RDS/IB: rds_ib_cm_handle_connect() forgot to unlock c_cm_lock
[linux-2.6.git] / net / rds / ib_send.c
1 /*
2  * Copyright (c) 2006 Oracle.  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
8  * OpenIB.org BSD license below:
9  *
10  *     Redistribution and use in source and binary forms, with or
11  *     without modification, are permitted provided that the following
12  *     conditions are met:
13  *
14  *      - Redistributions of source code must retain the above
15  *        copyright notice, this list of conditions and the following
16  *        disclaimer.
17  *
18  *      - Redistributions in binary form must reproduce the above
19  *        copyright notice, this list of conditions and the following
20  *        disclaimer in the documentation and/or other materials
21  *        provided with the distribution.
22  *
23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30  * SOFTWARE.
31  *
32  */
33 #include <linux/kernel.h>
34 #include <linux/in.h>
35 #include <linux/device.h>
36 #include <linux/dmapool.h>
37
38 #include "rds.h"
39 #include "ib.h"
40
41 /*
42  * Convert IB-specific error message to RDS error message and call core
43  * completion handler.
44  */
45 static void rds_ib_send_complete(struct rds_message *rm,
46                                  int wc_status,
47                                  void (*complete)(struct rds_message *rm, int status))
48 {
49         int notify_status;
50
51         switch (wc_status) {
52         case IB_WC_WR_FLUSH_ERR:
53                 return;
54
55         case IB_WC_SUCCESS:
56                 notify_status = RDS_RDMA_SUCCESS;
57                 break;
58
59         case IB_WC_REM_ACCESS_ERR:
60                 notify_status = RDS_RDMA_REMOTE_ERROR;
61                 break;
62
63         default:
64                 notify_status = RDS_RDMA_OTHER_ERROR;
65                 break;
66         }
67         complete(rm, notify_status);
68 }
69
70 static void rds_ib_send_unmap_data(struct rds_ib_connection *ic,
71                                    struct rm_data_op *op,
72                                    int wc_status)
73 {
74         if (op->op_nents)
75                 ib_dma_unmap_sg(ic->i_cm_id->device,
76                                 op->op_sg, op->op_nents,
77                                 DMA_TO_DEVICE);
78 }
79
80 static void rds_ib_send_unmap_rdma(struct rds_ib_connection *ic,
81                                    struct rm_rdma_op *op,
82                                    int wc_status)
83 {
84         if (op->op_mapped) {
85                 ib_dma_unmap_sg(ic->i_cm_id->device,
86                                 op->op_sg, op->op_nents,
87                                 op->op_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
88                 op->op_mapped = 0;
89         }
90
91         /* If the user asked for a completion notification on this
92          * message, we can implement three different semantics:
93          *  1.  Notify when we received the ACK on the RDS message
94          *      that was queued with the RDMA. This provides reliable
95          *      notification of RDMA status at the expense of a one-way
96          *      packet delay.
97          *  2.  Notify when the IB stack gives us the completion event for
98          *      the RDMA operation.
99          *  3.  Notify when the IB stack gives us the completion event for
100          *      the accompanying RDS messages.
101          * Here, we implement approach #3. To implement approach #2,
102          * we would need to take an event for the rdma WR. To implement #1,
103          * don't call rds_rdma_send_complete at all, and fall back to the notify
104          * handling in the ACK processing code.
105          *
106          * Note: There's no need to explicitly sync any RDMA buffers using
107          * ib_dma_sync_sg_for_cpu - the completion for the RDMA
108          * operation itself unmapped the RDMA buffers, which takes care
109          * of synching.
110          */
111         rds_ib_send_complete(container_of(op, struct rds_message, rdma),
112                              wc_status, rds_rdma_send_complete);
113
114         if (op->op_write)
115                 rds_stats_add(s_send_rdma_bytes, op->op_bytes);
116         else
117                 rds_stats_add(s_recv_rdma_bytes, op->op_bytes);
118 }
119
120 static void rds_ib_send_unmap_atomic(struct rds_ib_connection *ic,
121                                      struct rm_atomic_op *op,
122                                      int wc_status)
123 {
124         /* unmap atomic recvbuf */
125         if (op->op_mapped) {
126                 ib_dma_unmap_sg(ic->i_cm_id->device, op->op_sg, 1,
127                                 DMA_FROM_DEVICE);
128                 op->op_mapped = 0;
129         }
130
131         rds_ib_send_complete(container_of(op, struct rds_message, atomic),
132                              wc_status, rds_atomic_send_complete);
133
134         if (op->op_type == RDS_ATOMIC_TYPE_CSWP)
135                 rds_ib_stats_inc(s_ib_atomic_cswp);
136         else
137                 rds_ib_stats_inc(s_ib_atomic_fadd);
138 }
139
140 /*
141  * Unmap the resources associated with a struct send_work.
142  *
143  * Returns the rm for no good reason other than it is unobtainable
144  * other than by switching on wr.opcode, currently, and the caller,
145  * the event handler, needs it.
146  */
147 static struct rds_message *rds_ib_send_unmap_op(struct rds_ib_connection *ic,
148                                                 struct rds_ib_send_work *send,
149                                                 int wc_status)
150 {
151         struct rds_message *rm = NULL;
152
153         /* In the error case, wc.opcode sometimes contains garbage */
154         switch (send->s_wr.opcode) {
155         case IB_WR_SEND:
156                 if (send->s_op) {
157                         rm = container_of(send->s_op, struct rds_message, data);
158                         rds_ib_send_unmap_data(ic, send->s_op, wc_status);
159                 }
160                 break;
161         case IB_WR_RDMA_WRITE:
162         case IB_WR_RDMA_READ:
163                 if (send->s_op) {
164                         rm = container_of(send->s_op, struct rds_message, rdma);
165                         rds_ib_send_unmap_rdma(ic, send->s_op, wc_status);
166                 }
167                 break;
168         case IB_WR_ATOMIC_FETCH_AND_ADD:
169         case IB_WR_ATOMIC_CMP_AND_SWP:
170                 if (send->s_op) {
171                         rm = container_of(send->s_op, struct rds_message, atomic);
172                         rds_ib_send_unmap_atomic(ic, send->s_op, wc_status);
173                 }
174                 break;
175         default:
176                 if (printk_ratelimit())
177                         printk(KERN_NOTICE
178                                "RDS/IB: %s: unexpected opcode 0x%x in WR!\n",
179                                __func__, send->s_wr.opcode);
180                 break;
181         }
182
183         send->s_wr.opcode = 0xdead;
184
185         return rm;
186 }
187
188 void rds_ib_send_init_ring(struct rds_ib_connection *ic)
189 {
190         struct rds_ib_send_work *send;
191         u32 i;
192
193         for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) {
194                 struct ib_sge *sge;
195
196                 send->s_op = NULL;
197
198                 send->s_wr.wr_id = i;
199                 send->s_wr.sg_list = send->s_sge;
200                 send->s_wr.ex.imm_data = 0;
201
202                 sge = &send->s_sge[0];
203                 sge->addr = ic->i_send_hdrs_dma + (i * sizeof(struct rds_header));
204                 sge->length = sizeof(struct rds_header);
205                 sge->lkey = ic->i_mr->lkey;
206
207                 send->s_sge[1].lkey = ic->i_mr->lkey;
208         }
209 }
210
211 void rds_ib_send_clear_ring(struct rds_ib_connection *ic)
212 {
213         struct rds_ib_send_work *send;
214         u32 i;
215
216         for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) {
217                 if (send->s_op && send->s_wr.opcode != 0xdead)
218                         rds_ib_send_unmap_op(ic, send, IB_WC_WR_FLUSH_ERR);
219         }
220 }
221
222 /*
223  * The _oldest/_free ring operations here race cleanly with the alloc/unalloc
224  * operations performed in the send path.  As the sender allocs and potentially
225  * unallocs the next free entry in the ring it doesn't alter which is
226  * the next to be freed, which is what this is concerned with.
227  */
228 void rds_ib_send_cq_comp_handler(struct ib_cq *cq, void *context)
229 {
230         struct rds_connection *conn = context;
231         struct rds_ib_connection *ic = conn->c_transport_data;
232         struct rds_message *rm = NULL;
233         struct ib_wc wc;
234         struct rds_ib_send_work *send;
235         u32 completed;
236         u32 oldest;
237         u32 i = 0;
238         int ret;
239
240         rdsdebug("cq %p conn %p\n", cq, conn);
241         rds_ib_stats_inc(s_ib_tx_cq_call);
242         ret = ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
243         if (ret)
244                 rdsdebug("ib_req_notify_cq send failed: %d\n", ret);
245
246         while (ib_poll_cq(cq, 1, &wc) > 0) {
247                 rdsdebug("wc wr_id 0x%llx status %u byte_len %u imm_data %u\n",
248                          (unsigned long long)wc.wr_id, wc.status, wc.byte_len,
249                          be32_to_cpu(wc.ex.imm_data));
250                 rds_ib_stats_inc(s_ib_tx_cq_event);
251
252                 if (wc.wr_id == RDS_IB_ACK_WR_ID) {
253                         if (ic->i_ack_queued + HZ/2 < jiffies)
254                                 rds_ib_stats_inc(s_ib_tx_stalled);
255                         rds_ib_ack_send_complete(ic);
256                         continue;
257                 }
258
259                 oldest = rds_ib_ring_oldest(&ic->i_send_ring);
260
261                 completed = rds_ib_ring_completed(&ic->i_send_ring, wc.wr_id, oldest);
262
263                 for (i = 0; i < completed; i++) {
264                         send = &ic->i_sends[oldest];
265
266                         rm = rds_ib_send_unmap_op(ic, send, wc.status);
267
268                         if (send->s_queued + HZ/2 < jiffies)
269                                 rds_ib_stats_inc(s_ib_tx_stalled);
270
271                         if (send->s_op) {
272                                 if (send->s_op == rm->m_final_op) {
273                                         /* If anyone waited for this message to get flushed out, wake
274                                          * them up now */
275                                         rds_message_unmapped(rm);
276                                 }
277                                 rds_message_put(rm);
278                                 send->s_op = NULL;
279                         }
280
281                         oldest = (oldest + 1) % ic->i_send_ring.w_nr;
282                 }
283
284                 rds_ib_ring_free(&ic->i_send_ring, completed);
285
286                 if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags) ||
287                     test_bit(0, &conn->c_map_queued))
288                         queue_delayed_work(rds_wq, &conn->c_send_w, 0);
289
290                 /* We expect errors as the qp is drained during shutdown */
291                 if (wc.status != IB_WC_SUCCESS && rds_conn_up(conn)) {
292                         rds_ib_conn_error(conn,
293                                 "send completion on %pI4 "
294                                 "had status %u, disconnecting and reconnecting\n",
295                                 &conn->c_faddr, wc.status);
296                 }
297         }
298 }
299
300 /*
301  * This is the main function for allocating credits when sending
302  * messages.
303  *
304  * Conceptually, we have two counters:
305  *  -   send credits: this tells us how many WRs we're allowed
306  *      to submit without overruning the reciever's queue. For
307  *      each SEND WR we post, we decrement this by one.
308  *
309  *  -   posted credits: this tells us how many WRs we recently
310  *      posted to the receive queue. This value is transferred
311  *      to the peer as a "credit update" in a RDS header field.
312  *      Every time we transmit credits to the peer, we subtract
313  *      the amount of transferred credits from this counter.
314  *
315  * It is essential that we avoid situations where both sides have
316  * exhausted their send credits, and are unable to send new credits
317  * to the peer. We achieve this by requiring that we send at least
318  * one credit update to the peer before exhausting our credits.
319  * When new credits arrive, we subtract one credit that is withheld
320  * until we've posted new buffers and are ready to transmit these
321  * credits (see rds_ib_send_add_credits below).
322  *
323  * The RDS send code is essentially single-threaded; rds_send_xmit
324  * grabs c_send_lock to ensure exclusive access to the send ring.
325  * However, the ACK sending code is independent and can race with
326  * message SENDs.
327  *
328  * In the send path, we need to update the counters for send credits
329  * and the counter of posted buffers atomically - when we use the
330  * last available credit, we cannot allow another thread to race us
331  * and grab the posted credits counter.  Hence, we have to use a
332  * spinlock to protect the credit counter, or use atomics.
333  *
334  * Spinlocks shared between the send and the receive path are bad,
335  * because they create unnecessary delays. An early implementation
336  * using a spinlock showed a 5% degradation in throughput at some
337  * loads.
338  *
339  * This implementation avoids spinlocks completely, putting both
340  * counters into a single atomic, and updating that atomic using
341  * atomic_add (in the receive path, when receiving fresh credits),
342  * and using atomic_cmpxchg when updating the two counters.
343  */
344 int rds_ib_send_grab_credits(struct rds_ib_connection *ic,
345                              u32 wanted, u32 *adv_credits, int need_posted, int max_posted)
346 {
347         unsigned int avail, posted, got = 0, advertise;
348         long oldval, newval;
349
350         *adv_credits = 0;
351         if (!ic->i_flowctl)
352                 return wanted;
353
354 try_again:
355         advertise = 0;
356         oldval = newval = atomic_read(&ic->i_credits);
357         posted = IB_GET_POST_CREDITS(oldval);
358         avail = IB_GET_SEND_CREDITS(oldval);
359
360         rdsdebug("rds_ib_send_grab_credits(%u): credits=%u posted=%u\n",
361                         wanted, avail, posted);
362
363         /* The last credit must be used to send a credit update. */
364         if (avail && !posted)
365                 avail--;
366
367         if (avail < wanted) {
368                 struct rds_connection *conn = ic->i_cm_id->context;
369
370                 /* Oops, there aren't that many credits left! */
371                 set_bit(RDS_LL_SEND_FULL, &conn->c_flags);
372                 got = avail;
373         } else {
374                 /* Sometimes you get what you want, lalala. */
375                 got = wanted;
376         }
377         newval -= IB_SET_SEND_CREDITS(got);
378
379         /*
380          * If need_posted is non-zero, then the caller wants
381          * the posted regardless of whether any send credits are
382          * available.
383          */
384         if (posted && (got || need_posted)) {
385                 advertise = min_t(unsigned int, posted, max_posted);
386                 newval -= IB_SET_POST_CREDITS(advertise);
387         }
388
389         /* Finally bill everything */
390         if (atomic_cmpxchg(&ic->i_credits, oldval, newval) != oldval)
391                 goto try_again;
392
393         *adv_credits = advertise;
394         return got;
395 }
396
397 void rds_ib_send_add_credits(struct rds_connection *conn, unsigned int credits)
398 {
399         struct rds_ib_connection *ic = conn->c_transport_data;
400
401         if (credits == 0)
402                 return;
403
404         rdsdebug("rds_ib_send_add_credits(%u): current=%u%s\n",
405                         credits,
406                         IB_GET_SEND_CREDITS(atomic_read(&ic->i_credits)),
407                         test_bit(RDS_LL_SEND_FULL, &conn->c_flags) ? ", ll_send_full" : "");
408
409         atomic_add(IB_SET_SEND_CREDITS(credits), &ic->i_credits);
410         if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags))
411                 queue_delayed_work(rds_wq, &conn->c_send_w, 0);
412
413         WARN_ON(IB_GET_SEND_CREDITS(credits) >= 16384);
414
415         rds_ib_stats_inc(s_ib_rx_credit_updates);
416 }
417
418 void rds_ib_advertise_credits(struct rds_connection *conn, unsigned int posted)
419 {
420         struct rds_ib_connection *ic = conn->c_transport_data;
421
422         if (posted == 0)
423                 return;
424
425         atomic_add(IB_SET_POST_CREDITS(posted), &ic->i_credits);
426
427         /* Decide whether to send an update to the peer now.
428          * If we would send a credit update for every single buffer we
429          * post, we would end up with an ACK storm (ACK arrives,
430          * consumes buffer, we refill the ring, send ACK to remote
431          * advertising the newly posted buffer... ad inf)
432          *
433          * Performance pretty much depends on how often we send
434          * credit updates - too frequent updates mean lots of ACKs.
435          * Too infrequent updates, and the peer will run out of
436          * credits and has to throttle.
437          * For the time being, 16 seems to be a good compromise.
438          */
439         if (IB_GET_POST_CREDITS(atomic_read(&ic->i_credits)) >= 16)
440                 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
441 }
442
443 static inline void rds_ib_set_wr_signal_state(struct rds_ib_connection *ic,
444                                               struct rds_ib_send_work *send,
445                                               bool notify)
446 {
447         /*
448          * We want to delay signaling completions just enough to get
449          * the batching benefits but not so much that we create dead time
450          * on the wire.
451          */
452         if (ic->i_unsignaled_wrs-- == 0 || notify) {
453                 ic->i_unsignaled_wrs = rds_ib_sysctl_max_unsig_wrs;
454                 send->s_wr.send_flags |= IB_SEND_SIGNALED;
455         }
456 }
457
458 /*
459  * This can be called multiple times for a given message.  The first time
460  * we see a message we map its scatterlist into the IB device so that
461  * we can provide that mapped address to the IB scatter gather entries
462  * in the IB work requests.  We translate the scatterlist into a series
463  * of work requests that fragment the message.  These work requests complete
464  * in order so we pass ownership of the message to the completion handler
465  * once we send the final fragment.
466  *
467  * The RDS core uses the c_send_lock to only enter this function once
468  * per connection.  This makes sure that the tx ring alloc/unalloc pairs
469  * don't get out of sync and confuse the ring.
470  */
471 int rds_ib_xmit(struct rds_connection *conn, struct rds_message *rm,
472                 unsigned int hdr_off, unsigned int sg, unsigned int off)
473 {
474         struct rds_ib_connection *ic = conn->c_transport_data;
475         struct ib_device *dev = ic->i_cm_id->device;
476         struct rds_ib_send_work *send = NULL;
477         struct rds_ib_send_work *first;
478         struct rds_ib_send_work *prev;
479         struct ib_send_wr *failed_wr;
480         struct scatterlist *scat;
481         u32 pos;
482         u32 i;
483         u32 work_alloc;
484         u32 credit_alloc = 0;
485         u32 posted;
486         u32 adv_credits = 0;
487         int send_flags = 0;
488         int bytes_sent = 0;
489         int ret;
490         int flow_controlled = 0;
491
492         BUG_ON(off % RDS_FRAG_SIZE);
493         BUG_ON(hdr_off != 0 && hdr_off != sizeof(struct rds_header));
494
495         /* Do not send cong updates to IB loopback */
496         if (conn->c_loopback
497             && rm->m_inc.i_hdr.h_flags & RDS_FLAG_CONG_BITMAP) {
498                 rds_cong_map_updated(conn->c_fcong, ~(u64) 0);
499                 return sizeof(struct rds_header) + RDS_CONG_MAP_BYTES;
500         }
501
502         /* FIXME we may overallocate here */
503         if (be32_to_cpu(rm->m_inc.i_hdr.h_len) == 0)
504                 i = 1;
505         else
506                 i = ceil(be32_to_cpu(rm->m_inc.i_hdr.h_len), RDS_FRAG_SIZE);
507
508         work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos);
509         if (work_alloc == 0) {
510                 set_bit(RDS_LL_SEND_FULL, &conn->c_flags);
511                 rds_ib_stats_inc(s_ib_tx_ring_full);
512                 ret = -ENOMEM;
513                 goto out;
514         }
515
516         if (ic->i_flowctl) {
517                 credit_alloc = rds_ib_send_grab_credits(ic, work_alloc, &posted, 0, RDS_MAX_ADV_CREDIT);
518                 adv_credits += posted;
519                 if (credit_alloc < work_alloc) {
520                         rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - credit_alloc);
521                         work_alloc = credit_alloc;
522                         flow_controlled = 1;
523                 }
524                 if (work_alloc == 0) {
525                         set_bit(RDS_LL_SEND_FULL, &conn->c_flags);
526                         rds_ib_stats_inc(s_ib_tx_throttle);
527                         ret = -ENOMEM;
528                         goto out;
529                 }
530         }
531
532         /* map the message the first time we see it */
533         if (!ic->i_data_op) {
534                 if (rm->data.op_nents) {
535                         rm->data.op_count = ib_dma_map_sg(dev,
536                                                           rm->data.op_sg,
537                                                           rm->data.op_nents,
538                                                           DMA_TO_DEVICE);
539                         rdsdebug("ic %p mapping rm %p: %d\n", ic, rm, rm->data.op_count);
540                         if (rm->data.op_count == 0) {
541                                 rds_ib_stats_inc(s_ib_tx_sg_mapping_failure);
542                                 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
543                                 ret = -ENOMEM; /* XXX ? */
544                                 goto out;
545                         }
546                 } else {
547                         rm->data.op_count = 0;
548                 }
549
550                 rds_message_addref(rm);
551                 ic->i_data_op = &rm->data;
552
553                 /* Finalize the header */
554                 if (test_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags))
555                         rm->m_inc.i_hdr.h_flags |= RDS_FLAG_ACK_REQUIRED;
556                 if (test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags))
557                         rm->m_inc.i_hdr.h_flags |= RDS_FLAG_RETRANSMITTED;
558
559                 /* If it has a RDMA op, tell the peer we did it. This is
560                  * used by the peer to release use-once RDMA MRs. */
561                 if (rm->rdma.op_active) {
562                         struct rds_ext_header_rdma ext_hdr;
563
564                         ext_hdr.h_rdma_rkey = cpu_to_be32(rm->rdma.op_rkey);
565                         rds_message_add_extension(&rm->m_inc.i_hdr,
566                                         RDS_EXTHDR_RDMA, &ext_hdr, sizeof(ext_hdr));
567                 }
568                 if (rm->m_rdma_cookie) {
569                         rds_message_add_rdma_dest_extension(&rm->m_inc.i_hdr,
570                                         rds_rdma_cookie_key(rm->m_rdma_cookie),
571                                         rds_rdma_cookie_offset(rm->m_rdma_cookie));
572                 }
573
574                 /* Note - rds_ib_piggyb_ack clears the ACK_REQUIRED bit, so
575                  * we should not do this unless we have a chance of at least
576                  * sticking the header into the send ring. Which is why we
577                  * should call rds_ib_ring_alloc first. */
578                 rm->m_inc.i_hdr.h_ack = cpu_to_be64(rds_ib_piggyb_ack(ic));
579                 rds_message_make_checksum(&rm->m_inc.i_hdr);
580
581                 /*
582                  * Update adv_credits since we reset the ACK_REQUIRED bit.
583                  */
584                 if (ic->i_flowctl) {
585                         rds_ib_send_grab_credits(ic, 0, &posted, 1, RDS_MAX_ADV_CREDIT - adv_credits);
586                         adv_credits += posted;
587                         BUG_ON(adv_credits > 255);
588                 }
589         }
590
591         /* Sometimes you want to put a fence between an RDMA
592          * READ and the following SEND.
593          * We could either do this all the time
594          * or when requested by the user. Right now, we let
595          * the application choose.
596          */
597         if (rm->rdma.op_active && rm->rdma.op_fence)
598                 send_flags = IB_SEND_FENCE;
599
600         /* Each frag gets a header. Msgs may be 0 bytes */
601         send = &ic->i_sends[pos];
602         first = send;
603         prev = NULL;
604         scat = &ic->i_data_op->op_sg[sg];
605         i = 0;
606         do {
607                 unsigned int len = 0;
608
609                 /* Set up the header */
610                 send->s_wr.send_flags = send_flags;
611                 send->s_wr.opcode = IB_WR_SEND;
612                 send->s_wr.num_sge = 1;
613                 send->s_wr.next = NULL;
614                 send->s_queued = jiffies;
615                 send->s_op = NULL;
616
617                 send->s_sge[0].addr = ic->i_send_hdrs_dma
618                         + (pos * sizeof(struct rds_header));
619                 send->s_sge[0].length = sizeof(struct rds_header);
620
621                 memcpy(&ic->i_send_hdrs[pos], &rm->m_inc.i_hdr, sizeof(struct rds_header));
622
623                 /* Set up the data, if present */
624                 if (i < work_alloc
625                     && scat != &rm->data.op_sg[rm->data.op_count]) {
626                         len = min(RDS_FRAG_SIZE, ib_sg_dma_len(dev, scat) - off);
627                         send->s_wr.num_sge = 2;
628
629                         send->s_sge[1].addr = ib_sg_dma_address(dev, scat) + off;
630                         send->s_sge[1].length = len;
631
632                         bytes_sent += len;
633                         off += len;
634                         if (off == ib_sg_dma_len(dev, scat)) {
635                                 scat++;
636                                 off = 0;
637                         }
638                 }
639
640                 rds_ib_set_wr_signal_state(ic, send, 0);
641
642                 /*
643                  * Always signal the last one if we're stopping due to flow control.
644                  */
645                 if (ic->i_flowctl && flow_controlled && i == (work_alloc-1))
646                         send->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED;
647
648                 rdsdebug("send %p wr %p num_sge %u next %p\n", send,
649                          &send->s_wr, send->s_wr.num_sge, send->s_wr.next);
650
651                 if (ic->i_flowctl && adv_credits) {
652                         struct rds_header *hdr = &ic->i_send_hdrs[pos];
653
654                         /* add credit and redo the header checksum */
655                         hdr->h_credit = adv_credits;
656                         rds_message_make_checksum(hdr);
657                         adv_credits = 0;
658                         rds_ib_stats_inc(s_ib_tx_credit_updates);
659                 }
660
661                 if (prev)
662                         prev->s_wr.next = &send->s_wr;
663                 prev = send;
664
665                 pos = (pos + 1) % ic->i_send_ring.w_nr;
666                 send = &ic->i_sends[pos];
667                 i++;
668
669         } while (i < work_alloc
670                  && scat != &rm->data.op_sg[rm->data.op_count]);
671
672         /* Account the RDS header in the number of bytes we sent, but just once.
673          * The caller has no concept of fragmentation. */
674         if (hdr_off == 0)
675                 bytes_sent += sizeof(struct rds_header);
676
677         /* if we finished the message then send completion owns it */
678         if (scat == &rm->data.op_sg[rm->data.op_count]) {
679                 prev->s_op = ic->i_data_op;
680                 prev->s_wr.send_flags |= IB_SEND_SOLICITED;
681                 ic->i_data_op = NULL;
682         }
683
684         /* Put back wrs & credits we didn't use */
685         if (i < work_alloc) {
686                 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - i);
687                 work_alloc = i;
688         }
689         if (ic->i_flowctl && i < credit_alloc)
690                 rds_ib_send_add_credits(conn, credit_alloc - i);
691
692         /* XXX need to worry about failed_wr and partial sends. */
693         failed_wr = &first->s_wr;
694         ret = ib_post_send(ic->i_cm_id->qp, &first->s_wr, &failed_wr);
695         rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic,
696                  first, &first->s_wr, ret, failed_wr);
697         BUG_ON(failed_wr != &first->s_wr);
698         if (ret) {
699                 printk(KERN_WARNING "RDS/IB: ib_post_send to %pI4 "
700                        "returned %d\n", &conn->c_faddr, ret);
701                 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
702                 if (prev->s_op) {
703                         ic->i_data_op = prev->s_op;
704                         prev->s_op = NULL;
705                 }
706
707                 rds_ib_conn_error(ic->conn, "ib_post_send failed\n");
708                 goto out;
709         }
710
711         ret = bytes_sent;
712 out:
713         BUG_ON(adv_credits);
714         return ret;
715 }
716
717 /*
718  * Issue atomic operation.
719  * A simplified version of the rdma case, we always map 1 SG, and
720  * only 8 bytes, for the return value from the atomic operation.
721  */
722 int rds_ib_xmit_atomic(struct rds_connection *conn, struct rm_atomic_op *op)
723 {
724         struct rds_ib_connection *ic = conn->c_transport_data;
725         struct rds_ib_send_work *send = NULL;
726         struct ib_send_wr *failed_wr;
727         struct rds_ib_device *rds_ibdev;
728         u32 pos;
729         u32 work_alloc;
730         int ret;
731
732         rds_ibdev = ib_get_client_data(ic->i_cm_id->device, &rds_ib_client);
733
734         work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, 1, &pos);
735         if (work_alloc != 1) {
736                 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
737                 rds_ib_stats_inc(s_ib_tx_ring_full);
738                 ret = -ENOMEM;
739                 goto out;
740         }
741
742         /* address of send request in ring */
743         send = &ic->i_sends[pos];
744         send->s_queued = jiffies;
745
746         if (op->op_type == RDS_ATOMIC_TYPE_CSWP) {
747                 send->s_wr.opcode = IB_WR_ATOMIC_CMP_AND_SWP;
748                 send->s_wr.wr.atomic.compare_add = op->op_compare;
749                 send->s_wr.wr.atomic.swap = op->op_swap_add;
750         } else { /* FADD */
751                 send->s_wr.opcode = IB_WR_ATOMIC_FETCH_AND_ADD;
752                 send->s_wr.wr.atomic.compare_add = op->op_swap_add;
753                 send->s_wr.wr.atomic.swap = 0;
754         }
755         rds_ib_set_wr_signal_state(ic, send, op->op_notify);
756         send->s_wr.num_sge = 1;
757         send->s_wr.next = NULL;
758         send->s_wr.wr.atomic.remote_addr = op->op_remote_addr;
759         send->s_wr.wr.atomic.rkey = op->op_rkey;
760         send->s_op = op;
761         rds_message_addref(container_of(send->s_op, struct rds_message, atomic));
762
763         /* map 8 byte retval buffer to the device */
764         ret = ib_dma_map_sg(ic->i_cm_id->device, op->op_sg, 1, DMA_FROM_DEVICE);
765         rdsdebug("ic %p mapping atomic op %p. mapped %d pg\n", ic, op, ret);
766         if (ret != 1) {
767                 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
768                 rds_ib_stats_inc(s_ib_tx_sg_mapping_failure);
769                 ret = -ENOMEM; /* XXX ? */
770                 goto out;
771         }
772
773         /* Convert our struct scatterlist to struct ib_sge */
774         send->s_sge[0].addr = ib_sg_dma_address(ic->i_cm_id->device, op->op_sg);
775         send->s_sge[0].length = ib_sg_dma_len(ic->i_cm_id->device, op->op_sg);
776         send->s_sge[0].lkey = ic->i_mr->lkey;
777
778         rdsdebug("rva %Lx rpa %Lx len %u\n", op->op_remote_addr,
779                  send->s_sge[0].addr, send->s_sge[0].length);
780
781         failed_wr = &send->s_wr;
782         ret = ib_post_send(ic->i_cm_id->qp, &send->s_wr, &failed_wr);
783         rdsdebug("ic %p send %p (wr %p) ret %d wr %p\n", ic,
784                  send, &send->s_wr, ret, failed_wr);
785         BUG_ON(failed_wr != &send->s_wr);
786         if (ret) {
787                 printk(KERN_WARNING "RDS/IB: atomic ib_post_send to %pI4 "
788                        "returned %d\n", &conn->c_faddr, ret);
789                 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
790                 goto out;
791         }
792
793         if (unlikely(failed_wr != &send->s_wr)) {
794                 printk(KERN_WARNING "RDS/IB: atomic ib_post_send() rc=%d, but failed_wqe updated!\n", ret);
795                 BUG_ON(failed_wr != &send->s_wr);
796         }
797
798 out:
799         return ret;
800 }
801
802 int rds_ib_xmit_rdma(struct rds_connection *conn, struct rm_rdma_op *op)
803 {
804         struct rds_ib_connection *ic = conn->c_transport_data;
805         struct rds_ib_send_work *send = NULL;
806         struct rds_ib_send_work *first;
807         struct rds_ib_send_work *prev;
808         struct ib_send_wr *failed_wr;
809         struct rds_ib_device *rds_ibdev;
810         struct scatterlist *scat;
811         unsigned long len;
812         u64 remote_addr = op->op_remote_addr;
813         u32 pos;
814         u32 work_alloc;
815         u32 i;
816         u32 j;
817         int sent;
818         int ret;
819         int num_sge;
820
821         rds_ibdev = ib_get_client_data(ic->i_cm_id->device, &rds_ib_client);
822
823         /* map the op the first time we see it */
824         if (!op->op_mapped) {
825                 op->op_count = ib_dma_map_sg(ic->i_cm_id->device,
826                                              op->op_sg, op->op_nents, (op->op_write) ?
827                                              DMA_TO_DEVICE : DMA_FROM_DEVICE);
828                 rdsdebug("ic %p mapping op %p: %d\n", ic, op, op->op_count);
829                 if (op->op_count == 0) {
830                         rds_ib_stats_inc(s_ib_tx_sg_mapping_failure);
831                         ret = -ENOMEM; /* XXX ? */
832                         goto out;
833                 }
834
835                 op->op_mapped = 1;
836         }
837
838         /*
839          * Instead of knowing how to return a partial rdma read/write we insist that there
840          * be enough work requests to send the entire message.
841          */
842         i = ceil(op->op_count, rds_ibdev->max_sge);
843
844         work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos);
845         if (work_alloc != i) {
846                 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
847                 rds_ib_stats_inc(s_ib_tx_ring_full);
848                 ret = -ENOMEM;
849                 goto out;
850         }
851
852         send = &ic->i_sends[pos];
853         first = send;
854         prev = NULL;
855         scat = &op->op_sg[0];
856         sent = 0;
857         num_sge = op->op_count;
858
859         for (i = 0; i < work_alloc && scat != &op->op_sg[op->op_count]; i++) {
860                 send->s_wr.send_flags = 0;
861                 send->s_queued = jiffies;
862                 send->s_op = NULL;
863
864                 rds_ib_set_wr_signal_state(ic, send, op->op_notify);
865
866                 send->s_wr.opcode = op->op_write ? IB_WR_RDMA_WRITE : IB_WR_RDMA_READ;
867                 send->s_wr.wr.rdma.remote_addr = remote_addr;
868                 send->s_wr.wr.rdma.rkey = op->op_rkey;
869
870                 if (num_sge > rds_ibdev->max_sge) {
871                         send->s_wr.num_sge = rds_ibdev->max_sge;
872                         num_sge -= rds_ibdev->max_sge;
873                 } else {
874                         send->s_wr.num_sge = num_sge;
875                 }
876
877                 send->s_wr.next = NULL;
878
879                 if (prev)
880                         prev->s_wr.next = &send->s_wr;
881
882                 for (j = 0; j < send->s_wr.num_sge && scat != &op->op_sg[op->op_count]; j++) {
883                         len = ib_sg_dma_len(ic->i_cm_id->device, scat);
884                         send->s_sge[j].addr =
885                                  ib_sg_dma_address(ic->i_cm_id->device, scat);
886                         send->s_sge[j].length = len;
887                         send->s_sge[j].lkey = ic->i_mr->lkey;
888
889                         sent += len;
890                         rdsdebug("ic %p sent %d remote_addr %llu\n", ic, sent, remote_addr);
891
892                         remote_addr += len;
893                         scat++;
894                 }
895
896                 rdsdebug("send %p wr %p num_sge %u next %p\n", send,
897                         &send->s_wr, send->s_wr.num_sge, send->s_wr.next);
898
899                 prev = send;
900                 if (++send == &ic->i_sends[ic->i_send_ring.w_nr])
901                         send = ic->i_sends;
902         }
903
904         /* give a reference to the last op */
905         if (scat == &op->op_sg[op->op_count]) {
906                 prev->s_op = op;
907                 rds_message_addref(container_of(op, struct rds_message, rdma));
908         }
909
910         if (i < work_alloc) {
911                 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - i);
912                 work_alloc = i;
913         }
914
915         failed_wr = &first->s_wr;
916         ret = ib_post_send(ic->i_cm_id->qp, &first->s_wr, &failed_wr);
917         rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic,
918                  first, &first->s_wr, ret, failed_wr);
919         BUG_ON(failed_wr != &first->s_wr);
920         if (ret) {
921                 printk(KERN_WARNING "RDS/IB: rdma ib_post_send to %pI4 "
922                        "returned %d\n", &conn->c_faddr, ret);
923                 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
924                 goto out;
925         }
926
927         if (unlikely(failed_wr != &first->s_wr)) {
928                 printk(KERN_WARNING "RDS/IB: ib_post_send() rc=%d, but failed_wqe updated!\n", ret);
929                 BUG_ON(failed_wr != &first->s_wr);
930         }
931
932
933 out:
934         return ret;
935 }
936
937 void rds_ib_xmit_complete(struct rds_connection *conn)
938 {
939         struct rds_ib_connection *ic = conn->c_transport_data;
940
941         /* We may have a pending ACK or window update we were unable
942          * to send previously (due to flow control). Try again. */
943         rds_ib_attempt_ack(ic);
944 }