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 */
rpcrdma_max_call_header_size(unsigned int maxsegs)66 static 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 */
rpcrdma_max_reply_header_size(unsigned int maxsegs)91 static 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 */
rpcrdma_set_max_header_sizes(struct rpcrdma_xprt * r_xprt)116 void 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 */
rpcrdma_args_inline(struct rpcrdma_xprt * r_xprt,struct rpc_rqst * rqst)135 static 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 */
rpcrdma_results_inline(struct rpcrdma_xprt * r_xprt,struct rpc_rqst * rqst)166 static 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 */
176 static bool
rpcrdma_nonpayload_inline(const struct rpcrdma_xprt * r_xprt,const struct rpc_rqst * rqst)177 rpcrdma_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 */
193 static struct rpcrdma_mr_seg *
rpcrdma_convert_kvec(struct kvec * vec,struct rpcrdma_mr_seg * seg,unsigned int * n)194 rpcrdma_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
223 static int
rpcrdma_convert_iovs(struct rpcrdma_xprt * r_xprt,struct xdr_buf * xdrbuf,unsigned int pos,enum rpcrdma_chunktype type,struct rpcrdma_mr_seg * seg)224 rpcrdma_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
276 out:
277 if (unlikely(n > RPCRDMA_MAX_SEGS))
278 return -EIO;
279 return n;
280 }
281
282 static inline int
encode_item_present(struct xdr_stream * xdr)283 encode_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
295 static inline int
encode_item_not_present(struct xdr_stream * xdr)296 encode_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
308 static void
xdr_encode_rdma_segment(__be32 * iptr,struct rpcrdma_mr * mr)309 xdr_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
316 static int
encode_rdma_segment(struct xdr_stream * xdr,struct rpcrdma_mr * mr)317 encode_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
329 static int
encode_read_segment(struct xdr_stream * xdr,struct rpcrdma_mr * mr,u32 position)330 encode_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
rpcrdma_mr_prepare(struct rpcrdma_xprt * r_xprt,struct rpcrdma_req * req,struct rpcrdma_mr_seg * seg,int nsegs,bool writing,struct rpcrdma_mr ** mr)345 static 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
363 out_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 */
rpcrdma_encode_read_list(struct rpcrdma_xprt * r_xprt,struct rpcrdma_req * req,struct rpc_rqst * rqst,enum rpcrdma_chunktype rtype)385 static 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
421 done:
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 */
rpcrdma_encode_write_list(struct rpcrdma_xprt * r_xprt,struct rpcrdma_req * req,struct rpc_rqst * rqst,enum rpcrdma_chunktype wtype)440 static 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
487 done:
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 */
rpcrdma_encode_reply_chunk(struct rpcrdma_xprt * r_xprt,struct rpcrdma_req * req,struct rpc_rqst * rqst,enum rpcrdma_chunktype wtype)503 static 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
rpcrdma_sendctx_done(struct kref * kref)551 static 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 */
rpcrdma_sendctx_unmap(struct rpcrdma_sendctx * sc)566 void 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 */
rpcrdma_prepare_hdr_sge(struct rpcrdma_xprt * r_xprt,struct rpcrdma_req * req,u32 len)587 static 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
605 out_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 */
rpcrdma_prepare_msg_sges(struct rpcrdma_xprt * r_xprt,struct rpcrdma_req * req,struct xdr_buf * xdr,enum rpcrdma_chunktype rtype)613 static 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
702 map_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
714 out:
715 sc->sc_wr.num_sge += sge_no;
716 if (sc->sc_unmap_count)
717 kref_get(&req->rl_kref);
718 return true;
719
720 out_regbuf:
721 pr_err("rpcrdma: failed to DMA map a Send buffer\n");
722 return false;
723
724 out_mapping_overflow:
725 rpcrdma_sendctx_unmap(sc);
726 pr_err("rpcrdma: too many Send SGEs (%u)\n", sge_no);
727 return false;
728
729 out_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 */
745 int
rpcrdma_prepare_send_sges(struct rpcrdma_xprt * r_xprt,struct rpcrdma_req * req,u32 hdrlen,struct xdr_buf * xdr,enum rpcrdma_chunktype rtype)746 rpcrdma_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
769 err:
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 */
793 int
rpcrdma_marshal_req(struct rpcrdma_xprt * r_xprt,struct rpc_rqst * rqst)794 rpcrdma_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
912 out_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 */
937 static unsigned long
rpcrdma_inline_fixup(struct rpc_rqst * rqst,char * srcp,int copy_len,int pad)938 rpcrdma_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 */
1019 static bool
rpcrdma_is_bcall(struct rpcrdma_xprt * r_xprt,struct rpcrdma_rep * rep)1020 rpcrdma_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
1056 out_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
decode_rdma_segment(struct xdr_stream * xdr,u32 * length)1066 static 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
decode_write_chunk(struct xdr_stream * xdr,u32 * length)1084 static 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 */
decode_read_list(struct xdr_stream * xdr)1108 static 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 */
decode_write_list(struct xdr_stream * xdr,u32 * length)1122 static 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
decode_reply_chunk(struct xdr_stream * xdr,u32 * length)1147 static 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
1162 static int
rpcrdma_decode_msg(struct rpcrdma_xprt * r_xprt,struct rpcrdma_rep * rep,struct rpc_rqst * rqst)1163 rpcrdma_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
1192 static noinline int
rpcrdma_decode_nomsg(struct rpcrdma_xprt * r_xprt,struct rpcrdma_rep * rep)1193 rpcrdma_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
1217 static noinline int
rpcrdma_decode_error(struct rpcrdma_xprt * r_xprt,struct rpcrdma_rep * rep,struct rpc_rqst * rqst)1218 rpcrdma_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 */
rpcrdma_complete_rqst(struct rpcrdma_rep * rep)1257 void 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
1280 out:
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 */
1291 out_badheader:
1292 trace_xprtrdma_reply_hdr(rep);
1293 r_xprt->rx_stats.bad_reply_count++;
1294 goto out;
1295 }
1296
rpcrdma_reply_done(struct kref * kref)1297 static 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 */
rpcrdma_reply_handler(struct rpcrdma_rep * rep)1312 void 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 rpcrdma_post_recvs(r_xprt, false);
1366
1367 req = rpcr_to_rdmar(rqst);
1368 if (req->rl_reply) {
1369 trace_xprtrdma_leaked_rep(rqst, req->rl_reply);
1370 rpcrdma_recv_buffer_put(req->rl_reply);
1371 }
1372 req->rl_reply = rep;
1373 rep->rr_rqst = rqst;
1374
1375 trace_xprtrdma_reply(rqst->rq_task, rep, req, credits);
1376
1377 if (rep->rr_wc_flags & IB_WC_WITH_INVALIDATE)
1378 frwr_reminv(rep, &req->rl_registered);
1379 if (!list_empty(&req->rl_registered))
1380 frwr_unmap_async(r_xprt, req);
1381 /* LocalInv completion will complete the RPC */
1382 else
1383 kref_put(&req->rl_kref, rpcrdma_reply_done);
1384 return;
1385
1386 out_badversion:
1387 trace_xprtrdma_reply_vers(rep);
1388 goto out;
1389
1390 out_norqst:
1391 spin_unlock(&xprt->queue_lock);
1392 trace_xprtrdma_reply_rqst(rep);
1393 goto out;
1394
1395 out_shortreply:
1396 trace_xprtrdma_reply_short(rep);
1397
1398 out:
1399 rpcrdma_recv_buffer_put(rep);
1400 }
1401