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   1 /*
   2  * Copyright (c) 2003-2007 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
  40 /*
  41  * rpc_rdma.c
  42  *
  43  * This file contains the guts of the RPC RDMA protocol, and
  44  * does marshaling/unmarshaling, etc. It is also where interfacing
  45  * to the Linux RPC framework lives.
  46  */
  47
  48 #include "xprt_rdma.h"
  49
  50 #include <linux/highmem.h>
  51
  52 #ifdef RPC_DEBUG
  53 # define RPCDBG_FACILITY        RPCDBG_TRANS
  54 #endif
  55
  56 enum rpcrdma_chunktype {
  57         rpcrdma_noch = 0,
  58         rpcrdma_readch,
  59         rpcrdma_areadch,
  60         rpcrdma_writech,
  61         rpcrdma_replych
  62 };
  63
  64 #ifdef RPC_DEBUG
  65 static const char transfertypes[][12] = {
  66         "pure inline",  /* no chunks */
  67         " read chunk",  /* some argument via rdma read */
  68         "*read chunk",  /* entire request via rdma read */
  69         "write chunk",  /* some result via rdma write */
  70         "reply chunk"   /* entire reply via rdma write */
  71 };
  72 #endif
  73
  74 /*
  75  * Chunk assembly from upper layer xdr_buf.
  76  *
  77  * Prepare the passed-in xdr_buf into representation as RPC/RDMA chunk
  78  * elements. Segments are then coalesced when registered, if possible
  79  * within the selected memreg mode.
  80  *
  81  * Note, this routine is never called if the connection's memory
  82  * registration strategy is 0 (bounce buffers).
  83  */
  84
  85 static int
  86 rpcrdma_convert_iovs(struct xdr_buf *xdrbuf, int pos,
  87         enum rpcrdma_chunktype type, struct rpcrdma_mr_seg *seg, int nsegs)
  88 {
  89         int len, n = 0, p;
  90
  91         if (pos == 0 && xdrbuf->head[0].iov_len) {
  92                 seg[n].mr_page = NULL;
  93                 seg[n].mr_offset = xdrbuf->head[0].iov_base;
  94                 seg[n].mr_len = xdrbuf->head[0].iov_len;
  95                 pos += xdrbuf->head[0].iov_len;
  96                 ++n;
  97         }
  98
  99         if (xdrbuf->page_len && (xdrbuf->pages[0] != NULL)) {
 100                 if (n == nsegs)
 101                         return 0;
 102                 seg[n].mr_page = xdrbuf->pages[0];
 103                 seg[n].mr_offset = (void *)(unsigned long) xdrbuf->page_base;
 104                 seg[n].mr_len = min_t(u32,
 105                         PAGE_SIZE - xdrbuf->page_base, xdrbuf->page_len);
 106                 len = xdrbuf->page_len - seg[n].mr_len;
 107                 pos += len;
 108                 ++n;
 109                 p = 1;
 110                 while (len > 0) {
 111                         if (n == nsegs)
 112                                 return 0;
 113                         seg[n].mr_page = xdrbuf->pages[p];
 114                         seg[n].mr_offset = NULL;
 115                         seg[n].mr_len = min_t(u32, PAGE_SIZE, len);
 116                         len -= seg[n].mr_len;
 117                         ++n;
 118                         ++p;
 119                 }
 120         }
 121
 122         if (pos < xdrbuf->len && xdrbuf->tail[0].iov_len) {
 123                 if (n == nsegs)
 124                         return 0;
 125                 seg[n].mr_page = NULL;
 126                 seg[n].mr_offset = xdrbuf->tail[0].iov_base;
 127                 seg[n].mr_len = xdrbuf->tail[0].iov_len;
 128                 pos += xdrbuf->tail[0].iov_len;
 129                 ++n;
 130         }
 131
 132         if (pos < xdrbuf->len)
 133                 dprintk("RPC:       %s: marshaled only %d of %d\n",
 134                                 __func__, pos, xdrbuf->len);
 135
 136         return n;
 137 }
 138
 139 /*
 140  * Create read/write chunk lists, and reply chunks, for RDMA
 141  *
 142  *   Assume check against THRESHOLD has been done, and chunks are required.
 143  *   Assume only encoding one list entry for read|write chunks. The NFSv3
 144  *     protocol is simple enough to allow this as it only has a single "bulk
 145  *     result" in each procedure - complicated NFSv4 COMPOUNDs are not. (The
 146  *     RDMA/Sessions NFSv4 proposal addresses this for future v4 revs.)
 147  *
 148  * When used for a single reply chunk (which is a special write
 149  * chunk used for the entire reply, rather than just the data), it
 150  * is used primarily for READDIR and READLINK which would otherwise
 151  * be severely size-limited by a small rdma inline read max. The server
 152  * response will come back as an RDMA Write, followed by a message
 153  * of type RDMA_NOMSG carrying the xid and length. As a result, reply
 154  * chunks do not provide data alignment, however they do not require
 155  * "fixup" (moving the response to the upper layer buffer) either.
 156  *
 157  * Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
 158  *
 159  *  Read chunklist (a linked list):
 160  *   N elements, position P (same P for all chunks of same arg!):
 161  *    1 - PHLOO - 1 - PHLOO - ... - 1 - PHLOO - 0
 162  *
 163  *  Write chunklist (a list of (one) counted array):
 164  *   N elements:
 165  *    1 - N - HLOO - HLOO - ... - HLOO - 0
 166  *
 167  *  Reply chunk (a counted array):
 168  *   N elements:
 169  *    1 - N - HLOO - HLOO - ... - HLOO
 170  */
 171
 172 static unsigned int
 173 rpcrdma_create_chunks(struct rpc_rqst *rqst, struct xdr_buf *target,
 174                 struct rpcrdma_msg *headerp, enum rpcrdma_chunktype type)
 175 {
 176         struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
 177         struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(rqst->rq_task->tk_xprt);
 178         int nsegs, nchunks = 0;
 179         int pos;
 180         struct rpcrdma_mr_seg *seg = req->rl_segments;
 181         struct rpcrdma_read_chunk *cur_rchunk = NULL;
 182         struct rpcrdma_write_array *warray = NULL;
 183         struct rpcrdma_write_chunk *cur_wchunk = NULL;
 184         __be32 *iptr = headerp->rm_body.rm_chunks;
 185
 186         if (type == rpcrdma_readch || type == rpcrdma_areadch) {
 187                 /* a read chunk - server will RDMA Read our memory */
 188                 cur_rchunk = (struct rpcrdma_read_chunk *) iptr;
 189         } else {
 190                 /* a write or reply chunk - server will RDMA Write our memory */
 191                 *iptr++ = xdr_zero;     /* encode a NULL read chunk list */
 192                 if (type == rpcrdma_replych)
 193                         *iptr++ = xdr_zero;     /* a NULL write chunk list */
 194                 warray = (struct rpcrdma_write_array *) iptr;
 195                 cur_wchunk = (struct rpcrdma_write_chunk *) (warray + 1);
 196         }
 197
 198         if (type == rpcrdma_replych || type == rpcrdma_areadch)
 199                 pos = 0;
 200         else
 201                 pos = target->head[0].iov_len;
 202
 203         nsegs = rpcrdma_convert_iovs(target, pos, type, seg, RPCRDMA_MAX_SEGS);
 204         if (nsegs == 0)
 205                 return 0;
 206
 207         do {
 208                 /* bind/register the memory, then build chunk from result. */
 209                 int n = rpcrdma_register_external(seg, nsegs,
 210                                                 cur_wchunk != NULL, r_xprt);
 211                 if (n <= 0)
 212                         goto out;
 213                 if (cur_rchunk) {       /* read */
 214                         cur_rchunk->rc_discrim = xdr_one;
 215                         /* all read chunks have the same "position" */
 216                         cur_rchunk->rc_position = htonl(pos);
 217                         cur_rchunk->rc_target.rs_handle = htonl(seg->mr_rkey);
 218                         cur_rchunk->rc_target.rs_length = htonl(seg->mr_len);
 219                         xdr_encode_hyper(
 220                                         (__be32 *)&cur_rchunk->rc_target.rs_offset,
 221                                         seg->mr_base);
 222                         dprintk("RPC:       %s: read chunk "
 223                                 "elem %d@0x%llx:0x%x pos %d (%s)\n", __func__,
 224                                 seg->mr_len, (unsigned long long)seg->mr_base,
 225                                 seg->mr_rkey, pos, n < nsegs ? "more" : "last");
 226                         cur_rchunk++;
 227                         r_xprt->rx_stats.read_chunk_count++;
 228                 } else {                /* write/reply */
 229                         cur_wchunk->wc_target.rs_handle = htonl(seg->mr_rkey);
 230                         cur_wchunk->wc_target.rs_length = htonl(seg->mr_len);
 231                         xdr_encode_hyper(
 232                                         (__be32 *)&cur_wchunk->wc_target.rs_offset,
 233                                         seg->mr_base);
 234                         dprintk("RPC:       %s: %s chunk "
 235                                 "elem %d@0x%llx:0x%x (%s)\n", __func__,
 236                                 (type == rpcrdma_replych) ? "reply" : "write",
 237                                 seg->mr_len, (unsigned long long)seg->mr_base,
 238                                 seg->mr_rkey, n < nsegs ? "more" : "last");
 239                         cur_wchunk++;
 240                         if (type == rpcrdma_replych)
 241                                 r_xprt->rx_stats.reply_chunk_count++;
 242                         else
 243                                 r_xprt->rx_stats.write_chunk_count++;
 244                         r_xprt->rx_stats.total_rdma_request += seg->mr_len;
 245                 }
 246                 nchunks++;
 247                 seg   += n;
 248                 nsegs -= n;
 249         } while (nsegs);
 250
 251         /* success. all failures return above */
 252         req->rl_nchunks = nchunks;
 253
 254         BUG_ON(nchunks == 0);
 255
 256         /*
 257          * finish off header. If write, marshal discrim and nchunks.
 258          */
 259         if (cur_rchunk) {
 260                 iptr = (__be32 *) cur_rchunk;
 261                 *iptr++ = xdr_zero;     /* finish the read chunk list */
 262                 *iptr++ = xdr_zero;     /* encode a NULL write chunk list */
 263                 *iptr++ = xdr_zero;     /* encode a NULL reply chunk */
 264         } else {
 265                 warray->wc_discrim = xdr_one;
 266                 warray->wc_nchunks = htonl(nchunks);
 267                 iptr = (__be32 *) cur_wchunk;
 268                 if (type == rpcrdma_writech) {
 269                         *iptr++ = xdr_zero; /* finish the write chunk list */
 270                         *iptr++ = xdr_zero; /* encode a NULL reply chunk */
 271                 }
 272         }
 273
 274         /*
 275          * Return header size.
 276          */
 277         return (unsigned char *)iptr - (unsigned char *)headerp;
 278
 279 out:
 280         for (pos = 0; nchunks--;)
 281                 pos += rpcrdma_deregister_external(
 282                                 &req->rl_segments[pos], r_xprt, NULL);
 283         return 0;
 284 }
 285
 286 /*
 287  * Copy write data inline.
 288  * This function is used for "small" requests. Data which is passed
 289  * to RPC via iovecs (or page list) is copied directly into the
 290  * pre-registered memory buffer for this request. For small amounts
 291  * of data, this is efficient. The cutoff value is tunable.
 292  */
 293 static int
 294 rpcrdma_inline_pullup(struct rpc_rqst *rqst, int pad)
 295 {
 296         int i, npages, curlen;
 297         int copy_len;
 298         unsigned char *srcp, *destp;
 299         struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(rqst->rq_xprt);
 300
 301         destp = rqst->rq_svec[0].iov_base;
 302         curlen = rqst->rq_svec[0].iov_len;
 303         destp += curlen;
 304         /*
 305          * Do optional padding where it makes sense. Alignment of write
 306          * payload can help the server, if our setting is accurate.
 307          */
 308         pad -= (curlen + 36/*sizeof(struct rpcrdma_msg_padded)*/);
 309         if (pad < 0 || rqst->rq_slen - curlen < RPCRDMA_INLINE_PAD_THRESH)
 310                 pad = 0;        /* don't pad this request */
 311
 312         dprintk("RPC:       %s: pad %d destp 0x%p len %d hdrlen %d\n",
 313                 __func__, pad, destp, rqst->rq_slen, curlen);
 314
 315         copy_len = rqst->rq_snd_buf.page_len;
 316         r_xprt->rx_stats.pullup_copy_count += copy_len;
 317         npages = PAGE_ALIGN(rqst->rq_snd_buf.page_base+copy_len) >> PAGE_SHIFT;
 318         for (i = 0; copy_len && i < npages; i++) {
 319                 if (i == 0)
 320                         curlen = PAGE_SIZE - rqst->rq_snd_buf.page_base;
 321                 else
 322                         curlen = PAGE_SIZE;
 323                 if (curlen > copy_len)
 324                         curlen = copy_len;
 325                 dprintk("RPC:       %s: page %d destp 0x%p len %d curlen %d\n",
 326                         __func__, i, destp, copy_len, curlen);
 327                 srcp = kmap_atomic(rqst->rq_snd_buf.pages[i],
 328                                         KM_SKB_SUNRPC_DATA);
 329                 if (i == 0)
 330                         memcpy(destp, srcp+rqst->rq_snd_buf.page_base, curlen);
 331                 else
 332                         memcpy(destp, srcp, curlen);
 333                 kunmap_atomic(srcp, KM_SKB_SUNRPC_DATA);
 334                 rqst->rq_svec[0].iov_len += curlen;
 335                 destp += curlen;
 336                 copy_len -= curlen;
 337         }
 338         if (rqst->rq_snd_buf.tail[0].iov_len) {
 339                 curlen = rqst->rq_snd_buf.tail[0].iov_len;
 340                 if (destp != rqst->rq_snd_buf.tail[0].iov_base) {
 341                         memcpy(destp,
 342                                 rqst->rq_snd_buf.tail[0].iov_base, curlen);
 343                         r_xprt->rx_stats.pullup_copy_count += curlen;
 344                 }
 345                 dprintk("RPC:       %s: tail destp 0x%p len %d curlen %d\n",
 346                         __func__, destp, copy_len, curlen);
 347                 rqst->rq_svec[0].iov_len += curlen;
 348         }
 349         /* header now contains entire send message */
 350         return pad;
 351 }
 352
 353 /*
 354  * Marshal a request: the primary job of this routine is to choose
 355  * the transfer modes. See comments below.
 356  *
 357  * Uses multiple RDMA IOVs for a request:
 358  *  [0] -- RPC RDMA header, which uses memory from the *start* of the
 359  *         preregistered buffer that already holds the RPC data in
 360  *         its middle.
 361  *  [1] -- the RPC header/data, marshaled by RPC and the NFS protocol.
 362  *  [2] -- optional padding.
 363  *  [3] -- if padded, header only in [1] and data here.
 364  */
 365
 366 int
 367 rpcrdma_marshal_req(struct rpc_rqst *rqst)
 368 {
 369         struct rpc_xprt *xprt = rqst->rq_task->tk_xprt;
 370         struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
 371         struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
 372         char *base;
 373         size_t hdrlen, rpclen, padlen;
 374         enum rpcrdma_chunktype rtype, wtype;
 375         struct rpcrdma_msg *headerp;
 376
 377         /*
 378          * rpclen gets amount of data in first buffer, which is the
 379          * pre-registered buffer.
 380          */
 381         base = rqst->rq_svec[0].iov_base;
 382         rpclen = rqst->rq_svec[0].iov_len;
 383
 384         /* build RDMA header in private area at front */
 385         headerp = (struct rpcrdma_msg *) req->rl_base;
 386         /* don't htonl XID, it's already done in request */
 387         headerp->rm_xid = rqst->rq_xid;
 388         headerp->rm_vers = xdr_one;
 389         headerp->rm_credit = htonl(r_xprt->rx_buf.rb_max_requests);
 390         headerp->rm_type = __constant_htonl(RDMA_MSG);
 391
 392         /*
 393          * Chunks needed for results?
 394          *
 395          * o If the expected result is under the inline threshold, all ops
 396          *   return as inline (but see later).
 397          * o Large non-read ops return as a single reply chunk.
 398          * o Large read ops return data as write chunk(s), header as inline.
 399          *
 400          * Note: the NFS code sending down multiple result segments implies
 401          * the op is one of read, readdir[plus], readlink or NFSv4 getacl.
 402          */
 403
 404         /*
 405          * This code can handle read chunks, write chunks OR reply
 406          * chunks -- only one type. If the request is too big to fit
 407          * inline, then we will choose read chunks. If the request is
 408          * a READ, then use write chunks to separate the file data
 409          * into pages; otherwise use reply chunks.
 410          */
 411         if (rqst->rq_rcv_buf.buflen <= RPCRDMA_INLINE_READ_THRESHOLD(rqst))
 412                 wtype = rpcrdma_noch;
 413         else if (rqst->rq_rcv_buf.page_len == 0)
 414                 wtype = rpcrdma_replych;
 415         else if (rqst->rq_rcv_buf.flags & XDRBUF_READ)
 416                 wtype = rpcrdma_writech;
 417         else
 418                 wtype = rpcrdma_replych;
 419
 420         /*
 421          * Chunks needed for arguments?
 422          *
 423          * o If the total request is under the inline threshold, all ops
 424          *   are sent as inline.
 425          * o Large non-write ops are sent with the entire message as a
 426          *   single read chunk (protocol 0-position special case).
 427          * o Large write ops transmit data as read chunk(s), header as
 428          *   inline.
 429          *
 430          * Note: the NFS code sending down multiple argument segments
 431          * implies the op is a write.
 432          * TBD check NFSv4 setacl
 433          */
 434         if (rqst->rq_snd_buf.len <= RPCRDMA_INLINE_WRITE_THRESHOLD(rqst))
 435                 rtype = rpcrdma_noch;
 436         else if (rqst->rq_snd_buf.page_len == 0)
 437                 rtype = rpcrdma_areadch;
 438         else
 439                 rtype = rpcrdma_readch;
 440
 441         /* The following simplification is not true forever */
 442         if (rtype != rpcrdma_noch && wtype == rpcrdma_replych)
 443                 wtype = rpcrdma_noch;
 444         BUG_ON(rtype != rpcrdma_noch && wtype != rpcrdma_noch);
 445
 446         if (r_xprt->rx_ia.ri_memreg_strategy == RPCRDMA_BOUNCEBUFFERS &&
 447             (rtype != rpcrdma_noch || wtype != rpcrdma_noch)) {
 448                 /* forced to "pure inline"? */
 449                 dprintk("RPC:       %s: too much data (%d/%d) for inline\n",
 450                         __func__, rqst->rq_rcv_buf.len, rqst->rq_snd_buf.len);
 451                 return -1;
 452         }
 453
 454         hdrlen = 28; /*sizeof *headerp;*/
 455         padlen = 0;
 456
 457         /*
 458          * Pull up any extra send data into the preregistered buffer.
 459          * When padding is in use and applies to the transfer, insert
 460          * it and change the message type.
 461          */
 462         if (rtype == rpcrdma_noch) {
 463
 464                 padlen = rpcrdma_inline_pullup(rqst,
 465                                                 RPCRDMA_INLINE_PAD_VALUE(rqst));
 466
 467                 if (padlen) {
 468                         headerp->rm_type = __constant_htonl(RDMA_MSGP);
 469                         headerp->rm_body.rm_padded.rm_align =
 470                                 htonl(RPCRDMA_INLINE_PAD_VALUE(rqst));
 471                         headerp->rm_body.rm_padded.rm_thresh =
 472                                 __constant_htonl(RPCRDMA_INLINE_PAD_THRESH);
 473                         headerp->rm_body.rm_padded.rm_pempty[0] = xdr_zero;
 474                         headerp->rm_body.rm_padded.rm_pempty[1] = xdr_zero;
 475                         headerp->rm_body.rm_padded.rm_pempty[2] = xdr_zero;
 476                         hdrlen += 2 * sizeof(u32); /* extra words in padhdr */
 477                         BUG_ON(wtype != rpcrdma_noch);
 478
 479                 } else {
 480                         headerp->rm_body.rm_nochunks.rm_empty[0] = xdr_zero;
 481                         headerp->rm_body.rm_nochunks.rm_empty[1] = xdr_zero;
 482                         headerp->rm_body.rm_nochunks.rm_empty[2] = xdr_zero;
 483                         /* new length after pullup */
 484                         rpclen = rqst->rq_svec[0].iov_len;
 485                         /*
 486                          * Currently we try to not actually use read inline.
 487                          * Reply chunks have the desirable property that
 488                          * they land, packed, directly in the target buffers
 489                          * without headers, so they require no fixup. The
 490                          * additional RDMA Write op sends the same amount
 491                          * of data, streams on-the-wire and adds no overhead
 492                          * on receive. Therefore, we request a reply chunk
 493                          * for non-writes wherever feasible and efficient.
 494                          */
 495                         if (wtype == rpcrdma_noch &&
 496                             r_xprt->rx_ia.ri_memreg_strategy > RPCRDMA_REGISTER)
 497                                 wtype = rpcrdma_replych;
 498                 }
 499         }
 500
 501         /*
 502          * Marshal chunks. This routine will return the header length
 503          * consumed by marshaling.
 504          */
 505         if (rtype != rpcrdma_noch) {
 506                 hdrlen = rpcrdma_create_chunks(rqst,
 507                                         &rqst->rq_snd_buf, headerp, rtype);
 508                 wtype = rtype;  /* simplify dprintk */
 509
 510         } else if (wtype != rpcrdma_noch) {
 511                 hdrlen = rpcrdma_create_chunks(rqst,
 512                                         &rqst->rq_rcv_buf, headerp, wtype);
 513         }
 514
 515         if (hdrlen == 0)
 516                 return -1;
 517
 518         dprintk("RPC:       %s: %s: hdrlen %zd rpclen %zd padlen %zd\n"
 519                 "                   headerp 0x%p base 0x%p lkey 0x%x\n",
 520                 __func__, transfertypes[wtype], hdrlen, rpclen, padlen,
 521                 headerp, base, req->rl_iov.lkey);
 522
 523         /*
 524          * initialize send_iov's - normally only two: rdma chunk header and
 525          * single preregistered RPC header buffer, but if padding is present,
 526          * then use a preregistered (and zeroed) pad buffer between the RPC
 527          * header and any write data. In all non-rdma cases, any following
 528          * data has been copied into the RPC header buffer.
 529          */
 530         req->rl_send_iov[0].addr = req->rl_iov.addr;
 531         req->rl_send_iov[0].length = hdrlen;
 532         req->rl_send_iov[0].lkey = req->rl_iov.lkey;
 533
 534         req->rl_send_iov[1].addr = req->rl_iov.addr + (base - req->rl_base);
 535         req->rl_send_iov[1].length = rpclen;
 536         req->rl_send_iov[1].lkey = req->rl_iov.lkey;
 537
 538         req->rl_niovs = 2;
 539
 540         if (padlen) {
 541                 struct rpcrdma_ep *ep = &r_xprt->rx_ep;
 542
 543                 req->rl_send_iov[2].addr = ep->rep_pad.addr;
 544                 req->rl_send_iov[2].length = padlen;
 545                 req->rl_send_iov[2].lkey = ep->rep_pad.lkey;
 546
 547                 req->rl_send_iov[3].addr = req->rl_send_iov[1].addr + rpclen;
 548                 req->rl_send_iov[3].length = rqst->rq_slen - rpclen;
 549                 req->rl_send_iov[3].lkey = req->rl_iov.lkey;
 550
 551                 req->rl_niovs = 4;
 552         }
 553
 554         return 0;
 555 }
 556
 557 /*
 558  * Chase down a received write or reply chunklist to get length
 559  * RDMA'd by server. See map at rpcrdma_create_chunks()! :-)
 560  */
 561 static int
 562 rpcrdma_count_chunks(struct rpcrdma_rep *rep, int max, int wrchunk, __be32 **iptrp)
 563 {
 564         unsigned int i, total_len;
 565         struct rpcrdma_write_chunk *cur_wchunk;
 566
 567         i = ntohl(**iptrp);     /* get array count */
 568         if (i > max)
 569                 return -1;
 570         cur_wchunk = (struct rpcrdma_write_chunk *) (*iptrp + 1);
 571         total_len = 0;
 572         while (i--) {
 573                 struct rpcrdma_segment *seg = &cur_wchunk->wc_target;
 574                 ifdebug(FACILITY) {
 575                         u64 off;
 576                         xdr_decode_hyper((__be32 *)&seg->rs_offset, &off);
 577                         dprintk("RPC:       %s: chunk %d@0x%llx:0x%x\n",
 578                                 __func__,
 579                                 ntohl(seg->rs_length),
 580                                 (unsigned long long)off,
 581                                 ntohl(seg->rs_handle));
 582                 }
 583                 total_len += ntohl(seg->rs_length);
 584                 ++cur_wchunk;
 585         }
 586         /* check and adjust for properly terminated write chunk */
 587         if (wrchunk) {
 588                 __be32 *w = (__be32 *) cur_wchunk;
 589                 if (*w++ != xdr_zero)
 590                         return -1;
 591                 cur_wchunk = (struct rpcrdma_write_chunk *) w;
 592         }
 593         if ((char *) cur_wchunk > rep->rr_base + rep->rr_len)
 594                 return -1;
 595
 596         *iptrp = (__be32 *) cur_wchunk;
 597         return total_len;
 598 }
 599
 600 /*
 601  * Scatter inline received data back into provided iov's.
 602  */
 603 static void
 604 rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len)
 605 {
 606         int i, npages, curlen, olen;
 607         char *destp;
 608
 609         curlen = rqst->rq_rcv_buf.head[0].iov_len;
 610         if (curlen > copy_len) {        /* write chunk header fixup */
 611                 curlen = copy_len;
 612                 rqst->rq_rcv_buf.head[0].iov_len = curlen;
 613         }
 614
 615         dprintk("RPC:       %s: srcp 0x%p len %d hdrlen %d\n",
 616                 __func__, srcp, copy_len, curlen);
 617
 618         /* Shift pointer for first receive segment only */
 619         rqst->rq_rcv_buf.head[0].iov_base = srcp;
 620         srcp += curlen;
 621         copy_len -= curlen;
 622
 623         olen = copy_len;
 624         i = 0;
 625         rpcx_to_rdmax(rqst->rq_xprt)->rx_stats.fixup_copy_count += olen;
 626         if (copy_len && rqst->rq_rcv_buf.page_len) {
 627                 npages = PAGE_ALIGN(rqst->rq_rcv_buf.page_base +
 628                         rqst->rq_rcv_buf.page_len) >> PAGE_SHIFT;
 629                 for (; i < npages; i++) {
 630                         if (i == 0)
 631                                 curlen = PAGE_SIZE - rqst->rq_rcv_buf.page_base;
 632                         else
 633                                 curlen = PAGE_SIZE;
 634                         if (curlen > copy_len)
 635                                 curlen = copy_len;
 636                         dprintk("RPC:       %s: page %d"
 637                                 " srcp 0x%p len %d curlen %d\n",
 638                                 __func__, i, srcp, copy_len, curlen);
 639                         destp = kmap_atomic(rqst->rq_rcv_buf.pages[i],
 640                                                 KM_SKB_SUNRPC_DATA);
 641                         if (i == 0)
 642                                 memcpy(destp + rqst->rq_rcv_buf.page_base,
 643                                                 srcp, curlen);
 644                         else
 645                                 memcpy(destp, srcp, curlen);
 646                         flush_dcache_page(rqst->rq_rcv_buf.pages[i]);
 647                         kunmap_atomic(destp, KM_SKB_SUNRPC_DATA);
 648                         srcp += curlen;
 649                         copy_len -= curlen;
 650                         if (copy_len == 0)
 651                                 break;
 652                 }
 653                 rqst->rq_rcv_buf.page_len = olen - copy_len;
 654         } else
 655                 rqst->rq_rcv_buf.page_len = 0;
 656
 657         if (copy_len && rqst->rq_rcv_buf.tail[0].iov_len) {
 658                 curlen = copy_len;
 659                 if (curlen > rqst->rq_rcv_buf.tail[0].iov_len)
 660                         curlen = rqst->rq_rcv_buf.tail[0].iov_len;
 661                 if (rqst->rq_rcv_buf.tail[0].iov_base != srcp)
 662                         memcpy(rqst->rq_rcv_buf.tail[0].iov_base, srcp, curlen);
 663                 dprintk("RPC:       %s: tail srcp 0x%p len %d curlen %d\n",
 664                         __func__, srcp, copy_len, curlen);
 665                 rqst->rq_rcv_buf.tail[0].iov_len = curlen;
 666                 copy_len -= curlen; ++i;
 667         } else
 668                 rqst->rq_rcv_buf.tail[0].iov_len = 0;
 669
 670         if (copy_len)
 671                 dprintk("RPC:       %s: %d bytes in"
 672                         " %d extra segments (%d lost)\n",
 673                         __func__, olen, i, copy_len);
 674
 675         /* TBD avoid a warning from call_decode() */
 676         rqst->rq_private_buf = rqst->rq_rcv_buf;
 677 }
 678
 679 /*
 680  * This function is called when an async event is posted to
 681  * the connection which changes the connection state. All it
 682  * does at this point is mark the connection up/down, the rpc
 683  * timers do the rest.
 684  */
 685 void
 686 rpcrdma_conn_func(struct rpcrdma_ep *ep)
 687 {
 688         struct rpc_xprt *xprt = ep->rep_xprt;
 689
 690         spin_lock_bh(&xprt->transport_lock);
 691         if (ep->rep_connected > 0) {
 692                 if (!xprt_test_and_set_connected(xprt))
 693                         xprt_wake_pending_tasks(xprt, 0);
 694         } else {
 695                 if (xprt_test_and_clear_connected(xprt))
 696                         xprt_wake_pending_tasks(xprt, ep->rep_connected);
 697         }
 698         spin_unlock_bh(&xprt->transport_lock);
 699 }
 700
 701 /*
 702  * This function is called when memory window unbind which we are waiting
 703  * for completes. Just use rr_func (zeroed by upcall) to signal completion.
 704  */
 705 static void
 706 rpcrdma_unbind_func(struct rpcrdma_rep *rep)
 707 {
 708         wake_up(&rep->rr_unbind);
 709 }
 710
 711 /*
 712  * Called as a tasklet to do req/reply match and complete a request
 713  * Errors must result in the RPC task either being awakened, or
 714  * allowed to timeout, to discover the errors at that time.
 715  */
 716 void
 717 rpcrdma_reply_handler(struct rpcrdma_rep *rep)
 718 {
 719         struct rpcrdma_msg *headerp;
 720         struct rpcrdma_req *req;
 721         struct rpc_rqst *rqst;
 722         struct rpc_xprt *xprt = rep->rr_xprt;
 723         struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
 724         __be32 *iptr;
 725         int i, rdmalen, status;
 726
 727         /* Check status. If bad, signal disconnect and return rep to pool */
 728         if (rep->rr_len == ~0U) {
 729                 rpcrdma_recv_buffer_put(rep);
 730                 if (r_xprt->rx_ep.rep_connected == 1) {
 731                         r_xprt->rx_ep.rep_connected = -EIO;
 732                         rpcrdma_conn_func(&r_xprt->rx_ep);
 733                 }
 734                 return;
 735         }
 736         if (rep->rr_len < 28) {
 737                 dprintk("RPC:       %s: short/invalid reply\n", __func__);
 738                 goto repost;
 739         }
 740         headerp = (struct rpcrdma_msg *) rep->rr_base;
 741         if (headerp->rm_vers != xdr_one) {
 742                 dprintk("RPC:       %s: invalid version %d\n",
 743                         __func__, ntohl(headerp->rm_vers));
 744                 goto repost;
 745         }
 746
 747         /* Get XID and try for a match. */
 748         spin_lock(&xprt->transport_lock);
 749         rqst = xprt_lookup_rqst(xprt, headerp->rm_xid);
 750         if (rqst == NULL) {
 751                 spin_unlock(&xprt->transport_lock);
 752                 dprintk("RPC:       %s: reply 0x%p failed "
 753                         "to match any request xid 0x%08x len %d\n",
 754                         __func__, rep, headerp->rm_xid, rep->rr_len);
 755 repost:
 756                 r_xprt->rx_stats.bad_reply_count++;
 757                 rep->rr_func = rpcrdma_reply_handler;
 758                 if (rpcrdma_ep_post_recv(&r_xprt->rx_ia, &r_xprt->rx_ep, rep))
 759                         rpcrdma_recv_buffer_put(rep);
 760
 761                 return;
 762         }
 763
 764         /* get request object */
 765         req = rpcr_to_rdmar(rqst);
 766
 767         dprintk("RPC:       %s: reply 0x%p completes request 0x%p\n"
 768                 "                   RPC request 0x%p xid 0x%08x\n",
 769                         __func__, rep, req, rqst, headerp->rm_xid);
 770
 771         BUG_ON(!req || req->rl_reply);
 772
 773         /* from here on, the reply is no longer an orphan */
 774         req->rl_reply = rep;
 775
 776         /* check for expected message types */
 777         /* The order of some of these tests is important. */
 778         switch (headerp->rm_type) {
 779         case __constant_htonl(RDMA_MSG):
 780                 /* never expect read chunks */
 781                 /* never expect reply chunks (two ways to check) */
 782                 /* never expect write chunks without having offered RDMA */
 783                 if (headerp->rm_body.rm_chunks[0] != xdr_zero ||
 784                     (headerp->rm_body.rm_chunks[1] == xdr_zero &&
 785                      headerp->rm_body.rm_chunks[2] != xdr_zero) ||
 786                     (headerp->rm_body.rm_chunks[1] != xdr_zero &&
 787                      req->rl_nchunks == 0))
 788                         goto badheader;
 789                 if (headerp->rm_body.rm_chunks[1] != xdr_zero) {
 790                         /* count any expected write chunks in read reply */
 791                         /* start at write chunk array count */
 792                         iptr = &headerp->rm_body.rm_chunks[2];
 793                         rdmalen = rpcrdma_count_chunks(rep,
 794                                                 req->rl_nchunks, 1, &iptr);
 795                         /* check for validity, and no reply chunk after */
 796                         if (rdmalen < 0 || *iptr++ != xdr_zero)
 797                                 goto badheader;
 798                         rep->rr_len -=
 799                             ((unsigned char *)iptr - (unsigned char *)headerp);
 800                         status = rep->rr_len + rdmalen;
 801                         r_xprt->rx_stats.total_rdma_reply += rdmalen;
 802                 } else {
 803                         /* else ordinary inline */
 804                         iptr = (__be32 *)((unsigned char *)headerp + 28);
 805                         rep->rr_len -= 28; /*sizeof *headerp;*/
 806                         status = rep->rr_len;
 807                 }
 808                 /* Fix up the rpc results for upper layer */
 809                 rpcrdma_inline_fixup(rqst, (char *)iptr, rep->rr_len);
 810                 break;
 811
 812         case __constant_htonl(RDMA_NOMSG):
 813                 /* never expect read or write chunks, always reply chunks */
 814                 if (headerp->rm_body.rm_chunks[0] != xdr_zero ||
 815                     headerp->rm_body.rm_chunks[1] != xdr_zero ||
 816                     headerp->rm_body.rm_chunks[2] != xdr_one ||
 817                     req->rl_nchunks == 0)
 818                         goto badheader;
 819                 iptr = (__be32 *)((unsigned char *)headerp + 28);
 820                 rdmalen = rpcrdma_count_chunks(rep, req->rl_nchunks, 0, &iptr);
 821                 if (rdmalen < 0)
 822                         goto badheader;
 823                 r_xprt->rx_stats.total_rdma_reply += rdmalen;
 824                 /* Reply chunk buffer already is the reply vector - no fixup. */
 825                 status = rdmalen;
 826                 break;
 827
 828 badheader:
 829         default:
 830                 dprintk("%s: invalid rpcrdma reply header (type %d):"
 831                                 " chunks[012] == %d %d %d"
 832                                 " expected chunks <= %d\n",
 833                                 __func__, ntohl(headerp->rm_type),
 834                                 headerp->rm_body.rm_chunks[0],
 835                                 headerp->rm_body.rm_chunks[1],
 836                                 headerp->rm_body.rm_chunks[2],
 837                                 req->rl_nchunks);
 838                 status = -EIO;
 839                 r_xprt->rx_stats.bad_reply_count++;
 840                 break;
 841         }
 842
 843         /* If using mw bind, start the deregister process now. */
 844         /* (Note: if mr_free(), cannot perform it here, in tasklet context) */
 845         if (req->rl_nchunks) switch (r_xprt->rx_ia.ri_memreg_strategy) {
 846         case RPCRDMA_MEMWINDOWS:
 847                 for (i = 0; req->rl_nchunks-- > 1;)
 848                         i += rpcrdma_deregister_external(
 849                                 &req->rl_segments[i], r_xprt, NULL);
 850                 /* Optionally wait (not here) for unbinds to complete */
 851                 rep->rr_func = rpcrdma_unbind_func;
 852                 (void) rpcrdma_deregister_external(&req->rl_segments[i],
 853                                                    r_xprt, rep);
 854                 break;
 855         case RPCRDMA_MEMWINDOWS_ASYNC:
 856                 for (i = 0; req->rl_nchunks--;)
 857                         i += rpcrdma_deregister_external(&req->rl_segments[i],
 858                                                          r_xprt, NULL);
 859                 break;
 860         default:
 861                 break;
 862         }
 863
 864         dprintk("RPC:       %s: xprt_complete_rqst(0x%p, 0x%p, %d)\n",
 865                         __func__, xprt, rqst, status);
 866         xprt_complete_rqst(rqst->rq_task, status);
 867         spin_unlock(&xprt->transport_lock);
 868 }