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-rw-r--r--net/sunrpc/xprtrdma/svc_rdma_recvfrom.c586
1 files changed, 586 insertions, 0 deletions
diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
new file mode 100644
index 000000000000..ab54a736486e
--- /dev/null
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -0,0 +1,586 @@
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
115struct chunk_sge {
116 int start; /* sge no for this chunk */
117 int count; /* sge count for this chunk */
118};
119
120/* Encode a read-chunk-list as an array of IB SGE
121 *
122 * Assumptions:
123 * - chunk[0]->position points to pages[0] at an offset of 0
124 * - pages[] is not physically or virtually contigous and consists of
125 * PAGE_SIZE elements.
126 *
127 * Output:
128 * - sge array pointing into pages[] array.
129 * - chunk_sge array specifying sge index and count for each
130 * chunk in the read list
131 *
132 */
133static int rdma_rcl_to_sge(struct svcxprt_rdma *xprt,
134 struct svc_rqst *rqstp,
135 struct svc_rdma_op_ctxt *head,
136 struct rpcrdma_msg *rmsgp,
137 struct ib_sge *sge,
138 struct chunk_sge *ch_sge_ary,
139 int ch_count,
140 int byte_count)
141{
142 int sge_no;
143 int sge_bytes;
144 int page_off;
145 int page_no;
146 int ch_bytes;
147 int ch_no;
148 struct rpcrdma_read_chunk *ch;
149
150 sge_no = 0;
151 page_no = 0;
152 page_off = 0;
153 ch = (struct rpcrdma_read_chunk *)&rmsgp->rm_body.rm_chunks[0];
154 ch_no = 0;
155 ch_bytes = ch->rc_target.rs_length;
156 head->arg.head[0] = rqstp->rq_arg.head[0];
157 head->arg.tail[0] = rqstp->rq_arg.tail[0];
158 head->arg.pages = &head->pages[head->count];
159 head->sge[0].length = head->count; /* save count of hdr pages */
160 head->arg.page_base = 0;
161 head->arg.page_len = ch_bytes;
162 head->arg.len = rqstp->rq_arg.len + ch_bytes;
163 head->arg.buflen = rqstp->rq_arg.buflen + ch_bytes;
164 head->count++;
165 ch_sge_ary[0].start = 0;
166 while (byte_count) {
167 sge_bytes = min_t(int, PAGE_SIZE-page_off, ch_bytes);
168 sge[sge_no].addr =
169 ib_dma_map_page(xprt->sc_cm_id->device,
170 rqstp->rq_arg.pages[page_no],
171 page_off, sge_bytes,
172 DMA_FROM_DEVICE);
173 sge[sge_no].length = sge_bytes;
174 sge[sge_no].lkey = xprt->sc_phys_mr->lkey;
175 /*
176 * Don't bump head->count here because the same page
177 * may be used by multiple SGE.
178 */
179 head->arg.pages[page_no] = rqstp->rq_arg.pages[page_no];
180 rqstp->rq_respages = &rqstp->rq_arg.pages[page_no+1];
181
182 byte_count -= sge_bytes;
183 ch_bytes -= sge_bytes;
184 sge_no++;
185 /*
186 * If all bytes for this chunk have been mapped to an
187 * SGE, move to the next SGE
188 */
189 if (ch_bytes == 0) {
190 ch_sge_ary[ch_no].count =
191 sge_no - ch_sge_ary[ch_no].start;
192 ch_no++;
193 ch++;
194 ch_sge_ary[ch_no].start = sge_no;
195 ch_bytes = ch->rc_target.rs_length;
196 /* If bytes remaining account for next chunk */
197 if (byte_count) {
198 head->arg.page_len += ch_bytes;
199 head->arg.len += ch_bytes;
200 head->arg.buflen += ch_bytes;
201 }
202 }
203 /*
204 * If this SGE consumed all of the page, move to the
205 * next page
206 */
207 if ((sge_bytes + page_off) == PAGE_SIZE) {
208 page_no++;
209 page_off = 0;
210 /*
211 * If there are still bytes left to map, bump
212 * the page count
213 */
214 if (byte_count)
215 head->count++;
216 } else
217 page_off += sge_bytes;
218 }
219 BUG_ON(byte_count != 0);
220 return sge_no;
221}
222
223static void rdma_set_ctxt_sge(struct svc_rdma_op_ctxt *ctxt,
224 struct ib_sge *sge,
225 u64 *sgl_offset,
226 int count)
227{
228 int i;
229
230 ctxt->count = count;
231 for (i = 0; i < count; i++) {
232 ctxt->sge[i].addr = sge[i].addr;
233 ctxt->sge[i].length = sge[i].length;
234 *sgl_offset = *sgl_offset + sge[i].length;
235 }
236}
237
238static int rdma_read_max_sge(struct svcxprt_rdma *xprt, int sge_count)
239{
240#ifdef RDMA_TRANSPORT_IWARP
241 if ((RDMA_TRANSPORT_IWARP ==
242 rdma_node_get_transport(xprt->sc_cm_id->
243 device->node_type))
244 && sge_count > 1)
245 return 1;
246 else
247#endif
248 return min_t(int, sge_count, xprt->sc_max_sge);
249}
250
251/*
252 * Use RDMA_READ to read data from the advertised client buffer into the
253 * XDR stream starting at rq_arg.head[0].iov_base.
254 * Each chunk in the array
255 * contains the following fields:
256 * discrim - '1', This isn't used for data placement
257 * position - The xdr stream offset (the same for every chunk)
258 * handle - RMR for client memory region
259 * length - data transfer length
260 * offset - 64 bit tagged offset in remote memory region
261 *
262 * On our side, we need to read into a pagelist. The first page immediately
263 * follows the RPC header.
264 *
265 * This function returns 1 to indicate success. The data is not yet in
266 * the pagelist and therefore the RPC request must be deferred. The
267 * I/O completion will enqueue the transport again and
268 * svc_rdma_recvfrom will complete the request.
269 *
270 * NOTE: The ctxt must not be touched after the last WR has been posted
271 * because the I/O completion processing may occur on another
272 * processor and free / modify the context. Ne touche pas!
273 */
274static int rdma_read_xdr(struct svcxprt_rdma *xprt,
275 struct rpcrdma_msg *rmsgp,
276 struct svc_rqst *rqstp,
277 struct svc_rdma_op_ctxt *hdr_ctxt)
278{
279 struct ib_send_wr read_wr;
280 int err = 0;
281 int ch_no;
282 struct ib_sge *sge;
283 int ch_count;
284 int byte_count;
285 int sge_count;
286 u64 sgl_offset;
287 struct rpcrdma_read_chunk *ch;
288 struct svc_rdma_op_ctxt *ctxt = NULL;
289 struct svc_rdma_op_ctxt *head;
290 struct svc_rdma_op_ctxt *tmp_sge_ctxt;
291 struct svc_rdma_op_ctxt *tmp_ch_ctxt;
292 struct chunk_sge *ch_sge_ary;
293
294 /* If no read list is present, return 0 */
295 ch = svc_rdma_get_read_chunk(rmsgp);
296 if (!ch)
297 return 0;
298
299 /* Allocate temporary contexts to keep SGE */
300 BUG_ON(sizeof(struct ib_sge) < sizeof(struct chunk_sge));
301 tmp_sge_ctxt = svc_rdma_get_context(xprt);
302 sge = tmp_sge_ctxt->sge;
303 tmp_ch_ctxt = svc_rdma_get_context(xprt);
304 ch_sge_ary = (struct chunk_sge *)tmp_ch_ctxt->sge;
305
306 svc_rdma_rcl_chunk_counts(ch, &ch_count, &byte_count);
307 sge_count = rdma_rcl_to_sge(xprt, rqstp, hdr_ctxt, rmsgp,
308 sge, ch_sge_ary,
309 ch_count, byte_count);
310 head = svc_rdma_get_context(xprt);
311 sgl_offset = 0;
312 ch_no = 0;
313
314 for (ch = (struct rpcrdma_read_chunk *)&rmsgp->rm_body.rm_chunks[0];
315 ch->rc_discrim != 0; ch++, ch_no++) {
316next_sge:
317 if (!ctxt)
318 ctxt = head;
319 else {
320 ctxt->next = svc_rdma_get_context(xprt);
321 ctxt = ctxt->next;
322 }
323 ctxt->next = NULL;
324 ctxt->direction = DMA_FROM_DEVICE;
325 clear_bit(RDMACTXT_F_READ_DONE, &ctxt->flags);
326 clear_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags);
327 if ((ch+1)->rc_discrim == 0) {
328 /*
329 * Checked in sq_cq_reap to see if we need to
330 * be enqueued
331 */
332 set_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags);
333 ctxt->next = hdr_ctxt;
334 hdr_ctxt->next = head;
335 }
336
337 /* Prepare READ WR */
338 memset(&read_wr, 0, sizeof read_wr);
339 ctxt->wr_op = IB_WR_RDMA_READ;
340 read_wr.wr_id = (unsigned long)ctxt;
341 read_wr.opcode = IB_WR_RDMA_READ;
342 read_wr.send_flags = IB_SEND_SIGNALED;
343 read_wr.wr.rdma.rkey = ch->rc_target.rs_handle;
344 read_wr.wr.rdma.remote_addr =
345 get_unaligned(&(ch->rc_target.rs_offset)) +
346 sgl_offset;
347 read_wr.sg_list = &sge[ch_sge_ary[ch_no].start];
348 read_wr.num_sge =
349 rdma_read_max_sge(xprt, ch_sge_ary[ch_no].count);
350 rdma_set_ctxt_sge(ctxt, &sge[ch_sge_ary[ch_no].start],
351 &sgl_offset,
352 read_wr.num_sge);
353
354 /* Post the read */
355 err = svc_rdma_send(xprt, &read_wr);
356 if (err) {
357 printk(KERN_ERR "svcrdma: Error posting send = %d\n",
358 err);
359 /*
360 * Break the circular list so free knows when
361 * to stop if the error happened to occur on
362 * the last read
363 */
364 ctxt->next = NULL;
365 goto out;
366 }
367 atomic_inc(&rdma_stat_read);
368
369 if (read_wr.num_sge < ch_sge_ary[ch_no].count) {
370 ch_sge_ary[ch_no].count -= read_wr.num_sge;
371 ch_sge_ary[ch_no].start += read_wr.num_sge;
372 goto next_sge;
373 }
374 sgl_offset = 0;
375 err = 0;
376 }
377
378 out:
379 svc_rdma_put_context(tmp_sge_ctxt, 0);
380 svc_rdma_put_context(tmp_ch_ctxt, 0);
381
382 /* Detach arg pages. svc_recv will replenish them */
383 for (ch_no = 0; &rqstp->rq_pages[ch_no] < rqstp->rq_respages; ch_no++)
384 rqstp->rq_pages[ch_no] = NULL;
385
386 /*
387 * Detach res pages. svc_release must see a resused count of
388 * zero or it will attempt to put them.
389 */
390 while (rqstp->rq_resused)
391 rqstp->rq_respages[--rqstp->rq_resused] = NULL;
392
393 if (err) {
394 printk(KERN_ERR "svcrdma : RDMA_READ error = %d\n", err);
395 set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
396 /* Free the linked list of read contexts */
397 while (head != NULL) {
398 ctxt = head->next;
399 svc_rdma_put_context(head, 1);
400 head = ctxt;
401 }
402 return 0;
403 }
404
405 return 1;
406}
407
408static int rdma_read_complete(struct svc_rqst *rqstp,
409 struct svc_rdma_op_ctxt *data)
410{
411 struct svc_rdma_op_ctxt *head = data->next;
412 int page_no;
413 int ret;
414
415 BUG_ON(!head);
416
417 /* Copy RPC pages */
418 for (page_no = 0; page_no < head->count; page_no++) {
419 put_page(rqstp->rq_pages[page_no]);
420 rqstp->rq_pages[page_no] = head->pages[page_no];
421 }
422 /* Point rq_arg.pages past header */
423 rqstp->rq_arg.pages = &rqstp->rq_pages[head->sge[0].length];
424 rqstp->rq_arg.page_len = head->arg.page_len;
425 rqstp->rq_arg.page_base = head->arg.page_base;
426
427 /* rq_respages starts after the last arg page */
428 rqstp->rq_respages = &rqstp->rq_arg.pages[page_no];
429 rqstp->rq_resused = 0;
430
431 /* Rebuild rq_arg head and tail. */
432 rqstp->rq_arg.head[0] = head->arg.head[0];
433 rqstp->rq_arg.tail[0] = head->arg.tail[0];
434 rqstp->rq_arg.len = head->arg.len;
435 rqstp->rq_arg.buflen = head->arg.buflen;
436
437 /* XXX: What should this be? */
438 rqstp->rq_prot = IPPROTO_MAX;
439
440 /*
441 * Free the contexts we used to build the RDMA_READ. We have
442 * to be careful here because the context list uses the same
443 * next pointer used to chain the contexts associated with the
444 * RDMA_READ
445 */
446 data->next = NULL; /* terminate circular list */
447 do {
448 data = head->next;
449 svc_rdma_put_context(head, 0);
450 head = data;
451 } while (head != NULL);
452
453 ret = rqstp->rq_arg.head[0].iov_len
454 + rqstp->rq_arg.page_len
455 + rqstp->rq_arg.tail[0].iov_len;
456 dprintk("svcrdma: deferred read ret=%d, rq_arg.len =%d, "
457 "rq_arg.head[0].iov_base=%p, rq_arg.head[0].iov_len = %zd\n",
458 ret, rqstp->rq_arg.len, rqstp->rq_arg.head[0].iov_base,
459 rqstp->rq_arg.head[0].iov_len);
460
461 /* Indicate that we've consumed an RQ credit */
462 rqstp->rq_xprt_ctxt = rqstp->rq_xprt;
463 svc_xprt_received(rqstp->rq_xprt);
464 return ret;
465}
466
467/*
468 * Set up the rqstp thread context to point to the RQ buffer. If
469 * necessary, pull additional data from the client with an RDMA_READ
470 * request.
471 */
472int svc_rdma_recvfrom(struct svc_rqst *rqstp)
473{
474 struct svc_xprt *xprt = rqstp->rq_xprt;
475 struct svcxprt_rdma *rdma_xprt =
476 container_of(xprt, struct svcxprt_rdma, sc_xprt);
477 struct svc_rdma_op_ctxt *ctxt = NULL;
478 struct rpcrdma_msg *rmsgp;
479 int ret = 0;
480 int len;
481
482 dprintk("svcrdma: rqstp=%p\n", rqstp);
483
484 /*
485 * The rq_xprt_ctxt indicates if we've consumed an RQ credit
486 * or not. It is used in the rdma xpo_release_rqst function to
487 * determine whether or not to return an RQ WQE to the RQ.
488 */
489 rqstp->rq_xprt_ctxt = NULL;
490
491 spin_lock_bh(&rdma_xprt->sc_read_complete_lock);
492 if (!list_empty(&rdma_xprt->sc_read_complete_q)) {
493 ctxt = list_entry(rdma_xprt->sc_read_complete_q.next,
494 struct svc_rdma_op_ctxt,
495 dto_q);
496 list_del_init(&ctxt->dto_q);
497 }
498 spin_unlock_bh(&rdma_xprt->sc_read_complete_lock);
499 if (ctxt)
500 return rdma_read_complete(rqstp, ctxt);
501
502 spin_lock_bh(&rdma_xprt->sc_rq_dto_lock);
503 if (!list_empty(&rdma_xprt->sc_rq_dto_q)) {
504 ctxt = list_entry(rdma_xprt->sc_rq_dto_q.next,
505 struct svc_rdma_op_ctxt,
506 dto_q);
507 list_del_init(&ctxt->dto_q);
508 } else {
509 atomic_inc(&rdma_stat_rq_starve);
510 clear_bit(XPT_DATA, &xprt->xpt_flags);
511 ctxt = NULL;
512 }
513 spin_unlock_bh(&rdma_xprt->sc_rq_dto_lock);
514 if (!ctxt) {
515 /* This is the EAGAIN path. The svc_recv routine will
516 * return -EAGAIN, the nfsd thread will go to call into
517 * svc_recv again and we shouldn't be on the active
518 * transport list
519 */
520 if (test_bit(XPT_CLOSE, &xprt->xpt_flags))
521 goto close_out;
522
523 BUG_ON(ret);
524 goto out;
525 }
526 dprintk("svcrdma: processing ctxt=%p on xprt=%p, rqstp=%p, status=%d\n",
527 ctxt, rdma_xprt, rqstp, ctxt->wc_status);
528 BUG_ON(ctxt->wc_status != IB_WC_SUCCESS);
529 atomic_inc(&rdma_stat_recv);
530
531 /* Build up the XDR from the receive buffers. */
532 rdma_build_arg_xdr(rqstp, ctxt, ctxt->byte_len);
533
534 /* Decode the RDMA header. */
535 len = svc_rdma_xdr_decode_req(&rmsgp, rqstp);
536 rqstp->rq_xprt_hlen = len;
537
538 /* If the request is invalid, reply with an error */
539 if (len < 0) {
540 if (len == -ENOSYS)
541 (void)svc_rdma_send_error(rdma_xprt, rmsgp, ERR_VERS);
542 goto close_out;
543 }
544
545 /* Read read-list data. If we would need to wait, defer
546 * it. Not that in this case, we don't return the RQ credit
547 * until after the read completes.
548 */
549 if (rdma_read_xdr(rdma_xprt, rmsgp, rqstp, ctxt)) {
550 svc_xprt_received(xprt);
551 return 0;
552 }
553
554 /* Indicate we've consumed an RQ credit */
555 rqstp->rq_xprt_ctxt = rqstp->rq_xprt;
556
557 ret = rqstp->rq_arg.head[0].iov_len
558 + rqstp->rq_arg.page_len
559 + rqstp->rq_arg.tail[0].iov_len;
560 svc_rdma_put_context(ctxt, 0);
561 out:
562 dprintk("svcrdma: ret = %d, rq_arg.len =%d, "
563 "rq_arg.head[0].iov_base=%p, rq_arg.head[0].iov_len = %zd\n",
564 ret, rqstp->rq_arg.len,
565 rqstp->rq_arg.head[0].iov_base,
566 rqstp->rq_arg.head[0].iov_len);
567 rqstp->rq_prot = IPPROTO_MAX;
568 svc_xprt_copy_addrs(rqstp, xprt);
569 svc_xprt_received(xprt);
570 return ret;
571
572 close_out:
573 if (ctxt) {
574 svc_rdma_put_context(ctxt, 1);
575 /* Indicate we've consumed an RQ credit */
576 rqstp->rq_xprt_ctxt = rqstp->rq_xprt;
577 }
578 dprintk("svcrdma: transport %p is closing\n", xprt);
579 /*
580 * Set the close bit and enqueue it. svc_recv will see the
581 * close bit and call svc_xprt_delete
582 */
583 set_bit(XPT_CLOSE, &xprt->xpt_flags);
584 svc_xprt_received(xprt);
585 return 0;
586}