Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris...
[linux-2.6] / net / sunrpc / xprtrdma / rpc_rdma.c
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, unsigned 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                 ++n;
96         }
97
98         if (xdrbuf->page_len && (xdrbuf->pages[0] != NULL)) {
99                 if (n == nsegs)
100                         return 0;
101                 seg[n].mr_page = xdrbuf->pages[0];
102                 seg[n].mr_offset = (void *)(unsigned long) xdrbuf->page_base;
103                 seg[n].mr_len = min_t(u32,
104                         PAGE_SIZE - xdrbuf->page_base, xdrbuf->page_len);
105                 len = xdrbuf->page_len - seg[n].mr_len;
106                 ++n;
107                 p = 1;
108                 while (len > 0) {
109                         if (n == nsegs)
110                                 return 0;
111                         seg[n].mr_page = xdrbuf->pages[p];
112                         seg[n].mr_offset = NULL;
113                         seg[n].mr_len = min_t(u32, PAGE_SIZE, len);
114                         len -= seg[n].mr_len;
115                         ++n;
116                         ++p;
117                 }
118         }
119
120         if (xdrbuf->tail[0].iov_len) {
121                 if (n == nsegs)
122                         return 0;
123                 seg[n].mr_page = NULL;
124                 seg[n].mr_offset = xdrbuf->tail[0].iov_base;
125                 seg[n].mr_len = xdrbuf->tail[0].iov_len;
126                 ++n;
127         }
128
129         return n;
130 }
131
132 /*
133  * Create read/write chunk lists, and reply chunks, for RDMA
134  *
135  *   Assume check against THRESHOLD has been done, and chunks are required.
136  *   Assume only encoding one list entry for read|write chunks. The NFSv3
137  *     protocol is simple enough to allow this as it only has a single "bulk
138  *     result" in each procedure - complicated NFSv4 COMPOUNDs are not. (The
139  *     RDMA/Sessions NFSv4 proposal addresses this for future v4 revs.)
140  *
141  * When used for a single reply chunk (which is a special write
142  * chunk used for the entire reply, rather than just the data), it
143  * is used primarily for READDIR and READLINK which would otherwise
144  * be severely size-limited by a small rdma inline read max. The server
145  * response will come back as an RDMA Write, followed by a message
146  * of type RDMA_NOMSG carrying the xid and length. As a result, reply
147  * chunks do not provide data alignment, however they do not require
148  * "fixup" (moving the response to the upper layer buffer) either.
149  *
150  * Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
151  *
152  *  Read chunklist (a linked list):
153  *   N elements, position P (same P for all chunks of same arg!):
154  *    1 - PHLOO - 1 - PHLOO - ... - 1 - PHLOO - 0
155  *
156  *  Write chunklist (a list of (one) counted array):
157  *   N elements:
158  *    1 - N - HLOO - HLOO - ... - HLOO - 0
159  *
160  *  Reply chunk (a counted array):
161  *   N elements:
162  *    1 - N - HLOO - HLOO - ... - HLOO
163  */
164
165 static unsigned int
166 rpcrdma_create_chunks(struct rpc_rqst *rqst, struct xdr_buf *target,
167                 struct rpcrdma_msg *headerp, enum rpcrdma_chunktype type)
168 {
169         struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
170         struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(rqst->rq_task->tk_xprt);
171         int nsegs, nchunks = 0;
172         unsigned int pos;
173         struct rpcrdma_mr_seg *seg = req->rl_segments;
174         struct rpcrdma_read_chunk *cur_rchunk = NULL;
175         struct rpcrdma_write_array *warray = NULL;
176         struct rpcrdma_write_chunk *cur_wchunk = NULL;
177         __be32 *iptr = headerp->rm_body.rm_chunks;
178
179         if (type == rpcrdma_readch || type == rpcrdma_areadch) {
180                 /* a read chunk - server will RDMA Read our memory */
181                 cur_rchunk = (struct rpcrdma_read_chunk *) iptr;
182         } else {
183                 /* a write or reply chunk - server will RDMA Write our memory */
184                 *iptr++ = xdr_zero;     /* encode a NULL read chunk list */
185                 if (type == rpcrdma_replych)
186                         *iptr++ = xdr_zero;     /* a NULL write chunk list */
187                 warray = (struct rpcrdma_write_array *) iptr;
188                 cur_wchunk = (struct rpcrdma_write_chunk *) (warray + 1);
189         }
190
191         if (type == rpcrdma_replych || type == rpcrdma_areadch)
192                 pos = 0;
193         else
194                 pos = target->head[0].iov_len;
195
196         nsegs = rpcrdma_convert_iovs(target, pos, type, seg, RPCRDMA_MAX_SEGS);
197         if (nsegs == 0)
198                 return 0;
199
200         do {
201                 /* bind/register the memory, then build chunk from result. */
202                 int n = rpcrdma_register_external(seg, nsegs,
203                                                 cur_wchunk != NULL, r_xprt);
204                 if (n <= 0)
205                         goto out;
206                 if (cur_rchunk) {       /* read */
207                         cur_rchunk->rc_discrim = xdr_one;
208                         /* all read chunks have the same "position" */
209                         cur_rchunk->rc_position = htonl(pos);
210                         cur_rchunk->rc_target.rs_handle = htonl(seg->mr_rkey);
211                         cur_rchunk->rc_target.rs_length = htonl(seg->mr_len);
212                         xdr_encode_hyper(
213                                         (__be32 *)&cur_rchunk->rc_target.rs_offset,
214                                         seg->mr_base);
215                         dprintk("RPC:       %s: read chunk "
216                                 "elem %d@0x%llx:0x%x pos %u (%s)\n", __func__,
217                                 seg->mr_len, (unsigned long long)seg->mr_base,
218                                 seg->mr_rkey, pos, n < nsegs ? "more" : "last");
219                         cur_rchunk++;
220                         r_xprt->rx_stats.read_chunk_count++;
221                 } else {                /* write/reply */
222                         cur_wchunk->wc_target.rs_handle = htonl(seg->mr_rkey);
223                         cur_wchunk->wc_target.rs_length = htonl(seg->mr_len);
224                         xdr_encode_hyper(
225                                         (__be32 *)&cur_wchunk->wc_target.rs_offset,
226                                         seg->mr_base);
227                         dprintk("RPC:       %s: %s chunk "
228                                 "elem %d@0x%llx:0x%x (%s)\n", __func__,
229                                 (type == rpcrdma_replych) ? "reply" : "write",
230                                 seg->mr_len, (unsigned long long)seg->mr_base,
231                                 seg->mr_rkey, n < nsegs ? "more" : "last");
232                         cur_wchunk++;
233                         if (type == rpcrdma_replych)
234                                 r_xprt->rx_stats.reply_chunk_count++;
235                         else
236                                 r_xprt->rx_stats.write_chunk_count++;
237                         r_xprt->rx_stats.total_rdma_request += seg->mr_len;
238                 }
239                 nchunks++;
240                 seg   += n;
241                 nsegs -= n;
242         } while (nsegs);
243
244         /* success. all failures return above */
245         req->rl_nchunks = nchunks;
246
247         BUG_ON(nchunks == 0);
248
249         /*
250          * finish off header. If write, marshal discrim and nchunks.
251          */
252         if (cur_rchunk) {
253                 iptr = (__be32 *) cur_rchunk;
254                 *iptr++ = xdr_zero;     /* finish the read chunk list */
255                 *iptr++ = xdr_zero;     /* encode a NULL write chunk list */
256                 *iptr++ = xdr_zero;     /* encode a NULL reply chunk */
257         } else {
258                 warray->wc_discrim = xdr_one;
259                 warray->wc_nchunks = htonl(nchunks);
260                 iptr = (__be32 *) cur_wchunk;
261                 if (type == rpcrdma_writech) {
262                         *iptr++ = xdr_zero; /* finish the write chunk list */
263                         *iptr++ = xdr_zero; /* encode a NULL reply chunk */
264                 }
265         }
266
267         /*
268          * Return header size.
269          */
270         return (unsigned char *)iptr - (unsigned char *)headerp;
271
272 out:
273         for (pos = 0; nchunks--;)
274                 pos += rpcrdma_deregister_external(
275                                 &req->rl_segments[pos], r_xprt, NULL);
276         return 0;
277 }
278
279 /*
280  * Copy write data inline.
281  * This function is used for "small" requests. Data which is passed
282  * to RPC via iovecs (or page list) is copied directly into the
283  * pre-registered memory buffer for this request. For small amounts
284  * of data, this is efficient. The cutoff value is tunable.
285  */
286 static int
287 rpcrdma_inline_pullup(struct rpc_rqst *rqst, int pad)
288 {
289         int i, npages, curlen;
290         int copy_len;
291         unsigned char *srcp, *destp;
292         struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(rqst->rq_xprt);
293
294         destp = rqst->rq_svec[0].iov_base;
295         curlen = rqst->rq_svec[0].iov_len;
296         destp += curlen;
297         /*
298          * Do optional padding where it makes sense. Alignment of write
299          * payload can help the server, if our setting is accurate.
300          */
301         pad -= (curlen + 36/*sizeof(struct rpcrdma_msg_padded)*/);
302         if (pad < 0 || rqst->rq_slen - curlen < RPCRDMA_INLINE_PAD_THRESH)
303                 pad = 0;        /* don't pad this request */
304
305         dprintk("RPC:       %s: pad %d destp 0x%p len %d hdrlen %d\n",
306                 __func__, pad, destp, rqst->rq_slen, curlen);
307
308         copy_len = rqst->rq_snd_buf.page_len;
309         r_xprt->rx_stats.pullup_copy_count += copy_len;
310         npages = PAGE_ALIGN(rqst->rq_snd_buf.page_base+copy_len) >> PAGE_SHIFT;
311         for (i = 0; copy_len && i < npages; i++) {
312                 if (i == 0)
313                         curlen = PAGE_SIZE - rqst->rq_snd_buf.page_base;
314                 else
315                         curlen = PAGE_SIZE;
316                 if (curlen > copy_len)
317                         curlen = copy_len;
318                 dprintk("RPC:       %s: page %d destp 0x%p len %d curlen %d\n",
319                         __func__, i, destp, copy_len, curlen);
320                 srcp = kmap_atomic(rqst->rq_snd_buf.pages[i],
321                                         KM_SKB_SUNRPC_DATA);
322                 if (i == 0)
323                         memcpy(destp, srcp+rqst->rq_snd_buf.page_base, curlen);
324                 else
325                         memcpy(destp, srcp, curlen);
326                 kunmap_atomic(srcp, KM_SKB_SUNRPC_DATA);
327                 rqst->rq_svec[0].iov_len += curlen;
328                 destp += curlen;
329                 copy_len -= curlen;
330         }
331         if (rqst->rq_snd_buf.tail[0].iov_len) {
332                 curlen = rqst->rq_snd_buf.tail[0].iov_len;
333                 if (destp != rqst->rq_snd_buf.tail[0].iov_base) {
334                         memcpy(destp,
335                                 rqst->rq_snd_buf.tail[0].iov_base, curlen);
336                         r_xprt->rx_stats.pullup_copy_count += curlen;
337                 }
338                 dprintk("RPC:       %s: tail destp 0x%p len %d curlen %d\n",
339                         __func__, destp, copy_len, curlen);
340                 rqst->rq_svec[0].iov_len += curlen;
341         }
342         /* header now contains entire send message */
343         return pad;
344 }
345
346 /*
347  * Marshal a request: the primary job of this routine is to choose
348  * the transfer modes. See comments below.
349  *
350  * Uses multiple RDMA IOVs for a request:
351  *  [0] -- RPC RDMA header, which uses memory from the *start* of the
352  *         preregistered buffer that already holds the RPC data in
353  *         its middle.
354  *  [1] -- the RPC header/data, marshaled by RPC and the NFS protocol.
355  *  [2] -- optional padding.
356  *  [3] -- if padded, header only in [1] and data here.
357  */
358
359 int
360 rpcrdma_marshal_req(struct rpc_rqst *rqst)
361 {
362         struct rpc_xprt *xprt = rqst->rq_task->tk_xprt;
363         struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
364         struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
365         char *base;
366         size_t hdrlen, rpclen, padlen;
367         enum rpcrdma_chunktype rtype, wtype;
368         struct rpcrdma_msg *headerp;
369
370         /*
371          * rpclen gets amount of data in first buffer, which is the
372          * pre-registered buffer.
373          */
374         base = rqst->rq_svec[0].iov_base;
375         rpclen = rqst->rq_svec[0].iov_len;
376
377         /* build RDMA header in private area at front */
378         headerp = (struct rpcrdma_msg *) req->rl_base;
379         /* don't htonl XID, it's already done in request */
380         headerp->rm_xid = rqst->rq_xid;
381         headerp->rm_vers = xdr_one;
382         headerp->rm_credit = htonl(r_xprt->rx_buf.rb_max_requests);
383         headerp->rm_type = htonl(RDMA_MSG);
384
385         /*
386          * Chunks needed for results?
387          *
388          * o If the expected result is under the inline threshold, all ops
389          *   return as inline (but see later).
390          * o Large non-read ops return as a single reply chunk.
391          * o Large read ops return data as write chunk(s), header as inline.
392          *
393          * Note: the NFS code sending down multiple result segments implies
394          * the op is one of read, readdir[plus], readlink or NFSv4 getacl.
395          */
396
397         /*
398          * This code can handle read chunks, write chunks OR reply
399          * chunks -- only one type. If the request is too big to fit
400          * inline, then we will choose read chunks. If the request is
401          * a READ, then use write chunks to separate the file data
402          * into pages; otherwise use reply chunks.
403          */
404         if (rqst->rq_rcv_buf.buflen <= RPCRDMA_INLINE_READ_THRESHOLD(rqst))
405                 wtype = rpcrdma_noch;
406         else if (rqst->rq_rcv_buf.page_len == 0)
407                 wtype = rpcrdma_replych;
408         else if (rqst->rq_rcv_buf.flags & XDRBUF_READ)
409                 wtype = rpcrdma_writech;
410         else
411                 wtype = rpcrdma_replych;
412
413         /*
414          * Chunks needed for arguments?
415          *
416          * o If the total request is under the inline threshold, all ops
417          *   are sent as inline.
418          * o Large non-write ops are sent with the entire message as a
419          *   single read chunk (protocol 0-position special case).
420          * o Large write ops transmit data as read chunk(s), header as
421          *   inline.
422          *
423          * Note: the NFS code sending down multiple argument segments
424          * implies the op is a write.
425          * TBD check NFSv4 setacl
426          */
427         if (rqst->rq_snd_buf.len <= RPCRDMA_INLINE_WRITE_THRESHOLD(rqst))
428                 rtype = rpcrdma_noch;
429         else if (rqst->rq_snd_buf.page_len == 0)
430                 rtype = rpcrdma_areadch;
431         else
432                 rtype = rpcrdma_readch;
433
434         /* The following simplification is not true forever */
435         if (rtype != rpcrdma_noch && wtype == rpcrdma_replych)
436                 wtype = rpcrdma_noch;
437         BUG_ON(rtype != rpcrdma_noch && wtype != rpcrdma_noch);
438
439         if (r_xprt->rx_ia.ri_memreg_strategy == RPCRDMA_BOUNCEBUFFERS &&
440             (rtype != rpcrdma_noch || wtype != rpcrdma_noch)) {
441                 /* forced to "pure inline"? */
442                 dprintk("RPC:       %s: too much data (%d/%d) for inline\n",
443                         __func__, rqst->rq_rcv_buf.len, rqst->rq_snd_buf.len);
444                 return -1;
445         }
446
447         hdrlen = 28; /*sizeof *headerp;*/
448         padlen = 0;
449
450         /*
451          * Pull up any extra send data into the preregistered buffer.
452          * When padding is in use and applies to the transfer, insert
453          * it and change the message type.
454          */
455         if (rtype == rpcrdma_noch) {
456
457                 padlen = rpcrdma_inline_pullup(rqst,
458                                                 RPCRDMA_INLINE_PAD_VALUE(rqst));
459
460                 if (padlen) {
461                         headerp->rm_type = htonl(RDMA_MSGP);
462                         headerp->rm_body.rm_padded.rm_align =
463                                 htonl(RPCRDMA_INLINE_PAD_VALUE(rqst));
464                         headerp->rm_body.rm_padded.rm_thresh =
465                                 htonl(RPCRDMA_INLINE_PAD_THRESH);
466                         headerp->rm_body.rm_padded.rm_pempty[0] = xdr_zero;
467                         headerp->rm_body.rm_padded.rm_pempty[1] = xdr_zero;
468                         headerp->rm_body.rm_padded.rm_pempty[2] = xdr_zero;
469                         hdrlen += 2 * sizeof(u32); /* extra words in padhdr */
470                         BUG_ON(wtype != rpcrdma_noch);
471
472                 } else {
473                         headerp->rm_body.rm_nochunks.rm_empty[0] = xdr_zero;
474                         headerp->rm_body.rm_nochunks.rm_empty[1] = xdr_zero;
475                         headerp->rm_body.rm_nochunks.rm_empty[2] = xdr_zero;
476                         /* new length after pullup */
477                         rpclen = rqst->rq_svec[0].iov_len;
478                         /*
479                          * Currently we try to not actually use read inline.
480                          * Reply chunks have the desirable property that
481                          * they land, packed, directly in the target buffers
482                          * without headers, so they require no fixup. The
483                          * additional RDMA Write op sends the same amount
484                          * of data, streams on-the-wire and adds no overhead
485                          * on receive. Therefore, we request a reply chunk
486                          * for non-writes wherever feasible and efficient.
487                          */
488                         if (wtype == rpcrdma_noch &&
489                             r_xprt->rx_ia.ri_memreg_strategy > RPCRDMA_REGISTER)
490                                 wtype = rpcrdma_replych;
491                 }
492         }
493
494         /*
495          * Marshal chunks. This routine will return the header length
496          * consumed by marshaling.
497          */
498         if (rtype != rpcrdma_noch) {
499                 hdrlen = rpcrdma_create_chunks(rqst,
500                                         &rqst->rq_snd_buf, headerp, rtype);
501                 wtype = rtype;  /* simplify dprintk */
502
503         } else if (wtype != rpcrdma_noch) {
504                 hdrlen = rpcrdma_create_chunks(rqst,
505                                         &rqst->rq_rcv_buf, headerp, wtype);
506         }
507
508         if (hdrlen == 0)
509                 return -1;
510
511         dprintk("RPC:       %s: %s: hdrlen %zd rpclen %zd padlen %zd\n"
512                 "                   headerp 0x%p base 0x%p lkey 0x%x\n",
513                 __func__, transfertypes[wtype], hdrlen, rpclen, padlen,
514                 headerp, base, req->rl_iov.lkey);
515
516         /*
517          * initialize send_iov's - normally only two: rdma chunk header and
518          * single preregistered RPC header buffer, but if padding is present,
519          * then use a preregistered (and zeroed) pad buffer between the RPC
520          * header and any write data. In all non-rdma cases, any following
521          * data has been copied into the RPC header buffer.
522          */
523         req->rl_send_iov[0].addr = req->rl_iov.addr;
524         req->rl_send_iov[0].length = hdrlen;
525         req->rl_send_iov[0].lkey = req->rl_iov.lkey;
526
527         req->rl_send_iov[1].addr = req->rl_iov.addr + (base - req->rl_base);
528         req->rl_send_iov[1].length = rpclen;
529         req->rl_send_iov[1].lkey = req->rl_iov.lkey;
530
531         req->rl_niovs = 2;
532
533         if (padlen) {
534                 struct rpcrdma_ep *ep = &r_xprt->rx_ep;
535
536                 req->rl_send_iov[2].addr = ep->rep_pad.addr;
537                 req->rl_send_iov[2].length = padlen;
538                 req->rl_send_iov[2].lkey = ep->rep_pad.lkey;
539
540                 req->rl_send_iov[3].addr = req->rl_send_iov[1].addr + rpclen;
541                 req->rl_send_iov[3].length = rqst->rq_slen - rpclen;
542                 req->rl_send_iov[3].lkey = req->rl_iov.lkey;
543
544                 req->rl_niovs = 4;
545         }
546
547         return 0;
548 }
549
550 /*
551  * Chase down a received write or reply chunklist to get length
552  * RDMA'd by server. See map at rpcrdma_create_chunks()! :-)
553  */
554 static int
555 rpcrdma_count_chunks(struct rpcrdma_rep *rep, unsigned int max, int wrchunk, __be32 **iptrp)
556 {
557         unsigned int i, total_len;
558         struct rpcrdma_write_chunk *cur_wchunk;
559
560         i = ntohl(**iptrp);     /* get array count */
561         if (i > max)
562                 return -1;
563         cur_wchunk = (struct rpcrdma_write_chunk *) (*iptrp + 1);
564         total_len = 0;
565         while (i--) {
566                 struct rpcrdma_segment *seg = &cur_wchunk->wc_target;
567                 ifdebug(FACILITY) {
568                         u64 off;
569                         xdr_decode_hyper((__be32 *)&seg->rs_offset, &off);
570                         dprintk("RPC:       %s: chunk %d@0x%llx:0x%x\n",
571                                 __func__,
572                                 ntohl(seg->rs_length),
573                                 (unsigned long long)off,
574                                 ntohl(seg->rs_handle));
575                 }
576                 total_len += ntohl(seg->rs_length);
577                 ++cur_wchunk;
578         }
579         /* check and adjust for properly terminated write chunk */
580         if (wrchunk) {
581                 __be32 *w = (__be32 *) cur_wchunk;
582                 if (*w++ != xdr_zero)
583                         return -1;
584                 cur_wchunk = (struct rpcrdma_write_chunk *) w;
585         }
586         if ((char *) cur_wchunk > rep->rr_base + rep->rr_len)
587                 return -1;
588
589         *iptrp = (__be32 *) cur_wchunk;
590         return total_len;
591 }
592
593 /*
594  * Scatter inline received data back into provided iov's.
595  */
596 static void
597 rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len)
598 {
599         int i, npages, curlen, olen;
600         char *destp;
601
602         curlen = rqst->rq_rcv_buf.head[0].iov_len;
603         if (curlen > copy_len) {        /* write chunk header fixup */
604                 curlen = copy_len;
605                 rqst->rq_rcv_buf.head[0].iov_len = curlen;
606         }
607
608         dprintk("RPC:       %s: srcp 0x%p len %d hdrlen %d\n",
609                 __func__, srcp, copy_len, curlen);
610
611         /* Shift pointer for first receive segment only */
612         rqst->rq_rcv_buf.head[0].iov_base = srcp;
613         srcp += curlen;
614         copy_len -= curlen;
615
616         olen = copy_len;
617         i = 0;
618         rpcx_to_rdmax(rqst->rq_xprt)->rx_stats.fixup_copy_count += olen;
619         if (copy_len && rqst->rq_rcv_buf.page_len) {
620                 npages = PAGE_ALIGN(rqst->rq_rcv_buf.page_base +
621                         rqst->rq_rcv_buf.page_len) >> PAGE_SHIFT;
622                 for (; i < npages; i++) {
623                         if (i == 0)
624                                 curlen = PAGE_SIZE - rqst->rq_rcv_buf.page_base;
625                         else
626                                 curlen = PAGE_SIZE;
627                         if (curlen > copy_len)
628                                 curlen = copy_len;
629                         dprintk("RPC:       %s: page %d"
630                                 " srcp 0x%p len %d curlen %d\n",
631                                 __func__, i, srcp, copy_len, curlen);
632                         destp = kmap_atomic(rqst->rq_rcv_buf.pages[i],
633                                                 KM_SKB_SUNRPC_DATA);
634                         if (i == 0)
635                                 memcpy(destp + rqst->rq_rcv_buf.page_base,
636                                                 srcp, curlen);
637                         else
638                                 memcpy(destp, srcp, curlen);
639                         flush_dcache_page(rqst->rq_rcv_buf.pages[i]);
640                         kunmap_atomic(destp, KM_SKB_SUNRPC_DATA);
641                         srcp += curlen;
642                         copy_len -= curlen;
643                         if (copy_len == 0)
644                                 break;
645                 }
646                 rqst->rq_rcv_buf.page_len = olen - copy_len;
647         } else
648                 rqst->rq_rcv_buf.page_len = 0;
649
650         if (copy_len && rqst->rq_rcv_buf.tail[0].iov_len) {
651                 curlen = copy_len;
652                 if (curlen > rqst->rq_rcv_buf.tail[0].iov_len)
653                         curlen = rqst->rq_rcv_buf.tail[0].iov_len;
654                 if (rqst->rq_rcv_buf.tail[0].iov_base != srcp)
655                         memcpy(rqst->rq_rcv_buf.tail[0].iov_base, srcp, curlen);
656                 dprintk("RPC:       %s: tail srcp 0x%p len %d curlen %d\n",
657                         __func__, srcp, copy_len, curlen);
658                 rqst->rq_rcv_buf.tail[0].iov_len = curlen;
659                 copy_len -= curlen; ++i;
660         } else
661                 rqst->rq_rcv_buf.tail[0].iov_len = 0;
662
663         if (copy_len)
664                 dprintk("RPC:       %s: %d bytes in"
665                         " %d extra segments (%d lost)\n",
666                         __func__, olen, i, copy_len);
667
668         /* TBD avoid a warning from call_decode() */
669         rqst->rq_private_buf = rqst->rq_rcv_buf;
670 }
671
672 /*
673  * This function is called when an async event is posted to
674  * the connection which changes the connection state. All it
675  * does at this point is mark the connection up/down, the rpc
676  * timers do the rest.
677  */
678 void
679 rpcrdma_conn_func(struct rpcrdma_ep *ep)
680 {
681         struct rpc_xprt *xprt = ep->rep_xprt;
682
683         spin_lock_bh(&xprt->transport_lock);
684         if (ep->rep_connected > 0) {
685                 if (!xprt_test_and_set_connected(xprt))
686                         xprt_wake_pending_tasks(xprt, 0);
687         } else {
688                 if (xprt_test_and_clear_connected(xprt))
689                         xprt_wake_pending_tasks(xprt, ep->rep_connected);
690         }
691         spin_unlock_bh(&xprt->transport_lock);
692 }
693
694 /*
695  * This function is called when memory window unbind which we are waiting
696  * for completes. Just use rr_func (zeroed by upcall) to signal completion.
697  */
698 static void
699 rpcrdma_unbind_func(struct rpcrdma_rep *rep)
700 {
701         wake_up(&rep->rr_unbind);
702 }
703
704 /*
705  * Called as a tasklet to do req/reply match and complete a request
706  * Errors must result in the RPC task either being awakened, or
707  * allowed to timeout, to discover the errors at that time.
708  */
709 void
710 rpcrdma_reply_handler(struct rpcrdma_rep *rep)
711 {
712         struct rpcrdma_msg *headerp;
713         struct rpcrdma_req *req;
714         struct rpc_rqst *rqst;
715         struct rpc_xprt *xprt = rep->rr_xprt;
716         struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
717         __be32 *iptr;
718         int i, rdmalen, status;
719
720         /* Check status. If bad, signal disconnect and return rep to pool */
721         if (rep->rr_len == ~0U) {
722                 rpcrdma_recv_buffer_put(rep);
723                 if (r_xprt->rx_ep.rep_connected == 1) {
724                         r_xprt->rx_ep.rep_connected = -EIO;
725                         rpcrdma_conn_func(&r_xprt->rx_ep);
726                 }
727                 return;
728         }
729         if (rep->rr_len < 28) {
730                 dprintk("RPC:       %s: short/invalid reply\n", __func__);
731                 goto repost;
732         }
733         headerp = (struct rpcrdma_msg *) rep->rr_base;
734         if (headerp->rm_vers != xdr_one) {
735                 dprintk("RPC:       %s: invalid version %d\n",
736                         __func__, ntohl(headerp->rm_vers));
737                 goto repost;
738         }
739
740         /* Get XID and try for a match. */
741         spin_lock(&xprt->transport_lock);
742         rqst = xprt_lookup_rqst(xprt, headerp->rm_xid);
743         if (rqst == NULL) {
744                 spin_unlock(&xprt->transport_lock);
745                 dprintk("RPC:       %s: reply 0x%p failed "
746                         "to match any request xid 0x%08x len %d\n",
747                         __func__, rep, headerp->rm_xid, rep->rr_len);
748 repost:
749                 r_xprt->rx_stats.bad_reply_count++;
750                 rep->rr_func = rpcrdma_reply_handler;
751                 if (rpcrdma_ep_post_recv(&r_xprt->rx_ia, &r_xprt->rx_ep, rep))
752                         rpcrdma_recv_buffer_put(rep);
753
754                 return;
755         }
756
757         /* get request object */
758         req = rpcr_to_rdmar(rqst);
759
760         dprintk("RPC:       %s: reply 0x%p completes request 0x%p\n"
761                 "                   RPC request 0x%p xid 0x%08x\n",
762                         __func__, rep, req, rqst, headerp->rm_xid);
763
764         BUG_ON(!req || req->rl_reply);
765
766         /* from here on, the reply is no longer an orphan */
767         req->rl_reply = rep;
768
769         /* check for expected message types */
770         /* The order of some of these tests is important. */
771         switch (headerp->rm_type) {
772         case __constant_htonl(RDMA_MSG):
773                 /* never expect read chunks */
774                 /* never expect reply chunks (two ways to check) */
775                 /* never expect write chunks without having offered RDMA */
776                 if (headerp->rm_body.rm_chunks[0] != xdr_zero ||
777                     (headerp->rm_body.rm_chunks[1] == xdr_zero &&
778                      headerp->rm_body.rm_chunks[2] != xdr_zero) ||
779                     (headerp->rm_body.rm_chunks[1] != xdr_zero &&
780                      req->rl_nchunks == 0))
781                         goto badheader;
782                 if (headerp->rm_body.rm_chunks[1] != xdr_zero) {
783                         /* count any expected write chunks in read reply */
784                         /* start at write chunk array count */
785                         iptr = &headerp->rm_body.rm_chunks[2];
786                         rdmalen = rpcrdma_count_chunks(rep,
787                                                 req->rl_nchunks, 1, &iptr);
788                         /* check for validity, and no reply chunk after */
789                         if (rdmalen < 0 || *iptr++ != xdr_zero)
790                                 goto badheader;
791                         rep->rr_len -=
792                             ((unsigned char *)iptr - (unsigned char *)headerp);
793                         status = rep->rr_len + rdmalen;
794                         r_xprt->rx_stats.total_rdma_reply += rdmalen;
795                 } else {
796                         /* else ordinary inline */
797                         iptr = (__be32 *)((unsigned char *)headerp + 28);
798                         rep->rr_len -= 28; /*sizeof *headerp;*/
799                         status = rep->rr_len;
800                 }
801                 /* Fix up the rpc results for upper layer */
802                 rpcrdma_inline_fixup(rqst, (char *)iptr, rep->rr_len);
803                 break;
804
805         case __constant_htonl(RDMA_NOMSG):
806                 /* never expect read or write chunks, always reply chunks */
807                 if (headerp->rm_body.rm_chunks[0] != xdr_zero ||
808                     headerp->rm_body.rm_chunks[1] != xdr_zero ||
809                     headerp->rm_body.rm_chunks[2] != xdr_one ||
810                     req->rl_nchunks == 0)
811                         goto badheader;
812                 iptr = (__be32 *)((unsigned char *)headerp + 28);
813                 rdmalen = rpcrdma_count_chunks(rep, req->rl_nchunks, 0, &iptr);
814                 if (rdmalen < 0)
815                         goto badheader;
816                 r_xprt->rx_stats.total_rdma_reply += rdmalen;
817                 /* Reply chunk buffer already is the reply vector - no fixup. */
818                 status = rdmalen;
819                 break;
820
821 badheader:
822         default:
823                 dprintk("%s: invalid rpcrdma reply header (type %d):"
824                                 " chunks[012] == %d %d %d"
825                                 " expected chunks <= %d\n",
826                                 __func__, ntohl(headerp->rm_type),
827                                 headerp->rm_body.rm_chunks[0],
828                                 headerp->rm_body.rm_chunks[1],
829                                 headerp->rm_body.rm_chunks[2],
830                                 req->rl_nchunks);
831                 status = -EIO;
832                 r_xprt->rx_stats.bad_reply_count++;
833                 break;
834         }
835
836         /* If using mw bind, start the deregister process now. */
837         /* (Note: if mr_free(), cannot perform it here, in tasklet context) */
838         if (req->rl_nchunks) switch (r_xprt->rx_ia.ri_memreg_strategy) {
839         case RPCRDMA_MEMWINDOWS:
840                 for (i = 0; req->rl_nchunks-- > 1;)
841                         i += rpcrdma_deregister_external(
842                                 &req->rl_segments[i], r_xprt, NULL);
843                 /* Optionally wait (not here) for unbinds to complete */
844                 rep->rr_func = rpcrdma_unbind_func;
845                 (void) rpcrdma_deregister_external(&req->rl_segments[i],
846                                                    r_xprt, rep);
847                 break;
848         case RPCRDMA_MEMWINDOWS_ASYNC:
849                 for (i = 0; req->rl_nchunks--;)
850                         i += rpcrdma_deregister_external(&req->rl_segments[i],
851                                                          r_xprt, NULL);
852                 break;
853         default:
854                 break;
855         }
856
857         dprintk("RPC:       %s: xprt_complete_rqst(0x%p, 0x%p, %d)\n",
858                         __func__, xprt, rqst, status);
859         xprt_complete_rqst(rqst->rq_task, status);
860         spin_unlock(&xprt->transport_lock);
861 }