blob: 7c3a211e0e9a9e17ed388696ebff789512289cf4 [file] [log] [blame]
Tom Tuckerc06b5402007-12-12 16:13:25 -06001/*
Chuck Lever9a6a1802017-04-09 13:06:25 -04002 * Copyright (c) 2016 Oracle. All rights reserved.
Steve Wise0bf48282014-05-28 15:12:01 -05003 * Copyright (c) 2014 Open Grid Computing, Inc. All rights reserved.
Tom Tuckerc06b5402007-12-12 16:13:25 -06004 * Copyright (c) 2005-2006 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 * Author: Tom Tucker <tom@opengridcomputing.com>
42 */
43
Chuck Lever9a6a1802017-04-09 13:06:25 -040044/* Operation
45 *
46 * The main entry point is svc_rdma_sendto. This is called by the
47 * RPC server when an RPC Reply is ready to be transmitted to a client.
48 *
49 * The passed-in svc_rqst contains a struct xdr_buf which holds an
50 * XDR-encoded RPC Reply message. sendto must construct the RPC-over-RDMA
51 * transport header, post all Write WRs needed for this Reply, then post
52 * a Send WR conveying the transport header and the RPC message itself to
53 * the client.
54 *
55 * svc_rdma_sendto must fully transmit the Reply before returning, as
56 * the svc_rqst will be recycled as soon as sendto returns. Remaining
57 * resources referred to by the svc_rqst are also recycled at that time.
58 * Therefore any resources that must remain longer must be detached
59 * from the svc_rqst and released later.
60 *
61 * Page Management
62 *
63 * The I/O that performs Reply transmission is asynchronous, and may
64 * complete well after sendto returns. Thus pages under I/O must be
65 * removed from the svc_rqst before sendto returns.
66 *
67 * The logic here depends on Send Queue and completion ordering. Since
68 * the Send WR is always posted last, it will always complete last. Thus
69 * when it completes, it is guaranteed that all previous Write WRs have
70 * also completed.
71 *
72 * Write WRs are constructed and posted. Each Write segment gets its own
73 * svc_rdma_rw_ctxt, allowing the Write completion handler to find and
74 * DMA-unmap the pages under I/O for that Write segment. The Write
75 * completion handler does not release any pages.
76 *
77 * When the Send WR is constructed, it also gets its own svc_rdma_op_ctxt.
78 * The ownership of all of the Reply's pages are transferred into that
79 * ctxt, the Send WR is posted, and sendto returns.
80 *
81 * The svc_rdma_op_ctxt is presented when the Send WR completes. The
82 * Send completion handler finally releases the Reply's pages.
83 *
84 * This mechanism also assumes that completions on the transport's Send
85 * Completion Queue do not run in parallel. Otherwise a Write completion
86 * and Send completion running at the same time could release pages that
87 * are still DMA-mapped.
88 *
89 * Error Handling
90 *
91 * - If the Send WR is posted successfully, it will either complete
92 * successfully, or get flushed. Either way, the Send completion
93 * handler releases the Reply's pages.
94 * - If the Send WR cannot be not posted, the forward path releases
95 * the Reply's pages.
96 *
97 * This handles the case, without the use of page reference counting,
98 * where two different Write segments send portions of the same page.
99 */
100
Tom Tuckerc06b5402007-12-12 16:13:25 -0600101#include <linux/sunrpc/debug.h>
102#include <linux/sunrpc/rpc_rdma.h>
103#include <linux/spinlock.h>
104#include <asm/unaligned.h>
105#include <rdma/ib_verbs.h>
106#include <rdma/rdma_cm.h>
107#include <linux/sunrpc/svc_rdma.h>
108
109#define RPCDBG_FACILITY RPCDBG_SVCXPRT
110
Chuck Levercf570a92016-03-01 13:05:45 -0500111static u32 xdr_padsize(u32 len)
112{
113 return (len & 3) ? (4 - (len & 3)) : 0;
114}
115
Chuck Lever9a6a1802017-04-09 13:06:25 -0400116/* Returns length of transport header, in bytes.
117 */
118static unsigned int svc_rdma_reply_hdr_len(__be32 *rdma_resp)
119{
120 unsigned int nsegs;
121 __be32 *p;
122
123 p = rdma_resp;
124
125 /* RPC-over-RDMA V1 replies never have a Read list. */
126 p += rpcrdma_fixed_maxsz + 1;
127
128 /* Skip Write list. */
129 while (*p++ != xdr_zero) {
130 nsegs = be32_to_cpup(p++);
131 p += nsegs * rpcrdma_segment_maxsz;
132 }
133
134 /* Skip Reply chunk. */
135 if (*p++ != xdr_zero) {
136 nsegs = be32_to_cpup(p++);
137 p += nsegs * rpcrdma_segment_maxsz;
138 }
139
140 return (unsigned long)p - (unsigned long)rdma_resp;
141}
142
143/* One Write chunk is copied from Call transport header to Reply
144 * transport header. Each segment's length field is updated to
145 * reflect number of bytes consumed in the segment.
146 *
147 * Returns number of segments in this chunk.
148 */
149static unsigned int xdr_encode_write_chunk(__be32 *dst, __be32 *src,
150 unsigned int remaining)
151{
152 unsigned int i, nsegs;
153 u32 seg_len;
154
155 /* Write list discriminator */
156 *dst++ = *src++;
157
158 /* number of segments in this chunk */
159 nsegs = be32_to_cpup(src);
160 *dst++ = *src++;
161
162 for (i = nsegs; i; i--) {
163 /* segment's RDMA handle */
164 *dst++ = *src++;
165
166 /* bytes returned in this segment */
167 seg_len = be32_to_cpu(*src);
168 if (remaining >= seg_len) {
169 /* entire segment was consumed */
170 *dst = *src;
171 remaining -= seg_len;
172 } else {
173 /* segment only partly filled */
174 *dst = cpu_to_be32(remaining);
175 remaining = 0;
176 }
177 dst++; src++;
178
179 /* segment's RDMA offset */
180 *dst++ = *src++;
181 *dst++ = *src++;
182 }
183
184 return nsegs;
185}
186
187/* The client provided a Write list in the Call message. Fill in
188 * the segments in the first Write chunk in the Reply's transport
189 * header with the number of bytes consumed in each segment.
190 * Remaining chunks are returned unused.
191 *
192 * Assumptions:
193 * - Client has provided only one Write chunk
194 */
195static void svc_rdma_xdr_encode_write_list(__be32 *rdma_resp, __be32 *wr_ch,
196 unsigned int consumed)
197{
198 unsigned int nsegs;
199 __be32 *p, *q;
200
201 /* RPC-over-RDMA V1 replies never have a Read list. */
202 p = rdma_resp + rpcrdma_fixed_maxsz + 1;
203
204 q = wr_ch;
205 while (*q != xdr_zero) {
206 nsegs = xdr_encode_write_chunk(p, q, consumed);
207 q += 2 + nsegs * rpcrdma_segment_maxsz;
208 p += 2 + nsegs * rpcrdma_segment_maxsz;
209 consumed = 0;
210 }
211
212 /* Terminate Write list */
213 *p++ = xdr_zero;
214
215 /* Reply chunk discriminator; may be replaced later */
216 *p = xdr_zero;
217}
218
219/* The client provided a Reply chunk in the Call message. Fill in
220 * the segments in the Reply chunk in the Reply message with the
221 * number of bytes consumed in each segment.
222 *
223 * Assumptions:
224 * - Reply can always fit in the provided Reply chunk
225 */
226static void svc_rdma_xdr_encode_reply_chunk(__be32 *rdma_resp, __be32 *rp_ch,
227 unsigned int consumed)
228{
229 __be32 *p;
230
231 /* Find the Reply chunk in the Reply's xprt header.
232 * RPC-over-RDMA V1 replies never have a Read list.
233 */
234 p = rdma_resp + rpcrdma_fixed_maxsz + 1;
235
236 /* Skip past Write list */
237 while (*p++ != xdr_zero)
238 p += 1 + be32_to_cpup(p) * rpcrdma_segment_maxsz;
239
240 xdr_encode_write_chunk(p, rp_ch, consumed);
241}
242
Chuck Lever5fdca652016-11-29 11:04:42 -0500243/* Parse the RPC Call's transport header.
Chuck Lever10dc4512015-07-09 16:45:28 -0400244 */
Chuck Lever9a6a1802017-04-09 13:06:25 -0400245static void svc_rdma_get_write_arrays(__be32 *rdma_argp,
246 __be32 **write, __be32 **reply)
Chuck Lever10dc4512015-07-09 16:45:28 -0400247{
Chuck Lever5fdca652016-11-29 11:04:42 -0500248 __be32 *p;
Chuck Lever10dc4512015-07-09 16:45:28 -0400249
Chuck Lever9a6a1802017-04-09 13:06:25 -0400250 p = rdma_argp + rpcrdma_fixed_maxsz;
Chuck Lever10dc4512015-07-09 16:45:28 -0400251
Chuck Lever5fdca652016-11-29 11:04:42 -0500252 /* Read list */
253 while (*p++ != xdr_zero)
254 p += 5;
Chuck Lever10dc4512015-07-09 16:45:28 -0400255
Chuck Lever5fdca652016-11-29 11:04:42 -0500256 /* Write list */
257 if (*p != xdr_zero) {
Chuck Lever9a6a1802017-04-09 13:06:25 -0400258 *write = p;
Chuck Lever5fdca652016-11-29 11:04:42 -0500259 while (*p++ != xdr_zero)
260 p += 1 + be32_to_cpu(*p) * 4;
261 } else {
262 *write = NULL;
263 p++;
Chuck Lever10dc4512015-07-09 16:45:28 -0400264 }
265
Chuck Lever5fdca652016-11-29 11:04:42 -0500266 /* Reply chunk */
267 if (*p != xdr_zero)
Chuck Lever9a6a1802017-04-09 13:06:25 -0400268 *reply = p;
Chuck Lever5fdca652016-11-29 11:04:42 -0500269 else
270 *reply = NULL;
Chuck Lever10dc4512015-07-09 16:45:28 -0400271}
272
Chuck Lever25d552962016-09-13 10:53:23 -0400273/* RPC-over-RDMA Version One private extension: Remote Invalidation.
274 * Responder's choice: requester signals it can handle Send With
275 * Invalidate, and responder chooses one rkey to invalidate.
276 *
277 * Find a candidate rkey to invalidate when sending a reply. Picks the
Chuck Leverc238c4c2017-04-09 13:06:08 -0400278 * first R_key it finds in the chunk lists.
Chuck Lever25d552962016-09-13 10:53:23 -0400279 *
280 * Returns zero if RPC's chunk lists are empty.
281 */
Chuck Leverc238c4c2017-04-09 13:06:08 -0400282static u32 svc_rdma_get_inv_rkey(__be32 *rdma_argp,
283 __be32 *wr_lst, __be32 *rp_ch)
Chuck Lever25d552962016-09-13 10:53:23 -0400284{
Chuck Leverc238c4c2017-04-09 13:06:08 -0400285 __be32 *p;
Chuck Lever25d552962016-09-13 10:53:23 -0400286
Chuck Leverc238c4c2017-04-09 13:06:08 -0400287 p = rdma_argp + rpcrdma_fixed_maxsz;
288 if (*p != xdr_zero)
289 p += 2;
290 else if (wr_lst && be32_to_cpup(wr_lst + 1))
291 p = wr_lst + 2;
292 else if (rp_ch && be32_to_cpup(rp_ch + 1))
293 p = rp_ch + 2;
294 else
295 return 0;
296 return be32_to_cpup(p);
Chuck Lever25d552962016-09-13 10:53:23 -0400297}
298
Chuck Lever9a6a1802017-04-09 13:06:25 -0400299/* ib_dma_map_page() is used here because svc_rdma_dma_unmap()
300 * is used during completion to DMA-unmap this memory, and
301 * it uses ib_dma_unmap_page() exclusively.
302 */
303static int svc_rdma_dma_map_buf(struct svcxprt_rdma *rdma,
304 struct svc_rdma_op_ctxt *ctxt,
305 unsigned int sge_no,
306 unsigned char *base,
307 unsigned int len)
308{
309 unsigned long offset = (unsigned long)base & ~PAGE_MASK;
310 struct ib_device *dev = rdma->sc_cm_id->device;
311 dma_addr_t dma_addr;
312
313 dma_addr = ib_dma_map_page(dev, virt_to_page(base),
314 offset, len, DMA_TO_DEVICE);
315 if (ib_dma_mapping_error(dev, dma_addr))
Chuck Lever91a08eae2017-06-23 17:17:15 -0400316 goto out_maperr;
Chuck Lever9a6a1802017-04-09 13:06:25 -0400317
318 ctxt->sge[sge_no].addr = dma_addr;
319 ctxt->sge[sge_no].length = len;
320 ctxt->sge[sge_no].lkey = rdma->sc_pd->local_dma_lkey;
321 svc_rdma_count_mappings(rdma, ctxt);
322 return 0;
Chuck Lever91a08eae2017-06-23 17:17:15 -0400323
324out_maperr:
325 pr_err("svcrdma: failed to map buffer\n");
326 return -EIO;
Chuck Lever9a6a1802017-04-09 13:06:25 -0400327}
328
Chuck Lever6e6092c2017-04-09 13:05:44 -0400329static int svc_rdma_dma_map_page(struct svcxprt_rdma *rdma,
330 struct svc_rdma_op_ctxt *ctxt,
331 unsigned int sge_no,
332 struct page *page,
333 unsigned int offset,
334 unsigned int len)
335{
336 struct ib_device *dev = rdma->sc_cm_id->device;
337 dma_addr_t dma_addr;
338
339 dma_addr = ib_dma_map_page(dev, page, offset, len, DMA_TO_DEVICE);
340 if (ib_dma_mapping_error(dev, dma_addr))
Chuck Lever91a08eae2017-06-23 17:17:15 -0400341 goto out_maperr;
Chuck Lever6e6092c2017-04-09 13:05:44 -0400342
343 ctxt->sge[sge_no].addr = dma_addr;
344 ctxt->sge[sge_no].length = len;
345 ctxt->sge[sge_no].lkey = rdma->sc_pd->local_dma_lkey;
346 svc_rdma_count_mappings(rdma, ctxt);
347 return 0;
Chuck Lever91a08eae2017-06-23 17:17:15 -0400348
349out_maperr:
350 pr_err("svcrdma: failed to map page\n");
351 return -EIO;
Chuck Lever6e6092c2017-04-09 13:05:44 -0400352}
353
354/**
355 * svc_rdma_map_reply_hdr - DMA map the transport header buffer
356 * @rdma: controlling transport
357 * @ctxt: op_ctxt for the Send WR
358 * @rdma_resp: buffer containing transport header
359 * @len: length of transport header
360 *
361 * Returns:
362 * %0 if the header is DMA mapped,
363 * %-EIO if DMA mapping failed.
364 */
365int svc_rdma_map_reply_hdr(struct svcxprt_rdma *rdma,
366 struct svc_rdma_op_ctxt *ctxt,
367 __be32 *rdma_resp,
368 unsigned int len)
369{
370 ctxt->direction = DMA_TO_DEVICE;
371 ctxt->pages[0] = virt_to_page(rdma_resp);
372 ctxt->count = 1;
373 return svc_rdma_dma_map_page(rdma, ctxt, 0, ctxt->pages[0], 0, len);
374}
375
Chuck Lever9a6a1802017-04-09 13:06:25 -0400376/* Load the xdr_buf into the ctxt's sge array, and DMA map each
377 * element as it is added.
378 *
379 * Returns the number of sge elements loaded on success, or
380 * a negative errno on failure.
Tom Tuckerc06b5402007-12-12 16:13:25 -0600381 */
Chuck Lever9a6a1802017-04-09 13:06:25 -0400382static int svc_rdma_map_reply_msg(struct svcxprt_rdma *rdma,
383 struct svc_rdma_op_ctxt *ctxt,
384 struct xdr_buf *xdr, __be32 *wr_lst)
Tom Tuckerc06b5402007-12-12 16:13:25 -0600385{
Chuck Lever9a6a1802017-04-09 13:06:25 -0400386 unsigned int len, sge_no, remaining, page_off;
387 struct page **ppages;
388 unsigned char *base;
389 u32 xdr_pad;
Tom Tuckerc06b5402007-12-12 16:13:25 -0600390 int ret;
391
Chuck Lever9a6a1802017-04-09 13:06:25 -0400392 sge_no = 1;
Tom Tuckerc06b5402007-12-12 16:13:25 -0600393
Chuck Lever9a6a1802017-04-09 13:06:25 -0400394 ret = svc_rdma_dma_map_buf(rdma, ctxt, sge_no++,
395 xdr->head[0].iov_base,
396 xdr->head[0].iov_len);
397 if (ret < 0)
398 return ret;
Tom Tuckerc06b5402007-12-12 16:13:25 -0600399
Chuck Lever9a6a1802017-04-09 13:06:25 -0400400 /* If a Write chunk is present, the xdr_buf's page list
401 * is not included inline. However the Upper Layer may
402 * have added XDR padding in the tail buffer, and that
403 * should not be included inline.
404 */
405 if (wr_lst) {
406 base = xdr->tail[0].iov_base;
407 len = xdr->tail[0].iov_len;
408 xdr_pad = xdr_padsize(xdr->page_len);
Tom Tuckerc06b5402007-12-12 16:13:25 -0600409
Chuck Lever9a6a1802017-04-09 13:06:25 -0400410 if (len && xdr_pad) {
411 base += xdr_pad;
412 len -= xdr_pad;
Tom Tuckerc06b5402007-12-12 16:13:25 -0600413 }
Chuck Lever9a6a1802017-04-09 13:06:25 -0400414
415 goto tail;
Tom Tuckerc06b5402007-12-12 16:13:25 -0600416 }
Tom Tuckerc06b5402007-12-12 16:13:25 -0600417
Chuck Lever9a6a1802017-04-09 13:06:25 -0400418 ppages = xdr->pages + (xdr->page_base >> PAGE_SHIFT);
419 page_off = xdr->page_base & ~PAGE_MASK;
420 remaining = xdr->page_len;
421 while (remaining) {
422 len = min_t(u32, PAGE_SIZE - page_off, remaining);
Chuck Lever08ae4e72016-03-01 13:05:36 -0500423
Chuck Lever9a6a1802017-04-09 13:06:25 -0400424 ret = svc_rdma_dma_map_page(rdma, ctxt, sge_no++,
425 *ppages++, page_off, len);
426 if (ret < 0)
427 return ret;
Tom Tuckerc06b5402007-12-12 16:13:25 -0600428
Chuck Lever9a6a1802017-04-09 13:06:25 -0400429 remaining -= len;
430 page_off = 0;
Tom Tuckerc06b5402007-12-12 16:13:25 -0600431 }
Tom Tuckerc06b5402007-12-12 16:13:25 -0600432
Chuck Lever9a6a1802017-04-09 13:06:25 -0400433 base = xdr->tail[0].iov_base;
434 len = xdr->tail[0].iov_len;
435tail:
436 if (len) {
437 ret = svc_rdma_dma_map_buf(rdma, ctxt, sge_no++, base, len);
438 if (ret < 0)
439 return ret;
440 }
Chuck Lever08ae4e72016-03-01 13:05:36 -0500441
Chuck Lever9a6a1802017-04-09 13:06:25 -0400442 return sge_no - 1;
Tom Tuckerc06b5402007-12-12 16:13:25 -0600443}
444
Chuck Leverc55ab072017-04-09 13:06:00 -0400445/* The svc_rqst and all resources it owns are released as soon as
446 * svc_rdma_sendto returns. Transfer pages under I/O to the ctxt
447 * so they are released by the Send completion handler.
448 */
449static void svc_rdma_save_io_pages(struct svc_rqst *rqstp,
450 struct svc_rdma_op_ctxt *ctxt)
451{
452 int i, pages = rqstp->rq_next_page - rqstp->rq_respages;
453
454 ctxt->count += pages;
455 for (i = 0; i < pages; i++) {
456 ctxt->pages[i + 1] = rqstp->rq_respages[i];
457 rqstp->rq_respages[i] = NULL;
458 }
459 rqstp->rq_next_page = rqstp->rq_respages + 1;
460}
461
Chuck Lever17f5f7f2017-04-09 13:05:36 -0400462/**
463 * svc_rdma_post_send_wr - Set up and post one Send Work Request
464 * @rdma: controlling transport
465 * @ctxt: op_ctxt for transmitting the Send WR
466 * @num_sge: number of SGEs to send
467 * @inv_rkey: R_key argument to Send With Invalidate, or zero
468 *
469 * Returns:
470 * %0 if the Send* was posted successfully,
471 * %-ENOTCONN if the connection was lost or dropped,
472 * %-EINVAL if there was a problem with the Send we built,
473 * %-ENOMEM if ib_post_send failed.
474 */
475int svc_rdma_post_send_wr(struct svcxprt_rdma *rdma,
476 struct svc_rdma_op_ctxt *ctxt, int num_sge,
477 u32 inv_rkey)
478{
479 struct ib_send_wr *send_wr = &ctxt->send_wr;
480
481 dprintk("svcrdma: posting Send WR with %u sge(s)\n", num_sge);
482
483 send_wr->next = NULL;
484 ctxt->cqe.done = svc_rdma_wc_send;
485 send_wr->wr_cqe = &ctxt->cqe;
486 send_wr->sg_list = ctxt->sge;
487 send_wr->num_sge = num_sge;
488 send_wr->send_flags = IB_SEND_SIGNALED;
489 if (inv_rkey) {
490 send_wr->opcode = IB_WR_SEND_WITH_INV;
491 send_wr->ex.invalidate_rkey = inv_rkey;
492 } else {
493 send_wr->opcode = IB_WR_SEND;
494 }
495
496 return svc_rdma_send(rdma, send_wr);
497}
498
Chuck Lever9a6a1802017-04-09 13:06:25 -0400499/* Prepare the portion of the RPC Reply that will be transmitted
500 * via RDMA Send. The RPC-over-RDMA transport header is prepared
501 * in sge[0], and the RPC xdr_buf is prepared in following sges.
502 *
503 * Depending on whether a Write list or Reply chunk is present,
504 * the server may send all, a portion of, or none of the xdr_buf.
505 * In the latter case, only the transport header (sge[0]) is
506 * transmitted.
507 *
508 * RDMA Send is the last step of transmitting an RPC reply. Pages
509 * involved in the earlier RDMA Writes are here transferred out
510 * of the rqstp and into the ctxt's page array. These pages are
511 * DMA unmapped by each Write completion, but the subsequent Send
512 * completion finally releases these pages.
513 *
514 * Assumptions:
515 * - The Reply's transport header will never be larger than a page.
Tom Tuckerc06b5402007-12-12 16:13:25 -0600516 */
Chuck Lever9a6a1802017-04-09 13:06:25 -0400517static int svc_rdma_send_reply_msg(struct svcxprt_rdma *rdma,
518 __be32 *rdma_argp, __be32 *rdma_resp,
519 struct svc_rqst *rqstp,
520 __be32 *wr_lst, __be32 *rp_ch)
Tom Tuckerc06b5402007-12-12 16:13:25 -0600521{
Chuck Lever9ec64052016-05-04 10:53:05 -0400522 struct svc_rdma_op_ctxt *ctxt;
Chuck Lever9a6a1802017-04-09 13:06:25 -0400523 u32 inv_rkey;
524 int ret;
Tom Tucker0e7f0112008-04-23 16:49:54 -0500525
Chuck Lever9a6a1802017-04-09 13:06:25 -0400526 dprintk("svcrdma: sending %s reply: head=%zu, pagelen=%u, tail=%zu\n",
527 (rp_ch ? "RDMA_NOMSG" : "RDMA_MSG"),
528 rqstp->rq_res.head[0].iov_len,
529 rqstp->rq_res.page_len,
530 rqstp->rq_res.tail[0].iov_len);
531
Chuck Lever9ec64052016-05-04 10:53:05 -0400532 ctxt = svc_rdma_get_context(rdma);
Tom Tuckerc06b5402007-12-12 16:13:25 -0600533
Chuck Lever9a6a1802017-04-09 13:06:25 -0400534 ret = svc_rdma_map_reply_hdr(rdma, ctxt, rdma_resp,
535 svc_rdma_reply_hdr_len(rdma_resp));
536 if (ret < 0)
Tom Tuckerafd566e2008-10-03 15:45:03 -0500537 goto err;
Tom Tuckerafd566e2008-10-03 15:45:03 -0500538
Chuck Lever9a6a1802017-04-09 13:06:25 -0400539 if (!rp_ch) {
540 ret = svc_rdma_map_reply_msg(rdma, ctxt,
541 &rqstp->rq_res, wr_lst);
542 if (ret < 0)
Steve Wise0bf48282014-05-28 15:12:01 -0500543 goto err;
Chuck Lever3fe04ee2015-01-13 11:03:03 -0500544 }
Tom Tuckerc06b5402007-12-12 16:13:25 -0600545
Chuck Leverc55ab072017-04-09 13:06:00 -0400546 svc_rdma_save_io_pages(rqstp, ctxt);
Steve Wise0bf48282014-05-28 15:12:01 -0500547
Chuck Lever9a6a1802017-04-09 13:06:25 -0400548 inv_rkey = 0;
549 if (rdma->sc_snd_w_inv)
550 inv_rkey = svc_rdma_get_inv_rkey(rdma_argp, wr_lst, rp_ch);
551 ret = svc_rdma_post_send_wr(rdma, ctxt, 1 + ret, inv_rkey);
Tom Tuckerc06b5402007-12-12 16:13:25 -0600552 if (ret)
Tom Tuckerafd566e2008-10-03 15:45:03 -0500553 goto err;
Tom Tuckerc06b5402007-12-12 16:13:25 -0600554
Tom Tuckerafd566e2008-10-03 15:45:03 -0500555 return 0;
556
Chuck Lever9a6a1802017-04-09 13:06:25 -0400557err:
Steve Wise21515e42009-04-29 14:14:00 -0500558 svc_rdma_unmap_dma(ctxt);
Tom Tuckerafd566e2008-10-03 15:45:03 -0500559 svc_rdma_put_context(ctxt, 1);
Chuck Lever9ec64052016-05-04 10:53:05 -0400560 return ret;
Tom Tuckerc06b5402007-12-12 16:13:25 -0600561}
562
Chuck Lever4757d902017-04-09 13:06:41 -0400563/* Given the client-provided Write and Reply chunks, the server was not
564 * able to form a complete reply. Return an RDMA_ERROR message so the
565 * client can retire this RPC transaction. As above, the Send completion
566 * routine releases payload pages that were part of a previous RDMA Write.
567 *
568 * Remote Invalidation is skipped for simplicity.
569 */
570static int svc_rdma_send_error_msg(struct svcxprt_rdma *rdma,
571 __be32 *rdma_resp, struct svc_rqst *rqstp)
572{
573 struct svc_rdma_op_ctxt *ctxt;
574 __be32 *p;
575 int ret;
576
577 ctxt = svc_rdma_get_context(rdma);
578
579 /* Replace the original transport header with an
580 * RDMA_ERROR response. XID etc are preserved.
581 */
582 p = rdma_resp + 3;
583 *p++ = rdma_error;
584 *p = err_chunk;
585
586 ret = svc_rdma_map_reply_hdr(rdma, ctxt, rdma_resp, 20);
587 if (ret < 0)
588 goto err;
589
590 svc_rdma_save_io_pages(rqstp, ctxt);
591
592 ret = svc_rdma_post_send_wr(rdma, ctxt, 1 + ret, 0);
593 if (ret)
594 goto err;
595
596 return 0;
597
598err:
599 pr_err("svcrdma: failed to post Send WR (%d)\n", ret);
600 svc_rdma_unmap_dma(ctxt);
601 svc_rdma_put_context(ctxt, 1);
602 return ret;
603}
604
Tom Tuckerc06b5402007-12-12 16:13:25 -0600605void svc_rdma_prep_reply_hdr(struct svc_rqst *rqstp)
606{
607}
608
Chuck Lever9a6a1802017-04-09 13:06:25 -0400609/**
610 * svc_rdma_sendto - Transmit an RPC reply
611 * @rqstp: processed RPC request, reply XDR already in ::rq_res
612 *
613 * Any resources still associated with @rqstp are released upon return.
614 * If no reply message was possible, the connection is closed.
615 *
616 * Returns:
617 * %0 if an RPC reply has been successfully posted,
618 * %-ENOMEM if a resource shortage occurred (connection is lost),
619 * %-ENOTCONN if posting failed (connection is lost).
620 */
Tom Tuckerc06b5402007-12-12 16:13:25 -0600621int svc_rdma_sendto(struct svc_rqst *rqstp)
622{
623 struct svc_xprt *xprt = rqstp->rq_xprt;
624 struct svcxprt_rdma *rdma =
625 container_of(xprt, struct svcxprt_rdma, sc_xprt);
Chuck Lever9a6a1802017-04-09 13:06:25 -0400626 __be32 *p, *rdma_argp, *rdma_resp, *wr_lst, *rp_ch;
627 struct xdr_buf *xdr = &rqstp->rq_res;
Tom Tuckerc06b5402007-12-12 16:13:25 -0600628 struct page *res_page;
Chuck Lever9a6a1802017-04-09 13:06:25 -0400629 int ret;
Tom Tuckerc06b5402007-12-12 16:13:25 -0600630
Chuck Lever9a6a1802017-04-09 13:06:25 -0400631 /* Find the call's chunk lists to decide how to send the reply.
632 * Receive places the Call's xprt header at the start of page 0.
Chuck Levere5523bd2015-01-13 11:03:11 -0500633 */
634 rdma_argp = page_address(rqstp->rq_pages[0]);
Chuck Lever9a6a1802017-04-09 13:06:25 -0400635 svc_rdma_get_write_arrays(rdma_argp, &wr_lst, &rp_ch);
Tom Tuckerc06b5402007-12-12 16:13:25 -0600636
Chuck Lever9a6a1802017-04-09 13:06:25 -0400637 dprintk("svcrdma: preparing response for XID 0x%08x\n",
638 be32_to_cpup(rdma_argp));
Tom Tuckerc06b5402007-12-12 16:13:25 -0600639
Chuck Levere4eb42c2016-11-29 11:04:50 -0500640 /* Create the RDMA response header. xprt->xpt_mutex,
641 * acquired in svc_send(), serializes RPC replies. The
642 * code path below that inserts the credit grant value
643 * into each transport header runs only inside this
644 * critical section.
645 */
Chuck Lever78da2b32016-01-07 14:49:45 -0500646 ret = -ENOMEM;
647 res_page = alloc_page(GFP_KERNEL);
648 if (!res_page)
649 goto err0;
Tom Tuckerc06b5402007-12-12 16:13:25 -0600650 rdma_resp = page_address(res_page);
Chuck Lever98fc21d2017-02-07 11:58:23 -0500651
Chuck Lever9a6a1802017-04-09 13:06:25 -0400652 p = rdma_resp;
653 *p++ = *rdma_argp;
654 *p++ = *(rdma_argp + 1);
Chuck Lever98fc21d2017-02-07 11:58:23 -0500655 *p++ = rdma->sc_fc_credits;
Chuck Lever9a6a1802017-04-09 13:06:25 -0400656 *p++ = rp_ch ? rdma_nomsg : rdma_msg;
Chuck Lever98fc21d2017-02-07 11:58:23 -0500657
658 /* Start with empty chunks */
659 *p++ = xdr_zero;
660 *p++ = xdr_zero;
661 *p = xdr_zero;
Tom Tuckerc06b5402007-12-12 16:13:25 -0600662
Chuck Lever9a6a1802017-04-09 13:06:25 -0400663 if (wr_lst) {
664 /* XXX: Presume the client sent only one Write chunk */
665 ret = svc_rdma_send_write_chunk(rdma, wr_lst, xdr);
Chuck Lever08ae4e72016-03-01 13:05:36 -0500666 if (ret < 0)
Chuck Lever4757d902017-04-09 13:06:41 -0400667 goto err2;
Chuck Lever9a6a1802017-04-09 13:06:25 -0400668 svc_rdma_xdr_encode_write_list(rdma_resp, wr_lst, ret);
Tom Tuckerc06b5402007-12-12 16:13:25 -0600669 }
Chuck Lever9a6a1802017-04-09 13:06:25 -0400670 if (rp_ch) {
671 ret = svc_rdma_send_reply_chunk(rdma, rp_ch, wr_lst, xdr);
Chuck Lever08ae4e72016-03-01 13:05:36 -0500672 if (ret < 0)
Chuck Lever4757d902017-04-09 13:06:41 -0400673 goto err2;
Chuck Lever9a6a1802017-04-09 13:06:25 -0400674 svc_rdma_xdr_encode_reply_chunk(rdma_resp, rp_ch, ret);
Tom Tuckerc06b5402007-12-12 16:13:25 -0600675 }
Tom Tuckerc06b5402007-12-12 16:13:25 -0600676
Chuck Lever9ec64052016-05-04 10:53:05 -0400677 ret = svc_rdma_post_recv(rdma, GFP_KERNEL);
678 if (ret)
679 goto err1;
Chuck Lever9a6a1802017-04-09 13:06:25 -0400680 ret = svc_rdma_send_reply_msg(rdma, rdma_argp, rdma_resp, rqstp,
681 wr_lst, rp_ch);
Chuck Lever3e1eeb92016-03-01 13:06:11 -0500682 if (ret < 0)
Chuck Lever99952372016-09-13 10:52:59 -0400683 goto err0;
Chuck Lever9a6a1802017-04-09 13:06:25 -0400684 return 0;
Tom Tuckerafd566e2008-10-03 15:45:03 -0500685
Chuck Lever4757d902017-04-09 13:06:41 -0400686 err2:
Colin Ian Kingb20dae72017-07-13 18:51:15 +0100687 if (ret != -E2BIG && ret != -EINVAL)
Chuck Lever4757d902017-04-09 13:06:41 -0400688 goto err1;
689
690 ret = svc_rdma_post_recv(rdma, GFP_KERNEL);
691 if (ret)
692 goto err1;
693 ret = svc_rdma_send_error_msg(rdma, rdma_resp, rqstp);
694 if (ret < 0)
695 goto err0;
696 return 0;
697
Tom Tuckerafd566e2008-10-03 15:45:03 -0500698 err1:
699 put_page(res_page);
700 err0:
Chuck Lever9ec64052016-05-04 10:53:05 -0400701 pr_err("svcrdma: Could not send reply, err=%d. Closing transport.\n",
702 ret);
Chuck Lever9a6a1802017-04-09 13:06:25 -0400703 set_bit(XPT_CLOSE, &xprt->xpt_flags);
Chuck Lever3e1eeb92016-03-01 13:06:11 -0500704 return -ENOTCONN;
Tom Tuckerc06b5402007-12-12 16:13:25 -0600705}