SVCRDMA: Fix erroneous BUG_ON in send_write
[sfrench/cifs-2.6.git] / net / sunrpc / xprtrdma / svc_rdma_sendto.c
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:
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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.
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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 /* Encode an XDR as an array of IB SGE
53  *
54  * Assumptions:
55  * - head[0] is physically contiguous.
56  * - tail[0] is physically contiguous.
57  * - pages[] is not physically or virtually contigous and consists of
58  *   PAGE_SIZE elements.
59  *
60  * Output:
61  * SGE[0]              reserved for RCPRDMA header
62  * SGE[1]              data from xdr->head[]
63  * SGE[2..sge_count-2] data from xdr->pages[]
64  * SGE[sge_count-1]    data from xdr->tail.
65  *
66  */
67 static struct ib_sge *xdr_to_sge(struct svcxprt_rdma *xprt,
68                                  struct xdr_buf *xdr,
69                                  struct ib_sge *sge,
70                                  int *sge_count)
71 {
72         /* Max we need is the length of the XDR / pagesize + one for
73          * head + one for tail + one for RPCRDMA header
74          */
75         int sge_max = (xdr->len+PAGE_SIZE-1) / PAGE_SIZE + 3;
76         int sge_no;
77         u32 byte_count = xdr->len;
78         u32 sge_bytes;
79         u32 page_bytes;
80         int page_off;
81         int page_no;
82
83         /* Skip the first sge, this is for the RPCRDMA header */
84         sge_no = 1;
85
86         /* Head SGE */
87         sge[sge_no].addr = ib_dma_map_single(xprt->sc_cm_id->device,
88                                              xdr->head[0].iov_base,
89                                              xdr->head[0].iov_len,
90                                              DMA_TO_DEVICE);
91         sge_bytes = min_t(u32, byte_count, xdr->head[0].iov_len);
92         byte_count -= sge_bytes;
93         sge[sge_no].length = sge_bytes;
94         sge[sge_no].lkey = xprt->sc_phys_mr->lkey;
95         sge_no++;
96
97         /* pages SGE */
98         page_no = 0;
99         page_bytes = xdr->page_len;
100         page_off = xdr->page_base;
101         while (byte_count && page_bytes) {
102                 sge_bytes = min_t(u32, byte_count, (PAGE_SIZE-page_off));
103                 sge[sge_no].addr =
104                         ib_dma_map_page(xprt->sc_cm_id->device,
105                                         xdr->pages[page_no], page_off,
106                                         sge_bytes, DMA_TO_DEVICE);
107                 sge_bytes = min(sge_bytes, page_bytes);
108                 byte_count -= sge_bytes;
109                 page_bytes -= sge_bytes;
110                 sge[sge_no].length = sge_bytes;
111                 sge[sge_no].lkey = xprt->sc_phys_mr->lkey;
112
113                 sge_no++;
114                 page_no++;
115                 page_off = 0; /* reset for next time through loop */
116         }
117
118         /* Tail SGE */
119         if (byte_count && xdr->tail[0].iov_len) {
120                 sge[sge_no].addr =
121                         ib_dma_map_single(xprt->sc_cm_id->device,
122                                           xdr->tail[0].iov_base,
123                                           xdr->tail[0].iov_len,
124                                           DMA_TO_DEVICE);
125                 sge_bytes = min_t(u32, byte_count, xdr->tail[0].iov_len);
126                 byte_count -= sge_bytes;
127                 sge[sge_no].length = sge_bytes;
128                 sge[sge_no].lkey = xprt->sc_phys_mr->lkey;
129                 sge_no++;
130         }
131
132         BUG_ON(sge_no > sge_max);
133         BUG_ON(byte_count != 0);
134
135         *sge_count = sge_no;
136         return sge;
137 }
138
139
140 /* Assumptions:
141  * - The specified write_len can be represented in sc_max_sge * PAGE_SIZE
142  */
143 static int send_write(struct svcxprt_rdma *xprt, struct svc_rqst *rqstp,
144                       u32 rmr, u64 to,
145                       u32 xdr_off, int write_len,
146                       struct ib_sge *xdr_sge, int sge_count)
147 {
148         struct svc_rdma_op_ctxt *tmp_sge_ctxt;
149         struct ib_send_wr write_wr;
150         struct ib_sge *sge;
151         int xdr_sge_no;
152         int sge_no;
153         int sge_bytes;
154         int sge_off;
155         int bc;
156         struct svc_rdma_op_ctxt *ctxt;
157         int ret = 0;
158
159         BUG_ON(sge_count > RPCSVC_MAXPAGES);
160         dprintk("svcrdma: RDMA_WRITE rmr=%x, to=%llx, xdr_off=%d, "
161                 "write_len=%d, xdr_sge=%p, sge_count=%d\n",
162                 rmr, (unsigned long long)to, xdr_off,
163                 write_len, xdr_sge, sge_count);
164
165         ctxt = svc_rdma_get_context(xprt);
166         ctxt->count = 0;
167         tmp_sge_ctxt = svc_rdma_get_context(xprt);
168         sge = tmp_sge_ctxt->sge;
169
170         /* Find the SGE associated with xdr_off */
171         for (bc = xdr_off, xdr_sge_no = 1; bc && xdr_sge_no < sge_count;
172              xdr_sge_no++) {
173                 if (xdr_sge[xdr_sge_no].length > bc)
174                         break;
175                 bc -= xdr_sge[xdr_sge_no].length;
176         }
177
178         sge_off = bc;
179         bc = write_len;
180         sge_no = 0;
181
182         /* Copy the remaining SGE */
183         while (bc != 0 && xdr_sge_no < sge_count) {
184                 sge[sge_no].addr = xdr_sge[xdr_sge_no].addr + sge_off;
185                 sge[sge_no].lkey = xdr_sge[xdr_sge_no].lkey;
186                 sge_bytes = min((size_t)bc,
187                                 (size_t)(xdr_sge[xdr_sge_no].length-sge_off));
188                 sge[sge_no].length = sge_bytes;
189
190                 sge_off = 0;
191                 sge_no++;
192                 xdr_sge_no++;
193                 bc -= sge_bytes;
194         }
195
196         BUG_ON(bc != 0);
197         BUG_ON(xdr_sge_no > sge_count);
198
199         /* Prepare WRITE WR */
200         memset(&write_wr, 0, sizeof write_wr);
201         ctxt->wr_op = IB_WR_RDMA_WRITE;
202         write_wr.wr_id = (unsigned long)ctxt;
203         write_wr.sg_list = &sge[0];
204         write_wr.num_sge = sge_no;
205         write_wr.opcode = IB_WR_RDMA_WRITE;
206         write_wr.send_flags = IB_SEND_SIGNALED;
207         write_wr.wr.rdma.rkey = rmr;
208         write_wr.wr.rdma.remote_addr = to;
209
210         /* Post It */
211         atomic_inc(&rdma_stat_write);
212         if (svc_rdma_send(xprt, &write_wr)) {
213                 svc_rdma_put_context(ctxt, 1);
214                 /* Fatal error, close transport */
215                 ret = -EIO;
216         }
217         svc_rdma_put_context(tmp_sge_ctxt, 0);
218         return ret;
219 }
220
221 static int send_write_chunks(struct svcxprt_rdma *xprt,
222                              struct rpcrdma_msg *rdma_argp,
223                              struct rpcrdma_msg *rdma_resp,
224                              struct svc_rqst *rqstp,
225                              struct ib_sge *sge,
226                              int sge_count)
227 {
228         u32 xfer_len = rqstp->rq_res.page_len + rqstp->rq_res.tail[0].iov_len;
229         int write_len;
230         int max_write;
231         u32 xdr_off;
232         int chunk_off;
233         int chunk_no;
234         struct rpcrdma_write_array *arg_ary;
235         struct rpcrdma_write_array *res_ary;
236         int ret;
237
238         arg_ary = svc_rdma_get_write_array(rdma_argp);
239         if (!arg_ary)
240                 return 0;
241         res_ary = (struct rpcrdma_write_array *)
242                 &rdma_resp->rm_body.rm_chunks[1];
243
244         max_write = xprt->sc_max_sge * PAGE_SIZE;
245
246         /* Write chunks start at the pagelist */
247         for (xdr_off = rqstp->rq_res.head[0].iov_len, chunk_no = 0;
248              xfer_len && chunk_no < arg_ary->wc_nchunks;
249              chunk_no++) {
250                 struct rpcrdma_segment *arg_ch;
251                 u64 rs_offset;
252
253                 arg_ch = &arg_ary->wc_array[chunk_no].wc_target;
254                 write_len = min(xfer_len, arg_ch->rs_length);
255
256                 /* Prepare the response chunk given the length actually
257                  * written */
258                 rs_offset = get_unaligned(&(arg_ch->rs_offset));
259                 svc_rdma_xdr_encode_array_chunk(res_ary, chunk_no,
260                                             arg_ch->rs_handle,
261                                             rs_offset,
262                                             write_len);
263                 chunk_off = 0;
264                 while (write_len) {
265                         int this_write;
266                         this_write = min(write_len, max_write);
267                         ret = send_write(xprt, rqstp,
268                                          arg_ch->rs_handle,
269                                          rs_offset + chunk_off,
270                                          xdr_off,
271                                          this_write,
272                                          sge,
273                                          sge_count);
274                         if (ret) {
275                                 dprintk("svcrdma: RDMA_WRITE failed, ret=%d\n",
276                                         ret);
277                                 return -EIO;
278                         }
279                         chunk_off += this_write;
280                         xdr_off += this_write;
281                         xfer_len -= this_write;
282                         write_len -= this_write;
283                 }
284         }
285         /* Update the req with the number of chunks actually used */
286         svc_rdma_xdr_encode_write_list(rdma_resp, chunk_no);
287
288         return rqstp->rq_res.page_len + rqstp->rq_res.tail[0].iov_len;
289 }
290
291 static int send_reply_chunks(struct svcxprt_rdma *xprt,
292                              struct rpcrdma_msg *rdma_argp,
293                              struct rpcrdma_msg *rdma_resp,
294                              struct svc_rqst *rqstp,
295                              struct ib_sge *sge,
296                              int sge_count)
297 {
298         u32 xfer_len = rqstp->rq_res.len;
299         int write_len;
300         int max_write;
301         u32 xdr_off;
302         int chunk_no;
303         int chunk_off;
304         struct rpcrdma_segment *ch;
305         struct rpcrdma_write_array *arg_ary;
306         struct rpcrdma_write_array *res_ary;
307         int ret;
308
309         arg_ary = svc_rdma_get_reply_array(rdma_argp);
310         if (!arg_ary)
311                 return 0;
312         /* XXX: need to fix when reply lists occur with read-list and or
313          * write-list */
314         res_ary = (struct rpcrdma_write_array *)
315                 &rdma_resp->rm_body.rm_chunks[2];
316
317         max_write = xprt->sc_max_sge * PAGE_SIZE;
318
319         /* xdr offset starts at RPC message */
320         for (xdr_off = 0, chunk_no = 0;
321              xfer_len && chunk_no < arg_ary->wc_nchunks;
322              chunk_no++) {
323                 u64 rs_offset;
324                 ch = &arg_ary->wc_array[chunk_no].wc_target;
325                 write_len = min(xfer_len, ch->rs_length);
326
327
328                 /* Prepare the reply chunk given the length actually
329                  * written */
330                 rs_offset = get_unaligned(&(ch->rs_offset));
331                 svc_rdma_xdr_encode_array_chunk(res_ary, chunk_no,
332                                             ch->rs_handle, rs_offset,
333                                             write_len);
334                 chunk_off = 0;
335                 while (write_len) {
336                         int this_write;
337
338                         this_write = min(write_len, max_write);
339                         ret = send_write(xprt, rqstp,
340                                          ch->rs_handle,
341                                          rs_offset + chunk_off,
342                                          xdr_off,
343                                          this_write,
344                                          sge,
345                                          sge_count);
346                         if (ret) {
347                                 dprintk("svcrdma: RDMA_WRITE failed, ret=%d\n",
348                                         ret);
349                                 return -EIO;
350                         }
351                         chunk_off += this_write;
352                         xdr_off += this_write;
353                         xfer_len -= this_write;
354                         write_len -= this_write;
355                 }
356         }
357         /* Update the req with the number of chunks actually used */
358         svc_rdma_xdr_encode_reply_array(res_ary, chunk_no);
359
360         return rqstp->rq_res.len;
361 }
362
363 /* This function prepares the portion of the RPCRDMA message to be
364  * sent in the RDMA_SEND. This function is called after data sent via
365  * RDMA has already been transmitted. There are three cases:
366  * - The RPCRDMA header, RPC header, and payload are all sent in a
367  *   single RDMA_SEND. This is the "inline" case.
368  * - The RPCRDMA header and some portion of the RPC header and data
369  *   are sent via this RDMA_SEND and another portion of the data is
370  *   sent via RDMA.
371  * - The RPCRDMA header [NOMSG] is sent in this RDMA_SEND and the RPC
372  *   header and data are all transmitted via RDMA.
373  * In all three cases, this function prepares the RPCRDMA header in
374  * sge[0], the 'type' parameter indicates the type to place in the
375  * RPCRDMA header, and the 'byte_count' field indicates how much of
376  * the XDR to include in this RDMA_SEND.
377  */
378 static int send_reply(struct svcxprt_rdma *rdma,
379                       struct svc_rqst *rqstp,
380                       struct page *page,
381                       struct rpcrdma_msg *rdma_resp,
382                       struct svc_rdma_op_ctxt *ctxt,
383                       int sge_count,
384                       int byte_count)
385 {
386         struct ib_send_wr send_wr;
387         int sge_no;
388         int sge_bytes;
389         int page_no;
390         int ret;
391
392         /* Prepare the context */
393         ctxt->pages[0] = page;
394         ctxt->count = 1;
395
396         /* Prepare the SGE for the RPCRDMA Header */
397         ctxt->sge[0].addr =
398                 ib_dma_map_page(rdma->sc_cm_id->device,
399                                 page, 0, PAGE_SIZE, DMA_TO_DEVICE);
400         ctxt->direction = DMA_TO_DEVICE;
401         ctxt->sge[0].length = svc_rdma_xdr_get_reply_hdr_len(rdma_resp);
402         ctxt->sge[0].lkey = rdma->sc_phys_mr->lkey;
403
404         /* Determine how many of our SGE are to be transmitted */
405         for (sge_no = 1; byte_count && sge_no < sge_count; sge_no++) {
406                 sge_bytes = min((size_t)ctxt->sge[sge_no].length,
407                                 (size_t)byte_count);
408                 byte_count -= sge_bytes;
409         }
410         BUG_ON(byte_count != 0);
411
412         /* Save all respages in the ctxt and remove them from the
413          * respages array. They are our pages until the I/O
414          * completes.
415          */
416         for (page_no = 0; page_no < rqstp->rq_resused; page_no++) {
417                 ctxt->pages[page_no+1] = rqstp->rq_respages[page_no];
418                 ctxt->count++;
419                 rqstp->rq_respages[page_no] = NULL;
420         }
421
422         BUG_ON(sge_no > rdma->sc_max_sge);
423         memset(&send_wr, 0, sizeof send_wr);
424         ctxt->wr_op = IB_WR_SEND;
425         send_wr.wr_id = (unsigned long)ctxt;
426         send_wr.sg_list = ctxt->sge;
427         send_wr.num_sge = sge_no;
428         send_wr.opcode = IB_WR_SEND;
429         send_wr.send_flags =  IB_SEND_SIGNALED;
430
431         ret = svc_rdma_send(rdma, &send_wr);
432         if (ret)
433                 svc_rdma_put_context(ctxt, 1);
434
435         return ret;
436 }
437
438 void svc_rdma_prep_reply_hdr(struct svc_rqst *rqstp)
439 {
440 }
441
442 /*
443  * Return the start of an xdr buffer.
444  */
445 static void *xdr_start(struct xdr_buf *xdr)
446 {
447         return xdr->head[0].iov_base -
448                 (xdr->len -
449                  xdr->page_len -
450                  xdr->tail[0].iov_len -
451                  xdr->head[0].iov_len);
452 }
453
454 int svc_rdma_sendto(struct svc_rqst *rqstp)
455 {
456         struct svc_xprt *xprt = rqstp->rq_xprt;
457         struct svcxprt_rdma *rdma =
458                 container_of(xprt, struct svcxprt_rdma, sc_xprt);
459         struct rpcrdma_msg *rdma_argp;
460         struct rpcrdma_msg *rdma_resp;
461         struct rpcrdma_write_array *reply_ary;
462         enum rpcrdma_proc reply_type;
463         int ret;
464         int inline_bytes;
465         struct ib_sge *sge;
466         int sge_count = 0;
467         struct page *res_page;
468         struct svc_rdma_op_ctxt *ctxt;
469
470         dprintk("svcrdma: sending response for rqstp=%p\n", rqstp);
471
472         /* Get the RDMA request header. */
473         rdma_argp = xdr_start(&rqstp->rq_arg);
474
475         /* Build an SGE for the XDR */
476         ctxt = svc_rdma_get_context(rdma);
477         ctxt->direction = DMA_TO_DEVICE;
478         sge = xdr_to_sge(rdma, &rqstp->rq_res, ctxt->sge, &sge_count);
479
480         inline_bytes = rqstp->rq_res.len;
481
482         /* Create the RDMA response header */
483         res_page = svc_rdma_get_page();
484         rdma_resp = page_address(res_page);
485         reply_ary = svc_rdma_get_reply_array(rdma_argp);
486         if (reply_ary)
487                 reply_type = RDMA_NOMSG;
488         else
489                 reply_type = RDMA_MSG;
490         svc_rdma_xdr_encode_reply_header(rdma, rdma_argp,
491                                          rdma_resp, reply_type);
492
493         /* Send any write-chunk data and build resp write-list */
494         ret = send_write_chunks(rdma, rdma_argp, rdma_resp,
495                                 rqstp, sge, sge_count);
496         if (ret < 0) {
497                 printk(KERN_ERR "svcrdma: failed to send write chunks, rc=%d\n",
498                        ret);
499                 goto error;
500         }
501         inline_bytes -= ret;
502
503         /* Send any reply-list data and update resp reply-list */
504         ret = send_reply_chunks(rdma, rdma_argp, rdma_resp,
505                                 rqstp, sge, sge_count);
506         if (ret < 0) {
507                 printk(KERN_ERR "svcrdma: failed to send reply chunks, rc=%d\n",
508                        ret);
509                 goto error;
510         }
511         inline_bytes -= ret;
512
513         ret = send_reply(rdma, rqstp, res_page, rdma_resp, ctxt, sge_count,
514                          inline_bytes);
515         dprintk("svcrdma: send_reply returns %d\n", ret);
516         return ret;
517  error:
518         svc_rdma_put_context(ctxt, 0);
519         put_page(res_page);
520         return ret;
521 }