Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
[linux-2.6] / net / sunrpc / xprtrdma / svc_rdma_recvfrom.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:
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  */
57 static 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 struct 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  */
133 static 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
223 static 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
238 static int rdma_read_max_sge(struct svcxprt_rdma *xprt, int sge_count)
239 {
240         if ((RDMA_TRANSPORT_IWARP ==
241              rdma_node_get_transport(xprt->sc_cm_id->
242                                      device->node_type))
243             && sge_count > 1)
244                 return 1;
245         else
246                 return min_t(int, sge_count, xprt->sc_max_sge);
247 }
248
249 /*
250  * Use RDMA_READ to read data from the advertised client buffer into the
251  * XDR stream starting at rq_arg.head[0].iov_base.
252  * Each chunk in the array
253  * contains the following fields:
254  * discrim      - '1', This isn't used for data placement
255  * position     - The xdr stream offset (the same for every chunk)
256  * handle       - RMR for client memory region
257  * length       - data transfer length
258  * offset       - 64 bit tagged offset in remote memory region
259  *
260  * On our side, we need to read into a pagelist. The first page immediately
261  * follows the RPC header.
262  *
263  * This function returns:
264  * 0 - No error and no read-list found.
265  *
266  * 1 - Successful read-list processing. The data is not yet in
267  * the pagelist and therefore the RPC request must be deferred. The
268  * I/O completion will enqueue the transport again and
269  * svc_rdma_recvfrom will complete the request.
270  *
271  * <0 - Error processing/posting read-list.
272  *
273  * NOTE: The ctxt must not be touched after the last WR has been posted
274  * because the I/O completion processing may occur on another
275  * processor and free / modify the context. Ne touche pas!
276  */
277 static int rdma_read_xdr(struct svcxprt_rdma *xprt,
278                          struct rpcrdma_msg *rmsgp,
279                          struct svc_rqst *rqstp,
280                          struct svc_rdma_op_ctxt *hdr_ctxt)
281 {
282         struct ib_send_wr read_wr;
283         int err = 0;
284         int ch_no;
285         struct ib_sge *sge;
286         int ch_count;
287         int byte_count;
288         int sge_count;
289         u64 sgl_offset;
290         struct rpcrdma_read_chunk *ch;
291         struct svc_rdma_op_ctxt *ctxt = NULL;
292         struct svc_rdma_op_ctxt *tmp_sge_ctxt;
293         struct svc_rdma_op_ctxt *tmp_ch_ctxt;
294         struct chunk_sge *ch_sge_ary;
295
296         /* If no read list is present, return 0 */
297         ch = svc_rdma_get_read_chunk(rmsgp);
298         if (!ch)
299                 return 0;
300
301         /* Allocate temporary contexts to keep SGE */
302         BUG_ON(sizeof(struct ib_sge) < sizeof(struct chunk_sge));
303         tmp_sge_ctxt = svc_rdma_get_context(xprt);
304         sge = tmp_sge_ctxt->sge;
305         tmp_ch_ctxt = svc_rdma_get_context(xprt);
306         ch_sge_ary = (struct chunk_sge *)tmp_ch_ctxt->sge;
307
308         svc_rdma_rcl_chunk_counts(ch, &ch_count, &byte_count);
309         if (ch_count > RPCSVC_MAXPAGES)
310                 return -EINVAL;
311         sge_count = rdma_rcl_to_sge(xprt, rqstp, hdr_ctxt, rmsgp,
312                                     sge, ch_sge_ary,
313                                     ch_count, byte_count);
314         sgl_offset = 0;
315         ch_no = 0;
316
317         for (ch = (struct rpcrdma_read_chunk *)&rmsgp->rm_body.rm_chunks[0];
318              ch->rc_discrim != 0; ch++, ch_no++) {
319 next_sge:
320                 ctxt = svc_rdma_get_context(xprt);
321                 ctxt->direction = DMA_FROM_DEVICE;
322                 clear_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags);
323
324                 /* Prepare READ WR */
325                 memset(&read_wr, 0, sizeof read_wr);
326                 ctxt->wr_op = IB_WR_RDMA_READ;
327                 read_wr.wr_id = (unsigned long)ctxt;
328                 read_wr.opcode = IB_WR_RDMA_READ;
329                 read_wr.send_flags = IB_SEND_SIGNALED;
330                 read_wr.wr.rdma.rkey = ch->rc_target.rs_handle;
331                 read_wr.wr.rdma.remote_addr =
332                         get_unaligned(&(ch->rc_target.rs_offset)) +
333                         sgl_offset;
334                 read_wr.sg_list = &sge[ch_sge_ary[ch_no].start];
335                 read_wr.num_sge =
336                         rdma_read_max_sge(xprt, ch_sge_ary[ch_no].count);
337                 rdma_set_ctxt_sge(ctxt, &sge[ch_sge_ary[ch_no].start],
338                                   &sgl_offset,
339                                   read_wr.num_sge);
340                 if (((ch+1)->rc_discrim == 0) &&
341                     (read_wr.num_sge == ch_sge_ary[ch_no].count)) {
342                         /*
343                          * Mark the last RDMA_READ with a bit to
344                          * indicate all RPC data has been fetched from
345                          * the client and the RPC needs to be enqueued.
346                          */
347                         set_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags);
348                         ctxt->read_hdr = hdr_ctxt;
349                 }
350                 /* Post the read */
351                 err = svc_rdma_send(xprt, &read_wr);
352                 if (err) {
353                         printk(KERN_ERR "svcrdma: Error %d posting RDMA_READ\n",
354                                err);
355                         set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
356                         svc_rdma_put_context(ctxt, 0);
357                         goto out;
358                 }
359                 atomic_inc(&rdma_stat_read);
360
361                 if (read_wr.num_sge < ch_sge_ary[ch_no].count) {
362                         ch_sge_ary[ch_no].count -= read_wr.num_sge;
363                         ch_sge_ary[ch_no].start += read_wr.num_sge;
364                         goto next_sge;
365                 }
366                 sgl_offset = 0;
367                 err = 1;
368         }
369
370  out:
371         svc_rdma_put_context(tmp_sge_ctxt, 0);
372         svc_rdma_put_context(tmp_ch_ctxt, 0);
373
374         /* Detach arg pages. svc_recv will replenish them */
375         for (ch_no = 0; &rqstp->rq_pages[ch_no] < rqstp->rq_respages; ch_no++)
376                 rqstp->rq_pages[ch_no] = NULL;
377
378         /*
379          * Detach res pages. svc_release must see a resused count of
380          * zero or it will attempt to put them.
381          */
382         while (rqstp->rq_resused)
383                 rqstp->rq_respages[--rqstp->rq_resused] = NULL;
384
385         return err;
386 }
387
388 static int rdma_read_complete(struct svc_rqst *rqstp,
389                               struct svc_rdma_op_ctxt *head)
390 {
391         int page_no;
392         int ret;
393
394         BUG_ON(!head);
395
396         /* Copy RPC pages */
397         for (page_no = 0; page_no < head->count; page_no++) {
398                 put_page(rqstp->rq_pages[page_no]);
399                 rqstp->rq_pages[page_no] = head->pages[page_no];
400         }
401         /* Point rq_arg.pages past header */
402         rqstp->rq_arg.pages = &rqstp->rq_pages[head->sge[0].length];
403         rqstp->rq_arg.page_len = head->arg.page_len;
404         rqstp->rq_arg.page_base = head->arg.page_base;
405
406         /* rq_respages starts after the last arg page */
407         rqstp->rq_respages = &rqstp->rq_arg.pages[page_no];
408         rqstp->rq_resused = 0;
409
410         /* Rebuild rq_arg head and tail. */
411         rqstp->rq_arg.head[0] = head->arg.head[0];
412         rqstp->rq_arg.tail[0] = head->arg.tail[0];
413         rqstp->rq_arg.len = head->arg.len;
414         rqstp->rq_arg.buflen = head->arg.buflen;
415
416         /* Free the context */
417         svc_rdma_put_context(head, 0);
418
419         /* XXX: What should this be? */
420         rqstp->rq_prot = IPPROTO_MAX;
421         svc_xprt_copy_addrs(rqstp, rqstp->rq_xprt);
422
423         ret = rqstp->rq_arg.head[0].iov_len
424                 + rqstp->rq_arg.page_len
425                 + rqstp->rq_arg.tail[0].iov_len;
426         dprintk("svcrdma: deferred read ret=%d, rq_arg.len =%d, "
427                 "rq_arg.head[0].iov_base=%p, rq_arg.head[0].iov_len = %zd\n",
428                 ret, rqstp->rq_arg.len, rqstp->rq_arg.head[0].iov_base,
429                 rqstp->rq_arg.head[0].iov_len);
430
431         svc_xprt_received(rqstp->rq_xprt);
432         return ret;
433 }
434
435 /*
436  * Set up the rqstp thread context to point to the RQ buffer. If
437  * necessary, pull additional data from the client with an RDMA_READ
438  * request.
439  */
440 int svc_rdma_recvfrom(struct svc_rqst *rqstp)
441 {
442         struct svc_xprt *xprt = rqstp->rq_xprt;
443         struct svcxprt_rdma *rdma_xprt =
444                 container_of(xprt, struct svcxprt_rdma, sc_xprt);
445         struct svc_rdma_op_ctxt *ctxt = NULL;
446         struct rpcrdma_msg *rmsgp;
447         int ret = 0;
448         int len;
449
450         dprintk("svcrdma: rqstp=%p\n", rqstp);
451
452         spin_lock_bh(&rdma_xprt->sc_read_complete_lock);
453         if (!list_empty(&rdma_xprt->sc_read_complete_q)) {
454                 ctxt = list_entry(rdma_xprt->sc_read_complete_q.next,
455                                   struct svc_rdma_op_ctxt,
456                                   dto_q);
457                 list_del_init(&ctxt->dto_q);
458         }
459         spin_unlock_bh(&rdma_xprt->sc_read_complete_lock);
460         if (ctxt)
461                 return rdma_read_complete(rqstp, ctxt);
462
463         spin_lock_bh(&rdma_xprt->sc_rq_dto_lock);
464         if (!list_empty(&rdma_xprt->sc_rq_dto_q)) {
465                 ctxt = list_entry(rdma_xprt->sc_rq_dto_q.next,
466                                   struct svc_rdma_op_ctxt,
467                                   dto_q);
468                 list_del_init(&ctxt->dto_q);
469         } else {
470                 atomic_inc(&rdma_stat_rq_starve);
471                 clear_bit(XPT_DATA, &xprt->xpt_flags);
472                 ctxt = NULL;
473         }
474         spin_unlock_bh(&rdma_xprt->sc_rq_dto_lock);
475         if (!ctxt) {
476                 /* This is the EAGAIN path. The svc_recv routine will
477                  * return -EAGAIN, the nfsd thread will go to call into
478                  * svc_recv again and we shouldn't be on the active
479                  * transport list
480                  */
481                 if (test_bit(XPT_CLOSE, &xprt->xpt_flags))
482                         goto close_out;
483
484                 BUG_ON(ret);
485                 goto out;
486         }
487         dprintk("svcrdma: processing ctxt=%p on xprt=%p, rqstp=%p, status=%d\n",
488                 ctxt, rdma_xprt, rqstp, ctxt->wc_status);
489         BUG_ON(ctxt->wc_status != IB_WC_SUCCESS);
490         atomic_inc(&rdma_stat_recv);
491
492         /* Build up the XDR from the receive buffers. */
493         rdma_build_arg_xdr(rqstp, ctxt, ctxt->byte_len);
494
495         /* Decode the RDMA header. */
496         len = svc_rdma_xdr_decode_req(&rmsgp, rqstp);
497         rqstp->rq_xprt_hlen = len;
498
499         /* If the request is invalid, reply with an error */
500         if (len < 0) {
501                 if (len == -ENOSYS)
502                         svc_rdma_send_error(rdma_xprt, rmsgp, ERR_VERS);
503                 goto close_out;
504         }
505
506         /* Read read-list data. */
507         ret = rdma_read_xdr(rdma_xprt, rmsgp, rqstp, ctxt);
508         if (ret > 0) {
509                 /* read-list posted, defer until data received from client. */
510                 svc_xprt_received(xprt);
511                 return 0;
512         }
513         if (ret < 0) {
514                 /* Post of read-list failed, free context. */
515                 svc_rdma_put_context(ctxt, 1);
516                 return 0;
517         }
518
519         ret = rqstp->rq_arg.head[0].iov_len
520                 + rqstp->rq_arg.page_len
521                 + rqstp->rq_arg.tail[0].iov_len;
522         svc_rdma_put_context(ctxt, 0);
523  out:
524         dprintk("svcrdma: ret = %d, rq_arg.len =%d, "
525                 "rq_arg.head[0].iov_base=%p, rq_arg.head[0].iov_len = %zd\n",
526                 ret, rqstp->rq_arg.len,
527                 rqstp->rq_arg.head[0].iov_base,
528                 rqstp->rq_arg.head[0].iov_len);
529         rqstp->rq_prot = IPPROTO_MAX;
530         svc_xprt_copy_addrs(rqstp, xprt);
531         svc_xprt_received(xprt);
532         return ret;
533
534  close_out:
535         if (ctxt)
536                 svc_rdma_put_context(ctxt, 1);
537         dprintk("svcrdma: transport %p is closing\n", xprt);
538         /*
539          * Set the close bit and enqueue it. svc_recv will see the
540          * close bit and call svc_xprt_delete
541          */
542         set_bit(XPT_CLOSE, &xprt->xpt_flags);
543         svc_xprt_received(xprt);
544         return 0;
545 }