1 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
2 /*
3 * Copyright (c) 2016-2018 Oracle. All rights reserved.
4 * Copyright (c) 2014 Open Grid Computing, Inc. All rights reserved.
5 * Copyright (c) 2005-2006 Network Appliance, Inc. All rights reserved.
6 *
7 * This software is available to you under a choice of one of two
8 * licenses. You may choose to be licensed under the terms of the GNU
9 * General Public License (GPL) Version 2, available from the file
10 * COPYING in the main directory of this source tree, or the BSD-type
11 * license below:
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 *
17 * Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 *
20 * Redistributions in binary form must reproduce the above
21 * copyright notice, this list of conditions and the following
22 * disclaimer in the documentation and/or other materials provided
23 * with the distribution.
24 *
25 * Neither the name of the Network Appliance, Inc. nor the names of
26 * its contributors may be used to endorse or promote products
27 * derived from this software without specific prior written
28 * permission.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
31 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
32 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
33 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
34 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
35 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
36 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
37 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
38 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
39 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
40 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
41 *
42 * Author: Tom Tucker <tom@opengridcomputing.com>
43 */
44
45 /* Operation
46 *
47 * The main entry point is svc_rdma_recvfrom. This is called from
48 * svc_recv when the transport indicates there is incoming data to
49 * be read. "Data Ready" is signaled when an RDMA Receive completes,
50 * or when a set of RDMA Reads complete.
51 *
52 * An svc_rqst is passed in. This structure contains an array of
53 * free pages (rq_pages) that will contain the incoming RPC message.
54 *
55 * Short messages are moved directly into svc_rqst::rq_arg, and
56 * the RPC Call is ready to be processed by the Upper Layer.
57 * svc_rdma_recvfrom returns the length of the RPC Call message,
58 * completing the reception of the RPC Call.
59 *
60 * However, when an incoming message has Read chunks,
61 * svc_rdma_recvfrom must post RDMA Reads to pull the RPC Call's
62 * data payload from the client. svc_rdma_recvfrom sets up the
63 * RDMA Reads using pages in svc_rqst::rq_pages, which are
64 * transferred to an svc_rdma_recv_ctxt for the duration of the
65 * I/O. svc_rdma_recvfrom then returns zero, since the RPC message
66 * is still not yet ready.
67 *
68 * When the Read chunk payloads have become available on the
69 * server, "Data Ready" is raised again, and svc_recv calls
70 * svc_rdma_recvfrom again. This second call may use a different
71 * svc_rqst than the first one, thus any information that needs
72 * to be preserved across these two calls is kept in an
73 * svc_rdma_recv_ctxt.
74 *
75 * The second call to svc_rdma_recvfrom performs final assembly
76 * of the RPC Call message, using the RDMA Read sink pages kept in
77 * the svc_rdma_recv_ctxt. The xdr_buf is copied from the
78 * svc_rdma_recv_ctxt to the second svc_rqst. The second call returns
79 * the length of the completed RPC Call message.
80 *
81 * Page Management
82 *
83 * Pages under I/O must be transferred from the first svc_rqst to an
84 * svc_rdma_recv_ctxt before the first svc_rdma_recvfrom call returns.
85 *
86 * The first svc_rqst supplies pages for RDMA Reads. These are moved
87 * from rqstp::rq_pages into ctxt::pages. The consumed elements of
88 * the rq_pages array are set to NULL and refilled with the first
89 * svc_rdma_recvfrom call returns.
90 *
91 * During the second svc_rdma_recvfrom call, RDMA Read sink pages
92 * are transferred from the svc_rdma_recv_ctxt to the second svc_rqst
93 * (see rdma_read_complete() below).
94 */
95
96 #include <linux/spinlock.h>
97 #include <asm/unaligned.h>
98 #include <rdma/ib_verbs.h>
99 #include <rdma/rdma_cm.h>
100
101 #include <linux/sunrpc/xdr.h>
102 #include <linux/sunrpc/debug.h>
103 #include <linux/sunrpc/rpc_rdma.h>
104 #include <linux/sunrpc/svc_rdma.h>
105
106 #include "xprt_rdma.h"
107 #include <trace/events/rpcrdma.h>
108
109 #define RPCDBG_FACILITY RPCDBG_SVCXPRT
110
111 static void svc_rdma_wc_receive(struct ib_cq *cq, struct ib_wc *wc);
112
113 static inline struct svc_rdma_recv_ctxt *
svc_rdma_next_recv_ctxt(struct list_head * list)114 svc_rdma_next_recv_ctxt(struct list_head *list)
115 {
116 return list_first_entry_or_null(list, struct svc_rdma_recv_ctxt,
117 rc_list);
118 }
119
svc_rdma_recv_cid_init(struct svcxprt_rdma * rdma,struct rpc_rdma_cid * cid)120 static void svc_rdma_recv_cid_init(struct svcxprt_rdma *rdma,
121 struct rpc_rdma_cid *cid)
122 {
123 cid->ci_queue_id = rdma->sc_rq_cq->res.id;
124 cid->ci_completion_id = atomic_inc_return(&rdma->sc_completion_ids);
125 }
126
127 static struct svc_rdma_recv_ctxt *
svc_rdma_recv_ctxt_alloc(struct svcxprt_rdma * rdma)128 svc_rdma_recv_ctxt_alloc(struct svcxprt_rdma *rdma)
129 {
130 struct svc_rdma_recv_ctxt *ctxt;
131 dma_addr_t addr;
132 void *buffer;
133
134 ctxt = kmalloc(sizeof(*ctxt), GFP_KERNEL);
135 if (!ctxt)
136 goto fail0;
137 buffer = kmalloc(rdma->sc_max_req_size, GFP_KERNEL);
138 if (!buffer)
139 goto fail1;
140 addr = ib_dma_map_single(rdma->sc_pd->device, buffer,
141 rdma->sc_max_req_size, DMA_FROM_DEVICE);
142 if (ib_dma_mapping_error(rdma->sc_pd->device, addr))
143 goto fail2;
144
145 svc_rdma_recv_cid_init(rdma, &ctxt->rc_cid);
146
147 ctxt->rc_recv_wr.next = NULL;
148 ctxt->rc_recv_wr.wr_cqe = &ctxt->rc_cqe;
149 ctxt->rc_recv_wr.sg_list = &ctxt->rc_recv_sge;
150 ctxt->rc_recv_wr.num_sge = 1;
151 ctxt->rc_cqe.done = svc_rdma_wc_receive;
152 ctxt->rc_recv_sge.addr = addr;
153 ctxt->rc_recv_sge.length = rdma->sc_max_req_size;
154 ctxt->rc_recv_sge.lkey = rdma->sc_pd->local_dma_lkey;
155 ctxt->rc_recv_buf = buffer;
156 ctxt->rc_temp = false;
157 return ctxt;
158
159 fail2:
160 kfree(buffer);
161 fail1:
162 kfree(ctxt);
163 fail0:
164 return NULL;
165 }
166
svc_rdma_recv_ctxt_destroy(struct svcxprt_rdma * rdma,struct svc_rdma_recv_ctxt * ctxt)167 static void svc_rdma_recv_ctxt_destroy(struct svcxprt_rdma *rdma,
168 struct svc_rdma_recv_ctxt *ctxt)
169 {
170 ib_dma_unmap_single(rdma->sc_pd->device, ctxt->rc_recv_sge.addr,
171 ctxt->rc_recv_sge.length, DMA_FROM_DEVICE);
172 kfree(ctxt->rc_recv_buf);
173 kfree(ctxt);
174 }
175
176 /**
177 * svc_rdma_recv_ctxts_destroy - Release all recv_ctxt's for an xprt
178 * @rdma: svcxprt_rdma being torn down
179 *
180 */
svc_rdma_recv_ctxts_destroy(struct svcxprt_rdma * rdma)181 void svc_rdma_recv_ctxts_destroy(struct svcxprt_rdma *rdma)
182 {
183 struct svc_rdma_recv_ctxt *ctxt;
184 struct llist_node *node;
185
186 while ((node = llist_del_first(&rdma->sc_recv_ctxts))) {
187 ctxt = llist_entry(node, struct svc_rdma_recv_ctxt, rc_node);
188 svc_rdma_recv_ctxt_destroy(rdma, ctxt);
189 }
190 }
191
192 static struct svc_rdma_recv_ctxt *
svc_rdma_recv_ctxt_get(struct svcxprt_rdma * rdma)193 svc_rdma_recv_ctxt_get(struct svcxprt_rdma *rdma)
194 {
195 struct svc_rdma_recv_ctxt *ctxt;
196 struct llist_node *node;
197
198 node = llist_del_first(&rdma->sc_recv_ctxts);
199 if (!node)
200 goto out_empty;
201 ctxt = llist_entry(node, struct svc_rdma_recv_ctxt, rc_node);
202
203 out:
204 ctxt->rc_page_count = 0;
205 ctxt->rc_read_payload_length = 0;
206 return ctxt;
207
208 out_empty:
209 ctxt = svc_rdma_recv_ctxt_alloc(rdma);
210 if (!ctxt)
211 return NULL;
212 goto out;
213 }
214
215 /**
216 * svc_rdma_recv_ctxt_put - Return recv_ctxt to free list
217 * @rdma: controlling svcxprt_rdma
218 * @ctxt: object to return to the free list
219 *
220 */
svc_rdma_recv_ctxt_put(struct svcxprt_rdma * rdma,struct svc_rdma_recv_ctxt * ctxt)221 void svc_rdma_recv_ctxt_put(struct svcxprt_rdma *rdma,
222 struct svc_rdma_recv_ctxt *ctxt)
223 {
224 unsigned int i;
225
226 for (i = 0; i < ctxt->rc_page_count; i++)
227 put_page(ctxt->rc_pages[i]);
228
229 if (!ctxt->rc_temp)
230 llist_add(&ctxt->rc_node, &rdma->sc_recv_ctxts);
231 else
232 svc_rdma_recv_ctxt_destroy(rdma, ctxt);
233 }
234
235 /**
236 * svc_rdma_release_rqst - Release transport-specific per-rqst resources
237 * @rqstp: svc_rqst being released
238 *
239 * Ensure that the recv_ctxt is released whether or not a Reply
240 * was sent. For example, the client could close the connection,
241 * or svc_process could drop an RPC, before the Reply is sent.
242 */
svc_rdma_release_rqst(struct svc_rqst * rqstp)243 void svc_rdma_release_rqst(struct svc_rqst *rqstp)
244 {
245 struct svc_rdma_recv_ctxt *ctxt = rqstp->rq_xprt_ctxt;
246 struct svc_xprt *xprt = rqstp->rq_xprt;
247 struct svcxprt_rdma *rdma =
248 container_of(xprt, struct svcxprt_rdma, sc_xprt);
249
250 rqstp->rq_xprt_ctxt = NULL;
251 if (ctxt)
252 svc_rdma_recv_ctxt_put(rdma, ctxt);
253 }
254
__svc_rdma_post_recv(struct svcxprt_rdma * rdma,struct svc_rdma_recv_ctxt * ctxt)255 static int __svc_rdma_post_recv(struct svcxprt_rdma *rdma,
256 struct svc_rdma_recv_ctxt *ctxt)
257 {
258 int ret;
259
260 trace_svcrdma_post_recv(ctxt);
261 ret = ib_post_recv(rdma->sc_qp, &ctxt->rc_recv_wr, NULL);
262 if (ret)
263 goto err_post;
264 return 0;
265
266 err_post:
267 trace_svcrdma_rq_post_err(rdma, ret);
268 svc_rdma_recv_ctxt_put(rdma, ctxt);
269 return ret;
270 }
271
svc_rdma_post_recv(struct svcxprt_rdma * rdma)272 static int svc_rdma_post_recv(struct svcxprt_rdma *rdma)
273 {
274 struct svc_rdma_recv_ctxt *ctxt;
275
276 if (test_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags))
277 return 0;
278 ctxt = svc_rdma_recv_ctxt_get(rdma);
279 if (!ctxt)
280 return -ENOMEM;
281 return __svc_rdma_post_recv(rdma, ctxt);
282 }
283
284 /**
285 * svc_rdma_post_recvs - Post initial set of Recv WRs
286 * @rdma: fresh svcxprt_rdma
287 *
288 * Returns true if successful, otherwise false.
289 */
svc_rdma_post_recvs(struct svcxprt_rdma * rdma)290 bool svc_rdma_post_recvs(struct svcxprt_rdma *rdma)
291 {
292 struct svc_rdma_recv_ctxt *ctxt;
293 unsigned int i;
294 int ret;
295
296 for (i = 0; i < rdma->sc_max_requests; i++) {
297 ctxt = svc_rdma_recv_ctxt_get(rdma);
298 if (!ctxt)
299 return false;
300 ctxt->rc_temp = true;
301 ret = __svc_rdma_post_recv(rdma, ctxt);
302 if (ret)
303 return false;
304 }
305 return true;
306 }
307
308 /**
309 * svc_rdma_wc_receive - Invoked by RDMA provider for each polled Receive WC
310 * @cq: Completion Queue context
311 * @wc: Work Completion object
312 *
313 * NB: The svc_xprt/svcxprt_rdma is pinned whenever it's possible that
314 * the Receive completion handler could be running.
315 */
svc_rdma_wc_receive(struct ib_cq * cq,struct ib_wc * wc)316 static void svc_rdma_wc_receive(struct ib_cq *cq, struct ib_wc *wc)
317 {
318 struct svcxprt_rdma *rdma = cq->cq_context;
319 struct ib_cqe *cqe = wc->wr_cqe;
320 struct svc_rdma_recv_ctxt *ctxt;
321
322 /* WARNING: Only wc->wr_cqe and wc->status are reliable */
323 ctxt = container_of(cqe, struct svc_rdma_recv_ctxt, rc_cqe);
324
325 trace_svcrdma_wc_receive(wc, &ctxt->rc_cid);
326 if (wc->status != IB_WC_SUCCESS)
327 goto flushed;
328
329 if (svc_rdma_post_recv(rdma))
330 goto post_err;
331
332 /* All wc fields are now known to be valid */
333 ctxt->rc_byte_len = wc->byte_len;
334 ib_dma_sync_single_for_cpu(rdma->sc_pd->device,
335 ctxt->rc_recv_sge.addr,
336 wc->byte_len, DMA_FROM_DEVICE);
337
338 spin_lock(&rdma->sc_rq_dto_lock);
339 list_add_tail(&ctxt->rc_list, &rdma->sc_rq_dto_q);
340 /* Note the unlock pairs with the smp_rmb in svc_xprt_ready: */
341 set_bit(XPT_DATA, &rdma->sc_xprt.xpt_flags);
342 spin_unlock(&rdma->sc_rq_dto_lock);
343 if (!test_bit(RDMAXPRT_CONN_PENDING, &rdma->sc_flags))
344 svc_xprt_enqueue(&rdma->sc_xprt);
345 return;
346
347 flushed:
348 post_err:
349 svc_rdma_recv_ctxt_put(rdma, ctxt);
350 set_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags);
351 svc_xprt_enqueue(&rdma->sc_xprt);
352 }
353
354 /**
355 * svc_rdma_flush_recv_queues - Drain pending Receive work
356 * @rdma: svcxprt_rdma being shut down
357 *
358 */
svc_rdma_flush_recv_queues(struct svcxprt_rdma * rdma)359 void svc_rdma_flush_recv_queues(struct svcxprt_rdma *rdma)
360 {
361 struct svc_rdma_recv_ctxt *ctxt;
362
363 while ((ctxt = svc_rdma_next_recv_ctxt(&rdma->sc_read_complete_q))) {
364 list_del(&ctxt->rc_list);
365 svc_rdma_recv_ctxt_put(rdma, ctxt);
366 }
367 while ((ctxt = svc_rdma_next_recv_ctxt(&rdma->sc_rq_dto_q))) {
368 list_del(&ctxt->rc_list);
369 svc_rdma_recv_ctxt_put(rdma, ctxt);
370 }
371 }
372
svc_rdma_build_arg_xdr(struct svc_rqst * rqstp,struct svc_rdma_recv_ctxt * ctxt)373 static void svc_rdma_build_arg_xdr(struct svc_rqst *rqstp,
374 struct svc_rdma_recv_ctxt *ctxt)
375 {
376 struct xdr_buf *arg = &rqstp->rq_arg;
377
378 arg->head[0].iov_base = ctxt->rc_recv_buf;
379 arg->head[0].iov_len = ctxt->rc_byte_len;
380 arg->tail[0].iov_base = NULL;
381 arg->tail[0].iov_len = 0;
382 arg->page_len = 0;
383 arg->page_base = 0;
384 arg->buflen = ctxt->rc_byte_len;
385 arg->len = ctxt->rc_byte_len;
386 }
387
388 /* This accommodates the largest possible Write chunk.
389 */
390 #define MAX_BYTES_WRITE_CHUNK ((u32)(RPCSVC_MAXPAGES << PAGE_SHIFT))
391
392 /* This accommodates the largest possible Position-Zero
393 * Read chunk or Reply chunk.
394 */
395 #define MAX_BYTES_SPECIAL_CHUNK ((u32)((RPCSVC_MAXPAGES + 2) << PAGE_SHIFT))
396
397 /* Sanity check the Read list.
398 *
399 * Implementation limits:
400 * - This implementation supports only one Read chunk.
401 *
402 * Sanity checks:
403 * - Read list does not overflow Receive buffer.
404 * - Segment size limited by largest NFS data payload.
405 *
406 * The segment count is limited to how many segments can
407 * fit in the transport header without overflowing the
408 * buffer. That's about 40 Read segments for a 1KB inline
409 * threshold.
410 *
411 * Return values:
412 * %true: Read list is valid. @rctxt's xdr_stream is updated
413 * to point to the first byte past the Read list.
414 * %false: Read list is corrupt. @rctxt's xdr_stream is left
415 * in an unknown state.
416 */
xdr_check_read_list(struct svc_rdma_recv_ctxt * rctxt)417 static bool xdr_check_read_list(struct svc_rdma_recv_ctxt *rctxt)
418 {
419 u32 position, len;
420 bool first;
421 __be32 *p;
422
423 p = xdr_inline_decode(&rctxt->rc_stream, sizeof(*p));
424 if (!p)
425 return false;
426
427 len = 0;
428 first = true;
429 while (xdr_item_is_present(p)) {
430 p = xdr_inline_decode(&rctxt->rc_stream,
431 rpcrdma_readseg_maxsz * sizeof(*p));
432 if (!p)
433 return false;
434
435 if (first) {
436 position = be32_to_cpup(p);
437 first = false;
438 } else if (be32_to_cpup(p) != position) {
439 return false;
440 }
441 p += 2;
442 len += be32_to_cpup(p);
443
444 p = xdr_inline_decode(&rctxt->rc_stream, sizeof(*p));
445 if (!p)
446 return false;
447 }
448 return len <= MAX_BYTES_SPECIAL_CHUNK;
449 }
450
451 /* The segment count is limited to how many segments can
452 * fit in the transport header without overflowing the
453 * buffer. That's about 60 Write segments for a 1KB inline
454 * threshold.
455 */
xdr_check_write_chunk(struct svc_rdma_recv_ctxt * rctxt,u32 maxlen)456 static bool xdr_check_write_chunk(struct svc_rdma_recv_ctxt *rctxt, u32 maxlen)
457 {
458 u32 i, segcount, total;
459 __be32 *p;
460
461 p = xdr_inline_decode(&rctxt->rc_stream, sizeof(*p));
462 if (!p)
463 return false;
464 segcount = be32_to_cpup(p);
465
466 total = 0;
467 for (i = 0; i < segcount; i++) {
468 u32 handle, length;
469 u64 offset;
470
471 p = xdr_inline_decode(&rctxt->rc_stream,
472 rpcrdma_segment_maxsz * sizeof(*p));
473 if (!p)
474 return false;
475
476 xdr_decode_rdma_segment(p, &handle, &length, &offset);
477 trace_svcrdma_decode_wseg(handle, length, offset);
478
479 total += length;
480 }
481 return total <= maxlen;
482 }
483
484 /* Sanity check the Write list.
485 *
486 * Implementation limits:
487 * - This implementation currently supports only one Write chunk.
488 *
489 * Sanity checks:
490 * - Write list does not overflow Receive buffer.
491 * - Chunk size limited by largest NFS data payload.
492 *
493 * Return values:
494 * %true: Write list is valid. @rctxt's xdr_stream is updated
495 * to point to the first byte past the Write list.
496 * %false: Write list is corrupt. @rctxt's xdr_stream is left
497 * in an unknown state.
498 */
xdr_check_write_list(struct svc_rdma_recv_ctxt * rctxt)499 static bool xdr_check_write_list(struct svc_rdma_recv_ctxt *rctxt)
500 {
501 u32 chcount = 0;
502 __be32 *p;
503
504 p = xdr_inline_decode(&rctxt->rc_stream, sizeof(*p));
505 if (!p)
506 return false;
507 rctxt->rc_write_list = p;
508 while (xdr_item_is_present(p)) {
509 if (!xdr_check_write_chunk(rctxt, MAX_BYTES_WRITE_CHUNK))
510 return false;
511 ++chcount;
512 p = xdr_inline_decode(&rctxt->rc_stream, sizeof(*p));
513 if (!p)
514 return false;
515 }
516 if (!chcount)
517 rctxt->rc_write_list = NULL;
518 return chcount < 2;
519 }
520
521 /* Sanity check the Reply chunk.
522 *
523 * Sanity checks:
524 * - Reply chunk does not overflow Receive buffer.
525 * - Chunk size limited by largest NFS data payload.
526 *
527 * Return values:
528 * %true: Reply chunk is valid. @rctxt's xdr_stream is updated
529 * to point to the first byte past the Reply chunk.
530 * %false: Reply chunk is corrupt. @rctxt's xdr_stream is left
531 * in an unknown state.
532 */
xdr_check_reply_chunk(struct svc_rdma_recv_ctxt * rctxt)533 static bool xdr_check_reply_chunk(struct svc_rdma_recv_ctxt *rctxt)
534 {
535 __be32 *p;
536
537 p = xdr_inline_decode(&rctxt->rc_stream, sizeof(*p));
538 if (!p)
539 return false;
540 rctxt->rc_reply_chunk = NULL;
541 if (xdr_item_is_present(p)) {
542 if (!xdr_check_write_chunk(rctxt, MAX_BYTES_SPECIAL_CHUNK))
543 return false;
544 rctxt->rc_reply_chunk = p;
545 }
546 return true;
547 }
548
549 /* RPC-over-RDMA Version One private extension: Remote Invalidation.
550 * Responder's choice: requester signals it can handle Send With
551 * Invalidate, and responder chooses one R_key to invalidate.
552 *
553 * If there is exactly one distinct R_key in the received transport
554 * header, set rc_inv_rkey to that R_key. Otherwise, set it to zero.
555 *
556 * Perform this operation while the received transport header is
557 * still in the CPU cache.
558 */
svc_rdma_get_inv_rkey(struct svcxprt_rdma * rdma,struct svc_rdma_recv_ctxt * ctxt)559 static void svc_rdma_get_inv_rkey(struct svcxprt_rdma *rdma,
560 struct svc_rdma_recv_ctxt *ctxt)
561 {
562 __be32 inv_rkey, *p;
563 u32 i, segcount;
564
565 ctxt->rc_inv_rkey = 0;
566
567 if (!rdma->sc_snd_w_inv)
568 return;
569
570 inv_rkey = xdr_zero;
571 p = ctxt->rc_recv_buf;
572 p += rpcrdma_fixed_maxsz;
573
574 /* Read list */
575 while (xdr_item_is_present(p++)) {
576 p++; /* position */
577 if (inv_rkey == xdr_zero)
578 inv_rkey = *p;
579 else if (inv_rkey != *p)
580 return;
581 p += 4;
582 }
583
584 /* Write list */
585 while (xdr_item_is_present(p++)) {
586 segcount = be32_to_cpup(p++);
587 for (i = 0; i < segcount; i++) {
588 if (inv_rkey == xdr_zero)
589 inv_rkey = *p;
590 else if (inv_rkey != *p)
591 return;
592 p += 4;
593 }
594 }
595
596 /* Reply chunk */
597 if (xdr_item_is_present(p++)) {
598 segcount = be32_to_cpup(p++);
599 for (i = 0; i < segcount; i++) {
600 if (inv_rkey == xdr_zero)
601 inv_rkey = *p;
602 else if (inv_rkey != *p)
603 return;
604 p += 4;
605 }
606 }
607
608 ctxt->rc_inv_rkey = be32_to_cpu(inv_rkey);
609 }
610
611 /**
612 * svc_rdma_xdr_decode_req - Decode the transport header
613 * @rq_arg: xdr_buf containing ingress RPC/RDMA message
614 * @rctxt: state of decoding
615 *
616 * On entry, xdr->head[0].iov_base points to first byte of the
617 * RPC-over-RDMA transport header.
618 *
619 * On successful exit, head[0] points to first byte past the
620 * RPC-over-RDMA header. For RDMA_MSG, this is the RPC message.
621 *
622 * The length of the RPC-over-RDMA header is returned.
623 *
624 * Assumptions:
625 * - The transport header is entirely contained in the head iovec.
626 */
svc_rdma_xdr_decode_req(struct xdr_buf * rq_arg,struct svc_rdma_recv_ctxt * rctxt)627 static int svc_rdma_xdr_decode_req(struct xdr_buf *rq_arg,
628 struct svc_rdma_recv_ctxt *rctxt)
629 {
630 __be32 *p, *rdma_argp;
631 unsigned int hdr_len;
632
633 rdma_argp = rq_arg->head[0].iov_base;
634 xdr_init_decode(&rctxt->rc_stream, rq_arg, rdma_argp, NULL);
635
636 p = xdr_inline_decode(&rctxt->rc_stream,
637 rpcrdma_fixed_maxsz * sizeof(*p));
638 if (unlikely(!p))
639 goto out_short;
640 p++;
641 if (*p != rpcrdma_version)
642 goto out_version;
643 p += 2;
644 switch (*p) {
645 case rdma_msg:
646 break;
647 case rdma_nomsg:
648 break;
649 case rdma_done:
650 goto out_drop;
651 case rdma_error:
652 goto out_drop;
653 default:
654 goto out_proc;
655 }
656
657 if (!xdr_check_read_list(rctxt))
658 goto out_inval;
659 if (!xdr_check_write_list(rctxt))
660 goto out_inval;
661 if (!xdr_check_reply_chunk(rctxt))
662 goto out_inval;
663
664 rq_arg->head[0].iov_base = rctxt->rc_stream.p;
665 hdr_len = xdr_stream_pos(&rctxt->rc_stream);
666 rq_arg->head[0].iov_len -= hdr_len;
667 rq_arg->len -= hdr_len;
668 trace_svcrdma_decode_rqst(rctxt, rdma_argp, hdr_len);
669 return hdr_len;
670
671 out_short:
672 trace_svcrdma_decode_short_err(rctxt, rq_arg->len);
673 return -EINVAL;
674
675 out_version:
676 trace_svcrdma_decode_badvers_err(rctxt, rdma_argp);
677 return -EPROTONOSUPPORT;
678
679 out_drop:
680 trace_svcrdma_decode_drop_err(rctxt, rdma_argp);
681 return 0;
682
683 out_proc:
684 trace_svcrdma_decode_badproc_err(rctxt, rdma_argp);
685 return -EINVAL;
686
687 out_inval:
688 trace_svcrdma_decode_parse_err(rctxt, rdma_argp);
689 return -EINVAL;
690 }
691
rdma_read_complete(struct svc_rqst * rqstp,struct svc_rdma_recv_ctxt * head)692 static void rdma_read_complete(struct svc_rqst *rqstp,
693 struct svc_rdma_recv_ctxt *head)
694 {
695 int page_no;
696
697 /* Move Read chunk pages to rqstp so that they will be released
698 * when svc_process is done with them.
699 */
700 for (page_no = 0; page_no < head->rc_page_count; page_no++) {
701 put_page(rqstp->rq_pages[page_no]);
702 rqstp->rq_pages[page_no] = head->rc_pages[page_no];
703 }
704 head->rc_page_count = 0;
705
706 /* Point rq_arg.pages past header */
707 rqstp->rq_arg.pages = &rqstp->rq_pages[head->rc_hdr_count];
708 rqstp->rq_arg.page_len = head->rc_arg.page_len;
709
710 /* rq_respages starts after the last arg page */
711 rqstp->rq_respages = &rqstp->rq_pages[page_no];
712 rqstp->rq_next_page = rqstp->rq_respages + 1;
713
714 /* Rebuild rq_arg head and tail. */
715 rqstp->rq_arg.head[0] = head->rc_arg.head[0];
716 rqstp->rq_arg.tail[0] = head->rc_arg.tail[0];
717 rqstp->rq_arg.len = head->rc_arg.len;
718 rqstp->rq_arg.buflen = head->rc_arg.buflen;
719 }
720
svc_rdma_send_error(struct svcxprt_rdma * rdma,struct svc_rdma_recv_ctxt * rctxt,int status)721 static void svc_rdma_send_error(struct svcxprt_rdma *rdma,
722 struct svc_rdma_recv_ctxt *rctxt,
723 int status)
724 {
725 struct svc_rdma_send_ctxt *sctxt;
726
727 sctxt = svc_rdma_send_ctxt_get(rdma);
728 if (!sctxt)
729 return;
730 svc_rdma_send_error_msg(rdma, sctxt, rctxt, status);
731 }
732
733 /* By convention, backchannel calls arrive via rdma_msg type
734 * messages, and never populate the chunk lists. This makes
735 * the RPC/RDMA header small and fixed in size, so it is
736 * straightforward to check the RPC header's direction field.
737 */
svc_rdma_is_backchannel_reply(struct svc_xprt * xprt,__be32 * rdma_resp)738 static bool svc_rdma_is_backchannel_reply(struct svc_xprt *xprt,
739 __be32 *rdma_resp)
740 {
741 __be32 *p;
742
743 if (!xprt->xpt_bc_xprt)
744 return false;
745
746 p = rdma_resp + 3;
747 if (*p++ != rdma_msg)
748 return false;
749
750 if (*p++ != xdr_zero)
751 return false;
752 if (*p++ != xdr_zero)
753 return false;
754 if (*p++ != xdr_zero)
755 return false;
756
757 /* XID sanity */
758 if (*p++ != *rdma_resp)
759 return false;
760 /* call direction */
761 if (*p == cpu_to_be32(RPC_CALL))
762 return false;
763
764 return true;
765 }
766
767 /**
768 * svc_rdma_recvfrom - Receive an RPC call
769 * @rqstp: request structure into which to receive an RPC Call
770 *
771 * Returns:
772 * The positive number of bytes in the RPC Call message,
773 * %0 if there were no Calls ready to return,
774 * %-EINVAL if the Read chunk data is too large,
775 * %-ENOMEM if rdma_rw context pool was exhausted,
776 * %-ENOTCONN if posting failed (connection is lost),
777 * %-EIO if rdma_rw initialization failed (DMA mapping, etc).
778 *
779 * Called in a loop when XPT_DATA is set. XPT_DATA is cleared only
780 * when there are no remaining ctxt's to process.
781 *
782 * The next ctxt is removed from the "receive" lists.
783 *
784 * - If the ctxt completes a Read, then finish assembling the Call
785 * message and return the number of bytes in the message.
786 *
787 * - If the ctxt completes a Receive, then construct the Call
788 * message from the contents of the Receive buffer.
789 *
790 * - If there are no Read chunks in this message, then finish
791 * assembling the Call message and return the number of bytes
792 * in the message.
793 *
794 * - If there are Read chunks in this message, post Read WRs to
795 * pull that payload and return 0.
796 */
svc_rdma_recvfrom(struct svc_rqst * rqstp)797 int svc_rdma_recvfrom(struct svc_rqst *rqstp)
798 {
799 struct svc_xprt *xprt = rqstp->rq_xprt;
800 struct svcxprt_rdma *rdma_xprt =
801 container_of(xprt, struct svcxprt_rdma, sc_xprt);
802 struct svc_rdma_recv_ctxt *ctxt;
803 __be32 *p;
804 int ret;
805
806 rqstp->rq_xprt_ctxt = NULL;
807
808 spin_lock(&rdma_xprt->sc_rq_dto_lock);
809 ctxt = svc_rdma_next_recv_ctxt(&rdma_xprt->sc_read_complete_q);
810 if (ctxt) {
811 list_del(&ctxt->rc_list);
812 spin_unlock(&rdma_xprt->sc_rq_dto_lock);
813 rdma_read_complete(rqstp, ctxt);
814 goto complete;
815 }
816 ctxt = svc_rdma_next_recv_ctxt(&rdma_xprt->sc_rq_dto_q);
817 if (!ctxt) {
818 /* No new incoming requests, terminate the loop */
819 clear_bit(XPT_DATA, &xprt->xpt_flags);
820 spin_unlock(&rdma_xprt->sc_rq_dto_lock);
821 return 0;
822 }
823 list_del(&ctxt->rc_list);
824 spin_unlock(&rdma_xprt->sc_rq_dto_lock);
825
826 atomic_inc(&rdma_stat_recv);
827
828 svc_rdma_build_arg_xdr(rqstp, ctxt);
829
830 /* Prevent svc_xprt_release from releasing pages in rq_pages
831 * if we return 0 or an error.
832 */
833 rqstp->rq_respages = rqstp->rq_pages;
834 rqstp->rq_next_page = rqstp->rq_respages;
835
836 p = (__be32 *)rqstp->rq_arg.head[0].iov_base;
837 ret = svc_rdma_xdr_decode_req(&rqstp->rq_arg, ctxt);
838 if (ret < 0)
839 goto out_err;
840 if (ret == 0)
841 goto out_drop;
842 rqstp->rq_xprt_hlen = ret;
843
844 if (svc_rdma_is_backchannel_reply(xprt, p))
845 goto out_backchannel;
846
847 svc_rdma_get_inv_rkey(rdma_xprt, ctxt);
848
849 p += rpcrdma_fixed_maxsz;
850 if (*p != xdr_zero)
851 goto out_readchunk;
852
853 complete:
854 rqstp->rq_xprt_ctxt = ctxt;
855 rqstp->rq_prot = IPPROTO_MAX;
856 svc_xprt_copy_addrs(rqstp, xprt);
857 return rqstp->rq_arg.len;
858
859 out_readchunk:
860 ret = svc_rdma_recv_read_chunk(rdma_xprt, rqstp, ctxt, p);
861 if (ret < 0)
862 goto out_postfail;
863 return 0;
864
865 out_err:
866 svc_rdma_send_error(rdma_xprt, ctxt, ret);
867 svc_rdma_recv_ctxt_put(rdma_xprt, ctxt);
868 return 0;
869
870 out_postfail:
871 if (ret == -EINVAL)
872 svc_rdma_send_error(rdma_xprt, ctxt, ret);
873 svc_rdma_recv_ctxt_put(rdma_xprt, ctxt);
874 return ret;
875
876 out_backchannel:
877 svc_rdma_handle_bc_reply(rqstp, ctxt);
878 out_drop:
879 svc_rdma_recv_ctxt_put(rdma_xprt, ctxt);
880 return 0;
881 }
882
