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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// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
2/*
3 * Copyright (c) 2014-2017 Oracle. All rights reserved.
4 * Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
5 *
6 * This software is available to you under a choice of one of two
7 * licenses. You may choose to be licensed under the terms of the GNU
8 * General Public License (GPL) Version 2, available from the file
9 * COPYING in the main directory of this source tree, or the BSD-type
10 * license below:
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 *
16 * Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 *
19 * Redistributions in binary form must reproduce the above
20 * copyright notice, this list of conditions and the following
21 * disclaimer in the documentation and/or other materials provided
22 * with the distribution.
23 *
24 * Neither the name of the Network Appliance, Inc. nor the names of
25 * its contributors may be used to endorse or promote products
26 * derived from this software without specific prior written
27 * permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
30 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
31 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
32 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
33 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
34 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
35 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
39 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 */
41
42/*
43 * rpc_rdma.c
44 *
45 * This file contains the guts of the RPC RDMA protocol, and
46 * does marshaling/unmarshaling, etc. It is also where interfacing
47 * to the Linux RPC framework lives.
48 */
49
50#include <linux/highmem.h>
51
52#include <linux/sunrpc/svc_rdma.h>
53
54#include "xprt_rdma.h"
55#include <trace/events/rpcrdma.h>
56
57#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
58# define RPCDBG_FACILITY RPCDBG_TRANS
59#endif
60
61/* Returns size of largest RPC-over-RDMA header in a Call message
62 *
63 * The largest Call header contains a full-size Read list and a
64 * minimal Reply chunk.
65 */
66static unsigned int rpcrdma_max_call_header_size(unsigned int maxsegs)
67{
68 unsigned int size;
69
70 /* Fixed header fields and list discriminators */
71 size = RPCRDMA_HDRLEN_MIN;
72
73 /* Maximum Read list size */
74 size = maxsegs * rpcrdma_readchunk_maxsz * sizeof(__be32);
75
76 /* Minimal Read chunk size */
77 size += sizeof(__be32); /* segment count */
78 size += rpcrdma_segment_maxsz * sizeof(__be32);
79 size += sizeof(__be32); /* list discriminator */
80
81 dprintk("RPC: %s: max call header size = %u\n",
82 __func__, size);
83 return size;
84}
85
86/* Returns size of largest RPC-over-RDMA header in a Reply message
87 *
88 * There is only one Write list or one Reply chunk per Reply
89 * message. The larger list is the Write list.
90 */
91static unsigned int rpcrdma_max_reply_header_size(unsigned int maxsegs)
92{
93 unsigned int size;
94
95 /* Fixed header fields and list discriminators */
96 size = RPCRDMA_HDRLEN_MIN;
97
98 /* Maximum Write list size */
99 size = sizeof(__be32); /* segment count */
100 size += maxsegs * rpcrdma_segment_maxsz * sizeof(__be32);
101 size += sizeof(__be32); /* list discriminator */
102
103 dprintk("RPC: %s: max reply header size = %u\n",
104 __func__, size);
105 return size;
106}
107
108/**
109 * rpcrdma_set_max_header_sizes - Initialize inline payload sizes
110 * @r_xprt: transport instance to initialize
111 *
112 * The max_inline fields contain the maximum size of an RPC message
113 * so the marshaling code doesn't have to repeat this calculation
114 * for every RPC.
115 */
116void rpcrdma_set_max_header_sizes(struct rpcrdma_xprt *r_xprt)
117{
118 unsigned int maxsegs = r_xprt->rx_ia.ri_max_segs;
119 struct rpcrdma_ep *ep = &r_xprt->rx_ep;
120
121 ep->rep_max_inline_send =
122 ep->rep_inline_send - rpcrdma_max_call_header_size(maxsegs);
123 ep->rep_max_inline_recv =
124 ep->rep_inline_recv - rpcrdma_max_reply_header_size(maxsegs);
125}
126
127/* The client can send a request inline as long as the RPCRDMA header
128 * plus the RPC call fit under the transport's inline limit. If the
129 * combined call message size exceeds that limit, the client must use
130 * a Read chunk for this operation.
131 *
132 * A Read chunk is also required if sending the RPC call inline would
133 * exceed this device's max_sge limit.
134 */
135static bool rpcrdma_args_inline(struct rpcrdma_xprt *r_xprt,
136 struct rpc_rqst *rqst)
137{
138 struct xdr_buf *xdr = &rqst->rq_snd_buf;
139 unsigned int count, remaining, offset;
140
141 if (xdr->len > r_xprt->rx_ep.rep_max_inline_send)
142 return false;
143
144 if (xdr->page_len) {
145 remaining = xdr->page_len;
146 offset = offset_in_page(xdr->page_base);
147 count = RPCRDMA_MIN_SEND_SGES;
148 while (remaining) {
149 remaining -= min_t(unsigned int,
150 PAGE_SIZE - offset, remaining);
151 offset = 0;
152 if (++count > r_xprt->rx_ia.ri_max_send_sges)
153 return false;
154 }
155 }
156
157 return true;
158}
159
160/* The client can't know how large the actual reply will be. Thus it
161 * plans for the largest possible reply for that particular ULP
162 * operation. If the maximum combined reply message size exceeds that
163 * limit, the client must provide a write list or a reply chunk for
164 * this request.
165 */
166static bool rpcrdma_results_inline(struct rpcrdma_xprt *r_xprt,
167 struct rpc_rqst *rqst)
168{
169 return rqst->rq_rcv_buf.buflen <= r_xprt->rx_ep.rep_max_inline_recv;
170}
171
172/* The client is required to provide a Reply chunk if the maximum
173 * size of the non-payload part of the RPC Reply is larger than
174 * the inline threshold.
175 */
176static bool
177rpcrdma_nonpayload_inline(const struct rpcrdma_xprt *r_xprt,
178 const struct rpc_rqst *rqst)
179{
180 const struct xdr_buf *buf = &rqst->rq_rcv_buf;
181
182 return (buf->head[0].iov_len + buf->tail[0].iov_len) <
183 r_xprt->rx_ep.rep_max_inline_recv;
184}
185
186/* Split @vec on page boundaries into SGEs. FMR registers pages, not
187 * a byte range. Other modes coalesce these SGEs into a single MR
188 * when they can.
189 *
190 * Returns pointer to next available SGE, and bumps the total number
191 * of SGEs consumed.
192 */
193static struct rpcrdma_mr_seg *
194rpcrdma_convert_kvec(struct kvec *vec, struct rpcrdma_mr_seg *seg,
195 unsigned int *n)
196{
197 u32 remaining, page_offset;
198 char *base;
199
200 base = vec->iov_base;
201 page_offset = offset_in_page(base);
202 remaining = vec->iov_len;
203 while (remaining) {
204 seg->mr_page = NULL;
205 seg->mr_offset = base;
206 seg->mr_len = min_t(u32, PAGE_SIZE - page_offset, remaining);
207 remaining -= seg->mr_len;
208 base += seg->mr_len;
209 ++seg;
210 ++(*n);
211 page_offset = 0;
212 }
213 return seg;
214}
215
216/* Convert @xdrbuf into SGEs no larger than a page each. As they
217 * are registered, these SGEs are then coalesced into RDMA segments
218 * when the selected memreg mode supports it.
219 *
220 * Returns positive number of SGEs consumed, or a negative errno.
221 */
222
223static int
224rpcrdma_convert_iovs(struct rpcrdma_xprt *r_xprt, struct xdr_buf *xdrbuf,
225 unsigned int pos, enum rpcrdma_chunktype type,
226 struct rpcrdma_mr_seg *seg)
227{
228 unsigned long page_base;
229 unsigned int len, n;
230 struct page **ppages;
231
232 n = 0;
233 if (pos == 0)
234 seg = rpcrdma_convert_kvec(&xdrbuf->head[0], seg, &n);
235
236 len = xdrbuf->page_len;
237 ppages = xdrbuf->pages + (xdrbuf->page_base >> PAGE_SHIFT);
238 page_base = offset_in_page(xdrbuf->page_base);
239 while (len) {
240 /* ACL likes to be lazy in allocating pages - ACLs
241 * are small by default but can get huge.
242 */
243 if (unlikely(xdrbuf->flags & XDRBUF_SPARSE_PAGES)) {
244 if (!*ppages)
245 *ppages = alloc_page(GFP_NOWAIT | __GFP_NOWARN);
246 if (!*ppages)
247 return -ENOBUFS;
248 }
249 seg->mr_page = *ppages;
250 seg->mr_offset = (char *)page_base;
251 seg->mr_len = min_t(u32, PAGE_SIZE - page_base, len);
252 len -= seg->mr_len;
253 ++ppages;
254 ++seg;
255 ++n;
256 page_base = 0;
257 }
258
259 /* When encoding a Read chunk, the tail iovec contains an
260 * XDR pad and may be omitted.
261 */
262 if (type == rpcrdma_readch && r_xprt->rx_ia.ri_implicit_roundup)
263 goto out;
264
265 /* When encoding a Write chunk, some servers need to see an
266 * extra segment for non-XDR-aligned Write chunks. The upper
267 * layer provides space in the tail iovec that may be used
268 * for this purpose.
269 */
270 if (type == rpcrdma_writech && r_xprt->rx_ia.ri_implicit_roundup)
271 goto out;
272
273 if (xdrbuf->tail[0].iov_len)
274 seg = rpcrdma_convert_kvec(&xdrbuf->tail[0], seg, &n);
275
276out:
277 if (unlikely(n > RPCRDMA_MAX_SEGS))
278 return -EIO;
279 return n;
280}
281
282static inline int
283encode_item_present(struct xdr_stream *xdr)
284{
285 __be32 *p;
286
287 p = xdr_reserve_space(xdr, sizeof(*p));
288 if (unlikely(!p))
289 return -EMSGSIZE;
290
291 *p = xdr_one;
292 return 0;
293}
294
295static inline int
296encode_item_not_present(struct xdr_stream *xdr)
297{
298 __be32 *p;
299
300 p = xdr_reserve_space(xdr, sizeof(*p));
301 if (unlikely(!p))
302 return -EMSGSIZE;
303
304 *p = xdr_zero;
305 return 0;
306}
307
308static void
309xdr_encode_rdma_segment(__be32 *iptr, struct rpcrdma_mr *mr)
310{
311 *iptr++ = cpu_to_be32(mr->mr_handle);
312 *iptr++ = cpu_to_be32(mr->mr_length);
313 xdr_encode_hyper(iptr, mr->mr_offset);
314}
315
316static int
317encode_rdma_segment(struct xdr_stream *xdr, struct rpcrdma_mr *mr)
318{
319 __be32 *p;
320
321 p = xdr_reserve_space(xdr, 4 * sizeof(*p));
322 if (unlikely(!p))
323 return -EMSGSIZE;
324
325 xdr_encode_rdma_segment(p, mr);
326 return 0;
327}
328
329static int
330encode_read_segment(struct xdr_stream *xdr, struct rpcrdma_mr *mr,
331 u32 position)
332{
333 __be32 *p;
334
335 p = xdr_reserve_space(xdr, 6 * sizeof(*p));
336 if (unlikely(!p))
337 return -EMSGSIZE;
338
339 *p++ = xdr_one; /* Item present */
340 *p++ = cpu_to_be32(position);
341 xdr_encode_rdma_segment(p, mr);
342 return 0;
343}
344
345static struct rpcrdma_mr_seg *rpcrdma_mr_prepare(struct rpcrdma_xprt *r_xprt,
346 struct rpcrdma_req *req,
347 struct rpcrdma_mr_seg *seg,
348 int nsegs, bool writing,
349 struct rpcrdma_mr **mr)
350{
351 *mr = rpcrdma_mr_pop(&req->rl_free_mrs);
352 if (!*mr) {
353 *mr = rpcrdma_mr_get(r_xprt);
354 if (!*mr)
355 goto out_getmr_err;
356 trace_xprtrdma_mr_get(req);
357 (*mr)->mr_req = req;
358 }
359
360 rpcrdma_mr_push(*mr, &req->rl_registered);
361 return frwr_map(r_xprt, seg, nsegs, writing, req->rl_slot.rq_xid, *mr);
362
363out_getmr_err:
364 trace_xprtrdma_nomrs(req);
365 xprt_wait_for_buffer_space(&r_xprt->rx_xprt);
366 if (r_xprt->rx_ep.rep_connected != -ENODEV)
367 schedule_work(&r_xprt->rx_buf.rb_refresh_worker);
368 return ERR_PTR(-EAGAIN);
369}
370
371/* Register and XDR encode the Read list. Supports encoding a list of read
372 * segments that belong to a single read chunk.
373 *
374 * Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
375 *
376 * Read chunklist (a linked list):
377 * N elements, position P (same P for all chunks of same arg!):
378 * 1 - PHLOO - 1 - PHLOO - ... - 1 - PHLOO - 0
379 *
380 * Returns zero on success, or a negative errno if a failure occurred.
381 * @xdr is advanced to the next position in the stream.
382 *
383 * Only a single @pos value is currently supported.
384 */
385static int rpcrdma_encode_read_list(struct rpcrdma_xprt *r_xprt,
386 struct rpcrdma_req *req,
387 struct rpc_rqst *rqst,
388 enum rpcrdma_chunktype rtype)
389{
390 struct xdr_stream *xdr = &req->rl_stream;
391 struct rpcrdma_mr_seg *seg;
392 struct rpcrdma_mr *mr;
393 unsigned int pos;
394 int nsegs;
395
396 if (rtype == rpcrdma_noch)
397 goto done;
398
399 pos = rqst->rq_snd_buf.head[0].iov_len;
400 if (rtype == rpcrdma_areadch)
401 pos = 0;
402 seg = req->rl_segments;
403 nsegs = rpcrdma_convert_iovs(r_xprt, &rqst->rq_snd_buf, pos,
404 rtype, seg);
405 if (nsegs < 0)
406 return nsegs;
407
408 do {
409 seg = rpcrdma_mr_prepare(r_xprt, req, seg, nsegs, false, &mr);
410 if (IS_ERR(seg))
411 return PTR_ERR(seg);
412
413 if (encode_read_segment(xdr, mr, pos) < 0)
414 return -EMSGSIZE;
415
416 trace_xprtrdma_chunk_read(rqst->rq_task, pos, mr, nsegs);
417 r_xprt->rx_stats.read_chunk_count++;
418 nsegs -= mr->mr_nents;
419 } while (nsegs);
420
421done:
422 return encode_item_not_present(xdr);
423}
424
425/* Register and XDR encode the Write list. Supports encoding a list
426 * containing one array of plain segments that belong to a single
427 * write chunk.
428 *
429 * Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
430 *
431 * Write chunklist (a list of (one) counted array):
432 * N elements:
433 * 1 - N - HLOO - HLOO - ... - HLOO - 0
434 *
435 * Returns zero on success, or a negative errno if a failure occurred.
436 * @xdr is advanced to the next position in the stream.
437 *
438 * Only a single Write chunk is currently supported.
439 */
440static int rpcrdma_encode_write_list(struct rpcrdma_xprt *r_xprt,
441 struct rpcrdma_req *req,
442 struct rpc_rqst *rqst,
443 enum rpcrdma_chunktype wtype)
444{
445 struct xdr_stream *xdr = &req->rl_stream;
446 struct rpcrdma_mr_seg *seg;
447 struct rpcrdma_mr *mr;
448 int nsegs, nchunks;
449 __be32 *segcount;
450
451 if (wtype != rpcrdma_writech)
452 goto done;
453
454 seg = req->rl_segments;
455 nsegs = rpcrdma_convert_iovs(r_xprt, &rqst->rq_rcv_buf,
456 rqst->rq_rcv_buf.head[0].iov_len,
457 wtype, seg);
458 if (nsegs < 0)
459 return nsegs;
460
461 if (encode_item_present(xdr) < 0)
462 return -EMSGSIZE;
463 segcount = xdr_reserve_space(xdr, sizeof(*segcount));
464 if (unlikely(!segcount))
465 return -EMSGSIZE;
466 /* Actual value encoded below */
467
468 nchunks = 0;
469 do {
470 seg = rpcrdma_mr_prepare(r_xprt, req, seg, nsegs, true, &mr);
471 if (IS_ERR(seg))
472 return PTR_ERR(seg);
473
474 if (encode_rdma_segment(xdr, mr) < 0)
475 return -EMSGSIZE;
476
477 trace_xprtrdma_chunk_write(rqst->rq_task, mr, nsegs);
478 r_xprt->rx_stats.write_chunk_count++;
479 r_xprt->rx_stats.total_rdma_request += mr->mr_length;
480 nchunks++;
481 nsegs -= mr->mr_nents;
482 } while (nsegs);
483
484 /* Update count of segments in this Write chunk */
485 *segcount = cpu_to_be32(nchunks);
486
487done:
488 return encode_item_not_present(xdr);
489}
490
491/* Register and XDR encode the Reply chunk. Supports encoding an array
492 * of plain segments that belong to a single write (reply) chunk.
493 *
494 * Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
495 *
496 * Reply chunk (a counted array):
497 * N elements:
498 * 1 - N - HLOO - HLOO - ... - HLOO
499 *
500 * Returns zero on success, or a negative errno if a failure occurred.
501 * @xdr is advanced to the next position in the stream.
502 */
503static int rpcrdma_encode_reply_chunk(struct rpcrdma_xprt *r_xprt,
504 struct rpcrdma_req *req,
505 struct rpc_rqst *rqst,
506 enum rpcrdma_chunktype wtype)
507{
508 struct xdr_stream *xdr = &req->rl_stream;
509 struct rpcrdma_mr_seg *seg;
510 struct rpcrdma_mr *mr;
511 int nsegs, nchunks;
512 __be32 *segcount;
513
514 if (wtype != rpcrdma_replych)
515 return encode_item_not_present(xdr);
516
517 seg = req->rl_segments;
518 nsegs = rpcrdma_convert_iovs(r_xprt, &rqst->rq_rcv_buf, 0, wtype, seg);
519 if (nsegs < 0)
520 return nsegs;
521
522 if (encode_item_present(xdr) < 0)
523 return -EMSGSIZE;
524 segcount = xdr_reserve_space(xdr, sizeof(*segcount));
525 if (unlikely(!segcount))
526 return -EMSGSIZE;
527 /* Actual value encoded below */
528
529 nchunks = 0;
530 do {
531 seg = rpcrdma_mr_prepare(r_xprt, req, seg, nsegs, true, &mr);
532 if (IS_ERR(seg))
533 return PTR_ERR(seg);
534
535 if (encode_rdma_segment(xdr, mr) < 0)
536 return -EMSGSIZE;
537
538 trace_xprtrdma_chunk_reply(rqst->rq_task, mr, nsegs);
539 r_xprt->rx_stats.reply_chunk_count++;
540 r_xprt->rx_stats.total_rdma_request += mr->mr_length;
541 nchunks++;
542 nsegs -= mr->mr_nents;
543 } while (nsegs);
544
545 /* Update count of segments in the Reply chunk */
546 *segcount = cpu_to_be32(nchunks);
547
548 return 0;
549}
550
551static void rpcrdma_sendctx_done(struct kref *kref)
552{
553 struct rpcrdma_req *req =
554 container_of(kref, struct rpcrdma_req, rl_kref);
555 struct rpcrdma_rep *rep = req->rl_reply;
556
557 rpcrdma_complete_rqst(rep);
558 rep->rr_rxprt->rx_stats.reply_waits_for_send++;
559}
560
561/**
562 * rpcrdma_sendctx_unmap - DMA-unmap Send buffer
563 * @sc: sendctx containing SGEs to unmap
564 *
565 */
566void rpcrdma_sendctx_unmap(struct rpcrdma_sendctx *sc)
567{
568 struct ib_sge *sge;
569
570 if (!sc->sc_unmap_count)
571 return;
572
573 /* The first two SGEs contain the transport header and
574 * the inline buffer. These are always left mapped so
575 * they can be cheaply re-used.
576 */
577 for (sge = &sc->sc_sges[2]; sc->sc_unmap_count;
578 ++sge, --sc->sc_unmap_count)
579 ib_dma_unmap_page(sc->sc_device, sge->addr, sge->length,
580 DMA_TO_DEVICE);
581
582 kref_put(&sc->sc_req->rl_kref, rpcrdma_sendctx_done);
583}
584
585/* Prepare an SGE for the RPC-over-RDMA transport header.
586 */
587static bool rpcrdma_prepare_hdr_sge(struct rpcrdma_xprt *r_xprt,
588 struct rpcrdma_req *req, u32 len)
589{
590 struct rpcrdma_sendctx *sc = req->rl_sendctx;
591 struct rpcrdma_regbuf *rb = req->rl_rdmabuf;
592 struct ib_sge *sge = sc->sc_sges;
593
594 if (!rpcrdma_regbuf_dma_map(r_xprt, rb))
595 goto out_regbuf;
596 sge->addr = rdmab_addr(rb);
597 sge->length = len;
598 sge->lkey = rdmab_lkey(rb);
599
600 ib_dma_sync_single_for_device(rdmab_device(rb), sge->addr, sge->length,
601 DMA_TO_DEVICE);
602 sc->sc_wr.num_sge++;
603 return true;
604
605out_regbuf:
606 pr_err("rpcrdma: failed to DMA map a Send buffer\n");
607 return false;
608}
609
610/* Prepare the Send SGEs. The head and tail iovec, and each entry
611 * in the page list, gets its own SGE.
612 */
613static bool rpcrdma_prepare_msg_sges(struct rpcrdma_xprt *r_xprt,
614 struct rpcrdma_req *req,
615 struct xdr_buf *xdr,
616 enum rpcrdma_chunktype rtype)
617{
618 struct rpcrdma_sendctx *sc = req->rl_sendctx;
619 unsigned int sge_no, page_base, len, remaining;
620 struct rpcrdma_regbuf *rb = req->rl_sendbuf;
621 struct ib_sge *sge = sc->sc_sges;
622 struct page *page, **ppages;
623
624 /* The head iovec is straightforward, as it is already
625 * DMA-mapped. Sync the content that has changed.
626 */
627 if (!rpcrdma_regbuf_dma_map(r_xprt, rb))
628 goto out_regbuf;
629 sc->sc_device = rdmab_device(rb);
630 sge_no = 1;
631 sge[sge_no].addr = rdmab_addr(rb);
632 sge[sge_no].length = xdr->head[0].iov_len;
633 sge[sge_no].lkey = rdmab_lkey(rb);
634 ib_dma_sync_single_for_device(rdmab_device(rb), sge[sge_no].addr,
635 sge[sge_no].length, DMA_TO_DEVICE);
636
637 /* If there is a Read chunk, the page list is being handled
638 * via explicit RDMA, and thus is skipped here. However, the
639 * tail iovec may include an XDR pad for the page list, as
640 * well as additional content, and may not reside in the
641 * same page as the head iovec.
642 */
643 if (rtype == rpcrdma_readch) {
644 len = xdr->tail[0].iov_len;
645
646 /* Do not include the tail if it is only an XDR pad */
647 if (len < 4)
648 goto out;
649
650 page = virt_to_page(xdr->tail[0].iov_base);
651 page_base = offset_in_page(xdr->tail[0].iov_base);
652
653 /* If the content in the page list is an odd length,
654 * xdr_write_pages() has added a pad at the beginning
655 * of the tail iovec. Force the tail's non-pad content
656 * to land at the next XDR position in the Send message.
657 */
658 page_base += len & 3;
659 len -= len & 3;
660 goto map_tail;
661 }
662
663 /* If there is a page list present, temporarily DMA map
664 * and prepare an SGE for each page to be sent.
665 */
666 if (xdr->page_len) {
667 ppages = xdr->pages + (xdr->page_base >> PAGE_SHIFT);
668 page_base = offset_in_page(xdr->page_base);
669 remaining = xdr->page_len;
670 while (remaining) {
671 sge_no++;
672 if (sge_no > RPCRDMA_MAX_SEND_SGES - 2)
673 goto out_mapping_overflow;
674
675 len = min_t(u32, PAGE_SIZE - page_base, remaining);
676 sge[sge_no].addr =
677 ib_dma_map_page(rdmab_device(rb), *ppages,
678 page_base, len, DMA_TO_DEVICE);
679 if (ib_dma_mapping_error(rdmab_device(rb),
680 sge[sge_no].addr))
681 goto out_mapping_err;
682 sge[sge_no].length = len;
683 sge[sge_no].lkey = rdmab_lkey(rb);
684
685 sc->sc_unmap_count++;
686 ppages++;
687 remaining -= len;
688 page_base = 0;
689 }
690 }
691
692 /* The tail iovec is not always constructed in the same
693 * page where the head iovec resides (see, for example,
694 * gss_wrap_req_priv). To neatly accommodate that case,
695 * DMA map it separately.
696 */
697 if (xdr->tail[0].iov_len) {
698 page = virt_to_page(xdr->tail[0].iov_base);
699 page_base = offset_in_page(xdr->tail[0].iov_base);
700 len = xdr->tail[0].iov_len;
701
702map_tail:
703 sge_no++;
704 sge[sge_no].addr =
705 ib_dma_map_page(rdmab_device(rb), page, page_base, len,
706 DMA_TO_DEVICE);
707 if (ib_dma_mapping_error(rdmab_device(rb), sge[sge_no].addr))
708 goto out_mapping_err;
709 sge[sge_no].length = len;
710 sge[sge_no].lkey = rdmab_lkey(rb);
711 sc->sc_unmap_count++;
712 }
713
714out:
715 sc->sc_wr.num_sge += sge_no;
716 if (sc->sc_unmap_count)
717 kref_get(&req->rl_kref);
718 return true;
719
720out_regbuf:
721 pr_err("rpcrdma: failed to DMA map a Send buffer\n");
722 return false;
723
724out_mapping_overflow:
725 rpcrdma_sendctx_unmap(sc);
726 pr_err("rpcrdma: too many Send SGEs (%u)\n", sge_no);
727 return false;
728
729out_mapping_err:
730 rpcrdma_sendctx_unmap(sc);
731 trace_xprtrdma_dma_maperr(sge[sge_no].addr);
732 return false;
733}
734
735/**
736 * rpcrdma_prepare_send_sges - Construct SGEs for a Send WR
737 * @r_xprt: controlling transport
738 * @req: context of RPC Call being marshalled
739 * @hdrlen: size of transport header, in bytes
740 * @xdr: xdr_buf containing RPC Call
741 * @rtype: chunk type being encoded
742 *
743 * Returns 0 on success; otherwise a negative errno is returned.
744 */
745int
746rpcrdma_prepare_send_sges(struct rpcrdma_xprt *r_xprt,
747 struct rpcrdma_req *req, u32 hdrlen,
748 struct xdr_buf *xdr, enum rpcrdma_chunktype rtype)
749{
750 int ret;
751
752 ret = -EAGAIN;
753 req->rl_sendctx = rpcrdma_sendctx_get_locked(r_xprt);
754 if (!req->rl_sendctx)
755 goto err;
756 req->rl_sendctx->sc_wr.num_sge = 0;
757 req->rl_sendctx->sc_unmap_count = 0;
758 req->rl_sendctx->sc_req = req;
759 kref_init(&req->rl_kref);
760
761 ret = -EIO;
762 if (!rpcrdma_prepare_hdr_sge(r_xprt, req, hdrlen))
763 goto err;
764 if (rtype != rpcrdma_areadch)
765 if (!rpcrdma_prepare_msg_sges(r_xprt, req, xdr, rtype))
766 goto err;
767 return 0;
768
769err:
770 trace_xprtrdma_prepsend_failed(&req->rl_slot, ret);
771 return ret;
772}
773
774/**
775 * rpcrdma_marshal_req - Marshal and send one RPC request
776 * @r_xprt: controlling transport
777 * @rqst: RPC request to be marshaled
778 *
779 * For the RPC in "rqst", this function:
780 * - Chooses the transfer mode (eg., RDMA_MSG or RDMA_NOMSG)
781 * - Registers Read, Write, and Reply chunks
782 * - Constructs the transport header
783 * - Posts a Send WR to send the transport header and request
784 *
785 * Returns:
786 * %0 if the RPC was sent successfully,
787 * %-ENOTCONN if the connection was lost,
788 * %-EAGAIN if the caller should call again with the same arguments,
789 * %-ENOBUFS if the caller should call again after a delay,
790 * %-EMSGSIZE if the transport header is too small,
791 * %-EIO if a permanent problem occurred while marshaling.
792 */
793int
794rpcrdma_marshal_req(struct rpcrdma_xprt *r_xprt, struct rpc_rqst *rqst)
795{
796 struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
797 struct xdr_stream *xdr = &req->rl_stream;
798 enum rpcrdma_chunktype rtype, wtype;
799 bool ddp_allowed;
800 __be32 *p;
801 int ret;
802
803 rpcrdma_set_xdrlen(&req->rl_hdrbuf, 0);
804 xdr_init_encode(xdr, &req->rl_hdrbuf, rdmab_data(req->rl_rdmabuf),
805 rqst);
806
807 /* Fixed header fields */
808 ret = -EMSGSIZE;
809 p = xdr_reserve_space(xdr, 4 * sizeof(*p));
810 if (!p)
811 goto out_err;
812 *p++ = rqst->rq_xid;
813 *p++ = rpcrdma_version;
814 *p++ = cpu_to_be32(r_xprt->rx_buf.rb_max_requests);
815
816 /* When the ULP employs a GSS flavor that guarantees integrity
817 * or privacy, direct data placement of individual data items
818 * is not allowed.
819 */
820 ddp_allowed = !(rqst->rq_cred->cr_auth->au_flags &
821 RPCAUTH_AUTH_DATATOUCH);
822
823 /*
824 * Chunks needed for results?
825 *
826 * o If the expected result is under the inline threshold, all ops
827 * return as inline.
828 * o Large read ops return data as write chunk(s), header as
829 * inline.
830 * o Large non-read ops return as a single reply chunk.
831 */
832 if (rpcrdma_results_inline(r_xprt, rqst))
833 wtype = rpcrdma_noch;
834 else if ((ddp_allowed && rqst->rq_rcv_buf.flags & XDRBUF_READ) &&
835 rpcrdma_nonpayload_inline(r_xprt, rqst))
836 wtype = rpcrdma_writech;
837 else
838 wtype = rpcrdma_replych;
839
840 /*
841 * Chunks needed for arguments?
842 *
843 * o If the total request is under the inline threshold, all ops
844 * are sent as inline.
845 * o Large write ops transmit data as read chunk(s), header as
846 * inline.
847 * o Large non-write ops are sent with the entire message as a
848 * single read chunk (protocol 0-position special case).
849 *
850 * This assumes that the upper layer does not present a request
851 * that both has a data payload, and whose non-data arguments
852 * by themselves are larger than the inline threshold.
853 */
854 if (rpcrdma_args_inline(r_xprt, rqst)) {
855 *p++ = rdma_msg;
856 rtype = rpcrdma_noch;
857 } else if (ddp_allowed && rqst->rq_snd_buf.flags & XDRBUF_WRITE) {
858 *p++ = rdma_msg;
859 rtype = rpcrdma_readch;
860 } else {
861 r_xprt->rx_stats.nomsg_call_count++;
862 *p++ = rdma_nomsg;
863 rtype = rpcrdma_areadch;
864 }
865
866 /* If this is a retransmit, discard previously registered
867 * chunks. Very likely the connection has been replaced,
868 * so these registrations are invalid and unusable.
869 */
870 frwr_recycle(req);
871
872 /* This implementation supports the following combinations
873 * of chunk lists in one RPC-over-RDMA Call message:
874 *
875 * - Read list
876 * - Write list
877 * - Reply chunk
878 * - Read list + Reply chunk
879 *
880 * It might not yet support the following combinations:
881 *
882 * - Read list + Write list
883 *
884 * It does not support the following combinations:
885 *
886 * - Write list + Reply chunk
887 * - Read list + Write list + Reply chunk
888 *
889 * This implementation supports only a single chunk in each
890 * Read or Write list. Thus for example the client cannot
891 * send a Call message with a Position Zero Read chunk and a
892 * regular Read chunk at the same time.
893 */
894 ret = rpcrdma_encode_read_list(r_xprt, req, rqst, rtype);
895 if (ret)
896 goto out_err;
897 ret = rpcrdma_encode_write_list(r_xprt, req, rqst, wtype);
898 if (ret)
899 goto out_err;
900 ret = rpcrdma_encode_reply_chunk(r_xprt, req, rqst, wtype);
901 if (ret)
902 goto out_err;
903
904 ret = rpcrdma_prepare_send_sges(r_xprt, req, req->rl_hdrbuf.len,
905 &rqst->rq_snd_buf, rtype);
906 if (ret)
907 goto out_err;
908
909 trace_xprtrdma_marshal(req, rtype, wtype);
910 return 0;
911
912out_err:
913 trace_xprtrdma_marshal_failed(rqst, ret);
914 r_xprt->rx_stats.failed_marshal_count++;
915 frwr_reset(req);
916 return ret;
917}
918
919/**
920 * rpcrdma_inline_fixup - Scatter inline received data into rqst's iovecs
921 * @rqst: controlling RPC request
922 * @srcp: points to RPC message payload in receive buffer
923 * @copy_len: remaining length of receive buffer content
924 * @pad: Write chunk pad bytes needed (zero for pure inline)
925 *
926 * The upper layer has set the maximum number of bytes it can
927 * receive in each component of rq_rcv_buf. These values are set in
928 * the head.iov_len, page_len, tail.iov_len, and buflen fields.
929 *
930 * Unlike the TCP equivalent (xdr_partial_copy_from_skb), in
931 * many cases this function simply updates iov_base pointers in
932 * rq_rcv_buf to point directly to the received reply data, to
933 * avoid copying reply data.
934 *
935 * Returns the count of bytes which had to be memcopied.
936 */
937static unsigned long
938rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad)
939{
940 unsigned long fixup_copy_count;
941 int i, npages, curlen;
942 char *destp;
943 struct page **ppages;
944 int page_base;
945
946 /* The head iovec is redirected to the RPC reply message
947 * in the receive buffer, to avoid a memcopy.
948 */
949 rqst->rq_rcv_buf.head[0].iov_base = srcp;
950 rqst->rq_private_buf.head[0].iov_base = srcp;
951
952 /* The contents of the receive buffer that follow
953 * head.iov_len bytes are copied into the page list.
954 */
955 curlen = rqst->rq_rcv_buf.head[0].iov_len;
956 if (curlen > copy_len)
957 curlen = copy_len;
958 trace_xprtrdma_fixup(rqst, copy_len, curlen);
959 srcp += curlen;
960 copy_len -= curlen;
961
962 ppages = rqst->rq_rcv_buf.pages +
963 (rqst->rq_rcv_buf.page_base >> PAGE_SHIFT);
964 page_base = offset_in_page(rqst->rq_rcv_buf.page_base);
965 fixup_copy_count = 0;
966 if (copy_len && rqst->rq_rcv_buf.page_len) {
967 int pagelist_len;
968
969 pagelist_len = rqst->rq_rcv_buf.page_len;
970 if (pagelist_len > copy_len)
971 pagelist_len = copy_len;
972 npages = PAGE_ALIGN(page_base + pagelist_len) >> PAGE_SHIFT;
973 for (i = 0; i < npages; i++) {
974 curlen = PAGE_SIZE - page_base;
975 if (curlen > pagelist_len)
976 curlen = pagelist_len;
977
978 trace_xprtrdma_fixup_pg(rqst, i, srcp,
979 copy_len, curlen);
980 destp = kmap_atomic(ppages[i]);
981 memcpy(destp + page_base, srcp, curlen);
982 flush_dcache_page(ppages[i]);
983 kunmap_atomic(destp);
984 srcp += curlen;
985 copy_len -= curlen;
986 fixup_copy_count += curlen;
987 pagelist_len -= curlen;
988 if (!pagelist_len)
989 break;
990 page_base = 0;
991 }
992
993 /* Implicit padding for the last segment in a Write
994 * chunk is inserted inline at the front of the tail
995 * iovec. The upper layer ignores the content of
996 * the pad. Simply ensure inline content in the tail
997 * that follows the Write chunk is properly aligned.
998 */
999 if (pad)
1000 srcp -= pad;
1001 }
1002
1003 /* The tail iovec is redirected to the remaining data
1004 * in the receive buffer, to avoid a memcopy.
1005 */
1006 if (copy_len || pad) {
1007 rqst->rq_rcv_buf.tail[0].iov_base = srcp;
1008 rqst->rq_private_buf.tail[0].iov_base = srcp;
1009 }
1010
1011 return fixup_copy_count;
1012}
1013
1014/* By convention, backchannel calls arrive via rdma_msg type
1015 * messages, and never populate the chunk lists. This makes
1016 * the RPC/RDMA header small and fixed in size, so it is
1017 * straightforward to check the RPC header's direction field.
1018 */
1019static bool
1020rpcrdma_is_bcall(struct rpcrdma_xprt *r_xprt, struct rpcrdma_rep *rep)
1021#if defined(CONFIG_SUNRPC_BACKCHANNEL)
1022{
1023 struct xdr_stream *xdr = &rep->rr_stream;
1024 __be32 *p;
1025
1026 if (rep->rr_proc != rdma_msg)
1027 return false;
1028
1029 /* Peek at stream contents without advancing. */
1030 p = xdr_inline_decode(xdr, 0);
1031
1032 /* Chunk lists */
1033 if (*p++ != xdr_zero)
1034 return false;
1035 if (*p++ != xdr_zero)
1036 return false;
1037 if (*p++ != xdr_zero)
1038 return false;
1039
1040 /* RPC header */
1041 if (*p++ != rep->rr_xid)
1042 return false;
1043 if (*p != cpu_to_be32(RPC_CALL))
1044 return false;
1045
1046 /* Now that we are sure this is a backchannel call,
1047 * advance to the RPC header.
1048 */
1049 p = xdr_inline_decode(xdr, 3 * sizeof(*p));
1050 if (unlikely(!p))
1051 goto out_short;
1052
1053 rpcrdma_bc_receive_call(r_xprt, rep);
1054 return true;
1055
1056out_short:
1057 pr_warn("RPC/RDMA short backward direction call\n");
1058 return true;
1059}
1060#else /* CONFIG_SUNRPC_BACKCHANNEL */
1061{
1062 return false;
1063}
1064#endif /* CONFIG_SUNRPC_BACKCHANNEL */
1065
1066static int decode_rdma_segment(struct xdr_stream *xdr, u32 *length)
1067{
1068 u32 handle;
1069 u64 offset;
1070 __be32 *p;
1071
1072 p = xdr_inline_decode(xdr, 4 * sizeof(*p));
1073 if (unlikely(!p))
1074 return -EIO;
1075
1076 handle = be32_to_cpup(p++);
1077 *length = be32_to_cpup(p++);
1078 xdr_decode_hyper(p, &offset);
1079
1080 trace_xprtrdma_decode_seg(handle, *length, offset);
1081 return 0;
1082}
1083
1084static int decode_write_chunk(struct xdr_stream *xdr, u32 *length)
1085{
1086 u32 segcount, seglength;
1087 __be32 *p;
1088
1089 p = xdr_inline_decode(xdr, sizeof(*p));
1090 if (unlikely(!p))
1091 return -EIO;
1092
1093 *length = 0;
1094 segcount = be32_to_cpup(p);
1095 while (segcount--) {
1096 if (decode_rdma_segment(xdr, &seglength))
1097 return -EIO;
1098 *length += seglength;
1099 }
1100
1101 return 0;
1102}
1103
1104/* In RPC-over-RDMA Version One replies, a Read list is never
1105 * expected. This decoder is a stub that returns an error if
1106 * a Read list is present.
1107 */
1108static int decode_read_list(struct xdr_stream *xdr)
1109{
1110 __be32 *p;
1111
1112 p = xdr_inline_decode(xdr, sizeof(*p));
1113 if (unlikely(!p))
1114 return -EIO;
1115 if (unlikely(*p != xdr_zero))
1116 return -EIO;
1117 return 0;
1118}
1119
1120/* Supports only one Write chunk in the Write list
1121 */
1122static int decode_write_list(struct xdr_stream *xdr, u32 *length)
1123{
1124 u32 chunklen;
1125 bool first;
1126 __be32 *p;
1127
1128 *length = 0;
1129 first = true;
1130 do {
1131 p = xdr_inline_decode(xdr, sizeof(*p));
1132 if (unlikely(!p))
1133 return -EIO;
1134 if (*p == xdr_zero)
1135 break;
1136 if (!first)
1137 return -EIO;
1138
1139 if (decode_write_chunk(xdr, &chunklen))
1140 return -EIO;
1141 *length += chunklen;
1142 first = false;
1143 } while (true);
1144 return 0;
1145}
1146
1147static int decode_reply_chunk(struct xdr_stream *xdr, u32 *length)
1148{
1149 __be32 *p;
1150
1151 p = xdr_inline_decode(xdr, sizeof(*p));
1152 if (unlikely(!p))
1153 return -EIO;
1154
1155 *length = 0;
1156 if (*p != xdr_zero)
1157 if (decode_write_chunk(xdr, length))
1158 return -EIO;
1159 return 0;
1160}
1161
1162static int
1163rpcrdma_decode_msg(struct rpcrdma_xprt *r_xprt, struct rpcrdma_rep *rep,
1164 struct rpc_rqst *rqst)
1165{
1166 struct xdr_stream *xdr = &rep->rr_stream;
1167 u32 writelist, replychunk, rpclen;
1168 char *base;
1169
1170 /* Decode the chunk lists */
1171 if (decode_read_list(xdr))
1172 return -EIO;
1173 if (decode_write_list(xdr, &writelist))
1174 return -EIO;
1175 if (decode_reply_chunk(xdr, &replychunk))
1176 return -EIO;
1177
1178 /* RDMA_MSG sanity checks */
1179 if (unlikely(replychunk))
1180 return -EIO;
1181
1182 /* Build the RPC reply's Payload stream in rqst->rq_rcv_buf */
1183 base = (char *)xdr_inline_decode(xdr, 0);
1184 rpclen = xdr_stream_remaining(xdr);
1185 r_xprt->rx_stats.fixup_copy_count +=
1186 rpcrdma_inline_fixup(rqst, base, rpclen, writelist & 3);
1187
1188 r_xprt->rx_stats.total_rdma_reply += writelist;
1189 return rpclen + xdr_align_size(writelist);
1190}
1191
1192static noinline int
1193rpcrdma_decode_nomsg(struct rpcrdma_xprt *r_xprt, struct rpcrdma_rep *rep)
1194{
1195 struct xdr_stream *xdr = &rep->rr_stream;
1196 u32 writelist, replychunk;
1197
1198 /* Decode the chunk lists */
1199 if (decode_read_list(xdr))
1200 return -EIO;
1201 if (decode_write_list(xdr, &writelist))
1202 return -EIO;
1203 if (decode_reply_chunk(xdr, &replychunk))
1204 return -EIO;
1205
1206 /* RDMA_NOMSG sanity checks */
1207 if (unlikely(writelist))
1208 return -EIO;
1209 if (unlikely(!replychunk))
1210 return -EIO;
1211
1212 /* Reply chunk buffer already is the reply vector */
1213 r_xprt->rx_stats.total_rdma_reply += replychunk;
1214 return replychunk;
1215}
1216
1217static noinline int
1218rpcrdma_decode_error(struct rpcrdma_xprt *r_xprt, struct rpcrdma_rep *rep,
1219 struct rpc_rqst *rqst)
1220{
1221 struct xdr_stream *xdr = &rep->rr_stream;
1222 __be32 *p;
1223
1224 p = xdr_inline_decode(xdr, sizeof(*p));
1225 if (unlikely(!p))
1226 return -EIO;
1227
1228 switch (*p) {
1229 case err_vers:
1230 p = xdr_inline_decode(xdr, 2 * sizeof(*p));
1231 if (!p)
1232 break;
1233 dprintk("RPC: %s: server reports "
1234 "version error (%u-%u), xid %08x\n", __func__,
1235 be32_to_cpup(p), be32_to_cpu(*(p + 1)),
1236 be32_to_cpu(rep->rr_xid));
1237 break;
1238 case err_chunk:
1239 dprintk("RPC: %s: server reports "
1240 "header decoding error, xid %08x\n", __func__,
1241 be32_to_cpu(rep->rr_xid));
1242 break;
1243 default:
1244 dprintk("RPC: %s: server reports "
1245 "unrecognized error %d, xid %08x\n", __func__,
1246 be32_to_cpup(p), be32_to_cpu(rep->rr_xid));
1247 }
1248
1249 r_xprt->rx_stats.bad_reply_count++;
1250 return -EREMOTEIO;
1251}
1252
1253/* Perform XID lookup, reconstruction of the RPC reply, and
1254 * RPC completion while holding the transport lock to ensure
1255 * the rep, rqst, and rq_task pointers remain stable.
1256 */
1257void rpcrdma_complete_rqst(struct rpcrdma_rep *rep)
1258{
1259 struct rpcrdma_xprt *r_xprt = rep->rr_rxprt;
1260 struct rpc_xprt *xprt = &r_xprt->rx_xprt;
1261 struct rpc_rqst *rqst = rep->rr_rqst;
1262 int status;
1263
1264 switch (rep->rr_proc) {
1265 case rdma_msg:
1266 status = rpcrdma_decode_msg(r_xprt, rep, rqst);
1267 break;
1268 case rdma_nomsg:
1269 status = rpcrdma_decode_nomsg(r_xprt, rep);
1270 break;
1271 case rdma_error:
1272 status = rpcrdma_decode_error(r_xprt, rep, rqst);
1273 break;
1274 default:
1275 status = -EIO;
1276 }
1277 if (status < 0)
1278 goto out_badheader;
1279
1280out:
1281 spin_lock(&xprt->queue_lock);
1282 xprt_complete_rqst(rqst->rq_task, status);
1283 xprt_unpin_rqst(rqst);
1284 spin_unlock(&xprt->queue_lock);
1285 return;
1286
1287/* If the incoming reply terminated a pending RPC, the next
1288 * RPC call will post a replacement receive buffer as it is
1289 * being marshaled.
1290 */
1291out_badheader:
1292 trace_xprtrdma_reply_hdr(rep);
1293 r_xprt->rx_stats.bad_reply_count++;
1294 goto out;
1295}
1296
1297static void rpcrdma_reply_done(struct kref *kref)
1298{
1299 struct rpcrdma_req *req =
1300 container_of(kref, struct rpcrdma_req, rl_kref);
1301
1302 rpcrdma_complete_rqst(req->rl_reply);
1303}
1304
1305/**
1306 * rpcrdma_reply_handler - Process received RPC/RDMA messages
1307 * @rep: Incoming rpcrdma_rep object to process
1308 *
1309 * Errors must result in the RPC task either being awakened, or
1310 * allowed to timeout, to discover the errors at that time.
1311 */
1312void rpcrdma_reply_handler(struct rpcrdma_rep *rep)
1313{
1314 struct rpcrdma_xprt *r_xprt = rep->rr_rxprt;
1315 struct rpc_xprt *xprt = &r_xprt->rx_xprt;
1316 struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
1317 struct rpcrdma_req *req;
1318 struct rpc_rqst *rqst;
1319 u32 credits;
1320 __be32 *p;
1321
1322 /* Any data means we had a useful conversation, so
1323 * then we don't need to delay the next reconnect.
1324 */
1325 if (xprt->reestablish_timeout)
1326 xprt->reestablish_timeout = 0;
1327
1328 /* Fixed transport header fields */
1329 xdr_init_decode(&rep->rr_stream, &rep->rr_hdrbuf,
1330 rep->rr_hdrbuf.head[0].iov_base, NULL);
1331 p = xdr_inline_decode(&rep->rr_stream, 4 * sizeof(*p));
1332 if (unlikely(!p))
1333 goto out_shortreply;
1334 rep->rr_xid = *p++;
1335 rep->rr_vers = *p++;
1336 credits = be32_to_cpu(*p++);
1337 rep->rr_proc = *p++;
1338
1339 if (rep->rr_vers != rpcrdma_version)
1340 goto out_badversion;
1341
1342 if (rpcrdma_is_bcall(r_xprt, rep))
1343 return;
1344
1345 /* Match incoming rpcrdma_rep to an rpcrdma_req to
1346 * get context for handling any incoming chunks.
1347 */
1348 spin_lock(&xprt->queue_lock);
1349 rqst = xprt_lookup_rqst(xprt, rep->rr_xid);
1350 if (!rqst)
1351 goto out_norqst;
1352 xprt_pin_rqst(rqst);
1353 spin_unlock(&xprt->queue_lock);
1354
1355 if (credits == 0)
1356 credits = 1; /* don't deadlock */
1357 else if (credits > buf->rb_max_requests)
1358 credits = buf->rb_max_requests;
1359 if (buf->rb_credits != credits) {
1360 spin_lock(&xprt->transport_lock);
1361 buf->rb_credits = credits;
1362 xprt->cwnd = credits << RPC_CWNDSHIFT;
1363 spin_unlock(&xprt->transport_lock);
1364 }
1365
1366 req = rpcr_to_rdmar(rqst);
1367 if (req->rl_reply) {
1368 trace_xprtrdma_leaked_rep(rqst, req->rl_reply);
1369 rpcrdma_recv_buffer_put(req->rl_reply);
1370 }
1371 req->rl_reply = rep;
1372 rep->rr_rqst = rqst;
1373
1374 trace_xprtrdma_reply(rqst->rq_task, rep, req, credits);
1375
1376 if (rep->rr_wc_flags & IB_WC_WITH_INVALIDATE)
1377 frwr_reminv(rep, &req->rl_registered);
1378 if (!list_empty(&req->rl_registered))
1379 frwr_unmap_async(r_xprt, req);
1380 /* LocalInv completion will complete the RPC */
1381 else
1382 kref_put(&req->rl_kref, rpcrdma_reply_done);
1383 return;
1384
1385out_badversion:
1386 trace_xprtrdma_reply_vers(rep);
1387 goto out;
1388
1389out_norqst:
1390 spin_unlock(&xprt->queue_lock);
1391 trace_xprtrdma_reply_rqst(rep);
1392 goto out;
1393
1394out_shortreply:
1395 trace_xprtrdma_reply_short(rep);
1396
1397out:
1398 rpcrdma_recv_buffer_put(rep);
1399}