write_array *res_ary;
 236         int ret;
 237
 238         arg_ary = svc_rdma_get_write_array(rdma_argp);
 239         if (!arg_ary)
 240                 return 0;
 241         res_ary = (struct rpcrdma_write_array *)
 242                 &rdma_resp->rm_body.rm_chunks[1];
 243
 244         max_write = xprt->sc_max_sge * PAGE_SIZE;
 245
 246         /* Write chunks start at the pagelist */
 247         for (xdr_off = rqstp->rq_res.head[0].iov_len, chunk_no = 0;
 248              xfer_len && chunk_no < arg_ary->wc_nchunks;
 249              chunk_no++) {
 250                 struct rpcrdma_segment *arg_ch;
 251                 u64 rs_offset;
 252
 253                 arg_ch = &arg_ary->wc_array[chunk_no].wc_target;
 254                 write_len = min(xfer_len, arg_ch->rs_length);
 255
 256                 /* Prepare the response chunk given the length actually
 257                  * written */
 258                 rs_offset = get_unaligned(&(arg_ch->rs_offset));
 259                 svc_rdma_xdr_encode_array_chunk(res_ary, chunk_no,
 260                                             arg_ch->rs_handle,
 261                                             rs_offset,
 262                                             write_len);
 263                 chunk_off = 0;
 264                 while (write_len) {
 265                         int this_write;
 266                         this_write = min(write_len, max_write);
 267                         ret = send_write(xprt, rqstp,
 268                                          arg_ch->rs_handle,
 269                                          rs_offset + chunk_off,
 270                                          xdr_off,
 271                                          this_write,
 272                                          sge,
 273                                          sge_count);
 274                         if (ret) {
 275                                 dprintk("svcrdma: RDMA_WRITE failed, ret=%d\n",
 276                                         ret);
 277                                 return -EIO;
 278                         }
 279                         chunk_off += this_write;
 280                         xdr_off += this_write;
 281                         xfer_len -= this_write;
 282                         write_len -= this_write;
 283                 }
 284         }
 285         /* Update the req with the number of chunks actually used */
 286         svc_rdma_xdr_encode_write_list(rdma_resp, chunk_no);
 287
 288         return rqstp->rq_res.page_len + rqstp->rq_res.tail[0].iov_len;
 289 }
 290
 291 static int send_reply_chunks(struct svcxprt_rdma *xprt,
 292                              struct rpcrdma_msg *rdma_argp,
 293                              struct rpcrdma_msg *rdma_resp,
 294                              struct svc_rqst *rqstp,
 295                              struct ib_sge *sge,
 296                              int sge_count)
 297 {
 298         u32 xfer_len = rqstp->rq_res.len;
 299         int write_len;
 300         int max_write;
 301         u32 xdr_off;
 302         int chunk_no;
 303         int chunk_off;
 304         struct rpcrdma_segment *ch;
 305         struct rpcrdma_write_array *arg_ary;
 306         struct rpcrdma_write_array *res_ary;
 307         int ret;
 308
 309         arg_ary = svc_rdma_get_reply_array(rdma_argp);
 310         if (!arg_ary)
 311                 return 0;
 312         /* XXX: need to fix when reply lists occur with read-list and or
 313          * write-list */
 314         res_ary = (struct rpcrdma_write_array *)
 315                 &rdma_resp->rm_body.rm_chunks[2];
 316
 317         max_write = xprt->sc_max_sge * PAGE_SIZE;
 318
 319         /* xdr offset starts at RPC message */
 320         for (xdr_off = 0, chunk_no = 0;
 321              xfer_len && chunk_no < arg_ary->wc_nchunks;
 322              chunk_no++) {
 323                 u64 rs_offset;
 324                 ch = &arg_ary->wc_array[chunk_no].wc_target;
 325                 write_len = min(xfer_len, ch->rs_length);
 326
 327
 328                 /* Prepare the reply chunk given the length actually
 329                  * written */
 330                 rs_offset = get_unaligned(&(ch->rs_offset));
 331                 svc_rdma_xdr_encode_array_chunk(res_ary, chunk_no,
 332                                             ch->rs_handle, rs_offset,
 333                                             write_len);
 334                 chunk_off = 0;
 335                 while (write_len) {
 336                         int this_write;
 337
 338                         this_write = min(write_len, max_write);
 339                         ret = send_write(xprt, rqstp,
 340                                          ch->rs_handle,
 341                                          rs_offset + chunk_off,
 342                                          xdr_off,
 343                                          this_write,
 344                                          sge,
 345                                          sge_count);
 346                         if (ret) {
 347                                 dprintk("svcrdma: RDMA_WRITE failed, ret=%d\n",
 348                                         ret);
 349                                 return -EIO;
 350                         }
 351                         chunk_off += this_write;
 352                         xdr_off += this_write;
 353                         xfer_len -= this_write;
 354                         write_len -= this_write;
 355                 }
 356         }
 357         /* Update the req with the number of chunks actually used */
 358         svc_rdma_xdr_encode_reply_array(res_ary, chunk_no);
 359
 360         return rqstp->rq_res.len;
 361 }
 362
 363 /* This function prepares the portion of the RPCRDMA message to be
 364  * sent in the RDMA_SEND. This function is called after data sent via
 365  * RDMA has already been transmitted. There are three cases:
 366  * - The RPCRDMA header, RPC header, and payload are all sent in a
 367  *   single RDMA_SEND. This is the "inline" case.
 368  * - The RPCRDMA header and some portion of the RPC header and data
 369  *   are sent via this RDMA_SEND and another portion of the data is
 370  *   sent via RDMA.
 371  * - The RPCRDMA header [NOMSG] is sent in this RDMA_SEND and the RPC
 372  *   header and data are all transmitted via RDMA.
 373  * In all three cases, this function prepares the RPCRDMA header in
 374  * sge[0], the 'type' parameter indicates the type to place in the
 375  * RPCRDMA header, and the 'byte_count' field indicates how much of
 376  * the XDR to include in this RDMA_SEND.
 377  */
 378 static int send_reply(struct svcxprt_rdma *rdma,
 379                       struct svc_rqst *rqstp,
 380                       struct page *page,
 381                       struct rpcrdma_msg *rdma_resp,
 382                       struct svc_rdma_op_ctxt *ctxt,
 383                       int sge_count,
 384                       int byte_count)
 385 {
 386         struct ib_send_wr send_wr;
 387         int sge_no;
 388         int sge_bytes;
 389         int page_no;
 390         int ret;
 391
 392         /* Prepare the context */
 393         ctxt->pages[0] = page;
 394         ctxt->count = 1;
 395
 396         /* Prepare the SGE for the RPCRDMA Header */
 397         ctxt->sge[0].addr =
 398                 ib_dma_map_page(rdma->sc_cm_id->device,
 399                                 page, 0, PAGE_SIZE, DMA_TO_DEVICE);
 400         ctxt->direction = DMA_TO_DEVICE;
 401         ctxt->sge[0].length = svc_rdma_xdr_get_reply_hdr_len(rdma_resp);
 402         ctxt->sge[0].lkey = rdma->sc_phys_mr->lkey;
 403
 404         /* Determine how many of our SGE are to be transmitted */
 405         for (sge_no = 1; byte_count && sge_no < sge_count; sge_no++) {
 406                 sge_bytes = min((size_t)ctxt->sge[sge_no].length,
 407                                 (size_t)byte_count);
 408                 byte_count -= sge_bytes;
 409         }
 410         BUG_ON(byte_count != 0);
 411
 412         /* Save all respages in the ctxt and remove them from the
 413          * respages array. They are our pages until the I/O
 414          * completes.
 415          */
 416         for (page_no = 0; page_no < rqstp->rq_resused; page_no++) {
 417                 ctxt->pages[page_no+1] = rqstp->rq_respages[page_no];
 418                 ctxt->count++;
 419                 rqstp->rq_respages[page_no] = NULL;
 420         }
 421
 422         BUG_ON(sge_no > rdma->sc_max_sge);
 423         memset(&send_wr, 0, sizeof send_wr);
 424         ctxt->wr_op = IB_WR_SEND;
 425         send_wr.wr_id = (unsigned long)ctxt;
 426         send_wr.sg_list = ctxt->sge;
 427         send_wr.num_sge = sge_no;
 428         send_wr.opcode = IB_WR_SEND;
 429         send_wr.send_flags =  IB_SEND_SIGNALED;
 430
 431         ret = svc_rdma_send(rdma, &send_wr);
 432         if (ret)
 433                 svc_rdma_put_context(ctxt, 1);
 434
 435         return ret;
 436 }
 437
 438 void svc_rdma_prep_reply_hdr(struct svc_rqst *rqstp)
 439 {
 440 }
 441
 442 /*
 443  * Return the start of an xdr buffer.
 444  */
 445 static void *xdr_start(struct xdr_buf *xdr)
 446 {
 447         return xdr->head[0].iov_base -
 448                 (xdr->len -
 449                  xdr->page_len -
 450                  xdr->tail[0].iov_len -
 451                  xdr->head[0].iov_len);
 452 }
 453
 454 int svc_rdma_sendto(struct svc_rqst *rqstp)
 455 {
 456         struct svc_xprt *xprt = rqstp->rq_xprt;
 457         struct svcxprt_rdma *rdma =
 458                 container_of(xprt, struct svcxprt_rdma, sc_xprt);
 459         struct rpcrdma_msg *rdma_argp;
 460         struct rpcrdma_msg *rdma_resp;
 461         struct rpcrdma_write_array *reply_ary;
 462         enum rpcrdma_proc reply_type;
 463         int ret;
 464         int inline_bytes;
 465         struct ib_sge *sge;
 466         int sge_count = 0;
 467         struct page *res_page;
 468         struct svc_rdma_op_ctxt *ctxt;
 469
 470         dprintk("svcrdma: sending response for rqstp=%p\n", rqstp);
 471
 472         /* Get the RDMA request header. */
 473         rdma_argp = xdr_start(&rqstp->rq_arg);
 474
 475         /* Build an SGE for the XDR */
 476         ctxt = svc_rdma_get_context(rdma);
 477         ctxt->direction = DMA_TO_DEVICE;
 478         sge = xdr_to_sge(rdma, &rqstp->rq_res, ctxt->sge, &sge_count);
 479
 480         inline_bytes = rqstp->rq_res.len;
 481
 482         /* Create the RDMA response header */
 483         res_page = svc_rdma_get_page();
 484         rdma_resp = page_address(res_page);
 485         reply_ary = svc_rdma_get_reply_array(rdma_argp);
 486         if (reply_ary)
 487                 reply_type = RDMA_NOMSG;
 488         else
 489                 reply_type = RDMA_MSG;
 490         svc_rdma_xdr_encode_reply_header(rdma, rdma_argp,
 491                                          rdma_resp, reply_type);
 492
 493         /* Send any write-chunk data and build resp write-list */
 494         ret = send_write_chunks(rdma, rdma_argp, rdma_resp,
 495                                 rqstp, sge, sge_count);
 496         if (ret < 0) {
 497                 printk(KERN_ERR "svcrdma: failed to send write chunks, rc=%d\n",
 498                        ret);
 499                 goto error;
 500         }
 501         inline_bytes -= ret;
 502
 503         /* Send any reply-list data and update resp reply-list */
 504         ret = send_reply_chunks(rdma, rdma_argp, rdma_resp,
 505                                 rqstp, sge, sge_count);
 506         if (ret < 0) {
 507                 printk(KERN_ERR "svcrdma: failed to send reply chunks, rc=%d\n",
 508                        ret);
 509                 goto error;
 510         }
 511         inline_bytes -= ret;
 512
 513         ret = send_reply(rdma, rqstp, res_page, rdma_resp, ctxt, sge_count,
 514                          inline_bytes);
 515         dprintk("svcrdma: send_reply returns %d\n", ret);
 516         return ret;
 517  error:
 518         svc_rdma_put_context(ctxt, 0);
 519         put_page(res_page);
 520         return ret;
 521 }