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1/*
2 * Copyright (c) 2005-2006 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 * Author: Tom Tucker <tom@opengridcomputing.com>
40 */
41
42#include <linux/sunrpc/debug.h>
43#include <linux/sunrpc/rpc_rdma.h>
44#include <linux/spinlock.h>
45#include <asm/unaligned.h>
46#include <rdma/ib_verbs.h>
47#include <rdma/rdma_cm.h>
48#include <linux/sunrpc/svc_rdma.h>
49
50#define RPCDBG_FACILITY RPCDBG_SVCXPRT
51
52/*
53 * Replace the pages in the rq_argpages array with the pages from the SGE in
54 * the RDMA_RECV completion. The SGL should contain full pages up until the
55 * last one.
56 */
57static void rdma_build_arg_xdr(struct svc_rqst *rqstp,
58 struct svc_rdma_op_ctxt *ctxt,
59 u32 byte_count)
60{
61 struct page *page;
62 u32 bc;
63 int sge_no;
64
65 /* Swap the page in the SGE with the page in argpages */
66 page = ctxt->pages[0];
67 put_page(rqstp->rq_pages[0]);
68 rqstp->rq_pages[0] = page;
69
70 /* Set up the XDR head */
71 rqstp->rq_arg.head[0].iov_base = page_address(page);
72 rqstp->rq_arg.head[0].iov_len = min(byte_count, ctxt->sge[0].length);
73 rqstp->rq_arg.len = byte_count;
74 rqstp->rq_arg.buflen = byte_count;
75
76 /* Compute bytes past head in the SGL */
77 bc = byte_count - rqstp->rq_arg.head[0].iov_len;
78
79 /* If data remains, store it in the pagelist */
80 rqstp->rq_arg.page_len = bc;
81 rqstp->rq_arg.page_base = 0;
82 rqstp->rq_arg.pages = &rqstp->rq_pages[1];
83 sge_no = 1;
84 while (bc && sge_no < ctxt->count) {
85 page = ctxt->pages[sge_no];
86 put_page(rqstp->rq_pages[sge_no]);
87 rqstp->rq_pages[sge_no] = page;
88 bc -= min(bc, ctxt->sge[sge_no].length);
89 rqstp->rq_arg.buflen += ctxt->sge[sge_no].length;
90 sge_no++;
91 }
92 rqstp->rq_respages = &rqstp->rq_pages[sge_no];
93
94 /* We should never run out of SGE because the limit is defined to
95 * support the max allowed RPC data length
96 */
97 BUG_ON(bc && (sge_no == ctxt->count));
98 BUG_ON((rqstp->rq_arg.head[0].iov_len + rqstp->rq_arg.page_len)
99 != byte_count);
100 BUG_ON(rqstp->rq_arg.len != byte_count);
101
102 /* If not all pages were used from the SGL, free the remaining ones */
103 bc = sge_no;
104 while (sge_no < ctxt->count) {
105 page = ctxt->pages[sge_no++];
106 put_page(page);
107 }
108 ctxt->count = bc;
109
110 /* Set up tail */
111 rqstp->rq_arg.tail[0].iov_base = NULL;
112 rqstp->rq_arg.tail[0].iov_len = 0;
113}
114
115/* Encode a read-chunk-list as an array of IB SGE
116 *
117 * Assumptions:
118 * - chunk[0]->position points to pages[0] at an offset of 0
119 * - pages[] is not physically or virtually contiguous and consists of
120 * PAGE_SIZE elements.
121 *
122 * Output:
123 * - sge array pointing into pages[] array.
124 * - chunk_sge array specifying sge index and count for each
125 * chunk in the read list
126 *
127 */
128static int map_read_chunks(struct svcxprt_rdma *xprt,
129 struct svc_rqst *rqstp,
130 struct svc_rdma_op_ctxt *head,
131 struct rpcrdma_msg *rmsgp,
132 struct svc_rdma_req_map *rpl_map,
133 struct svc_rdma_req_map *chl_map,
134 int ch_count,
135 int byte_count)
136{
137 int sge_no;
138 int sge_bytes;
139 int page_off;
140 int page_no;
141 int ch_bytes;
142 int ch_no;
143 struct rpcrdma_read_chunk *ch;
144
145 sge_no = 0;
146 page_no = 0;
147 page_off = 0;
148 ch = (struct rpcrdma_read_chunk *)&rmsgp->rm_body.rm_chunks[0];
149 ch_no = 0;
150 ch_bytes = ntohl(ch->rc_target.rs_length);
151 head->arg.head[0] = rqstp->rq_arg.head[0];
152 head->arg.tail[0] = rqstp->rq_arg.tail[0];
153 head->arg.pages = &head->pages[head->count];
154 head->hdr_count = head->count; /* save count of hdr pages */
155 head->arg.page_base = 0;
156 head->arg.page_len = ch_bytes;
157 head->arg.len = rqstp->rq_arg.len + ch_bytes;
158 head->arg.buflen = rqstp->rq_arg.buflen + ch_bytes;
159 head->count++;
160 chl_map->ch[0].start = 0;
161 while (byte_count) {
162 rpl_map->sge[sge_no].iov_base =
163 page_address(rqstp->rq_arg.pages[page_no]) + page_off;
164 sge_bytes = min_t(int, PAGE_SIZE-page_off, ch_bytes);
165 rpl_map->sge[sge_no].iov_len = sge_bytes;
166 /*
167 * Don't bump head->count here because the same page
168 * may be used by multiple SGE.
169 */
170 head->arg.pages[page_no] = rqstp->rq_arg.pages[page_no];
171 rqstp->rq_respages = &rqstp->rq_arg.pages[page_no+1];
172
173 byte_count -= sge_bytes;
174 ch_bytes -= sge_bytes;
175 sge_no++;
176 /*
177 * If all bytes for this chunk have been mapped to an
178 * SGE, move to the next SGE
179 */
180 if (ch_bytes == 0) {
181 chl_map->ch[ch_no].count =
182 sge_no - chl_map->ch[ch_no].start;
183 ch_no++;
184 ch++;
185 chl_map->ch[ch_no].start = sge_no;
186 ch_bytes = ntohl(ch->rc_target.rs_length);
187 /* If bytes remaining account for next chunk */
188 if (byte_count) {
189 head->arg.page_len += ch_bytes;
190 head->arg.len += ch_bytes;
191 head->arg.buflen += ch_bytes;
192 }
193 }
194 /*
195 * If this SGE consumed all of the page, move to the
196 * next page
197 */
198 if ((sge_bytes + page_off) == PAGE_SIZE) {
199 page_no++;
200 page_off = 0;
201 /*
202 * If there are still bytes left to map, bump
203 * the page count
204 */
205 if (byte_count)
206 head->count++;
207 } else
208 page_off += sge_bytes;
209 }
210 BUG_ON(byte_count != 0);
211 return sge_no;
212}
213
214/* Map a read-chunk-list to an XDR and fast register the page-list.
215 *
216 * Assumptions:
217 * - chunk[0] position points to pages[0] at an offset of 0
218 * - pages[] will be made physically contiguous by creating a one-off memory
219 * region using the fastreg verb.
220 * - byte_count is # of bytes in read-chunk-list
221 * - ch_count is # of chunks in read-chunk-list
222 *
223 * Output:
224 * - sge array pointing into pages[] array.
225 * - chunk_sge array specifying sge index and count for each
226 * chunk in the read list
227 */
228static int fast_reg_read_chunks(struct svcxprt_rdma *xprt,
229 struct svc_rqst *rqstp,
230 struct svc_rdma_op_ctxt *head,
231 struct rpcrdma_msg *rmsgp,
232 struct svc_rdma_req_map *rpl_map,
233 struct svc_rdma_req_map *chl_map,
234 int ch_count,
235 int byte_count)
236{
237 int page_no;
238 int ch_no;
239 u32 offset;
240 struct rpcrdma_read_chunk *ch;
241 struct svc_rdma_fastreg_mr *frmr;
242 int ret = 0;
243
244 frmr = svc_rdma_get_frmr(xprt);
245 if (IS_ERR(frmr))
246 return -ENOMEM;
247
248 head->frmr = frmr;
249 head->arg.head[0] = rqstp->rq_arg.head[0];
250 head->arg.tail[0] = rqstp->rq_arg.tail[0];
251 head->arg.pages = &head->pages[head->count];
252 head->hdr_count = head->count; /* save count of hdr pages */
253 head->arg.page_base = 0;
254 head->arg.page_len = byte_count;
255 head->arg.len = rqstp->rq_arg.len + byte_count;
256 head->arg.buflen = rqstp->rq_arg.buflen + byte_count;
257
258 /* Fast register the page list */
259 frmr->kva = page_address(rqstp->rq_arg.pages[0]);
260 frmr->direction = DMA_FROM_DEVICE;
261 frmr->access_flags = (IB_ACCESS_LOCAL_WRITE|IB_ACCESS_REMOTE_WRITE);
262 frmr->map_len = byte_count;
263 frmr->page_list_len = PAGE_ALIGN(byte_count) >> PAGE_SHIFT;
264 for (page_no = 0; page_no < frmr->page_list_len; page_no++) {
265 frmr->page_list->page_list[page_no] =
266 ib_dma_map_page(xprt->sc_cm_id->device,
267 rqstp->rq_arg.pages[page_no], 0,
268 PAGE_SIZE, DMA_FROM_DEVICE);
269 if (ib_dma_mapping_error(xprt->sc_cm_id->device,
270 frmr->page_list->page_list[page_no]))
271 goto fatal_err;
272 atomic_inc(&xprt->sc_dma_used);
273 head->arg.pages[page_no] = rqstp->rq_arg.pages[page_no];
274 }
275 head->count += page_no;
276
277 /* rq_respages points one past arg pages */
278 rqstp->rq_respages = &rqstp->rq_arg.pages[page_no];
279
280 /* Create the reply and chunk maps */
281 offset = 0;
282 ch = (struct rpcrdma_read_chunk *)&rmsgp->rm_body.rm_chunks[0];
283 for (ch_no = 0; ch_no < ch_count; ch_no++) {
284 int len = ntohl(ch->rc_target.rs_length);
285 rpl_map->sge[ch_no].iov_base = frmr->kva + offset;
286 rpl_map->sge[ch_no].iov_len = len;
287 chl_map->ch[ch_no].count = 1;
288 chl_map->ch[ch_no].start = ch_no;
289 offset += len;
290 ch++;
291 }
292
293 ret = svc_rdma_fastreg(xprt, frmr);
294 if (ret)
295 goto fatal_err;
296
297 return ch_no;
298
299 fatal_err:
300 printk("svcrdma: error fast registering xdr for xprt %p", xprt);
301 svc_rdma_put_frmr(xprt, frmr);
302 return -EIO;
303}
304
305static int rdma_set_ctxt_sge(struct svcxprt_rdma *xprt,
306 struct svc_rdma_op_ctxt *ctxt,
307 struct svc_rdma_fastreg_mr *frmr,
308 struct kvec *vec,
309 u64 *sgl_offset,
310 int count)
311{
312 int i;
313 unsigned long off;
314
315 ctxt->count = count;
316 ctxt->direction = DMA_FROM_DEVICE;
317 for (i = 0; i < count; i++) {
318 ctxt->sge[i].length = 0; /* in case map fails */
319 if (!frmr) {
320 BUG_ON(!virt_to_page(vec[i].iov_base));
321 off = (unsigned long)vec[i].iov_base & ~PAGE_MASK;
322 ctxt->sge[i].addr =
323 ib_dma_map_page(xprt->sc_cm_id->device,
324 virt_to_page(vec[i].iov_base),
325 off,
326 vec[i].iov_len,
327 DMA_FROM_DEVICE);
328 if (ib_dma_mapping_error(xprt->sc_cm_id->device,
329 ctxt->sge[i].addr))
330 return -EINVAL;
331 ctxt->sge[i].lkey = xprt->sc_dma_lkey;
332 atomic_inc(&xprt->sc_dma_used);
333 } else {
334 ctxt->sge[i].addr = (unsigned long)vec[i].iov_base;
335 ctxt->sge[i].lkey = frmr->mr->lkey;
336 }
337 ctxt->sge[i].length = vec[i].iov_len;
338 *sgl_offset = *sgl_offset + vec[i].iov_len;
339 }
340 return 0;
341}
342
343static int rdma_read_max_sge(struct svcxprt_rdma *xprt, int sge_count)
344{
345 if ((rdma_node_get_transport(xprt->sc_cm_id->device->node_type) ==
346 RDMA_TRANSPORT_IWARP) &&
347 sge_count > 1)
348 return 1;
349 else
350 return min_t(int, sge_count, xprt->sc_max_sge);
351}
352
353/*
354 * Use RDMA_READ to read data from the advertised client buffer into the
355 * XDR stream starting at rq_arg.head[0].iov_base.
356 * Each chunk in the array
357 * contains the following fields:
358 * discrim - '1', This isn't used for data placement
359 * position - The xdr stream offset (the same for every chunk)
360 * handle - RMR for client memory region
361 * length - data transfer length
362 * offset - 64 bit tagged offset in remote memory region
363 *
364 * On our side, we need to read into a pagelist. The first page immediately
365 * follows the RPC header.
366 *
367 * This function returns:
368 * 0 - No error and no read-list found.
369 *
370 * 1 - Successful read-list processing. The data is not yet in
371 * the pagelist and therefore the RPC request must be deferred. The
372 * I/O completion will enqueue the transport again and
373 * svc_rdma_recvfrom will complete the request.
374 *
375 * <0 - Error processing/posting read-list.
376 *
377 * NOTE: The ctxt must not be touched after the last WR has been posted
378 * because the I/O completion processing may occur on another
379 * processor and free / modify the context. Ne touche pas!
380 */
381static int rdma_read_xdr(struct svcxprt_rdma *xprt,
382 struct rpcrdma_msg *rmsgp,
383 struct svc_rqst *rqstp,
384 struct svc_rdma_op_ctxt *hdr_ctxt)
385{
386 struct ib_send_wr read_wr;
387 struct ib_send_wr inv_wr;
388 int err = 0;
389 int ch_no;
390 int ch_count;
391 int byte_count;
392 int sge_count;
393 u64 sgl_offset;
394 struct rpcrdma_read_chunk *ch;
395 struct svc_rdma_op_ctxt *ctxt = NULL;
396 struct svc_rdma_req_map *rpl_map;
397 struct svc_rdma_req_map *chl_map;
398
399 /* If no read list is present, return 0 */
400 ch = svc_rdma_get_read_chunk(rmsgp);
401 if (!ch)
402 return 0;
403
404 svc_rdma_rcl_chunk_counts(ch, &ch_count, &byte_count);
405 if (ch_count > RPCSVC_MAXPAGES)
406 return -EINVAL;
407
408 /* Allocate temporary reply and chunk maps */
409 rpl_map = svc_rdma_get_req_map();
410 chl_map = svc_rdma_get_req_map();
411
412 if (!xprt->sc_frmr_pg_list_len)
413 sge_count = map_read_chunks(xprt, rqstp, hdr_ctxt, rmsgp,
414 rpl_map, chl_map, ch_count,
415 byte_count);
416 else
417 sge_count = fast_reg_read_chunks(xprt, rqstp, hdr_ctxt, rmsgp,
418 rpl_map, chl_map, ch_count,
419 byte_count);
420 if (sge_count < 0) {
421 err = -EIO;
422 goto out;
423 }
424
425 sgl_offset = 0;
426 ch_no = 0;
427
428 for (ch = (struct rpcrdma_read_chunk *)&rmsgp->rm_body.rm_chunks[0];
429 ch->rc_discrim != 0; ch++, ch_no++) {
430 u64 rs_offset;
431next_sge:
432 ctxt = svc_rdma_get_context(xprt);
433 ctxt->direction = DMA_FROM_DEVICE;
434 ctxt->frmr = hdr_ctxt->frmr;
435 ctxt->read_hdr = NULL;
436 clear_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags);
437 clear_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags);
438
439 /* Prepare READ WR */
440 memset(&read_wr, 0, sizeof read_wr);
441 read_wr.wr_id = (unsigned long)ctxt;
442 read_wr.opcode = IB_WR_RDMA_READ;
443 ctxt->wr_op = read_wr.opcode;
444 read_wr.send_flags = IB_SEND_SIGNALED;
445 read_wr.wr.rdma.rkey = ntohl(ch->rc_target.rs_handle);
446 xdr_decode_hyper((__be32 *)&ch->rc_target.rs_offset,
447 &rs_offset);
448 read_wr.wr.rdma.remote_addr = rs_offset + sgl_offset;
449 read_wr.sg_list = ctxt->sge;
450 read_wr.num_sge =
451 rdma_read_max_sge(xprt, chl_map->ch[ch_no].count);
452 err = rdma_set_ctxt_sge(xprt, ctxt, hdr_ctxt->frmr,
453 &rpl_map->sge[chl_map->ch[ch_no].start],
454 &sgl_offset,
455 read_wr.num_sge);
456 if (err) {
457 svc_rdma_unmap_dma(ctxt);
458 svc_rdma_put_context(ctxt, 0);
459 goto out;
460 }
461 if (((ch+1)->rc_discrim == 0) &&
462 (read_wr.num_sge == chl_map->ch[ch_no].count)) {
463 /*
464 * Mark the last RDMA_READ with a bit to
465 * indicate all RPC data has been fetched from
466 * the client and the RPC needs to be enqueued.
467 */
468 set_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags);
469 if (hdr_ctxt->frmr) {
470 set_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags);
471 /*
472 * Invalidate the local MR used to map the data
473 * sink.
474 */
475 if (xprt->sc_dev_caps &
476 SVCRDMA_DEVCAP_READ_W_INV) {
477 read_wr.opcode =
478 IB_WR_RDMA_READ_WITH_INV;
479 ctxt->wr_op = read_wr.opcode;
480 read_wr.ex.invalidate_rkey =
481 ctxt->frmr->mr->lkey;
482 } else {
483 /* Prepare INVALIDATE WR */
484 memset(&inv_wr, 0, sizeof inv_wr);
485 inv_wr.opcode = IB_WR_LOCAL_INV;
486 inv_wr.send_flags = IB_SEND_SIGNALED;
487 inv_wr.ex.invalidate_rkey =
488 hdr_ctxt->frmr->mr->lkey;
489 read_wr.next = &inv_wr;
490 }
491 }
492 ctxt->read_hdr = hdr_ctxt;
493 }
494 /* Post the read */
495 err = svc_rdma_send(xprt, &read_wr);
496 if (err) {
497 printk(KERN_ERR "svcrdma: Error %d posting RDMA_READ\n",
498 err);
499 set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
500 svc_rdma_unmap_dma(ctxt);
501 svc_rdma_put_context(ctxt, 0);
502 goto out;
503 }
504 atomic_inc(&rdma_stat_read);
505
506 if (read_wr.num_sge < chl_map->ch[ch_no].count) {
507 chl_map->ch[ch_no].count -= read_wr.num_sge;
508 chl_map->ch[ch_no].start += read_wr.num_sge;
509 goto next_sge;
510 }
511 sgl_offset = 0;
512 err = 1;
513 }
514
515 out:
516 svc_rdma_put_req_map(rpl_map);
517 svc_rdma_put_req_map(chl_map);
518
519 /* Detach arg pages. svc_recv will replenish them */
520 for (ch_no = 0; &rqstp->rq_pages[ch_no] < rqstp->rq_respages; ch_no++)
521 rqstp->rq_pages[ch_no] = NULL;
522
523 /*
524 * Detach res pages. svc_release must see a resused count of
525 * zero or it will attempt to put them.
526 */
527 while (rqstp->rq_resused)
528 rqstp->rq_respages[--rqstp->rq_resused] = NULL;
529
530 return err;
531}
532
533static int rdma_read_complete(struct svc_rqst *rqstp,
534 struct svc_rdma_op_ctxt *head)
535{
536 int page_no;
537 int ret;
538
539 BUG_ON(!head);
540
541 /* Copy RPC pages */
542 for (page_no = 0; page_no < head->count; page_no++) {
543 put_page(rqstp->rq_pages[page_no]);
544 rqstp->rq_pages[page_no] = head->pages[page_no];
545 }
546 /* Point rq_arg.pages past header */
547 rqstp->rq_arg.pages = &rqstp->rq_pages[head->hdr_count];
548 rqstp->rq_arg.page_len = head->arg.page_len;
549 rqstp->rq_arg.page_base = head->arg.page_base;
550
551 /* rq_respages starts after the last arg page */
552 rqstp->rq_respages = &rqstp->rq_arg.pages[page_no];
553 rqstp->rq_resused = 0;
554
555 /* Rebuild rq_arg head and tail. */
556 rqstp->rq_arg.head[0] = head->arg.head[0];
557 rqstp->rq_arg.tail[0] = head->arg.tail[0];
558 rqstp->rq_arg.len = head->arg.len;
559 rqstp->rq_arg.buflen = head->arg.buflen;
560
561 /* Free the context */
562 svc_rdma_put_context(head, 0);
563
564 /* XXX: What should this be? */
565 rqstp->rq_prot = IPPROTO_MAX;
566 svc_xprt_copy_addrs(rqstp, rqstp->rq_xprt);
567
568 ret = rqstp->rq_arg.head[0].iov_len
569 + rqstp->rq_arg.page_len
570 + rqstp->rq_arg.tail[0].iov_len;
571 dprintk("svcrdma: deferred read ret=%d, rq_arg.len =%d, "
572 "rq_arg.head[0].iov_base=%p, rq_arg.head[0].iov_len = %zd\n",
573 ret, rqstp->rq_arg.len, rqstp->rq_arg.head[0].iov_base,
574 rqstp->rq_arg.head[0].iov_len);
575
576 return ret;
577}
578
579/*
580 * Set up the rqstp thread context to point to the RQ buffer. If
581 * necessary, pull additional data from the client with an RDMA_READ
582 * request.
583 */
584int svc_rdma_recvfrom(struct svc_rqst *rqstp)
585{
586 struct svc_xprt *xprt = rqstp->rq_xprt;
587 struct svcxprt_rdma *rdma_xprt =
588 container_of(xprt, struct svcxprt_rdma, sc_xprt);
589 struct svc_rdma_op_ctxt *ctxt = NULL;
590 struct rpcrdma_msg *rmsgp;
591 int ret = 0;
592 int len;
593
594 dprintk("svcrdma: rqstp=%p\n", rqstp);
595
596 spin_lock_bh(&rdma_xprt->sc_rq_dto_lock);
597 if (!list_empty(&rdma_xprt->sc_read_complete_q)) {
598 ctxt = list_entry(rdma_xprt->sc_read_complete_q.next,
599 struct svc_rdma_op_ctxt,
600 dto_q);
601 list_del_init(&ctxt->dto_q);
602 }
603 if (ctxt) {
604 spin_unlock_bh(&rdma_xprt->sc_rq_dto_lock);
605 return rdma_read_complete(rqstp, ctxt);
606 }
607
608 if (!list_empty(&rdma_xprt->sc_rq_dto_q)) {
609 ctxt = list_entry(rdma_xprt->sc_rq_dto_q.next,
610 struct svc_rdma_op_ctxt,
611 dto_q);
612 list_del_init(&ctxt->dto_q);
613 } else {
614 atomic_inc(&rdma_stat_rq_starve);
615 clear_bit(XPT_DATA, &xprt->xpt_flags);
616 ctxt = NULL;
617 }
618 spin_unlock_bh(&rdma_xprt->sc_rq_dto_lock);
619 if (!ctxt) {
620 /* This is the EAGAIN path. The svc_recv routine will
621 * return -EAGAIN, the nfsd thread will go to call into
622 * svc_recv again and we shouldn't be on the active
623 * transport list
624 */
625 if (test_bit(XPT_CLOSE, &xprt->xpt_flags))
626 goto close_out;
627
628 BUG_ON(ret);
629 goto out;
630 }
631 dprintk("svcrdma: processing ctxt=%p on xprt=%p, rqstp=%p, status=%d\n",
632 ctxt, rdma_xprt, rqstp, ctxt->wc_status);
633 BUG_ON(ctxt->wc_status != IB_WC_SUCCESS);
634 atomic_inc(&rdma_stat_recv);
635
636 /* Build up the XDR from the receive buffers. */
637 rdma_build_arg_xdr(rqstp, ctxt, ctxt->byte_len);
638
639 /* Decode the RDMA header. */
640 len = svc_rdma_xdr_decode_req(&rmsgp, rqstp);
641 rqstp->rq_xprt_hlen = len;
642
643 /* If the request is invalid, reply with an error */
644 if (len < 0) {
645 if (len == -ENOSYS)
646 svc_rdma_send_error(rdma_xprt, rmsgp, ERR_VERS);
647 goto close_out;
648 }
649
650 /* Read read-list data. */
651 ret = rdma_read_xdr(rdma_xprt, rmsgp, rqstp, ctxt);
652 if (ret > 0) {
653 /* read-list posted, defer until data received from client. */
654 goto defer;
655 }
656 if (ret < 0) {
657 /* Post of read-list failed, free context. */
658 svc_rdma_put_context(ctxt, 1);
659 return 0;
660 }
661
662 ret = rqstp->rq_arg.head[0].iov_len
663 + rqstp->rq_arg.page_len
664 + rqstp->rq_arg.tail[0].iov_len;
665 svc_rdma_put_context(ctxt, 0);
666 out:
667 dprintk("svcrdma: ret = %d, rq_arg.len =%d, "
668 "rq_arg.head[0].iov_base=%p, rq_arg.head[0].iov_len = %zd\n",
669 ret, rqstp->rq_arg.len,
670 rqstp->rq_arg.head[0].iov_base,
671 rqstp->rq_arg.head[0].iov_len);
672 rqstp->rq_prot = IPPROTO_MAX;
673 svc_xprt_copy_addrs(rqstp, xprt);
674 return ret;
675
676 close_out:
677 if (ctxt)
678 svc_rdma_put_context(ctxt, 1);
679 dprintk("svcrdma: transport %p is closing\n", xprt);
680 /*
681 * Set the close bit and enqueue it. svc_recv will see the
682 * close bit and call svc_xprt_delete
683 */
684 set_bit(XPT_CLOSE, &xprt->xpt_flags);
685defer:
686 return 0;
687}
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
111static void svc_rdma_wc_receive(struct ib_cq *cq, struct ib_wc *wc);
112
113static inline struct svc_rdma_recv_ctxt *
114svc_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
120static struct svc_rdma_recv_ctxt *
121svc_rdma_recv_ctxt_alloc(struct svcxprt_rdma *rdma)
122{
123 struct svc_rdma_recv_ctxt *ctxt;
124 dma_addr_t addr;
125 void *buffer;
126
127 ctxt = kmalloc(sizeof(*ctxt), GFP_KERNEL);
128 if (!ctxt)
129 goto fail0;
130 buffer = kmalloc(rdma->sc_max_req_size, GFP_KERNEL);
131 if (!buffer)
132 goto fail1;
133 addr = ib_dma_map_single(rdma->sc_pd->device, buffer,
134 rdma->sc_max_req_size, DMA_FROM_DEVICE);
135 if (ib_dma_mapping_error(rdma->sc_pd->device, addr))
136 goto fail2;
137
138 ctxt->rc_recv_wr.next = NULL;
139 ctxt->rc_recv_wr.wr_cqe = &ctxt->rc_cqe;
140 ctxt->rc_recv_wr.sg_list = &ctxt->rc_recv_sge;
141 ctxt->rc_recv_wr.num_sge = 1;
142 ctxt->rc_cqe.done = svc_rdma_wc_receive;
143 ctxt->rc_recv_sge.addr = addr;
144 ctxt->rc_recv_sge.length = rdma->sc_max_req_size;
145 ctxt->rc_recv_sge.lkey = rdma->sc_pd->local_dma_lkey;
146 ctxt->rc_recv_buf = buffer;
147 ctxt->rc_temp = false;
148 return ctxt;
149
150fail2:
151 kfree(buffer);
152fail1:
153 kfree(ctxt);
154fail0:
155 return NULL;
156}
157
158static void svc_rdma_recv_ctxt_destroy(struct svcxprt_rdma *rdma,
159 struct svc_rdma_recv_ctxt *ctxt)
160{
161 ib_dma_unmap_single(rdma->sc_pd->device, ctxt->rc_recv_sge.addr,
162 ctxt->rc_recv_sge.length, DMA_FROM_DEVICE);
163 kfree(ctxt->rc_recv_buf);
164 kfree(ctxt);
165}
166
167/**
168 * svc_rdma_recv_ctxts_destroy - Release all recv_ctxt's for an xprt
169 * @rdma: svcxprt_rdma being torn down
170 *
171 */
172void svc_rdma_recv_ctxts_destroy(struct svcxprt_rdma *rdma)
173{
174 struct svc_rdma_recv_ctxt *ctxt;
175 struct llist_node *node;
176
177 while ((node = llist_del_first(&rdma->sc_recv_ctxts))) {
178 ctxt = llist_entry(node, struct svc_rdma_recv_ctxt, rc_node);
179 svc_rdma_recv_ctxt_destroy(rdma, ctxt);
180 }
181}
182
183static struct svc_rdma_recv_ctxt *
184svc_rdma_recv_ctxt_get(struct svcxprt_rdma *rdma)
185{
186 struct svc_rdma_recv_ctxt *ctxt;
187 struct llist_node *node;
188
189 node = llist_del_first(&rdma->sc_recv_ctxts);
190 if (!node)
191 goto out_empty;
192 ctxt = llist_entry(node, struct svc_rdma_recv_ctxt, rc_node);
193
194out:
195 ctxt->rc_page_count = 0;
196 return ctxt;
197
198out_empty:
199 ctxt = svc_rdma_recv_ctxt_alloc(rdma);
200 if (!ctxt)
201 return NULL;
202 goto out;
203}
204
205/**
206 * svc_rdma_recv_ctxt_put - Return recv_ctxt to free list
207 * @rdma: controlling svcxprt_rdma
208 * @ctxt: object to return to the free list
209 *
210 */
211void svc_rdma_recv_ctxt_put(struct svcxprt_rdma *rdma,
212 struct svc_rdma_recv_ctxt *ctxt)
213{
214 unsigned int i;
215
216 for (i = 0; i < ctxt->rc_page_count; i++)
217 put_page(ctxt->rc_pages[i]);
218
219 if (!ctxt->rc_temp)
220 llist_add(&ctxt->rc_node, &rdma->sc_recv_ctxts);
221 else
222 svc_rdma_recv_ctxt_destroy(rdma, ctxt);
223}
224
225static int __svc_rdma_post_recv(struct svcxprt_rdma *rdma,
226 struct svc_rdma_recv_ctxt *ctxt)
227{
228 int ret;
229
230 svc_xprt_get(&rdma->sc_xprt);
231 ret = ib_post_recv(rdma->sc_qp, &ctxt->rc_recv_wr, NULL);
232 trace_svcrdma_post_recv(&ctxt->rc_recv_wr, ret);
233 if (ret)
234 goto err_post;
235 return 0;
236
237err_post:
238 svc_rdma_recv_ctxt_put(rdma, ctxt);
239 svc_xprt_put(&rdma->sc_xprt);
240 return ret;
241}
242
243static int svc_rdma_post_recv(struct svcxprt_rdma *rdma)
244{
245 struct svc_rdma_recv_ctxt *ctxt;
246
247 ctxt = svc_rdma_recv_ctxt_get(rdma);
248 if (!ctxt)
249 return -ENOMEM;
250 return __svc_rdma_post_recv(rdma, ctxt);
251}
252
253/**
254 * svc_rdma_post_recvs - Post initial set of Recv WRs
255 * @rdma: fresh svcxprt_rdma
256 *
257 * Returns true if successful, otherwise false.
258 */
259bool svc_rdma_post_recvs(struct svcxprt_rdma *rdma)
260{
261 struct svc_rdma_recv_ctxt *ctxt;
262 unsigned int i;
263 int ret;
264
265 for (i = 0; i < rdma->sc_max_requests; i++) {
266 ctxt = svc_rdma_recv_ctxt_get(rdma);
267 if (!ctxt)
268 return false;
269 ctxt->rc_temp = true;
270 ret = __svc_rdma_post_recv(rdma, ctxt);
271 if (ret)
272 return false;
273 }
274 return true;
275}
276
277/**
278 * svc_rdma_wc_receive - Invoked by RDMA provider for each polled Receive WC
279 * @cq: Completion Queue context
280 * @wc: Work Completion object
281 *
282 * NB: The svc_xprt/svcxprt_rdma is pinned whenever it's possible that
283 * the Receive completion handler could be running.
284 */
285static void svc_rdma_wc_receive(struct ib_cq *cq, struct ib_wc *wc)
286{
287 struct svcxprt_rdma *rdma = cq->cq_context;
288 struct ib_cqe *cqe = wc->wr_cqe;
289 struct svc_rdma_recv_ctxt *ctxt;
290
291 trace_svcrdma_wc_receive(wc);
292
293 /* WARNING: Only wc->wr_cqe and wc->status are reliable */
294 ctxt = container_of(cqe, struct svc_rdma_recv_ctxt, rc_cqe);
295
296 if (wc->status != IB_WC_SUCCESS)
297 goto flushed;
298
299 if (svc_rdma_post_recv(rdma))
300 goto post_err;
301
302 /* All wc fields are now known to be valid */
303 ctxt->rc_byte_len = wc->byte_len;
304 ib_dma_sync_single_for_cpu(rdma->sc_pd->device,
305 ctxt->rc_recv_sge.addr,
306 wc->byte_len, DMA_FROM_DEVICE);
307
308 spin_lock(&rdma->sc_rq_dto_lock);
309 list_add_tail(&ctxt->rc_list, &rdma->sc_rq_dto_q);
310 /* Note the unlock pairs with the smp_rmb in svc_xprt_ready: */
311 set_bit(XPT_DATA, &rdma->sc_xprt.xpt_flags);
312 spin_unlock(&rdma->sc_rq_dto_lock);
313 if (!test_bit(RDMAXPRT_CONN_PENDING, &rdma->sc_flags))
314 svc_xprt_enqueue(&rdma->sc_xprt);
315 goto out;
316
317flushed:
318post_err:
319 svc_rdma_recv_ctxt_put(rdma, ctxt);
320 set_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags);
321 svc_xprt_enqueue(&rdma->sc_xprt);
322out:
323 svc_xprt_put(&rdma->sc_xprt);
324}
325
326/**
327 * svc_rdma_flush_recv_queues - Drain pending Receive work
328 * @rdma: svcxprt_rdma being shut down
329 *
330 */
331void svc_rdma_flush_recv_queues(struct svcxprt_rdma *rdma)
332{
333 struct svc_rdma_recv_ctxt *ctxt;
334
335 while ((ctxt = svc_rdma_next_recv_ctxt(&rdma->sc_read_complete_q))) {
336 list_del(&ctxt->rc_list);
337 svc_rdma_recv_ctxt_put(rdma, ctxt);
338 }
339 while ((ctxt = svc_rdma_next_recv_ctxt(&rdma->sc_rq_dto_q))) {
340 list_del(&ctxt->rc_list);
341 svc_rdma_recv_ctxt_put(rdma, ctxt);
342 }
343}
344
345static void svc_rdma_build_arg_xdr(struct svc_rqst *rqstp,
346 struct svc_rdma_recv_ctxt *ctxt)
347{
348 struct xdr_buf *arg = &rqstp->rq_arg;
349
350 arg->head[0].iov_base = ctxt->rc_recv_buf;
351 arg->head[0].iov_len = ctxt->rc_byte_len;
352 arg->tail[0].iov_base = NULL;
353 arg->tail[0].iov_len = 0;
354 arg->page_len = 0;
355 arg->page_base = 0;
356 arg->buflen = ctxt->rc_byte_len;
357 arg->len = ctxt->rc_byte_len;
358}
359
360/* This accommodates the largest possible Write chunk,
361 * in one segment.
362 */
363#define MAX_BYTES_WRITE_SEG ((u32)(RPCSVC_MAXPAGES << PAGE_SHIFT))
364
365/* This accommodates the largest possible Position-Zero
366 * Read chunk or Reply chunk, in one segment.
367 */
368#define MAX_BYTES_SPECIAL_SEG ((u32)((RPCSVC_MAXPAGES + 2) << PAGE_SHIFT))
369
370/* Sanity check the Read list.
371 *
372 * Implementation limits:
373 * - This implementation supports only one Read chunk.
374 *
375 * Sanity checks:
376 * - Read list does not overflow buffer.
377 * - Segment size limited by largest NFS data payload.
378 *
379 * The segment count is limited to how many segments can
380 * fit in the transport header without overflowing the
381 * buffer. That's about 40 Read segments for a 1KB inline
382 * threshold.
383 *
384 * Returns pointer to the following Write list.
385 */
386static __be32 *xdr_check_read_list(__be32 *p, const __be32 *end)
387{
388 u32 position;
389 bool first;
390
391 first = true;
392 while (*p++ != xdr_zero) {
393 if (first) {
394 position = be32_to_cpup(p++);
395 first = false;
396 } else if (be32_to_cpup(p++) != position) {
397 return NULL;
398 }
399 p++; /* handle */
400 if (be32_to_cpup(p++) > MAX_BYTES_SPECIAL_SEG)
401 return NULL;
402 p += 2; /* offset */
403
404 if (p > end)
405 return NULL;
406 }
407 return p;
408}
409
410/* The segment count is limited to how many segments can
411 * fit in the transport header without overflowing the
412 * buffer. That's about 60 Write segments for a 1KB inline
413 * threshold.
414 */
415static __be32 *xdr_check_write_chunk(__be32 *p, const __be32 *end,
416 u32 maxlen)
417{
418 u32 i, segcount;
419
420 segcount = be32_to_cpup(p++);
421 for (i = 0; i < segcount; i++) {
422 p++; /* handle */
423 if (be32_to_cpup(p++) > maxlen)
424 return NULL;
425 p += 2; /* offset */
426
427 if (p > end)
428 return NULL;
429 }
430
431 return p;
432}
433
434/* Sanity check the Write list.
435 *
436 * Implementation limits:
437 * - This implementation supports only one Write chunk.
438 *
439 * Sanity checks:
440 * - Write list does not overflow buffer.
441 * - Segment size limited by largest NFS data payload.
442 *
443 * Returns pointer to the following Reply chunk.
444 */
445static __be32 *xdr_check_write_list(__be32 *p, const __be32 *end)
446{
447 u32 chcount;
448
449 chcount = 0;
450 while (*p++ != xdr_zero) {
451 p = xdr_check_write_chunk(p, end, MAX_BYTES_WRITE_SEG);
452 if (!p)
453 return NULL;
454 if (chcount++ > 1)
455 return NULL;
456 }
457 return p;
458}
459
460/* Sanity check the Reply chunk.
461 *
462 * Sanity checks:
463 * - Reply chunk does not overflow buffer.
464 * - Segment size limited by largest NFS data payload.
465 *
466 * Returns pointer to the following RPC header.
467 */
468static __be32 *xdr_check_reply_chunk(__be32 *p, const __be32 *end)
469{
470 if (*p++ != xdr_zero) {
471 p = xdr_check_write_chunk(p, end, MAX_BYTES_SPECIAL_SEG);
472 if (!p)
473 return NULL;
474 }
475 return p;
476}
477
478/* RPC-over-RDMA Version One private extension: Remote Invalidation.
479 * Responder's choice: requester signals it can handle Send With
480 * Invalidate, and responder chooses one R_key to invalidate.
481 *
482 * If there is exactly one distinct R_key in the received transport
483 * header, set rc_inv_rkey to that R_key. Otherwise, set it to zero.
484 *
485 * Perform this operation while the received transport header is
486 * still in the CPU cache.
487 */
488static void svc_rdma_get_inv_rkey(struct svcxprt_rdma *rdma,
489 struct svc_rdma_recv_ctxt *ctxt)
490{
491 __be32 inv_rkey, *p;
492 u32 i, segcount;
493
494 ctxt->rc_inv_rkey = 0;
495
496 if (!rdma->sc_snd_w_inv)
497 return;
498
499 inv_rkey = xdr_zero;
500 p = ctxt->rc_recv_buf;
501 p += rpcrdma_fixed_maxsz;
502
503 /* Read list */
504 while (*p++ != xdr_zero) {
505 p++; /* position */
506 if (inv_rkey == xdr_zero)
507 inv_rkey = *p;
508 else if (inv_rkey != *p)
509 return;
510 p += 4;
511 }
512
513 /* Write list */
514 while (*p++ != xdr_zero) {
515 segcount = be32_to_cpup(p++);
516 for (i = 0; i < segcount; i++) {
517 if (inv_rkey == xdr_zero)
518 inv_rkey = *p;
519 else if (inv_rkey != *p)
520 return;
521 p += 4;
522 }
523 }
524
525 /* Reply chunk */
526 if (*p++ != xdr_zero) {
527 segcount = be32_to_cpup(p++);
528 for (i = 0; i < segcount; i++) {
529 if (inv_rkey == xdr_zero)
530 inv_rkey = *p;
531 else if (inv_rkey != *p)
532 return;
533 p += 4;
534 }
535 }
536
537 ctxt->rc_inv_rkey = be32_to_cpu(inv_rkey);
538}
539
540/* On entry, xdr->head[0].iov_base points to first byte in the
541 * RPC-over-RDMA header.
542 *
543 * On successful exit, head[0] points to first byte past the
544 * RPC-over-RDMA header. For RDMA_MSG, this is the RPC message.
545 * The length of the RPC-over-RDMA header is returned.
546 *
547 * Assumptions:
548 * - The transport header is entirely contained in the head iovec.
549 */
550static int svc_rdma_xdr_decode_req(struct xdr_buf *rq_arg)
551{
552 __be32 *p, *end, *rdma_argp;
553 unsigned int hdr_len;
554
555 /* Verify that there's enough bytes for header + something */
556 if (rq_arg->len <= RPCRDMA_HDRLEN_ERR)
557 goto out_short;
558
559 rdma_argp = rq_arg->head[0].iov_base;
560 if (*(rdma_argp + 1) != rpcrdma_version)
561 goto out_version;
562
563 switch (*(rdma_argp + 3)) {
564 case rdma_msg:
565 break;
566 case rdma_nomsg:
567 break;
568
569 case rdma_done:
570 goto out_drop;
571
572 case rdma_error:
573 goto out_drop;
574
575 default:
576 goto out_proc;
577 }
578
579 end = (__be32 *)((unsigned long)rdma_argp + rq_arg->len);
580 p = xdr_check_read_list(rdma_argp + 4, end);
581 if (!p)
582 goto out_inval;
583 p = xdr_check_write_list(p, end);
584 if (!p)
585 goto out_inval;
586 p = xdr_check_reply_chunk(p, end);
587 if (!p)
588 goto out_inval;
589 if (p > end)
590 goto out_inval;
591
592 rq_arg->head[0].iov_base = p;
593 hdr_len = (unsigned long)p - (unsigned long)rdma_argp;
594 rq_arg->head[0].iov_len -= hdr_len;
595 rq_arg->len -= hdr_len;
596 trace_svcrdma_decode_rqst(rdma_argp, hdr_len);
597 return hdr_len;
598
599out_short:
600 trace_svcrdma_decode_short(rq_arg->len);
601 return -EINVAL;
602
603out_version:
604 trace_svcrdma_decode_badvers(rdma_argp);
605 return -EPROTONOSUPPORT;
606
607out_drop:
608 trace_svcrdma_decode_drop(rdma_argp);
609 return 0;
610
611out_proc:
612 trace_svcrdma_decode_badproc(rdma_argp);
613 return -EINVAL;
614
615out_inval:
616 trace_svcrdma_decode_parse(rdma_argp);
617 return -EINVAL;
618}
619
620static void rdma_read_complete(struct svc_rqst *rqstp,
621 struct svc_rdma_recv_ctxt *head)
622{
623 int page_no;
624
625 /* Move Read chunk pages to rqstp so that they will be released
626 * when svc_process is done with them.
627 */
628 for (page_no = 0; page_no < head->rc_page_count; page_no++) {
629 put_page(rqstp->rq_pages[page_no]);
630 rqstp->rq_pages[page_no] = head->rc_pages[page_no];
631 }
632 head->rc_page_count = 0;
633
634 /* Point rq_arg.pages past header */
635 rqstp->rq_arg.pages = &rqstp->rq_pages[head->rc_hdr_count];
636 rqstp->rq_arg.page_len = head->rc_arg.page_len;
637
638 /* rq_respages starts after the last arg page */
639 rqstp->rq_respages = &rqstp->rq_pages[page_no];
640 rqstp->rq_next_page = rqstp->rq_respages + 1;
641
642 /* Rebuild rq_arg head and tail. */
643 rqstp->rq_arg.head[0] = head->rc_arg.head[0];
644 rqstp->rq_arg.tail[0] = head->rc_arg.tail[0];
645 rqstp->rq_arg.len = head->rc_arg.len;
646 rqstp->rq_arg.buflen = head->rc_arg.buflen;
647}
648
649static void svc_rdma_send_error(struct svcxprt_rdma *xprt,
650 __be32 *rdma_argp, int status)
651{
652 struct svc_rdma_send_ctxt *ctxt;
653 unsigned int length;
654 __be32 *p;
655 int ret;
656
657 ctxt = svc_rdma_send_ctxt_get(xprt);
658 if (!ctxt)
659 return;
660
661 p = ctxt->sc_xprt_buf;
662 *p++ = *rdma_argp;
663 *p++ = *(rdma_argp + 1);
664 *p++ = xprt->sc_fc_credits;
665 *p++ = rdma_error;
666 switch (status) {
667 case -EPROTONOSUPPORT:
668 *p++ = err_vers;
669 *p++ = rpcrdma_version;
670 *p++ = rpcrdma_version;
671 trace_svcrdma_err_vers(*rdma_argp);
672 break;
673 default:
674 *p++ = err_chunk;
675 trace_svcrdma_err_chunk(*rdma_argp);
676 }
677 length = (unsigned long)p - (unsigned long)ctxt->sc_xprt_buf;
678 svc_rdma_sync_reply_hdr(xprt, ctxt, length);
679
680 ctxt->sc_send_wr.opcode = IB_WR_SEND;
681 ret = svc_rdma_send(xprt, &ctxt->sc_send_wr);
682 if (ret)
683 svc_rdma_send_ctxt_put(xprt, ctxt);
684}
685
686/* By convention, backchannel calls arrive via rdma_msg type
687 * messages, and never populate the chunk lists. This makes
688 * the RPC/RDMA header small and fixed in size, so it is
689 * straightforward to check the RPC header's direction field.
690 */
691static bool svc_rdma_is_backchannel_reply(struct svc_xprt *xprt,
692 __be32 *rdma_resp)
693{
694 __be32 *p;
695
696 if (!xprt->xpt_bc_xprt)
697 return false;
698
699 p = rdma_resp + 3;
700 if (*p++ != rdma_msg)
701 return false;
702
703 if (*p++ != xdr_zero)
704 return false;
705 if (*p++ != xdr_zero)
706 return false;
707 if (*p++ != xdr_zero)
708 return false;
709
710 /* XID sanity */
711 if (*p++ != *rdma_resp)
712 return false;
713 /* call direction */
714 if (*p == cpu_to_be32(RPC_CALL))
715 return false;
716
717 return true;
718}
719
720/**
721 * svc_rdma_recvfrom - Receive an RPC call
722 * @rqstp: request structure into which to receive an RPC Call
723 *
724 * Returns:
725 * The positive number of bytes in the RPC Call message,
726 * %0 if there were no Calls ready to return,
727 * %-EINVAL if the Read chunk data is too large,
728 * %-ENOMEM if rdma_rw context pool was exhausted,
729 * %-ENOTCONN if posting failed (connection is lost),
730 * %-EIO if rdma_rw initialization failed (DMA mapping, etc).
731 *
732 * Called in a loop when XPT_DATA is set. XPT_DATA is cleared only
733 * when there are no remaining ctxt's to process.
734 *
735 * The next ctxt is removed from the "receive" lists.
736 *
737 * - If the ctxt completes a Read, then finish assembling the Call
738 * message and return the number of bytes in the message.
739 *
740 * - If the ctxt completes a Receive, then construct the Call
741 * message from the contents of the Receive buffer.
742 *
743 * - If there are no Read chunks in this message, then finish
744 * assembling the Call message and return the number of bytes
745 * in the message.
746 *
747 * - If there are Read chunks in this message, post Read WRs to
748 * pull that payload and return 0.
749 */
750int svc_rdma_recvfrom(struct svc_rqst *rqstp)
751{
752 struct svc_xprt *xprt = rqstp->rq_xprt;
753 struct svcxprt_rdma *rdma_xprt =
754 container_of(xprt, struct svcxprt_rdma, sc_xprt);
755 struct svc_rdma_recv_ctxt *ctxt;
756 __be32 *p;
757 int ret;
758
759 spin_lock(&rdma_xprt->sc_rq_dto_lock);
760 ctxt = svc_rdma_next_recv_ctxt(&rdma_xprt->sc_read_complete_q);
761 if (ctxt) {
762 list_del(&ctxt->rc_list);
763 spin_unlock(&rdma_xprt->sc_rq_dto_lock);
764 rdma_read_complete(rqstp, ctxt);
765 goto complete;
766 }
767 ctxt = svc_rdma_next_recv_ctxt(&rdma_xprt->sc_rq_dto_q);
768 if (!ctxt) {
769 /* No new incoming requests, terminate the loop */
770 clear_bit(XPT_DATA, &xprt->xpt_flags);
771 spin_unlock(&rdma_xprt->sc_rq_dto_lock);
772 return 0;
773 }
774 list_del(&ctxt->rc_list);
775 spin_unlock(&rdma_xprt->sc_rq_dto_lock);
776
777 atomic_inc(&rdma_stat_recv);
778
779 svc_rdma_build_arg_xdr(rqstp, ctxt);
780
781 /* Prevent svc_xprt_release from releasing pages in rq_pages
782 * if we return 0 or an error.
783 */
784 rqstp->rq_respages = rqstp->rq_pages;
785 rqstp->rq_next_page = rqstp->rq_respages;
786
787 p = (__be32 *)rqstp->rq_arg.head[0].iov_base;
788 ret = svc_rdma_xdr_decode_req(&rqstp->rq_arg);
789 if (ret < 0)
790 goto out_err;
791 if (ret == 0)
792 goto out_drop;
793 rqstp->rq_xprt_hlen = ret;
794
795 if (svc_rdma_is_backchannel_reply(xprt, p)) {
796 ret = svc_rdma_handle_bc_reply(xprt->xpt_bc_xprt, p,
797 &rqstp->rq_arg);
798 svc_rdma_recv_ctxt_put(rdma_xprt, ctxt);
799 return ret;
800 }
801 svc_rdma_get_inv_rkey(rdma_xprt, ctxt);
802
803 p += rpcrdma_fixed_maxsz;
804 if (*p != xdr_zero)
805 goto out_readchunk;
806
807complete:
808 rqstp->rq_xprt_ctxt = ctxt;
809 rqstp->rq_prot = IPPROTO_MAX;
810 svc_xprt_copy_addrs(rqstp, xprt);
811 return rqstp->rq_arg.len;
812
813out_readchunk:
814 ret = svc_rdma_recv_read_chunk(rdma_xprt, rqstp, ctxt, p);
815 if (ret < 0)
816 goto out_postfail;
817 return 0;
818
819out_err:
820 svc_rdma_send_error(rdma_xprt, p, ret);
821 svc_rdma_recv_ctxt_put(rdma_xprt, ctxt);
822 return 0;
823
824out_postfail:
825 if (ret == -EINVAL)
826 svc_rdma_send_error(rdma_xprt, p, ret);
827 svc_rdma_recv_ctxt_put(rdma_xprt, ctxt);
828 return ret;
829
830out_drop:
831 svc_rdma_recv_ctxt_put(rdma_xprt, ctxt);
832 return 0;
833}