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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 /*
  53  * Replace the pages in the rq_argpages array with the pages from the SGE in
  54  * the RDMA_RECV completion. The SGL should contain full pages up until the
  55  * last one.
  56  */
  57 static void rdma_build_arg_xdr(struct svc_rqst *rqstp,
  58                                struct svc_rdma_op_ctxt *ctxt,
  59                                u32 byte_count)
  60 {
  61         struct page *page;
  62         u32 bc;
  63         int sge_no;
  64
  65         /* Swap the page in the SGE with the page in argpages */
  66         page = ctxt->pages[0];
  67         put_page(rqstp->rq_pages[0]);
  68         rqstp->rq_pages[0] = page;
  69
  70         /* Set up the XDR head */
  71         rqstp->rq_arg.head[0].iov_base = page_address(page);
  72         rqstp->rq_arg.head[0].iov_len = min(byte_count, ctxt->sge[0].length);
  73         rqstp->rq_arg.len = byte_count;
  74         rqstp->rq_arg.buflen = byte_count;
  75
  76         /* Compute bytes past head in the SGL */
  77         bc = byte_count - rqstp->rq_arg.head[0].iov_len;
  78
  79         /* If data remains, store it in the pagelist */
  80         rqstp->rq_arg.page_len = bc;
  81         rqstp->rq_arg.page_base = 0;
  82         rqstp->rq_arg.pages = &rqstp->rq_pages[1];
  83         sge_no = 1;
  84         while (bc && sge_no < ctxt->count) {
  85                 page = ctxt->pages[sge_no];
  86                 put_page(rqstp->rq_pages[sge_no]);
  87                 rqstp->rq_pages[sge_no] = page;
  88                 bc -= min(bc, ctxt->sge[sge_no].length);
  89                 rqstp->rq_arg.buflen += ctxt->sge[sge_no].length;
  90                 sge_no++;
  91         }
  92         rqstp->rq_respages = &rqstp->rq_pages[sge_no];
  93
  94         /* We should never run out of SGE because the limit is defined to
  95          * support the max allowed RPC data length
  96          */
  97         BUG_ON(bc && (sge_no == ctxt->count));
  98         BUG_ON((rqstp->rq_arg.head[0].iov_len + rqstp->rq_arg.page_len)
  99                != byte_count);
 100         BUG_ON(rqstp->rq_arg.len != byte_count);
 101
 102         /* If not all pages were used from the SGL, free the remaining ones */
 103         bc = sge_no;
 104         while (sge_no < ctxt->count) {
 105                 page = ctxt->pages[sge_no++];
 106                 put_page(page);
 107         }
 108         ctxt->count = bc;
 109
 110         /* Set up tail */
 111         rqstp->rq_arg.tail[0].iov_base = NULL;
 112         rqstp->rq_arg.tail[0].iov_len = 0;
 113 }
 114
 115 /* Encode a read-chunk-list as an array of IB SGE
 116  *
 117  * Assumptions:
 118  * - chunk[0]->position points to pages[0] at an offset of 0
 119  * - pages[] is not physically or virtually contigous and consists of
 120  *   PAGE_SIZE elements.
 121  *
 122  * Output:
 123  * - sge array pointing into pages[] array.
 124  * - chunk_sge array specifying sge index and count for each
 125  *   chunk in the read list
 126  *
 127  */
 128 static int rdma_rcl_to_sge(struct svcxprt_rdma *xprt,
 129                            struct svc_rqst *rqstp,
 130                            struct svc_rdma_op_ctxt *head,
 131                            struct rpcrdma_msg *rmsgp,
 132                            struct svc_rdma_req_map *rpl_map,
 133                            struct svc_rdma_req_map *chl_map,
 134                            int ch_count,
 135                            int byte_count)
 136 {
 137         int sge_no;
 138         int sge_bytes;
 139         int page_off;
 140         int page_no;
 141         int ch_bytes;
 142         int ch_no;
 143         struct rpcrdma_read_chunk *ch;
 144
 145         sge_no = 0;
 146         page_no = 0;
 147         page_off = 0;
 148         ch = (struct rpcrdma_read_chunk *)&rmsgp->rm_body.rm_chunks[0];
 149         ch_no = 0;
 150         ch_bytes = ch->rc_target.rs_length;
 151         head->arg.head[0] = rqstp->rq_arg.head[0];
 152         head->arg.tail[0] = rqstp->rq_arg.tail[0];
 153         head->arg.pages = &head->pages[head->count];
 154         head->hdr_count = head->count; /* save count of hdr pages */
 155         head->arg.page_base = 0;
 156         head->arg.page_len = ch_bytes;
 157         head->arg.len = rqstp->rq_arg.len + ch_bytes;
 158         head->arg.buflen = rqstp->rq_arg.buflen + ch_bytes;
 159         head->count++;
 160         chl_map->ch[0].start = 0;
 161         while (byte_count) {
 162                 rpl_map->sge[sge_no].iov_base =
 163                         page_address(rqstp->rq_arg.pages[page_no]) + page_off;
 164                 sge_bytes = min_t(int, PAGE_SIZE-page_off, ch_bytes);
 165                 rpl_map->sge[sge_no].iov_len = sge_bytes;
 166                 /*
 167                  * Don't bump head->count here because the same page
 168                  * may be used by multiple SGE.
 169                  */
 170                 head->arg.pages[page_no] = rqstp->rq_arg.pages[page_no];
 171                 rqstp->rq_respages = &rqstp->rq_arg.pages[page_no+1];
 172
 173                 byte_count -= sge_bytes;
 174                 ch_bytes -= sge_bytes;
 175                 sge_no++;
 176                 /*
 177                  * If all bytes for this chunk have been mapped to an
 178                  * SGE, move to the next SGE
 179                  */
 180                 if (ch_bytes == 0) {
 181                         chl_map->ch[ch_no].count =
 182                                 sge_no - chl_map->ch[ch_no].start;
 183                         ch_no++;
 184                         ch++;
 185                         chl_map->ch[ch_no].start = sge_no;
 186                         ch_bytes = ch->rc_target.rs_length;
 187                         /* If bytes remaining account for next chunk */
 188                         if (byte_count) {
 189                                 head->arg.page_len += ch_bytes;
 190                                 head->arg.len += ch_bytes;
 191                                 head->arg.buflen += ch_bytes;
 192                         }
 193                 }
 194                 /*
 195                  * If this SGE consumed all of the page, move to the
 196                  * next page
 197                  */
 198                 if ((sge_bytes + page_off) == PAGE_SIZE) {
 199                         page_no++;
 200                         page_off = 0;
 201                         /*
 202                          * If there are still bytes left to map, bump
 203                          * the page count
 204                          */
 205                         if (byte_count)
 206                                 head->count++;
 207                 } else
 208                         page_off += sge_bytes;
 209         }
 210         BUG_ON(byte_count != 0);
 211         return sge_no;
 212 }
 213
 214 static void rdma_set_ctxt_sge(struct svcxprt_rdma *xprt,
 215                               struct svc_rdma_op_ctxt *ctxt,
 216                               struct kvec *vec,
 217                               u64 *sgl_offset,
 218                               int count)
 219 {
 220         int i;
 221
 222         ctxt->count = count;
 223         ctxt->direction = DMA_FROM_DEVICE;
 224         for (i = 0; i < count; i++) {
 225                 ctxt->sge[i].addr =
 226                         ib_dma_map_single(xprt->sc_cm_id->device,
 227                                           vec[i].iov_base, vec[i].iov_len,
 228                                           DMA_FROM_DEVICE);
 229                 ctxt->sge[i].length = vec[i].iov_len;
 230                 ctxt->sge[i].lkey = xprt->sc_phys_mr->lkey;
 231                 *sgl_offset = *sgl_offset + vec[i].iov_len;
 232         }
 233 }
 234
 235 static int rdma_read_max_sge(struct svcxprt_rdma *xprt, int sge_count)
 236 {
 237         if ((RDMA_TRANSPORT_IWARP ==
 238              rdma_node_get_transport(xprt->sc_cm_id->
 239                                      device->node_type))
 240             && sge_count > 1)
 241                 return 1;
 242         else
 243                 return min_t(int, sge_count, xprt->sc_max_sge);
 244 }
 245
 246 /*
 247  * Use RDMA_READ to read data from the advertised client buffer into the
 248  * XDR stream starting at rq_arg.head[0].iov_base.
 249  * Each chunk in the array
 250  * contains the following fields:
 251  * discrim      - '1', This isn't used for data placement
 252  * position     - The xdr stream offset (the same for every chunk)
 253  * handle       - RMR for client memory region
 254  * length       - data transfer length
 255  * offset       - 64 bit tagged offset in remote memory region
 256  *
 257  * On our side, we need to read into a pagelist. The first page immediately
 258  * follows the RPC header.
 259  *
 260  * This function returns:
 261  * 0 - No error and no read-list found.
 262  *
 263  * 1 - Successful read-list processing. The data is not yet in
 264  * the pagelist and therefore the RPC request must be deferred. The
 265  * I/O completion will enqueue the transport again and
 266  * svc_rdma_recvfrom will complete the request.
 267  *
 268  * <0 - Error processing/posting read-list.
 269  *
 270  * NOTE: The ctxt must not be touched after the last WR has been posted
 271  * because the I/O completion processing may occur on another
 272  * processor and free / modify the context. Ne touche pas!
 273  */
 274 static int rdma_read_xdr(struct svcxprt_rdma *xprt,
 275                          struct rpcrdma_msg *rmsgp,
 276                          struct svc_rqst *rqstp,
 277                          struct svc_rdma_op_ctxt *hdr_ctxt)
 278 {
 279         struct ib_send_wr read_wr;
 280         int err = 0;
 281         int ch_no;
 282         int ch_count;
 283         int byte_count;
 284         int sge_count;
 285         u64 sgl_offset;
 286         struct rpcrdma_read_chunk *ch;
 287         struct svc_rdma_op_ctxt *ctxt = NULL;
 288         struct svc_rdma_req_map *rpl_map;
 289         struct svc_rdma_req_map *chl_map;
 290
 291         /* If no read list is present, return 0 */
 292         ch = svc_rdma_get_read_chunk(rmsgp);
 293         if (!ch)
 294                 return 0;
 295
 296         /* Allocate temporary reply and chunk maps */
 297         rpl_map = svc_rdma_get_req_map();
 298         chl_map = svc_rdma_get_req_map();
 299
 300         svc_rdma_rcl_chunk_counts(ch, &ch_count, &byte_count);
 301         if (ch_count > RPCSVC_MAXPAGES)
 302                 return -EINVAL;
 303         sge_count = rdma_rcl_to_sge(xprt, rqstp, hdr_ctxt, rmsgp,
 304                                     rpl_map, chl_map,
 305                                     ch_count, byte_count);
 306         sgl_offset = 0;
 307         ch_no = 0;
 308
 309         for (ch = (struct rpcrdma_read_chunk *)&rmsgp->rm_body.rm_chunks[0];
 310              ch->rc_discrim != 0; ch++, ch_no++) {
 311 next_sge:
 312                 ctxt = svc_rdma_get_context(xprt);
 313                 ctxt->direction = DMA_FROM_DEVICE;
 314                 clear_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags);
 315
 316                 /* Prepare READ WR */
 317                 memset(&read_wr, 0, sizeof read_wr);
 318                 ctxt->wr_op = IB_WR_RDMA_READ;
 319                 read_wr.wr_id = (unsigned long)ctxt;
 320                 read_wr.opcode = IB_WR_RDMA_READ;
 321                 read_wr.send_flags = IB_SEND_SIGNALED;
 322                 read_wr.wr.rdma.rkey = ch->rc_target.rs_handle;
 323                 read_wr.wr.rdma.remote_addr =
 324                         get_unaligned(&(ch->rc_target.rs_offset)) +
 325                         sgl_offset;
 326                 read_wr.sg_list = ctxt->sge;
 327                 read_wr.num_sge =
 328                         rdma_read_max_sge(xprt, chl_map->ch[ch_no].count);
 329                 rdma_set_ctxt_sge(xprt, ctxt,
 330                                   &rpl_map->sge[chl_map->ch[ch_no].start],
 331                                   &sgl_offset,
 332                                   read_wr.num_sge);
 333                 if (((ch+1)->rc_discrim == 0) &&
 334                     (read_wr.num_sge == chl_map->ch[ch_no].count)) {
 335                         /*
 336                          * Mark the last RDMA_READ with a bit to
 337                          * indicate all RPC data has been fetched from
 338                          * the client and the RPC needs to be enqueued.
 339                          */
 340                         set_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags);
 341                         ctxt->read_hdr = hdr_ctxt;
 342                 }
 343                 /* Post the read */
 344                 err = svc_rdma_send(xprt, &read_wr);
 345                 if (err) {
 346                         printk(KERN_ERR "svcrdma: Error %d posting RDMA_READ\n",
 347                                err);
 348                         set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
 349                         svc_rdma_put_context(ctxt, 0);
 350                         goto out;
 351                 }
 352                 atomic_inc(&rdma_stat_read);
 353
 354                 if (read_wr.num_sge < chl_map->ch[ch_no].count) {
 355                         chl_map->ch[ch_no].count -= read_wr.num_sge;
 356                         chl_map->ch[ch_no].start += read_wr.num_sge;
 357                         goto next_sge;
 358                 }
 359                 sgl_offset = 0;
 360                 err = 1;
 361         }
 362
 363  out:
 364         svc_rdma_put_req_map(rpl_map);
 365         svc_rdma_put_req_map(chl_map);
 366
 367         /* Detach arg pages. svc_recv will replenish them */
 368         for (ch_no = 0; &rqstp->rq_pages[ch_no] < rqstp->rq_respages; ch_no++)
 369                 rqstp->rq_pages[ch_no] = NULL;
 370
 371         /*
 372          * Detach res pages. svc_release must see a resused count of
 373          * zero or it will attempt to put them.
 374          */
 375         while (rqstp->rq_resused)
 376                 rqstp->rq_respages[--rqstp->rq_resused] = NULL;
 377
 378         return err;
 379 }
 380
 381 static int rdma_read_complete(struct svc_rqst *rqstp,
 382                               struct svc_rdma_op_ctxt *head)
 383 {
 384         int page_no;
 385         int ret;
 386
 387         BUG_ON(!head);
 388
 389         /* Copy RPC pages */
 390         for (page_no = 0; page_no < head->count; page_no++) {
 391                 put_page(rqstp->rq_pages[page_no]);
 392                 rqstp->rq_pages[page_no] = head->pages[page_no];
 393         }
 394         /* Point rq_arg.pages past header */
 395         rqstp->rq_arg.pages = &rqstp->rq_pages[head->hdr_count];
 396         rqstp->rq_arg.page_len = head->arg.page_len;
 397         rqstp->rq_arg.page_base = head->arg.page_base;
 398
 399         /* rq_respages starts after the last arg page */
 400         rqstp->rq_respages = &rqstp->rq_arg.pages[page_no];
 401         rqstp->rq_resused = 0;
 402
 403         /* Rebuild rq_arg head and tail. */
 404         rqstp->rq_arg.head[0] = head->arg.head[0];
 405         rqstp->rq_arg.tail[0] = head->arg.tail[0];
 406         rqstp->rq_arg.len = head->arg.len;
 407         rqstp->rq_arg.buflen = head->arg.buflen;
 408
 409         /* Free the context */
 410         svc_rdma_put_context(head, 0);
 411
 412         /* XXX: What should this be? */
 413         rqstp->rq_prot = IPPROTO_MAX;
 414         svc_xprt_copy_addrs(rqstp, rqstp->rq_xprt);
 415
 416         ret = rqstp->rq_arg.head[0].iov_len
 417                 + rqstp->rq_arg.page_len
 418                 + rqstp->rq_arg.tail[0].iov_len;
 419         dprintk("svcrdma: deferred read ret=%d, rq_arg.len =%d, "
 420                 "rq_arg.head[0].iov_base=%p, rq_arg.head[0].iov_len = %zd\n",
 421                 ret, rqstp->rq_arg.len, rqstp->rq_arg.head[0].iov_base,
 422                 rqstp->rq_arg.head[0].iov_len);
 423
 424         svc_xprt_received(rqstp->rq_xprt);
 425         return ret;
 426 }
 427
 428 /*
 429  * Set up the rqstp thread context to point to the RQ buffer. If
 430  * necessary, pull additional data from the client with an RDMA_READ
 431  * request.
 432  */
 433 int svc_rdma_recvfrom(struct svc_rqst *rqstp)
 434 {
 435         struct svc_xprt *xprt = rqstp->rq_xprt;
 436         struct svcxprt_rdma *rdma_xprt =
 437                 container_of(xprt, struct svcxprt_rdma, sc_xprt);
 438         struct svc_rdma_op_ctxt *ctxt = NULL;
 439         struct rpcrdma_msg *rmsgp;
 440         int ret = 0;
 441         int len;
 442
 443         dprintk("svcrdma: rqstp=%p\n", rqstp);
 444
 445         spin_lock_bh(&rdma_xprt->sc_read_complete_lock);
 446         if (!list_empty(&rdma_xprt->sc_read_complete_q)) {
 447                 ctxt = list_entry(rdma_xprt->sc_read_complete_q.next,
 448                                   struct svc_rdma_op_ctxt,
 449                                   dto_q);
 450                 list_del_init(&ctxt->dto_q);
 451         }
 452         spin_unlock_bh(&rdma_xprt->sc_read_complete_lock);
 453         if (ctxt)
 454                 return rdma_read_complete(rqstp, ctxt);
 455
 456         spin_lock_bh(&rdma_xprt->sc_rq_dto_lock);
 457         if (!list_empty(&rdma_xprt->sc_rq_dto_q)) {
 458                 ctxt = list_entry(rdma_xprt->sc_rq_dto_q.next,
 459                                   struct svc_rdma_op_ctxt,
 460                                   dto_q);
 461                 list_del_init(&ctxt->dto_q);
 462         } else {
 463                 atomic_inc(&rdma_stat_rq_starve);
 464                 clear_bit(XPT_DATA, &xprt->xpt_flags);
 465                 ctxt = NULL;
 466         }
 467         spin_unlock_bh(&rdma_xprt->sc_rq_dto_lock);
 468         if (!ctxt) {
 469                 /* This is the EAGAIN path. The svc_recv routine will
 470                  * return -EAGAIN, the nfsd thread will go to call into
 471                  * svc_recv again and we shouldn't be on the active
 472                  * transport list
 473                  */
 474                 if (test_bit(XPT_CLOSE, &xprt->xpt_flags))
 475                         goto close_out;
 476
 477                 BUG_ON(ret);
 478                 goto out;
 479         }
 480         dprintk("svcrdma: processing ctxt=%p on xprt=%p, rqstp=%p, status=%d\n",
 481                 ctxt, rdma_xprt, rqstp, ctxt->wc_status);
 482         BUG_ON(ctxt->wc_status != IB_WC_SUCCESS);
 483         atomic_inc(&rdma_stat_recv);
 484
 485         /* Build up the XDR from the receive buffers. */
 486         rdma_build_arg_xdr(rqstp, ctxt, ctxt->byte_len);
 487
 488         /* Decode the RDMA header. */
 489         len = svc_rdma_xdr_decode_req(&rmsgp, rqstp);
 490         rqstp->rq_xprt_hlen = len;
 491
 492         /* If the request is invalid, reply with an error */
 493         if (len < 0) {
 494                 if (len == -ENOSYS)
 495                         svc_rdma_send_error(rdma_xprt, rmsgp, ERR_VERS);
 496                 goto close_out;
 497         }
 498
 499         /* Read read-list data. */
 500         ret = rdma_read_xdr(rdma_xprt, rmsgp, rqstp, ctxt);
 501         if (ret > 0) {
 502                 /* read-list posted, defer until data received from client. */
 503                 svc_xprt_received(xprt);
 504                 return 0;
 505         }
 506         if (ret < 0) {
 507                 /* Post of read-list failed, free context. */
 508                 svc_rdma_put_context(ctxt, 1);
 509                 return 0;
 510         }
 511
 512         ret = rqstp->rq_arg.head[0].iov_len
 513                 + rqstp->rq_arg.page_len
 514                 + rqstp->rq_arg.tail[0].iov_len;
 515         svc_rdma_put_context(ctxt, 0);
 516  out:
 517         dprintk("svcrdma: ret = %d, rq_arg.len =%d, "
 518                 "rq_arg.head[0].iov_base=%p, rq_arg.head[0].iov_len = %zd\n",
 519                 ret, rqstp->rq_arg.len,
 520                 rqstp->rq_arg.head[0].iov_base,
 521                 rqstp->rq_arg.head[0].iov_len);
 522         rqstp->rq_prot = IPPROTO_MAX;
 523         svc_xprt_copy_addrs(rqstp, xprt);
 524         svc_xprt_received(xprt);
 525         return ret;
 526
 527  close_out:
 528         if (ctxt)
 529                 svc_rdma_put_context(ctxt, 1);
 530         dprintk("svcrdma: transport %p is closing\n", xprt);
 531         /*
 532          * Set the close bit and enqueue it. svc_recv will see the
 533          * close bit and call svc_xprt_delete
 534          */
 535         set_bit(XPT_CLOSE, &xprt->xpt_flags);
 536         svc_xprt_received(xprt);
 537         return 0;
 538 }