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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#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
53# define RPCDBG_FACILITY RPCDBG_TRANS
54#endif
55
56enum rpcrdma_chunktype {
57 rpcrdma_noch = 0,
58 rpcrdma_readch,
59 rpcrdma_areadch,
60 rpcrdma_writech,
61 rpcrdma_replych
62};
63
64#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
65static 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/* The client can send a request inline as long as the RPCRDMA header
75 * plus the RPC call fit under the transport's inline limit. If the
76 * combined call message size exceeds that limit, the client must use
77 * the read chunk list for this operation.
78 */
79static bool rpcrdma_args_inline(struct rpc_rqst *rqst)
80{
81 unsigned int callsize = RPCRDMA_HDRLEN_MIN + rqst->rq_snd_buf.len;
82
83 return callsize <= RPCRDMA_INLINE_WRITE_THRESHOLD(rqst);
84}
85
86/* The client can't know how large the actual reply will be. Thus it
87 * plans for the largest possible reply for that particular ULP
88 * operation. If the maximum combined reply message size exceeds that
89 * limit, the client must provide a write list or a reply chunk for
90 * this request.
91 */
92static bool rpcrdma_results_inline(struct rpc_rqst *rqst)
93{
94 unsigned int repsize = RPCRDMA_HDRLEN_MIN + rqst->rq_rcv_buf.buflen;
95
96 return repsize <= RPCRDMA_INLINE_READ_THRESHOLD(rqst);
97}
98
99static int
100rpcrdma_tail_pullup(struct xdr_buf *buf)
101{
102 size_t tlen = buf->tail[0].iov_len;
103 size_t skip = tlen & 3;
104
105 /* Do not include the tail if it is only an XDR pad */
106 if (tlen < 4)
107 return 0;
108
109 /* xdr_write_pages() adds a pad at the beginning of the tail
110 * if the content in "buf->pages" is unaligned. Force the
111 * tail's actual content to land at the next XDR position
112 * after the head instead.
113 */
114 if (skip) {
115 unsigned char *src, *dst;
116 unsigned int count;
117
118 src = buf->tail[0].iov_base;
119 dst = buf->head[0].iov_base;
120 dst += buf->head[0].iov_len;
121
122 src += skip;
123 tlen -= skip;
124
125 dprintk("RPC: %s: skip=%zu, memmove(%p, %p, %zu)\n",
126 __func__, skip, dst, src, tlen);
127
128 for (count = tlen; count; count--)
129 *dst++ = *src++;
130 }
131
132 return tlen;
133}
134
135/* Split "vec" on page boundaries into segments. FMR registers pages,
136 * not a byte range. Other modes coalesce these segments into a single
137 * MR when they can.
138 */
139static int
140rpcrdma_convert_kvec(struct kvec *vec, struct rpcrdma_mr_seg *seg,
141 int n, int nsegs)
142{
143 size_t page_offset;
144 u32 remaining;
145 char *base;
146
147 base = vec->iov_base;
148 page_offset = offset_in_page(base);
149 remaining = vec->iov_len;
150 while (remaining && n < nsegs) {
151 seg[n].mr_page = NULL;
152 seg[n].mr_offset = base;
153 seg[n].mr_len = min_t(u32, PAGE_SIZE - page_offset, remaining);
154 remaining -= seg[n].mr_len;
155 base += seg[n].mr_len;
156 ++n;
157 page_offset = 0;
158 }
159 return n;
160}
161
162/*
163 * Chunk assembly from upper layer xdr_buf.
164 *
165 * Prepare the passed-in xdr_buf into representation as RPC/RDMA chunk
166 * elements. Segments are then coalesced when registered, if possible
167 * within the selected memreg mode.
168 *
169 * Returns positive number of segments converted, or a negative errno.
170 */
171
172static int
173rpcrdma_convert_iovs(struct xdr_buf *xdrbuf, unsigned int pos,
174 enum rpcrdma_chunktype type, struct rpcrdma_mr_seg *seg, int nsegs)
175{
176 int len, n = 0, p;
177 int page_base;
178 struct page **ppages;
179
180 if (pos == 0) {
181 n = rpcrdma_convert_kvec(&xdrbuf->head[0], seg, n, nsegs);
182 if (n == nsegs)
183 return -EIO;
184 }
185
186 len = xdrbuf->page_len;
187 ppages = xdrbuf->pages + (xdrbuf->page_base >> PAGE_SHIFT);
188 page_base = xdrbuf->page_base & ~PAGE_MASK;
189 p = 0;
190 while (len && n < nsegs) {
191 if (!ppages[p]) {
192 /* alloc the pagelist for receiving buffer */
193 ppages[p] = alloc_page(GFP_ATOMIC);
194 if (!ppages[p])
195 return -ENOMEM;
196 }
197 seg[n].mr_page = ppages[p];
198 seg[n].mr_offset = (void *)(unsigned long) page_base;
199 seg[n].mr_len = min_t(u32, PAGE_SIZE - page_base, len);
200 if (seg[n].mr_len > PAGE_SIZE)
201 return -EIO;
202 len -= seg[n].mr_len;
203 ++n;
204 ++p;
205 page_base = 0; /* page offset only applies to first page */
206 }
207
208 /* Message overflows the seg array */
209 if (len && n == nsegs)
210 return -EIO;
211
212 /* When encoding the read list, the tail is always sent inline */
213 if (type == rpcrdma_readch)
214 return n;
215
216 if (xdrbuf->tail[0].iov_len) {
217 /* the rpcrdma protocol allows us to omit any trailing
218 * xdr pad bytes, saving the server an RDMA operation. */
219 if (xdrbuf->tail[0].iov_len < 4 && xprt_rdma_pad_optimize)
220 return n;
221 n = rpcrdma_convert_kvec(&xdrbuf->tail[0], seg, n, nsegs);
222 if (n == nsegs)
223 return -EIO;
224 }
225
226 return n;
227}
228
229/*
230 * Create read/write chunk lists, and reply chunks, for RDMA
231 *
232 * Assume check against THRESHOLD has been done, and chunks are required.
233 * Assume only encoding one list entry for read|write chunks. The NFSv3
234 * protocol is simple enough to allow this as it only has a single "bulk
235 * result" in each procedure - complicated NFSv4 COMPOUNDs are not. (The
236 * RDMA/Sessions NFSv4 proposal addresses this for future v4 revs.)
237 *
238 * When used for a single reply chunk (which is a special write
239 * chunk used for the entire reply, rather than just the data), it
240 * is used primarily for READDIR and READLINK which would otherwise
241 * be severely size-limited by a small rdma inline read max. The server
242 * response will come back as an RDMA Write, followed by a message
243 * of type RDMA_NOMSG carrying the xid and length. As a result, reply
244 * chunks do not provide data alignment, however they do not require
245 * "fixup" (moving the response to the upper layer buffer) either.
246 *
247 * Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
248 *
249 * Read chunklist (a linked list):
250 * N elements, position P (same P for all chunks of same arg!):
251 * 1 - PHLOO - 1 - PHLOO - ... - 1 - PHLOO - 0
252 *
253 * Write chunklist (a list of (one) counted array):
254 * N elements:
255 * 1 - N - HLOO - HLOO - ... - HLOO - 0
256 *
257 * Reply chunk (a counted array):
258 * N elements:
259 * 1 - N - HLOO - HLOO - ... - HLOO
260 *
261 * Returns positive RPC/RDMA header size, or negative errno.
262 */
263
264static ssize_t
265rpcrdma_create_chunks(struct rpc_rqst *rqst, struct xdr_buf *target,
266 struct rpcrdma_msg *headerp, enum rpcrdma_chunktype type)
267{
268 struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
269 struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(rqst->rq_xprt);
270 int n, nsegs, nchunks = 0;
271 unsigned int pos;
272 struct rpcrdma_mr_seg *seg = req->rl_segments;
273 struct rpcrdma_read_chunk *cur_rchunk = NULL;
274 struct rpcrdma_write_array *warray = NULL;
275 struct rpcrdma_write_chunk *cur_wchunk = NULL;
276 __be32 *iptr = headerp->rm_body.rm_chunks;
277 int (*map)(struct rpcrdma_xprt *, struct rpcrdma_mr_seg *, int, bool);
278
279 if (type == rpcrdma_readch || type == rpcrdma_areadch) {
280 /* a read chunk - server will RDMA Read our memory */
281 cur_rchunk = (struct rpcrdma_read_chunk *) iptr;
282 } else {
283 /* a write or reply chunk - server will RDMA Write our memory */
284 *iptr++ = xdr_zero; /* encode a NULL read chunk list */
285 if (type == rpcrdma_replych)
286 *iptr++ = xdr_zero; /* a NULL write chunk list */
287 warray = (struct rpcrdma_write_array *) iptr;
288 cur_wchunk = (struct rpcrdma_write_chunk *) (warray + 1);
289 }
290
291 if (type == rpcrdma_replych || type == rpcrdma_areadch)
292 pos = 0;
293 else
294 pos = target->head[0].iov_len;
295
296 nsegs = rpcrdma_convert_iovs(target, pos, type, seg, RPCRDMA_MAX_SEGS);
297 if (nsegs < 0)
298 return nsegs;
299
300 map = r_xprt->rx_ia.ri_ops->ro_map;
301 do {
302 n = map(r_xprt, seg, nsegs, cur_wchunk != NULL);
303 if (n <= 0)
304 goto out;
305 if (cur_rchunk) { /* read */
306 cur_rchunk->rc_discrim = xdr_one;
307 /* all read chunks have the same "position" */
308 cur_rchunk->rc_position = cpu_to_be32(pos);
309 cur_rchunk->rc_target.rs_handle =
310 cpu_to_be32(seg->mr_rkey);
311 cur_rchunk->rc_target.rs_length =
312 cpu_to_be32(seg->mr_len);
313 xdr_encode_hyper(
314 (__be32 *)&cur_rchunk->rc_target.rs_offset,
315 seg->mr_base);
316 dprintk("RPC: %s: read chunk "
317 "elem %d@0x%llx:0x%x pos %u (%s)\n", __func__,
318 seg->mr_len, (unsigned long long)seg->mr_base,
319 seg->mr_rkey, pos, n < nsegs ? "more" : "last");
320 cur_rchunk++;
321 r_xprt->rx_stats.read_chunk_count++;
322 } else { /* write/reply */
323 cur_wchunk->wc_target.rs_handle =
324 cpu_to_be32(seg->mr_rkey);
325 cur_wchunk->wc_target.rs_length =
326 cpu_to_be32(seg->mr_len);
327 xdr_encode_hyper(
328 (__be32 *)&cur_wchunk->wc_target.rs_offset,
329 seg->mr_base);
330 dprintk("RPC: %s: %s chunk "
331 "elem %d@0x%llx:0x%x (%s)\n", __func__,
332 (type == rpcrdma_replych) ? "reply" : "write",
333 seg->mr_len, (unsigned long long)seg->mr_base,
334 seg->mr_rkey, n < nsegs ? "more" : "last");
335 cur_wchunk++;
336 if (type == rpcrdma_replych)
337 r_xprt->rx_stats.reply_chunk_count++;
338 else
339 r_xprt->rx_stats.write_chunk_count++;
340 r_xprt->rx_stats.total_rdma_request += seg->mr_len;
341 }
342 nchunks++;
343 seg += n;
344 nsegs -= n;
345 } while (nsegs);
346
347 /* success. all failures return above */
348 req->rl_nchunks = nchunks;
349
350 /*
351 * finish off header. If write, marshal discrim and nchunks.
352 */
353 if (cur_rchunk) {
354 iptr = (__be32 *) cur_rchunk;
355 *iptr++ = xdr_zero; /* finish the read chunk list */
356 *iptr++ = xdr_zero; /* encode a NULL write chunk list */
357 *iptr++ = xdr_zero; /* encode a NULL reply chunk */
358 } else {
359 warray->wc_discrim = xdr_one;
360 warray->wc_nchunks = cpu_to_be32(nchunks);
361 iptr = (__be32 *) cur_wchunk;
362 if (type == rpcrdma_writech) {
363 *iptr++ = xdr_zero; /* finish the write chunk list */
364 *iptr++ = xdr_zero; /* encode a NULL reply chunk */
365 }
366 }
367
368 /*
369 * Return header size.
370 */
371 return (unsigned char *)iptr - (unsigned char *)headerp;
372
373out:
374 for (pos = 0; nchunks--;)
375 pos += r_xprt->rx_ia.ri_ops->ro_unmap(r_xprt,
376 &req->rl_segments[pos]);
377 return n;
378}
379
380/*
381 * Copy write data inline.
382 * This function is used for "small" requests. Data which is passed
383 * to RPC via iovecs (or page list) is copied directly into the
384 * pre-registered memory buffer for this request. For small amounts
385 * of data, this is efficient. The cutoff value is tunable.
386 */
387static void rpcrdma_inline_pullup(struct rpc_rqst *rqst)
388{
389 int i, npages, curlen;
390 int copy_len;
391 unsigned char *srcp, *destp;
392 struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(rqst->rq_xprt);
393 int page_base;
394 struct page **ppages;
395
396 destp = rqst->rq_svec[0].iov_base;
397 curlen = rqst->rq_svec[0].iov_len;
398 destp += curlen;
399
400 dprintk("RPC: %s: destp 0x%p len %d hdrlen %d\n",
401 __func__, destp, rqst->rq_slen, curlen);
402
403 copy_len = rqst->rq_snd_buf.page_len;
404
405 if (rqst->rq_snd_buf.tail[0].iov_len) {
406 curlen = rqst->rq_snd_buf.tail[0].iov_len;
407 if (destp + copy_len != rqst->rq_snd_buf.tail[0].iov_base) {
408 memmove(destp + copy_len,
409 rqst->rq_snd_buf.tail[0].iov_base, curlen);
410 r_xprt->rx_stats.pullup_copy_count += curlen;
411 }
412 dprintk("RPC: %s: tail destp 0x%p len %d\n",
413 __func__, destp + copy_len, curlen);
414 rqst->rq_svec[0].iov_len += curlen;
415 }
416 r_xprt->rx_stats.pullup_copy_count += copy_len;
417
418 page_base = rqst->rq_snd_buf.page_base;
419 ppages = rqst->rq_snd_buf.pages + (page_base >> PAGE_SHIFT);
420 page_base &= ~PAGE_MASK;
421 npages = PAGE_ALIGN(page_base+copy_len) >> PAGE_SHIFT;
422 for (i = 0; copy_len && i < npages; i++) {
423 curlen = PAGE_SIZE - page_base;
424 if (curlen > copy_len)
425 curlen = copy_len;
426 dprintk("RPC: %s: page %d destp 0x%p len %d curlen %d\n",
427 __func__, i, destp, copy_len, curlen);
428 srcp = kmap_atomic(ppages[i]);
429 memcpy(destp, srcp+page_base, curlen);
430 kunmap_atomic(srcp);
431 rqst->rq_svec[0].iov_len += curlen;
432 destp += curlen;
433 copy_len -= curlen;
434 page_base = 0;
435 }
436 /* header now contains entire send message */
437}
438
439/*
440 * Marshal a request: the primary job of this routine is to choose
441 * the transfer modes. See comments below.
442 *
443 * Uses multiple RDMA IOVs for a request:
444 * [0] -- RPC RDMA header, which uses memory from the *start* of the
445 * preregistered buffer that already holds the RPC data in
446 * its middle.
447 * [1] -- the RPC header/data, marshaled by RPC and the NFS protocol.
448 * [2] -- optional padding.
449 * [3] -- if padded, header only in [1] and data here.
450 *
451 * Returns zero on success, otherwise a negative errno.
452 */
453
454int
455rpcrdma_marshal_req(struct rpc_rqst *rqst)
456{
457 struct rpc_xprt *xprt = rqst->rq_xprt;
458 struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
459 struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
460 char *base;
461 size_t rpclen;
462 ssize_t hdrlen;
463 enum rpcrdma_chunktype rtype, wtype;
464 struct rpcrdma_msg *headerp;
465
466#if defined(CONFIG_SUNRPC_BACKCHANNEL)
467 if (test_bit(RPC_BC_PA_IN_USE, &rqst->rq_bc_pa_state))
468 return rpcrdma_bc_marshal_reply(rqst);
469#endif
470
471 /*
472 * rpclen gets amount of data in first buffer, which is the
473 * pre-registered buffer.
474 */
475 base = rqst->rq_svec[0].iov_base;
476 rpclen = rqst->rq_svec[0].iov_len;
477
478 headerp = rdmab_to_msg(req->rl_rdmabuf);
479 /* don't byte-swap XID, it's already done in request */
480 headerp->rm_xid = rqst->rq_xid;
481 headerp->rm_vers = rpcrdma_version;
482 headerp->rm_credit = cpu_to_be32(r_xprt->rx_buf.rb_max_requests);
483 headerp->rm_type = rdma_msg;
484
485 /*
486 * Chunks needed for results?
487 *
488 * o Read ops return data as write chunk(s), header as inline.
489 * o If the expected result is under the inline threshold, all ops
490 * return as inline.
491 * o Large non-read ops return as a single reply chunk.
492 */
493 if (rqst->rq_rcv_buf.flags & XDRBUF_READ)
494 wtype = rpcrdma_writech;
495 else if (rpcrdma_results_inline(rqst))
496 wtype = rpcrdma_noch;
497 else
498 wtype = rpcrdma_replych;
499
500 /*
501 * Chunks needed for arguments?
502 *
503 * o If the total request is under the inline threshold, all ops
504 * are sent as inline.
505 * o Large write ops transmit data as read chunk(s), header as
506 * inline.
507 * o Large non-write ops are sent with the entire message as a
508 * single read chunk (protocol 0-position special case).
509 *
510 * This assumes that the upper layer does not present a request
511 * that both has a data payload, and whose non-data arguments
512 * by themselves are larger than the inline threshold.
513 */
514 if (rpcrdma_args_inline(rqst)) {
515 rtype = rpcrdma_noch;
516 } else if (rqst->rq_snd_buf.flags & XDRBUF_WRITE) {
517 rtype = rpcrdma_readch;
518 } else {
519 r_xprt->rx_stats.nomsg_call_count++;
520 headerp->rm_type = htonl(RDMA_NOMSG);
521 rtype = rpcrdma_areadch;
522 rpclen = 0;
523 }
524
525 /* The following simplification is not true forever */
526 if (rtype != rpcrdma_noch && wtype == rpcrdma_replych)
527 wtype = rpcrdma_noch;
528 if (rtype != rpcrdma_noch && wtype != rpcrdma_noch) {
529 dprintk("RPC: %s: cannot marshal multiple chunk lists\n",
530 __func__);
531 return -EIO;
532 }
533
534 hdrlen = RPCRDMA_HDRLEN_MIN;
535
536 /*
537 * Pull up any extra send data into the preregistered buffer.
538 * When padding is in use and applies to the transfer, insert
539 * it and change the message type.
540 */
541 if (rtype == rpcrdma_noch) {
542
543 rpcrdma_inline_pullup(rqst);
544
545 headerp->rm_body.rm_nochunks.rm_empty[0] = xdr_zero;
546 headerp->rm_body.rm_nochunks.rm_empty[1] = xdr_zero;
547 headerp->rm_body.rm_nochunks.rm_empty[2] = xdr_zero;
548 /* new length after pullup */
549 rpclen = rqst->rq_svec[0].iov_len;
550 } else if (rtype == rpcrdma_readch)
551 rpclen += rpcrdma_tail_pullup(&rqst->rq_snd_buf);
552 if (rtype != rpcrdma_noch) {
553 hdrlen = rpcrdma_create_chunks(rqst, &rqst->rq_snd_buf,
554 headerp, rtype);
555 wtype = rtype; /* simplify dprintk */
556
557 } else if (wtype != rpcrdma_noch) {
558 hdrlen = rpcrdma_create_chunks(rqst, &rqst->rq_rcv_buf,
559 headerp, wtype);
560 }
561 if (hdrlen < 0)
562 return hdrlen;
563
564 dprintk("RPC: %s: %s: hdrlen %zd rpclen %zd"
565 " headerp 0x%p base 0x%p lkey 0x%x\n",
566 __func__, transfertypes[wtype], hdrlen, rpclen,
567 headerp, base, rdmab_lkey(req->rl_rdmabuf));
568
569 /*
570 * initialize send_iov's - normally only two: rdma chunk header and
571 * single preregistered RPC header buffer, but if padding is present,
572 * then use a preregistered (and zeroed) pad buffer between the RPC
573 * header and any write data. In all non-rdma cases, any following
574 * data has been copied into the RPC header buffer.
575 */
576 req->rl_send_iov[0].addr = rdmab_addr(req->rl_rdmabuf);
577 req->rl_send_iov[0].length = hdrlen;
578 req->rl_send_iov[0].lkey = rdmab_lkey(req->rl_rdmabuf);
579
580 req->rl_niovs = 1;
581 if (rtype == rpcrdma_areadch)
582 return 0;
583
584 req->rl_send_iov[1].addr = rdmab_addr(req->rl_sendbuf);
585 req->rl_send_iov[1].length = rpclen;
586 req->rl_send_iov[1].lkey = rdmab_lkey(req->rl_sendbuf);
587
588 req->rl_niovs = 2;
589 return 0;
590}
591
592/*
593 * Chase down a received write or reply chunklist to get length
594 * RDMA'd by server. See map at rpcrdma_create_chunks()! :-)
595 */
596static int
597rpcrdma_count_chunks(struct rpcrdma_rep *rep, unsigned int max, int wrchunk, __be32 **iptrp)
598{
599 unsigned int i, total_len;
600 struct rpcrdma_write_chunk *cur_wchunk;
601 char *base = (char *)rdmab_to_msg(rep->rr_rdmabuf);
602
603 i = be32_to_cpu(**iptrp);
604 if (i > max)
605 return -1;
606 cur_wchunk = (struct rpcrdma_write_chunk *) (*iptrp + 1);
607 total_len = 0;
608 while (i--) {
609 struct rpcrdma_segment *seg = &cur_wchunk->wc_target;
610 ifdebug(FACILITY) {
611 u64 off;
612 xdr_decode_hyper((__be32 *)&seg->rs_offset, &off);
613 dprintk("RPC: %s: chunk %d@0x%llx:0x%x\n",
614 __func__,
615 be32_to_cpu(seg->rs_length),
616 (unsigned long long)off,
617 be32_to_cpu(seg->rs_handle));
618 }
619 total_len += be32_to_cpu(seg->rs_length);
620 ++cur_wchunk;
621 }
622 /* check and adjust for properly terminated write chunk */
623 if (wrchunk) {
624 __be32 *w = (__be32 *) cur_wchunk;
625 if (*w++ != xdr_zero)
626 return -1;
627 cur_wchunk = (struct rpcrdma_write_chunk *) w;
628 }
629 if ((char *)cur_wchunk > base + rep->rr_len)
630 return -1;
631
632 *iptrp = (__be32 *) cur_wchunk;
633 return total_len;
634}
635
636/*
637 * Scatter inline received data back into provided iov's.
638 */
639static void
640rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad)
641{
642 int i, npages, curlen, olen;
643 char *destp;
644 struct page **ppages;
645 int page_base;
646
647 curlen = rqst->rq_rcv_buf.head[0].iov_len;
648 if (curlen > copy_len) { /* write chunk header fixup */
649 curlen = copy_len;
650 rqst->rq_rcv_buf.head[0].iov_len = curlen;
651 }
652
653 dprintk("RPC: %s: srcp 0x%p len %d hdrlen %d\n",
654 __func__, srcp, copy_len, curlen);
655
656 /* Shift pointer for first receive segment only */
657 rqst->rq_rcv_buf.head[0].iov_base = srcp;
658 srcp += curlen;
659 copy_len -= curlen;
660
661 olen = copy_len;
662 i = 0;
663 rpcx_to_rdmax(rqst->rq_xprt)->rx_stats.fixup_copy_count += olen;
664 page_base = rqst->rq_rcv_buf.page_base;
665 ppages = rqst->rq_rcv_buf.pages + (page_base >> PAGE_SHIFT);
666 page_base &= ~PAGE_MASK;
667
668 if (copy_len && rqst->rq_rcv_buf.page_len) {
669 npages = PAGE_ALIGN(page_base +
670 rqst->rq_rcv_buf.page_len) >> PAGE_SHIFT;
671 for (; i < npages; i++) {
672 curlen = PAGE_SIZE - page_base;
673 if (curlen > copy_len)
674 curlen = copy_len;
675 dprintk("RPC: %s: page %d"
676 " srcp 0x%p len %d curlen %d\n",
677 __func__, i, srcp, copy_len, curlen);
678 destp = kmap_atomic(ppages[i]);
679 memcpy(destp + page_base, srcp, curlen);
680 flush_dcache_page(ppages[i]);
681 kunmap_atomic(destp);
682 srcp += curlen;
683 copy_len -= curlen;
684 if (copy_len == 0)
685 break;
686 page_base = 0;
687 }
688 }
689
690 if (copy_len && rqst->rq_rcv_buf.tail[0].iov_len) {
691 curlen = copy_len;
692 if (curlen > rqst->rq_rcv_buf.tail[0].iov_len)
693 curlen = rqst->rq_rcv_buf.tail[0].iov_len;
694 if (rqst->rq_rcv_buf.tail[0].iov_base != srcp)
695 memmove(rqst->rq_rcv_buf.tail[0].iov_base, srcp, curlen);
696 dprintk("RPC: %s: tail srcp 0x%p len %d curlen %d\n",
697 __func__, srcp, copy_len, curlen);
698 rqst->rq_rcv_buf.tail[0].iov_len = curlen;
699 copy_len -= curlen; ++i;
700 } else
701 rqst->rq_rcv_buf.tail[0].iov_len = 0;
702
703 if (pad) {
704 /* implicit padding on terminal chunk */
705 unsigned char *p = rqst->rq_rcv_buf.tail[0].iov_base;
706 while (pad--)
707 p[rqst->rq_rcv_buf.tail[0].iov_len++] = 0;
708 }
709
710 if (copy_len)
711 dprintk("RPC: %s: %d bytes in"
712 " %d extra segments (%d lost)\n",
713 __func__, olen, i, copy_len);
714
715 /* TBD avoid a warning from call_decode() */
716 rqst->rq_private_buf = rqst->rq_rcv_buf;
717}
718
719void
720rpcrdma_connect_worker(struct work_struct *work)
721{
722 struct rpcrdma_ep *ep =
723 container_of(work, struct rpcrdma_ep, rep_connect_worker.work);
724 struct rpcrdma_xprt *r_xprt =
725 container_of(ep, struct rpcrdma_xprt, rx_ep);
726 struct rpc_xprt *xprt = &r_xprt->rx_xprt;
727
728 spin_lock_bh(&xprt->transport_lock);
729 if (++xprt->connect_cookie == 0) /* maintain a reserved value */
730 ++xprt->connect_cookie;
731 if (ep->rep_connected > 0) {
732 if (!xprt_test_and_set_connected(xprt))
733 xprt_wake_pending_tasks(xprt, 0);
734 } else {
735 if (xprt_test_and_clear_connected(xprt))
736 xprt_wake_pending_tasks(xprt, -ENOTCONN);
737 }
738 spin_unlock_bh(&xprt->transport_lock);
739}
740
741#if defined(CONFIG_SUNRPC_BACKCHANNEL)
742/* By convention, backchannel calls arrive via rdma_msg type
743 * messages, and never populate the chunk lists. This makes
744 * the RPC/RDMA header small and fixed in size, so it is
745 * straightforward to check the RPC header's direction field.
746 */
747static bool
748rpcrdma_is_bcall(struct rpcrdma_msg *headerp)
749{
750 __be32 *p = (__be32 *)headerp;
751
752 if (headerp->rm_type != rdma_msg)
753 return false;
754 if (headerp->rm_body.rm_chunks[0] != xdr_zero)
755 return false;
756 if (headerp->rm_body.rm_chunks[1] != xdr_zero)
757 return false;
758 if (headerp->rm_body.rm_chunks[2] != xdr_zero)
759 return false;
760
761 /* sanity */
762 if (p[7] != headerp->rm_xid)
763 return false;
764 /* call direction */
765 if (p[8] != cpu_to_be32(RPC_CALL))
766 return false;
767
768 return true;
769}
770#endif /* CONFIG_SUNRPC_BACKCHANNEL */
771
772/*
773 * This function is called when an async event is posted to
774 * the connection which changes the connection state. All it
775 * does at this point is mark the connection up/down, the rpc
776 * timers do the rest.
777 */
778void
779rpcrdma_conn_func(struct rpcrdma_ep *ep)
780{
781 schedule_delayed_work(&ep->rep_connect_worker, 0);
782}
783
784/* Process received RPC/RDMA messages.
785 *
786 * Errors must result in the RPC task either being awakened, or
787 * allowed to timeout, to discover the errors at that time.
788 */
789void
790rpcrdma_reply_handler(struct rpcrdma_rep *rep)
791{
792 struct rpcrdma_msg *headerp;
793 struct rpcrdma_req *req;
794 struct rpc_rqst *rqst;
795 struct rpcrdma_xprt *r_xprt = rep->rr_rxprt;
796 struct rpc_xprt *xprt = &r_xprt->rx_xprt;
797 __be32 *iptr;
798 int rdmalen, status, rmerr;
799 unsigned long cwnd;
800
801 dprintk("RPC: %s: incoming rep %p\n", __func__, rep);
802
803 if (rep->rr_len == RPCRDMA_BAD_LEN)
804 goto out_badstatus;
805 if (rep->rr_len < RPCRDMA_HDRLEN_ERR)
806 goto out_shortreply;
807
808 headerp = rdmab_to_msg(rep->rr_rdmabuf);
809#if defined(CONFIG_SUNRPC_BACKCHANNEL)
810 if (rpcrdma_is_bcall(headerp))
811 goto out_bcall;
812#endif
813
814 /* Match incoming rpcrdma_rep to an rpcrdma_req to
815 * get context for handling any incoming chunks.
816 */
817 spin_lock_bh(&xprt->transport_lock);
818 rqst = xprt_lookup_rqst(xprt, headerp->rm_xid);
819 if (!rqst)
820 goto out_nomatch;
821
822 req = rpcr_to_rdmar(rqst);
823 if (req->rl_reply)
824 goto out_duplicate;
825
826 /* Sanity checking has passed. We are now committed
827 * to complete this transaction.
828 */
829 list_del_init(&rqst->rq_list);
830 spin_unlock_bh(&xprt->transport_lock);
831 dprintk("RPC: %s: reply %p completes request %p (xid 0x%08x)\n",
832 __func__, rep, req, be32_to_cpu(headerp->rm_xid));
833
834 /* from here on, the reply is no longer an orphan */
835 req->rl_reply = rep;
836 xprt->reestablish_timeout = 0;
837
838 if (headerp->rm_vers != rpcrdma_version)
839 goto out_badversion;
840
841 /* check for expected message types */
842 /* The order of some of these tests is important. */
843 switch (headerp->rm_type) {
844 case rdma_msg:
845 /* never expect read chunks */
846 /* never expect reply chunks (two ways to check) */
847 /* never expect write chunks without having offered RDMA */
848 if (headerp->rm_body.rm_chunks[0] != xdr_zero ||
849 (headerp->rm_body.rm_chunks[1] == xdr_zero &&
850 headerp->rm_body.rm_chunks[2] != xdr_zero) ||
851 (headerp->rm_body.rm_chunks[1] != xdr_zero &&
852 req->rl_nchunks == 0))
853 goto badheader;
854 if (headerp->rm_body.rm_chunks[1] != xdr_zero) {
855 /* count any expected write chunks in read reply */
856 /* start at write chunk array count */
857 iptr = &headerp->rm_body.rm_chunks[2];
858 rdmalen = rpcrdma_count_chunks(rep,
859 req->rl_nchunks, 1, &iptr);
860 /* check for validity, and no reply chunk after */
861 if (rdmalen < 0 || *iptr++ != xdr_zero)
862 goto badheader;
863 rep->rr_len -=
864 ((unsigned char *)iptr - (unsigned char *)headerp);
865 status = rep->rr_len + rdmalen;
866 r_xprt->rx_stats.total_rdma_reply += rdmalen;
867 /* special case - last chunk may omit padding */
868 if (rdmalen &= 3) {
869 rdmalen = 4 - rdmalen;
870 status += rdmalen;
871 }
872 } else {
873 /* else ordinary inline */
874 rdmalen = 0;
875 iptr = (__be32 *)((unsigned char *)headerp +
876 RPCRDMA_HDRLEN_MIN);
877 rep->rr_len -= RPCRDMA_HDRLEN_MIN;
878 status = rep->rr_len;
879 }
880 /* Fix up the rpc results for upper layer */
881 rpcrdma_inline_fixup(rqst, (char *)iptr, rep->rr_len, rdmalen);
882 break;
883
884 case rdma_nomsg:
885 /* never expect read or write chunks, always reply chunks */
886 if (headerp->rm_body.rm_chunks[0] != xdr_zero ||
887 headerp->rm_body.rm_chunks[1] != xdr_zero ||
888 headerp->rm_body.rm_chunks[2] != xdr_one ||
889 req->rl_nchunks == 0)
890 goto badheader;
891 iptr = (__be32 *)((unsigned char *)headerp +
892 RPCRDMA_HDRLEN_MIN);
893 rdmalen = rpcrdma_count_chunks(rep, req->rl_nchunks, 0, &iptr);
894 if (rdmalen < 0)
895 goto badheader;
896 r_xprt->rx_stats.total_rdma_reply += rdmalen;
897 /* Reply chunk buffer already is the reply vector - no fixup. */
898 status = rdmalen;
899 break;
900
901 case rdma_error:
902 goto out_rdmaerr;
903
904badheader:
905 default:
906 dprintk("%s: invalid rpcrdma reply header (type %d):"
907 " chunks[012] == %d %d %d"
908 " expected chunks <= %d\n",
909 __func__, be32_to_cpu(headerp->rm_type),
910 headerp->rm_body.rm_chunks[0],
911 headerp->rm_body.rm_chunks[1],
912 headerp->rm_body.rm_chunks[2],
913 req->rl_nchunks);
914 status = -EIO;
915 r_xprt->rx_stats.bad_reply_count++;
916 break;
917 }
918
919out:
920 /* Invalidate and flush the data payloads before waking the
921 * waiting application. This guarantees the memory region is
922 * properly fenced from the server before the application
923 * accesses the data. It also ensures proper send flow
924 * control: waking the next RPC waits until this RPC has
925 * relinquished all its Send Queue entries.
926 */
927 if (req->rl_nchunks)
928 r_xprt->rx_ia.ri_ops->ro_unmap_sync(r_xprt, req);
929
930 spin_lock_bh(&xprt->transport_lock);
931 cwnd = xprt->cwnd;
932 xprt->cwnd = atomic_read(&r_xprt->rx_buf.rb_credits) << RPC_CWNDSHIFT;
933 if (xprt->cwnd > cwnd)
934 xprt_release_rqst_cong(rqst->rq_task);
935
936 xprt_complete_rqst(rqst->rq_task, status);
937 spin_unlock_bh(&xprt->transport_lock);
938 dprintk("RPC: %s: xprt_complete_rqst(0x%p, 0x%p, %d)\n",
939 __func__, xprt, rqst, status);
940 return;
941
942out_badstatus:
943 rpcrdma_recv_buffer_put(rep);
944 if (r_xprt->rx_ep.rep_connected == 1) {
945 r_xprt->rx_ep.rep_connected = -EIO;
946 rpcrdma_conn_func(&r_xprt->rx_ep);
947 }
948 return;
949
950#if defined(CONFIG_SUNRPC_BACKCHANNEL)
951out_bcall:
952 rpcrdma_bc_receive_call(r_xprt, rep);
953 return;
954#endif
955
956/* If the incoming reply terminated a pending RPC, the next
957 * RPC call will post a replacement receive buffer as it is
958 * being marshaled.
959 */
960out_badversion:
961 dprintk("RPC: %s: invalid version %d\n",
962 __func__, be32_to_cpu(headerp->rm_vers));
963 status = -EIO;
964 r_xprt->rx_stats.bad_reply_count++;
965 goto out;
966
967out_rdmaerr:
968 rmerr = be32_to_cpu(headerp->rm_body.rm_error.rm_err);
969 switch (rmerr) {
970 case ERR_VERS:
971 pr_err("%s: server reports header version error (%u-%u)\n",
972 __func__,
973 be32_to_cpu(headerp->rm_body.rm_error.rm_vers_low),
974 be32_to_cpu(headerp->rm_body.rm_error.rm_vers_high));
975 break;
976 case ERR_CHUNK:
977 pr_err("%s: server reports header decoding error\n",
978 __func__);
979 break;
980 default:
981 pr_err("%s: server reports unknown error %d\n",
982 __func__, rmerr);
983 }
984 status = -EREMOTEIO;
985 r_xprt->rx_stats.bad_reply_count++;
986 goto out;
987
988/* If no pending RPC transaction was matched, post a replacement
989 * receive buffer before returning.
990 */
991out_shortreply:
992 dprintk("RPC: %s: short/invalid reply\n", __func__);
993 goto repost;
994
995out_nomatch:
996 spin_unlock_bh(&xprt->transport_lock);
997 dprintk("RPC: %s: no match for incoming xid 0x%08x len %d\n",
998 __func__, be32_to_cpu(headerp->rm_xid),
999 rep->rr_len);
1000 goto repost;
1001
1002out_duplicate:
1003 spin_unlock_bh(&xprt->transport_lock);
1004 dprintk("RPC: %s: "
1005 "duplicate reply %p to RPC request %p: xid 0x%08x\n",
1006 __func__, rep, req, be32_to_cpu(headerp->rm_xid));
1007
1008repost:
1009 r_xprt->rx_stats.bad_reply_count++;
1010 if (rpcrdma_ep_post_recv(&r_xprt->rx_ia, &r_xprt->rx_ep, rep))
1011 rpcrdma_recv_buffer_put(rep);
1012}
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#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
53# define RPCDBG_FACILITY RPCDBG_TRANS
54#endif
55
56static const char transfertypes[][12] = {
57 "inline", /* no chunks */
58 "read list", /* some argument via rdma read */
59 "*read list", /* entire request via rdma read */
60 "write list", /* some result via rdma write */
61 "reply chunk" /* entire reply via rdma write */
62};
63
64/* Returns size of largest RPC-over-RDMA header in a Call message
65 *
66 * The largest Call header contains a full-size Read list and a
67 * minimal Reply chunk.
68 */
69static unsigned int rpcrdma_max_call_header_size(unsigned int maxsegs)
70{
71 unsigned int size;
72
73 /* Fixed header fields and list discriminators */
74 size = RPCRDMA_HDRLEN_MIN;
75
76 /* Maximum Read list size */
77 maxsegs += 2; /* segment for head and tail buffers */
78 size = maxsegs * sizeof(struct rpcrdma_read_chunk);
79
80 /* Minimal Read chunk size */
81 size += sizeof(__be32); /* segment count */
82 size += sizeof(struct rpcrdma_segment);
83 size += sizeof(__be32); /* list discriminator */
84
85 dprintk("RPC: %s: max call header size = %u\n",
86 __func__, size);
87 return size;
88}
89
90/* Returns size of largest RPC-over-RDMA header in a Reply message
91 *
92 * There is only one Write list or one Reply chunk per Reply
93 * message. The larger list is the Write list.
94 */
95static unsigned int rpcrdma_max_reply_header_size(unsigned int maxsegs)
96{
97 unsigned int size;
98
99 /* Fixed header fields and list discriminators */
100 size = RPCRDMA_HDRLEN_MIN;
101
102 /* Maximum Write list size */
103 maxsegs += 2; /* segment for head and tail buffers */
104 size = sizeof(__be32); /* segment count */
105 size += maxsegs * sizeof(struct rpcrdma_segment);
106 size += sizeof(__be32); /* list discriminator */
107
108 dprintk("RPC: %s: max reply header size = %u\n",
109 __func__, size);
110 return size;
111}
112
113void rpcrdma_set_max_header_sizes(struct rpcrdma_xprt *r_xprt)
114{
115 struct rpcrdma_create_data_internal *cdata = &r_xprt->rx_data;
116 struct rpcrdma_ia *ia = &r_xprt->rx_ia;
117 unsigned int maxsegs = ia->ri_max_segs;
118
119 ia->ri_max_inline_write = cdata->inline_wsize -
120 rpcrdma_max_call_header_size(maxsegs);
121 ia->ri_max_inline_read = cdata->inline_rsize -
122 rpcrdma_max_reply_header_size(maxsegs);
123}
124
125/* The client can send a request inline as long as the RPCRDMA header
126 * plus the RPC call fit under the transport's inline limit. If the
127 * combined call message size exceeds that limit, the client must use
128 * a Read chunk for this operation.
129 *
130 * A Read chunk is also required if sending the RPC call inline would
131 * exceed this device's max_sge limit.
132 */
133static bool rpcrdma_args_inline(struct rpcrdma_xprt *r_xprt,
134 struct rpc_rqst *rqst)
135{
136 struct xdr_buf *xdr = &rqst->rq_snd_buf;
137 unsigned int count, remaining, offset;
138
139 if (xdr->len > r_xprt->rx_ia.ri_max_inline_write)
140 return false;
141
142 if (xdr->page_len) {
143 remaining = xdr->page_len;
144 offset = xdr->page_base & ~PAGE_MASK;
145 count = 0;
146 while (remaining) {
147 remaining -= min_t(unsigned int,
148 PAGE_SIZE - offset, remaining);
149 offset = 0;
150 if (++count > r_xprt->rx_ia.ri_max_send_sges)
151 return false;
152 }
153 }
154
155 return true;
156}
157
158/* The client can't know how large the actual reply will be. Thus it
159 * plans for the largest possible reply for that particular ULP
160 * operation. If the maximum combined reply message size exceeds that
161 * limit, the client must provide a write list or a reply chunk for
162 * this request.
163 */
164static bool rpcrdma_results_inline(struct rpcrdma_xprt *r_xprt,
165 struct rpc_rqst *rqst)
166{
167 struct rpcrdma_ia *ia = &r_xprt->rx_ia;
168
169 return rqst->rq_rcv_buf.buflen <= ia->ri_max_inline_read;
170}
171
172/* Split "vec" on page boundaries into segments. FMR registers pages,
173 * not a byte range. Other modes coalesce these segments into a single
174 * MR when they can.
175 */
176static int
177rpcrdma_convert_kvec(struct kvec *vec, struct rpcrdma_mr_seg *seg, int n)
178{
179 size_t page_offset;
180 u32 remaining;
181 char *base;
182
183 base = vec->iov_base;
184 page_offset = offset_in_page(base);
185 remaining = vec->iov_len;
186 while (remaining && n < RPCRDMA_MAX_SEGS) {
187 seg[n].mr_page = NULL;
188 seg[n].mr_offset = base;
189 seg[n].mr_len = min_t(u32, PAGE_SIZE - page_offset, remaining);
190 remaining -= seg[n].mr_len;
191 base += seg[n].mr_len;
192 ++n;
193 page_offset = 0;
194 }
195 return n;
196}
197
198/*
199 * Chunk assembly from upper layer xdr_buf.
200 *
201 * Prepare the passed-in xdr_buf into representation as RPC/RDMA chunk
202 * elements. Segments are then coalesced when registered, if possible
203 * within the selected memreg mode.
204 *
205 * Returns positive number of segments converted, or a negative errno.
206 */
207
208static int
209rpcrdma_convert_iovs(struct rpcrdma_xprt *r_xprt, struct xdr_buf *xdrbuf,
210 unsigned int pos, enum rpcrdma_chunktype type,
211 struct rpcrdma_mr_seg *seg)
212{
213 int len, n, p, page_base;
214 struct page **ppages;
215
216 n = 0;
217 if (pos == 0) {
218 n = rpcrdma_convert_kvec(&xdrbuf->head[0], seg, n);
219 if (n == RPCRDMA_MAX_SEGS)
220 goto out_overflow;
221 }
222
223 len = xdrbuf->page_len;
224 ppages = xdrbuf->pages + (xdrbuf->page_base >> PAGE_SHIFT);
225 page_base = xdrbuf->page_base & ~PAGE_MASK;
226 p = 0;
227 while (len && n < RPCRDMA_MAX_SEGS) {
228 if (!ppages[p]) {
229 /* alloc the pagelist for receiving buffer */
230 ppages[p] = alloc_page(GFP_ATOMIC);
231 if (!ppages[p])
232 return -EAGAIN;
233 }
234 seg[n].mr_page = ppages[p];
235 seg[n].mr_offset = (void *)(unsigned long) page_base;
236 seg[n].mr_len = min_t(u32, PAGE_SIZE - page_base, len);
237 if (seg[n].mr_len > PAGE_SIZE)
238 goto out_overflow;
239 len -= seg[n].mr_len;
240 ++n;
241 ++p;
242 page_base = 0; /* page offset only applies to first page */
243 }
244
245 /* Message overflows the seg array */
246 if (len && n == RPCRDMA_MAX_SEGS)
247 goto out_overflow;
248
249 /* When encoding a Read chunk, the tail iovec contains an
250 * XDR pad and may be omitted.
251 */
252 if (type == rpcrdma_readch && r_xprt->rx_ia.ri_implicit_roundup)
253 return n;
254
255 /* When encoding a Write chunk, some servers need to see an
256 * extra segment for non-XDR-aligned Write chunks. The upper
257 * layer provides space in the tail iovec that may be used
258 * for this purpose.
259 */
260 if (type == rpcrdma_writech && r_xprt->rx_ia.ri_implicit_roundup)
261 return n;
262
263 if (xdrbuf->tail[0].iov_len) {
264 n = rpcrdma_convert_kvec(&xdrbuf->tail[0], seg, n);
265 if (n == RPCRDMA_MAX_SEGS)
266 goto out_overflow;
267 }
268
269 return n;
270
271out_overflow:
272 pr_err("rpcrdma: segment array overflow\n");
273 return -EIO;
274}
275
276static inline __be32 *
277xdr_encode_rdma_segment(__be32 *iptr, struct rpcrdma_mw *mw)
278{
279 *iptr++ = cpu_to_be32(mw->mw_handle);
280 *iptr++ = cpu_to_be32(mw->mw_length);
281 return xdr_encode_hyper(iptr, mw->mw_offset);
282}
283
284/* XDR-encode the Read list. Supports encoding a list of read
285 * segments that belong to a single read chunk.
286 *
287 * Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
288 *
289 * Read chunklist (a linked list):
290 * N elements, position P (same P for all chunks of same arg!):
291 * 1 - PHLOO - 1 - PHLOO - ... - 1 - PHLOO - 0
292 *
293 * Returns a pointer to the XDR word in the RDMA header following
294 * the end of the Read list, or an error pointer.
295 */
296static __be32 *
297rpcrdma_encode_read_list(struct rpcrdma_xprt *r_xprt,
298 struct rpcrdma_req *req, struct rpc_rqst *rqst,
299 __be32 *iptr, enum rpcrdma_chunktype rtype)
300{
301 struct rpcrdma_mr_seg *seg;
302 struct rpcrdma_mw *mw;
303 unsigned int pos;
304 int n, nsegs;
305
306 if (rtype == rpcrdma_noch) {
307 *iptr++ = xdr_zero; /* item not present */
308 return iptr;
309 }
310
311 pos = rqst->rq_snd_buf.head[0].iov_len;
312 if (rtype == rpcrdma_areadch)
313 pos = 0;
314 seg = req->rl_segments;
315 nsegs = rpcrdma_convert_iovs(r_xprt, &rqst->rq_snd_buf, pos,
316 rtype, seg);
317 if (nsegs < 0)
318 return ERR_PTR(nsegs);
319
320 do {
321 n = r_xprt->rx_ia.ri_ops->ro_map(r_xprt, seg, nsegs,
322 false, &mw);
323 if (n < 0)
324 return ERR_PTR(n);
325 list_add(&mw->mw_list, &req->rl_registered);
326
327 *iptr++ = xdr_one; /* item present */
328
329 /* All read segments in this chunk
330 * have the same "position".
331 */
332 *iptr++ = cpu_to_be32(pos);
333 iptr = xdr_encode_rdma_segment(iptr, mw);
334
335 dprintk("RPC: %5u %s: pos %u %u@0x%016llx:0x%08x (%s)\n",
336 rqst->rq_task->tk_pid, __func__, pos,
337 mw->mw_length, (unsigned long long)mw->mw_offset,
338 mw->mw_handle, n < nsegs ? "more" : "last");
339
340 r_xprt->rx_stats.read_chunk_count++;
341 seg += n;
342 nsegs -= n;
343 } while (nsegs);
344
345 /* Finish Read list */
346 *iptr++ = xdr_zero; /* Next item not present */
347 return iptr;
348}
349
350/* XDR-encode the Write list. Supports encoding a list containing
351 * one array of plain segments that belong to a single write chunk.
352 *
353 * Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
354 *
355 * Write chunklist (a list of (one) counted array):
356 * N elements:
357 * 1 - N - HLOO - HLOO - ... - HLOO - 0
358 *
359 * Returns a pointer to the XDR word in the RDMA header following
360 * the end of the Write list, or an error pointer.
361 */
362static __be32 *
363rpcrdma_encode_write_list(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req,
364 struct rpc_rqst *rqst, __be32 *iptr,
365 enum rpcrdma_chunktype wtype)
366{
367 struct rpcrdma_mr_seg *seg;
368 struct rpcrdma_mw *mw;
369 int n, nsegs, nchunks;
370 __be32 *segcount;
371
372 if (wtype != rpcrdma_writech) {
373 *iptr++ = xdr_zero; /* no Write list present */
374 return iptr;
375 }
376
377 seg = req->rl_segments;
378 nsegs = rpcrdma_convert_iovs(r_xprt, &rqst->rq_rcv_buf,
379 rqst->rq_rcv_buf.head[0].iov_len,
380 wtype, seg);
381 if (nsegs < 0)
382 return ERR_PTR(nsegs);
383
384 *iptr++ = xdr_one; /* Write list present */
385 segcount = iptr++; /* save location of segment count */
386
387 nchunks = 0;
388 do {
389 n = r_xprt->rx_ia.ri_ops->ro_map(r_xprt, seg, nsegs,
390 true, &mw);
391 if (n < 0)
392 return ERR_PTR(n);
393 list_add(&mw->mw_list, &req->rl_registered);
394
395 iptr = xdr_encode_rdma_segment(iptr, mw);
396
397 dprintk("RPC: %5u %s: %u@0x016%llx:0x%08x (%s)\n",
398 rqst->rq_task->tk_pid, __func__,
399 mw->mw_length, (unsigned long long)mw->mw_offset,
400 mw->mw_handle, n < nsegs ? "more" : "last");
401
402 r_xprt->rx_stats.write_chunk_count++;
403 r_xprt->rx_stats.total_rdma_request += seg->mr_len;
404 nchunks++;
405 seg += n;
406 nsegs -= n;
407 } while (nsegs);
408
409 /* Update count of segments in this Write chunk */
410 *segcount = cpu_to_be32(nchunks);
411
412 /* Finish Write list */
413 *iptr++ = xdr_zero; /* Next item not present */
414 return iptr;
415}
416
417/* XDR-encode the Reply chunk. Supports encoding an array of plain
418 * segments that belong to a single write (reply) chunk.
419 *
420 * Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
421 *
422 * Reply chunk (a counted array):
423 * N elements:
424 * 1 - N - HLOO - HLOO - ... - HLOO
425 *
426 * Returns a pointer to the XDR word in the RDMA header following
427 * the end of the Reply chunk, or an error pointer.
428 */
429static __be32 *
430rpcrdma_encode_reply_chunk(struct rpcrdma_xprt *r_xprt,
431 struct rpcrdma_req *req, struct rpc_rqst *rqst,
432 __be32 *iptr, enum rpcrdma_chunktype wtype)
433{
434 struct rpcrdma_mr_seg *seg;
435 struct rpcrdma_mw *mw;
436 int n, nsegs, nchunks;
437 __be32 *segcount;
438
439 if (wtype != rpcrdma_replych) {
440 *iptr++ = xdr_zero; /* no Reply chunk present */
441 return iptr;
442 }
443
444 seg = req->rl_segments;
445 nsegs = rpcrdma_convert_iovs(r_xprt, &rqst->rq_rcv_buf, 0, wtype, seg);
446 if (nsegs < 0)
447 return ERR_PTR(nsegs);
448
449 *iptr++ = xdr_one; /* Reply chunk present */
450 segcount = iptr++; /* save location of segment count */
451
452 nchunks = 0;
453 do {
454 n = r_xprt->rx_ia.ri_ops->ro_map(r_xprt, seg, nsegs,
455 true, &mw);
456 if (n < 0)
457 return ERR_PTR(n);
458 list_add(&mw->mw_list, &req->rl_registered);
459
460 iptr = xdr_encode_rdma_segment(iptr, mw);
461
462 dprintk("RPC: %5u %s: %u@0x%016llx:0x%08x (%s)\n",
463 rqst->rq_task->tk_pid, __func__,
464 mw->mw_length, (unsigned long long)mw->mw_offset,
465 mw->mw_handle, n < nsegs ? "more" : "last");
466
467 r_xprt->rx_stats.reply_chunk_count++;
468 r_xprt->rx_stats.total_rdma_request += seg->mr_len;
469 nchunks++;
470 seg += n;
471 nsegs -= n;
472 } while (nsegs);
473
474 /* Update count of segments in the Reply chunk */
475 *segcount = cpu_to_be32(nchunks);
476
477 return iptr;
478}
479
480/* Prepare the RPC-over-RDMA header SGE.
481 */
482static bool
483rpcrdma_prepare_hdr_sge(struct rpcrdma_ia *ia, struct rpcrdma_req *req,
484 u32 len)
485{
486 struct rpcrdma_regbuf *rb = req->rl_rdmabuf;
487 struct ib_sge *sge = &req->rl_send_sge[0];
488
489 if (unlikely(!rpcrdma_regbuf_is_mapped(rb))) {
490 if (!__rpcrdma_dma_map_regbuf(ia, rb))
491 return false;
492 sge->addr = rdmab_addr(rb);
493 sge->lkey = rdmab_lkey(rb);
494 }
495 sge->length = len;
496
497 ib_dma_sync_single_for_device(ia->ri_device, sge->addr,
498 sge->length, DMA_TO_DEVICE);
499 req->rl_send_wr.num_sge++;
500 return true;
501}
502
503/* Prepare the Send SGEs. The head and tail iovec, and each entry
504 * in the page list, gets its own SGE.
505 */
506static bool
507rpcrdma_prepare_msg_sges(struct rpcrdma_ia *ia, struct rpcrdma_req *req,
508 struct xdr_buf *xdr, enum rpcrdma_chunktype rtype)
509{
510 unsigned int sge_no, page_base, len, remaining;
511 struct rpcrdma_regbuf *rb = req->rl_sendbuf;
512 struct ib_device *device = ia->ri_device;
513 struct ib_sge *sge = req->rl_send_sge;
514 u32 lkey = ia->ri_pd->local_dma_lkey;
515 struct page *page, **ppages;
516
517 /* The head iovec is straightforward, as it is already
518 * DMA-mapped. Sync the content that has changed.
519 */
520 if (!rpcrdma_dma_map_regbuf(ia, rb))
521 return false;
522 sge_no = 1;
523 sge[sge_no].addr = rdmab_addr(rb);
524 sge[sge_no].length = xdr->head[0].iov_len;
525 sge[sge_no].lkey = rdmab_lkey(rb);
526 ib_dma_sync_single_for_device(device, sge[sge_no].addr,
527 sge[sge_no].length, DMA_TO_DEVICE);
528
529 /* If there is a Read chunk, the page list is being handled
530 * via explicit RDMA, and thus is skipped here. However, the
531 * tail iovec may include an XDR pad for the page list, as
532 * well as additional content, and may not reside in the
533 * same page as the head iovec.
534 */
535 if (rtype == rpcrdma_readch) {
536 len = xdr->tail[0].iov_len;
537
538 /* Do not include the tail if it is only an XDR pad */
539 if (len < 4)
540 goto out;
541
542 page = virt_to_page(xdr->tail[0].iov_base);
543 page_base = (unsigned long)xdr->tail[0].iov_base & ~PAGE_MASK;
544
545 /* If the content in the page list is an odd length,
546 * xdr_write_pages() has added a pad at the beginning
547 * of the tail iovec. Force the tail's non-pad content
548 * to land at the next XDR position in the Send message.
549 */
550 page_base += len & 3;
551 len -= len & 3;
552 goto map_tail;
553 }
554
555 /* If there is a page list present, temporarily DMA map
556 * and prepare an SGE for each page to be sent.
557 */
558 if (xdr->page_len) {
559 ppages = xdr->pages + (xdr->page_base >> PAGE_SHIFT);
560 page_base = xdr->page_base & ~PAGE_MASK;
561 remaining = xdr->page_len;
562 while (remaining) {
563 sge_no++;
564 if (sge_no > RPCRDMA_MAX_SEND_SGES - 2)
565 goto out_mapping_overflow;
566
567 len = min_t(u32, PAGE_SIZE - page_base, remaining);
568 sge[sge_no].addr = ib_dma_map_page(device, *ppages,
569 page_base, len,
570 DMA_TO_DEVICE);
571 if (ib_dma_mapping_error(device, sge[sge_no].addr))
572 goto out_mapping_err;
573 sge[sge_no].length = len;
574 sge[sge_no].lkey = lkey;
575
576 req->rl_mapped_sges++;
577 ppages++;
578 remaining -= len;
579 page_base = 0;
580 }
581 }
582
583 /* The tail iovec is not always constructed in the same
584 * page where the head iovec resides (see, for example,
585 * gss_wrap_req_priv). To neatly accommodate that case,
586 * DMA map it separately.
587 */
588 if (xdr->tail[0].iov_len) {
589 page = virt_to_page(xdr->tail[0].iov_base);
590 page_base = (unsigned long)xdr->tail[0].iov_base & ~PAGE_MASK;
591 len = xdr->tail[0].iov_len;
592
593map_tail:
594 sge_no++;
595 sge[sge_no].addr = ib_dma_map_page(device, page,
596 page_base, len,
597 DMA_TO_DEVICE);
598 if (ib_dma_mapping_error(device, sge[sge_no].addr))
599 goto out_mapping_err;
600 sge[sge_no].length = len;
601 sge[sge_no].lkey = lkey;
602 req->rl_mapped_sges++;
603 }
604
605out:
606 req->rl_send_wr.num_sge = sge_no + 1;
607 return true;
608
609out_mapping_overflow:
610 pr_err("rpcrdma: too many Send SGEs (%u)\n", sge_no);
611 return false;
612
613out_mapping_err:
614 pr_err("rpcrdma: Send mapping error\n");
615 return false;
616}
617
618bool
619rpcrdma_prepare_send_sges(struct rpcrdma_ia *ia, struct rpcrdma_req *req,
620 u32 hdrlen, struct xdr_buf *xdr,
621 enum rpcrdma_chunktype rtype)
622{
623 req->rl_send_wr.num_sge = 0;
624 req->rl_mapped_sges = 0;
625
626 if (!rpcrdma_prepare_hdr_sge(ia, req, hdrlen))
627 goto out_map;
628
629 if (rtype != rpcrdma_areadch)
630 if (!rpcrdma_prepare_msg_sges(ia, req, xdr, rtype))
631 goto out_map;
632
633 return true;
634
635out_map:
636 pr_err("rpcrdma: failed to DMA map a Send buffer\n");
637 return false;
638}
639
640void
641rpcrdma_unmap_sges(struct rpcrdma_ia *ia, struct rpcrdma_req *req)
642{
643 struct ib_device *device = ia->ri_device;
644 struct ib_sge *sge;
645 int count;
646
647 sge = &req->rl_send_sge[2];
648 for (count = req->rl_mapped_sges; count--; sge++)
649 ib_dma_unmap_page(device, sge->addr, sge->length,
650 DMA_TO_DEVICE);
651 req->rl_mapped_sges = 0;
652}
653
654/*
655 * Marshal a request: the primary job of this routine is to choose
656 * the transfer modes. See comments below.
657 *
658 * Returns zero on success, otherwise a negative errno.
659 */
660
661int
662rpcrdma_marshal_req(struct rpc_rqst *rqst)
663{
664 struct rpc_xprt *xprt = rqst->rq_xprt;
665 struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
666 struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
667 enum rpcrdma_chunktype rtype, wtype;
668 struct rpcrdma_msg *headerp;
669 bool ddp_allowed;
670 ssize_t hdrlen;
671 size_t rpclen;
672 __be32 *iptr;
673
674#if defined(CONFIG_SUNRPC_BACKCHANNEL)
675 if (test_bit(RPC_BC_PA_IN_USE, &rqst->rq_bc_pa_state))
676 return rpcrdma_bc_marshal_reply(rqst);
677#endif
678
679 headerp = rdmab_to_msg(req->rl_rdmabuf);
680 /* don't byte-swap XID, it's already done in request */
681 headerp->rm_xid = rqst->rq_xid;
682 headerp->rm_vers = rpcrdma_version;
683 headerp->rm_credit = cpu_to_be32(r_xprt->rx_buf.rb_max_requests);
684 headerp->rm_type = rdma_msg;
685
686 /* When the ULP employs a GSS flavor that guarantees integrity
687 * or privacy, direct data placement of individual data items
688 * is not allowed.
689 */
690 ddp_allowed = !(rqst->rq_cred->cr_auth->au_flags &
691 RPCAUTH_AUTH_DATATOUCH);
692
693 /*
694 * Chunks needed for results?
695 *
696 * o If the expected result is under the inline threshold, all ops
697 * return as inline.
698 * o Large read ops return data as write chunk(s), header as
699 * inline.
700 * o Large non-read ops return as a single reply chunk.
701 */
702 if (rpcrdma_results_inline(r_xprt, rqst))
703 wtype = rpcrdma_noch;
704 else if (ddp_allowed && rqst->rq_rcv_buf.flags & XDRBUF_READ)
705 wtype = rpcrdma_writech;
706 else
707 wtype = rpcrdma_replych;
708
709 /*
710 * Chunks needed for arguments?
711 *
712 * o If the total request is under the inline threshold, all ops
713 * are sent as inline.
714 * o Large write ops transmit data as read chunk(s), header as
715 * inline.
716 * o Large non-write ops are sent with the entire message as a
717 * single read chunk (protocol 0-position special case).
718 *
719 * This assumes that the upper layer does not present a request
720 * that both has a data payload, and whose non-data arguments
721 * by themselves are larger than the inline threshold.
722 */
723 if (rpcrdma_args_inline(r_xprt, rqst)) {
724 rtype = rpcrdma_noch;
725 rpclen = rqst->rq_snd_buf.len;
726 } else if (ddp_allowed && rqst->rq_snd_buf.flags & XDRBUF_WRITE) {
727 rtype = rpcrdma_readch;
728 rpclen = rqst->rq_snd_buf.head[0].iov_len +
729 rqst->rq_snd_buf.tail[0].iov_len;
730 } else {
731 r_xprt->rx_stats.nomsg_call_count++;
732 headerp->rm_type = htonl(RDMA_NOMSG);
733 rtype = rpcrdma_areadch;
734 rpclen = 0;
735 }
736
737 /* This implementation supports the following combinations
738 * of chunk lists in one RPC-over-RDMA Call message:
739 *
740 * - Read list
741 * - Write list
742 * - Reply chunk
743 * - Read list + Reply chunk
744 *
745 * It might not yet support the following combinations:
746 *
747 * - Read list + Write list
748 *
749 * It does not support the following combinations:
750 *
751 * - Write list + Reply chunk
752 * - Read list + Write list + Reply chunk
753 *
754 * This implementation supports only a single chunk in each
755 * Read or Write list. Thus for example the client cannot
756 * send a Call message with a Position Zero Read chunk and a
757 * regular Read chunk at the same time.
758 */
759 iptr = headerp->rm_body.rm_chunks;
760 iptr = rpcrdma_encode_read_list(r_xprt, req, rqst, iptr, rtype);
761 if (IS_ERR(iptr))
762 goto out_unmap;
763 iptr = rpcrdma_encode_write_list(r_xprt, req, rqst, iptr, wtype);
764 if (IS_ERR(iptr))
765 goto out_unmap;
766 iptr = rpcrdma_encode_reply_chunk(r_xprt, req, rqst, iptr, wtype);
767 if (IS_ERR(iptr))
768 goto out_unmap;
769 hdrlen = (unsigned char *)iptr - (unsigned char *)headerp;
770
771 dprintk("RPC: %5u %s: %s/%s: hdrlen %zd rpclen %zd\n",
772 rqst->rq_task->tk_pid, __func__,
773 transfertypes[rtype], transfertypes[wtype],
774 hdrlen, rpclen);
775
776 if (!rpcrdma_prepare_send_sges(&r_xprt->rx_ia, req, hdrlen,
777 &rqst->rq_snd_buf, rtype)) {
778 iptr = ERR_PTR(-EIO);
779 goto out_unmap;
780 }
781 return 0;
782
783out_unmap:
784 r_xprt->rx_ia.ri_ops->ro_unmap_safe(r_xprt, req, false);
785 return PTR_ERR(iptr);
786}
787
788/*
789 * Chase down a received write or reply chunklist to get length
790 * RDMA'd by server. See map at rpcrdma_create_chunks()! :-)
791 */
792static int
793rpcrdma_count_chunks(struct rpcrdma_rep *rep, int wrchunk, __be32 **iptrp)
794{
795 unsigned int i, total_len;
796 struct rpcrdma_write_chunk *cur_wchunk;
797 char *base = (char *)rdmab_to_msg(rep->rr_rdmabuf);
798
799 i = be32_to_cpu(**iptrp);
800 cur_wchunk = (struct rpcrdma_write_chunk *) (*iptrp + 1);
801 total_len = 0;
802 while (i--) {
803 struct rpcrdma_segment *seg = &cur_wchunk->wc_target;
804 ifdebug(FACILITY) {
805 u64 off;
806 xdr_decode_hyper((__be32 *)&seg->rs_offset, &off);
807 dprintk("RPC: %s: chunk %d@0x%016llx:0x%08x\n",
808 __func__,
809 be32_to_cpu(seg->rs_length),
810 (unsigned long long)off,
811 be32_to_cpu(seg->rs_handle));
812 }
813 total_len += be32_to_cpu(seg->rs_length);
814 ++cur_wchunk;
815 }
816 /* check and adjust for properly terminated write chunk */
817 if (wrchunk) {
818 __be32 *w = (__be32 *) cur_wchunk;
819 if (*w++ != xdr_zero)
820 return -1;
821 cur_wchunk = (struct rpcrdma_write_chunk *) w;
822 }
823 if ((char *)cur_wchunk > base + rep->rr_len)
824 return -1;
825
826 *iptrp = (__be32 *) cur_wchunk;
827 return total_len;
828}
829
830/**
831 * rpcrdma_inline_fixup - Scatter inline received data into rqst's iovecs
832 * @rqst: controlling RPC request
833 * @srcp: points to RPC message payload in receive buffer
834 * @copy_len: remaining length of receive buffer content
835 * @pad: Write chunk pad bytes needed (zero for pure inline)
836 *
837 * The upper layer has set the maximum number of bytes it can
838 * receive in each component of rq_rcv_buf. These values are set in
839 * the head.iov_len, page_len, tail.iov_len, and buflen fields.
840 *
841 * Unlike the TCP equivalent (xdr_partial_copy_from_skb), in
842 * many cases this function simply updates iov_base pointers in
843 * rq_rcv_buf to point directly to the received reply data, to
844 * avoid copying reply data.
845 *
846 * Returns the count of bytes which had to be memcopied.
847 */
848static unsigned long
849rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad)
850{
851 unsigned long fixup_copy_count;
852 int i, npages, curlen;
853 char *destp;
854 struct page **ppages;
855 int page_base;
856
857 /* The head iovec is redirected to the RPC reply message
858 * in the receive buffer, to avoid a memcopy.
859 */
860 rqst->rq_rcv_buf.head[0].iov_base = srcp;
861 rqst->rq_private_buf.head[0].iov_base = srcp;
862
863 /* The contents of the receive buffer that follow
864 * head.iov_len bytes are copied into the page list.
865 */
866 curlen = rqst->rq_rcv_buf.head[0].iov_len;
867 if (curlen > copy_len)
868 curlen = copy_len;
869 dprintk("RPC: %s: srcp 0x%p len %d hdrlen %d\n",
870 __func__, srcp, copy_len, curlen);
871 srcp += curlen;
872 copy_len -= curlen;
873
874 page_base = rqst->rq_rcv_buf.page_base;
875 ppages = rqst->rq_rcv_buf.pages + (page_base >> PAGE_SHIFT);
876 page_base &= ~PAGE_MASK;
877 fixup_copy_count = 0;
878 if (copy_len && rqst->rq_rcv_buf.page_len) {
879 int pagelist_len;
880
881 pagelist_len = rqst->rq_rcv_buf.page_len;
882 if (pagelist_len > copy_len)
883 pagelist_len = copy_len;
884 npages = PAGE_ALIGN(page_base + pagelist_len) >> PAGE_SHIFT;
885 for (i = 0; i < npages; i++) {
886 curlen = PAGE_SIZE - page_base;
887 if (curlen > pagelist_len)
888 curlen = pagelist_len;
889
890 dprintk("RPC: %s: page %d"
891 " srcp 0x%p len %d curlen %d\n",
892 __func__, i, srcp, copy_len, curlen);
893 destp = kmap_atomic(ppages[i]);
894 memcpy(destp + page_base, srcp, curlen);
895 flush_dcache_page(ppages[i]);
896 kunmap_atomic(destp);
897 srcp += curlen;
898 copy_len -= curlen;
899 fixup_copy_count += curlen;
900 pagelist_len -= curlen;
901 if (!pagelist_len)
902 break;
903 page_base = 0;
904 }
905
906 /* Implicit padding for the last segment in a Write
907 * chunk is inserted inline at the front of the tail
908 * iovec. The upper layer ignores the content of
909 * the pad. Simply ensure inline content in the tail
910 * that follows the Write chunk is properly aligned.
911 */
912 if (pad)
913 srcp -= pad;
914 }
915
916 /* The tail iovec is redirected to the remaining data
917 * in the receive buffer, to avoid a memcopy.
918 */
919 if (copy_len || pad) {
920 rqst->rq_rcv_buf.tail[0].iov_base = srcp;
921 rqst->rq_private_buf.tail[0].iov_base = srcp;
922 }
923
924 return fixup_copy_count;
925}
926
927#if defined(CONFIG_SUNRPC_BACKCHANNEL)
928/* By convention, backchannel calls arrive via rdma_msg type
929 * messages, and never populate the chunk lists. This makes
930 * the RPC/RDMA header small and fixed in size, so it is
931 * straightforward to check the RPC header's direction field.
932 */
933static bool
934rpcrdma_is_bcall(struct rpcrdma_msg *headerp)
935{
936 __be32 *p = (__be32 *)headerp;
937
938 if (headerp->rm_type != rdma_msg)
939 return false;
940 if (headerp->rm_body.rm_chunks[0] != xdr_zero)
941 return false;
942 if (headerp->rm_body.rm_chunks[1] != xdr_zero)
943 return false;
944 if (headerp->rm_body.rm_chunks[2] != xdr_zero)
945 return false;
946
947 /* sanity */
948 if (p[7] != headerp->rm_xid)
949 return false;
950 /* call direction */
951 if (p[8] != cpu_to_be32(RPC_CALL))
952 return false;
953
954 return true;
955}
956#endif /* CONFIG_SUNRPC_BACKCHANNEL */
957
958/* Process received RPC/RDMA messages.
959 *
960 * Errors must result in the RPC task either being awakened, or
961 * allowed to timeout, to discover the errors at that time.
962 */
963void
964rpcrdma_reply_handler(struct work_struct *work)
965{
966 struct rpcrdma_rep *rep =
967 container_of(work, struct rpcrdma_rep, rr_work);
968 struct rpcrdma_msg *headerp;
969 struct rpcrdma_req *req;
970 struct rpc_rqst *rqst;
971 struct rpcrdma_xprt *r_xprt = rep->rr_rxprt;
972 struct rpc_xprt *xprt = &r_xprt->rx_xprt;
973 __be32 *iptr;
974 int rdmalen, status, rmerr;
975 unsigned long cwnd;
976
977 dprintk("RPC: %s: incoming rep %p\n", __func__, rep);
978
979 if (rep->rr_len == RPCRDMA_BAD_LEN)
980 goto out_badstatus;
981 if (rep->rr_len < RPCRDMA_HDRLEN_ERR)
982 goto out_shortreply;
983
984 headerp = rdmab_to_msg(rep->rr_rdmabuf);
985#if defined(CONFIG_SUNRPC_BACKCHANNEL)
986 if (rpcrdma_is_bcall(headerp))
987 goto out_bcall;
988#endif
989
990 /* Match incoming rpcrdma_rep to an rpcrdma_req to
991 * get context for handling any incoming chunks.
992 */
993 spin_lock_bh(&xprt->transport_lock);
994 rqst = xprt_lookup_rqst(xprt, headerp->rm_xid);
995 if (!rqst)
996 goto out_nomatch;
997
998 req = rpcr_to_rdmar(rqst);
999 if (req->rl_reply)
1000 goto out_duplicate;
1001
1002 /* Sanity checking has passed. We are now committed
1003 * to complete this transaction.
1004 */
1005 list_del_init(&rqst->rq_list);
1006 spin_unlock_bh(&xprt->transport_lock);
1007 dprintk("RPC: %s: reply %p completes request %p (xid 0x%08x)\n",
1008 __func__, rep, req, be32_to_cpu(headerp->rm_xid));
1009
1010 /* from here on, the reply is no longer an orphan */
1011 req->rl_reply = rep;
1012 xprt->reestablish_timeout = 0;
1013
1014 if (headerp->rm_vers != rpcrdma_version)
1015 goto out_badversion;
1016
1017 /* check for expected message types */
1018 /* The order of some of these tests is important. */
1019 switch (headerp->rm_type) {
1020 case rdma_msg:
1021 /* never expect read chunks */
1022 /* never expect reply chunks (two ways to check) */
1023 /* never expect write chunks without having offered RDMA */
1024 if (headerp->rm_body.rm_chunks[0] != xdr_zero ||
1025 (headerp->rm_body.rm_chunks[1] == xdr_zero &&
1026 headerp->rm_body.rm_chunks[2] != xdr_zero) ||
1027 (headerp->rm_body.rm_chunks[1] != xdr_zero &&
1028 list_empty(&req->rl_registered)))
1029 goto badheader;
1030 if (headerp->rm_body.rm_chunks[1] != xdr_zero) {
1031 /* count any expected write chunks in read reply */
1032 /* start at write chunk array count */
1033 iptr = &headerp->rm_body.rm_chunks[2];
1034 rdmalen = rpcrdma_count_chunks(rep, 1, &iptr);
1035 /* check for validity, and no reply chunk after */
1036 if (rdmalen < 0 || *iptr++ != xdr_zero)
1037 goto badheader;
1038 rep->rr_len -=
1039 ((unsigned char *)iptr - (unsigned char *)headerp);
1040 status = rep->rr_len + rdmalen;
1041 r_xprt->rx_stats.total_rdma_reply += rdmalen;
1042 /* special case - last chunk may omit padding */
1043 if (rdmalen &= 3) {
1044 rdmalen = 4 - rdmalen;
1045 status += rdmalen;
1046 }
1047 } else {
1048 /* else ordinary inline */
1049 rdmalen = 0;
1050 iptr = (__be32 *)((unsigned char *)headerp +
1051 RPCRDMA_HDRLEN_MIN);
1052 rep->rr_len -= RPCRDMA_HDRLEN_MIN;
1053 status = rep->rr_len;
1054 }
1055
1056 r_xprt->rx_stats.fixup_copy_count +=
1057 rpcrdma_inline_fixup(rqst, (char *)iptr, rep->rr_len,
1058 rdmalen);
1059 break;
1060
1061 case rdma_nomsg:
1062 /* never expect read or write chunks, always reply chunks */
1063 if (headerp->rm_body.rm_chunks[0] != xdr_zero ||
1064 headerp->rm_body.rm_chunks[1] != xdr_zero ||
1065 headerp->rm_body.rm_chunks[2] != xdr_one ||
1066 list_empty(&req->rl_registered))
1067 goto badheader;
1068 iptr = (__be32 *)((unsigned char *)headerp +
1069 RPCRDMA_HDRLEN_MIN);
1070 rdmalen = rpcrdma_count_chunks(rep, 0, &iptr);
1071 if (rdmalen < 0)
1072 goto badheader;
1073 r_xprt->rx_stats.total_rdma_reply += rdmalen;
1074 /* Reply chunk buffer already is the reply vector - no fixup. */
1075 status = rdmalen;
1076 break;
1077
1078 case rdma_error:
1079 goto out_rdmaerr;
1080
1081badheader:
1082 default:
1083 dprintk("RPC: %5u %s: invalid rpcrdma reply (type %u)\n",
1084 rqst->rq_task->tk_pid, __func__,
1085 be32_to_cpu(headerp->rm_type));
1086 status = -EIO;
1087 r_xprt->rx_stats.bad_reply_count++;
1088 break;
1089 }
1090
1091out:
1092 /* Invalidate and flush the data payloads before waking the
1093 * waiting application. This guarantees the memory region is
1094 * properly fenced from the server before the application
1095 * accesses the data. It also ensures proper send flow
1096 * control: waking the next RPC waits until this RPC has
1097 * relinquished all its Send Queue entries.
1098 */
1099 if (!list_empty(&req->rl_registered))
1100 r_xprt->rx_ia.ri_ops->ro_unmap_sync(r_xprt, req);
1101
1102 spin_lock_bh(&xprt->transport_lock);
1103 cwnd = xprt->cwnd;
1104 xprt->cwnd = atomic_read(&r_xprt->rx_buf.rb_credits) << RPC_CWNDSHIFT;
1105 if (xprt->cwnd > cwnd)
1106 xprt_release_rqst_cong(rqst->rq_task);
1107
1108 xprt_complete_rqst(rqst->rq_task, status);
1109 spin_unlock_bh(&xprt->transport_lock);
1110 dprintk("RPC: %s: xprt_complete_rqst(0x%p, 0x%p, %d)\n",
1111 __func__, xprt, rqst, status);
1112 return;
1113
1114out_badstatus:
1115 rpcrdma_recv_buffer_put(rep);
1116 if (r_xprt->rx_ep.rep_connected == 1) {
1117 r_xprt->rx_ep.rep_connected = -EIO;
1118 rpcrdma_conn_func(&r_xprt->rx_ep);
1119 }
1120 return;
1121
1122#if defined(CONFIG_SUNRPC_BACKCHANNEL)
1123out_bcall:
1124 rpcrdma_bc_receive_call(r_xprt, rep);
1125 return;
1126#endif
1127
1128/* If the incoming reply terminated a pending RPC, the next
1129 * RPC call will post a replacement receive buffer as it is
1130 * being marshaled.
1131 */
1132out_badversion:
1133 dprintk("RPC: %s: invalid version %d\n",
1134 __func__, be32_to_cpu(headerp->rm_vers));
1135 status = -EIO;
1136 r_xprt->rx_stats.bad_reply_count++;
1137 goto out;
1138
1139out_rdmaerr:
1140 rmerr = be32_to_cpu(headerp->rm_body.rm_error.rm_err);
1141 switch (rmerr) {
1142 case ERR_VERS:
1143 pr_err("%s: server reports header version error (%u-%u)\n",
1144 __func__,
1145 be32_to_cpu(headerp->rm_body.rm_error.rm_vers_low),
1146 be32_to_cpu(headerp->rm_body.rm_error.rm_vers_high));
1147 break;
1148 case ERR_CHUNK:
1149 pr_err("%s: server reports header decoding error\n",
1150 __func__);
1151 break;
1152 default:
1153 pr_err("%s: server reports unknown error %d\n",
1154 __func__, rmerr);
1155 }
1156 status = -EREMOTEIO;
1157 r_xprt->rx_stats.bad_reply_count++;
1158 goto out;
1159
1160/* If no pending RPC transaction was matched, post a replacement
1161 * receive buffer before returning.
1162 */
1163out_shortreply:
1164 dprintk("RPC: %s: short/invalid reply\n", __func__);
1165 goto repost;
1166
1167out_nomatch:
1168 spin_unlock_bh(&xprt->transport_lock);
1169 dprintk("RPC: %s: no match for incoming xid 0x%08x len %d\n",
1170 __func__, be32_to_cpu(headerp->rm_xid),
1171 rep->rr_len);
1172 goto repost;
1173
1174out_duplicate:
1175 spin_unlock_bh(&xprt->transport_lock);
1176 dprintk("RPC: %s: "
1177 "duplicate reply %p to RPC request %p: xid 0x%08x\n",
1178 __func__, rep, req, be32_to_cpu(headerp->rm_xid));
1179
1180repost:
1181 r_xprt->rx_stats.bad_reply_count++;
1182 if (rpcrdma_ep_post_recv(&r_xprt->rx_ia, rep))
1183 rpcrdma_recv_buffer_put(rep);
1184}