myri10ge: update firmware headers to 1.4.41
[linux-2.6.git] / net / rds / iw_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 "rdma.h"
40 #include "iw.h"
41
42 static void rds_iw_send_rdma_complete(struct rds_message *rm,
43                                       int wc_status)
44 {
45         int notify_status;
46
47         switch (wc_status) {
48         case IB_WC_WR_FLUSH_ERR:
49                 return;
50
51         case IB_WC_SUCCESS:
52                 notify_status = RDS_RDMA_SUCCESS;
53                 break;
54
55         case IB_WC_REM_ACCESS_ERR:
56                 notify_status = RDS_RDMA_REMOTE_ERROR;
57                 break;
58
59         default:
60                 notify_status = RDS_RDMA_OTHER_ERROR;
61                 break;
62         }
63         rds_rdma_send_complete(rm, notify_status);
64 }
65
66 static void rds_iw_send_unmap_rdma(struct rds_iw_connection *ic,
67                                    struct rds_rdma_op *op)
68 {
69         if (op->r_mapped) {
70                 ib_dma_unmap_sg(ic->i_cm_id->device,
71                         op->r_sg, op->r_nents,
72                         op->r_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
73                 op->r_mapped = 0;
74         }
75 }
76
77 static void rds_iw_send_unmap_rm(struct rds_iw_connection *ic,
78                           struct rds_iw_send_work *send,
79                           int wc_status)
80 {
81         struct rds_message *rm = send->s_rm;
82
83         rdsdebug("ic %p send %p rm %p\n", ic, send, rm);
84
85         ib_dma_unmap_sg(ic->i_cm_id->device,
86                      rm->m_sg, rm->m_nents,
87                      DMA_TO_DEVICE);
88
89         if (rm->m_rdma_op != NULL) {
90                 rds_iw_send_unmap_rdma(ic, rm->m_rdma_op);
91
92                 /* If the user asked for a completion notification on this
93                  * message, we can implement three different semantics:
94                  *  1.  Notify when we received the ACK on the RDS message
95                  *      that was queued with the RDMA. This provides reliable
96                  *      notification of RDMA status at the expense of a one-way
97                  *      packet delay.
98                  *  2.  Notify when the IB stack gives us the completion event for
99                  *      the RDMA operation.
100                  *  3.  Notify when the IB stack gives us the completion event for
101                  *      the accompanying RDS messages.
102                  * Here, we implement approach #3. To implement approach #2,
103                  * call rds_rdma_send_complete from the cq_handler. To implement #1,
104                  * don't call rds_rdma_send_complete at all, and fall back to the notify
105                  * handling in the ACK processing code.
106                  *
107                  * Note: There's no need to explicitly sync any RDMA buffers using
108                  * ib_dma_sync_sg_for_cpu - the completion for the RDMA
109                  * operation itself unmapped the RDMA buffers, which takes care
110                  * of synching.
111                  */
112                 rds_iw_send_rdma_complete(rm, wc_status);
113
114                 if (rm->m_rdma_op->r_write)
115                         rds_stats_add(s_send_rdma_bytes, rm->m_rdma_op->r_bytes);
116                 else
117                         rds_stats_add(s_recv_rdma_bytes, rm->m_rdma_op->r_bytes);
118         }
119
120         /* If anyone waited for this message to get flushed out, wake
121          * them up now */
122         rds_message_unmapped(rm);
123
124         rds_message_put(rm);
125         send->s_rm = NULL;
126 }
127
128 void rds_iw_send_init_ring(struct rds_iw_connection *ic)
129 {
130         struct rds_iw_send_work *send;
131         u32 i;
132
133         for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) {
134                 struct ib_sge *sge;
135
136                 send->s_rm = NULL;
137                 send->s_op = NULL;
138                 send->s_mapping = NULL;
139
140                 send->s_wr.next = NULL;
141                 send->s_wr.wr_id = i;
142                 send->s_wr.sg_list = send->s_sge;
143                 send->s_wr.num_sge = 1;
144                 send->s_wr.opcode = IB_WR_SEND;
145                 send->s_wr.send_flags = 0;
146                 send->s_wr.ex.imm_data = 0;
147
148                 sge = rds_iw_data_sge(ic, send->s_sge);
149                 sge->lkey = 0;
150
151                 sge = rds_iw_header_sge(ic, send->s_sge);
152                 sge->addr = ic->i_send_hdrs_dma + (i * sizeof(struct rds_header));
153                 sge->length = sizeof(struct rds_header);
154                 sge->lkey = 0;
155
156                 send->s_mr = ib_alloc_fast_reg_mr(ic->i_pd, fastreg_message_size);
157                 if (IS_ERR(send->s_mr)) {
158                         printk(KERN_WARNING "RDS/IW: ib_alloc_fast_reg_mr failed\n");
159                         break;
160                 }
161
162                 send->s_page_list = ib_alloc_fast_reg_page_list(
163                         ic->i_cm_id->device, fastreg_message_size);
164                 if (IS_ERR(send->s_page_list)) {
165                         printk(KERN_WARNING "RDS/IW: ib_alloc_fast_reg_page_list failed\n");
166                         break;
167                 }
168         }
169 }
170
171 void rds_iw_send_clear_ring(struct rds_iw_connection *ic)
172 {
173         struct rds_iw_send_work *send;
174         u32 i;
175
176         for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) {
177                 BUG_ON(!send->s_mr);
178                 ib_dereg_mr(send->s_mr);
179                 BUG_ON(!send->s_page_list);
180                 ib_free_fast_reg_page_list(send->s_page_list);
181                 if (send->s_wr.opcode == 0xdead)
182                         continue;
183                 if (send->s_rm)
184                         rds_iw_send_unmap_rm(ic, send, IB_WC_WR_FLUSH_ERR);
185                 if (send->s_op)
186                         rds_iw_send_unmap_rdma(ic, send->s_op);
187         }
188 }
189
190 /*
191  * The _oldest/_free ring operations here race cleanly with the alloc/unalloc
192  * operations performed in the send path.  As the sender allocs and potentially
193  * unallocs the next free entry in the ring it doesn't alter which is
194  * the next to be freed, which is what this is concerned with.
195  */
196 void rds_iw_send_cq_comp_handler(struct ib_cq *cq, void *context)
197 {
198         struct rds_connection *conn = context;
199         struct rds_iw_connection *ic = conn->c_transport_data;
200         struct ib_wc wc;
201         struct rds_iw_send_work *send;
202         u32 completed;
203         u32 oldest;
204         u32 i;
205         int ret;
206
207         rdsdebug("cq %p conn %p\n", cq, conn);
208         rds_iw_stats_inc(s_iw_tx_cq_call);
209         ret = ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
210         if (ret)
211                 rdsdebug("ib_req_notify_cq send failed: %d\n", ret);
212
213         while (ib_poll_cq(cq, 1, &wc) > 0) {
214                 rdsdebug("wc wr_id 0x%llx status %u byte_len %u imm_data %u\n",
215                          (unsigned long long)wc.wr_id, wc.status, wc.byte_len,
216                          be32_to_cpu(wc.ex.imm_data));
217                 rds_iw_stats_inc(s_iw_tx_cq_event);
218
219                 if (wc.status != IB_WC_SUCCESS) {
220                         printk(KERN_ERR "WC Error:  status = %d opcode = %d\n", wc.status, wc.opcode);
221                         break;
222                 }
223
224                 if (wc.opcode == IB_WC_LOCAL_INV && wc.wr_id == RDS_IW_LOCAL_INV_WR_ID) {
225                         ic->i_fastreg_posted = 0;
226                         continue;
227                 }
228
229                 if (wc.opcode == IB_WC_FAST_REG_MR && wc.wr_id == RDS_IW_FAST_REG_WR_ID) {
230                         ic->i_fastreg_posted = 1;
231                         continue;
232                 }
233
234                 if (wc.wr_id == RDS_IW_ACK_WR_ID) {
235                         if (ic->i_ack_queued + HZ/2 < jiffies)
236                                 rds_iw_stats_inc(s_iw_tx_stalled);
237                         rds_iw_ack_send_complete(ic);
238                         continue;
239                 }
240
241                 oldest = rds_iw_ring_oldest(&ic->i_send_ring);
242
243                 completed = rds_iw_ring_completed(&ic->i_send_ring, wc.wr_id, oldest);
244
245                 for (i = 0; i < completed; i++) {
246                         send = &ic->i_sends[oldest];
247
248                         /* In the error case, wc.opcode sometimes contains garbage */
249                         switch (send->s_wr.opcode) {
250                         case IB_WR_SEND:
251                                 if (send->s_rm)
252                                         rds_iw_send_unmap_rm(ic, send, wc.status);
253                                 break;
254                         case IB_WR_FAST_REG_MR:
255                         case IB_WR_RDMA_WRITE:
256                         case IB_WR_RDMA_READ:
257                         case IB_WR_RDMA_READ_WITH_INV:
258                                 /* Nothing to be done - the SG list will be unmapped
259                                  * when the SEND completes. */
260                                 break;
261                         default:
262                                 if (printk_ratelimit())
263                                         printk(KERN_NOTICE
264                                                 "RDS/IW: %s: unexpected opcode 0x%x in WR!\n",
265                                                 __func__, send->s_wr.opcode);
266                                 break;
267                         }
268
269                         send->s_wr.opcode = 0xdead;
270                         send->s_wr.num_sge = 1;
271                         if (send->s_queued + HZ/2 < jiffies)
272                                 rds_iw_stats_inc(s_iw_tx_stalled);
273
274                         /* If a RDMA operation produced an error, signal this right
275                          * away. If we don't, the subsequent SEND that goes with this
276                          * RDMA will be canceled with ERR_WFLUSH, and the application
277                          * never learn that the RDMA failed. */
278                         if (unlikely(wc.status == IB_WC_REM_ACCESS_ERR && send->s_op)) {
279                                 struct rds_message *rm;
280
281                                 rm = rds_send_get_message(conn, send->s_op);
282                                 if (rm)
283                                         rds_iw_send_rdma_complete(rm, wc.status);
284                         }
285
286                         oldest = (oldest + 1) % ic->i_send_ring.w_nr;
287                 }
288
289                 rds_iw_ring_free(&ic->i_send_ring, completed);
290
291                 if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags)
292                  || test_bit(0, &conn->c_map_queued))
293                         queue_delayed_work(rds_wq, &conn->c_send_w, 0);
294
295                 /* We expect errors as the qp is drained during shutdown */
296                 if (wc.status != IB_WC_SUCCESS && rds_conn_up(conn)) {
297                         rds_iw_conn_error(conn,
298                                 "send completion on %pI4 "
299                                 "had status %u, disconnecting and reconnecting\n",
300                                 &conn->c_faddr, wc.status);
301                 }
302         }
303 }
304
305 /*
306  * This is the main function for allocating credits when sending
307  * messages.
308  *
309  * Conceptually, we have two counters:
310  *  -   send credits: this tells us how many WRs we're allowed
311  *      to submit without overruning the reciever's queue. For
312  *      each SEND WR we post, we decrement this by one.
313  *
314  *  -   posted credits: this tells us how many WRs we recently
315  *      posted to the receive queue. This value is transferred
316  *      to the peer as a "credit update" in a RDS header field.
317  *      Every time we transmit credits to the peer, we subtract
318  *      the amount of transferred credits from this counter.
319  *
320  * It is essential that we avoid situations where both sides have
321  * exhausted their send credits, and are unable to send new credits
322  * to the peer. We achieve this by requiring that we send at least
323  * one credit update to the peer before exhausting our credits.
324  * When new credits arrive, we subtract one credit that is withheld
325  * until we've posted new buffers and are ready to transmit these
326  * credits (see rds_iw_send_add_credits below).
327  *
328  * The RDS send code is essentially single-threaded; rds_send_xmit
329  * grabs c_send_lock to ensure exclusive access to the send ring.
330  * However, the ACK sending code is independent and can race with
331  * message SENDs.
332  *
333  * In the send path, we need to update the counters for send credits
334  * and the counter of posted buffers atomically - when we use the
335  * last available credit, we cannot allow another thread to race us
336  * and grab the posted credits counter.  Hence, we have to use a
337  * spinlock to protect the credit counter, or use atomics.
338  *
339  * Spinlocks shared between the send and the receive path are bad,
340  * because they create unnecessary delays. An early implementation
341  * using a spinlock showed a 5% degradation in throughput at some
342  * loads.
343  *
344  * This implementation avoids spinlocks completely, putting both
345  * counters into a single atomic, and updating that atomic using
346  * atomic_add (in the receive path, when receiving fresh credits),
347  * and using atomic_cmpxchg when updating the two counters.
348  */
349 int rds_iw_send_grab_credits(struct rds_iw_connection *ic,
350                              u32 wanted, u32 *adv_credits, int need_posted)
351 {
352         unsigned int avail, posted, got = 0, advertise;
353         long oldval, newval;
354
355         *adv_credits = 0;
356         if (!ic->i_flowctl)
357                 return wanted;
358
359 try_again:
360         advertise = 0;
361         oldval = newval = atomic_read(&ic->i_credits);
362         posted = IB_GET_POST_CREDITS(oldval);
363         avail = IB_GET_SEND_CREDITS(oldval);
364
365         rdsdebug("rds_iw_send_grab_credits(%u): credits=%u posted=%u\n",
366                         wanted, avail, posted);
367
368         /* The last credit must be used to send a credit update. */
369         if (avail && !posted)
370                 avail--;
371
372         if (avail < wanted) {
373                 struct rds_connection *conn = ic->i_cm_id->context;
374
375                 /* Oops, there aren't that many credits left! */
376                 set_bit(RDS_LL_SEND_FULL, &conn->c_flags);
377                 got = avail;
378         } else {
379                 /* Sometimes you get what you want, lalala. */
380                 got = wanted;
381         }
382         newval -= IB_SET_SEND_CREDITS(got);
383
384         /*
385          * If need_posted is non-zero, then the caller wants
386          * the posted regardless of whether any send credits are
387          * available.
388          */
389         if (posted && (got || need_posted)) {
390                 advertise = min_t(unsigned int, posted, RDS_MAX_ADV_CREDIT);
391                 newval -= IB_SET_POST_CREDITS(advertise);
392         }
393
394         /* Finally bill everything */
395         if (atomic_cmpxchg(&ic->i_credits, oldval, newval) != oldval)
396                 goto try_again;
397
398         *adv_credits = advertise;
399         return got;
400 }
401
402 void rds_iw_send_add_credits(struct rds_connection *conn, unsigned int credits)
403 {
404         struct rds_iw_connection *ic = conn->c_transport_data;
405
406         if (credits == 0)
407                 return;
408
409         rdsdebug("rds_iw_send_add_credits(%u): current=%u%s\n",
410                         credits,
411                         IB_GET_SEND_CREDITS(atomic_read(&ic->i_credits)),
412                         test_bit(RDS_LL_SEND_FULL, &conn->c_flags) ? ", ll_send_full" : "");
413
414         atomic_add(IB_SET_SEND_CREDITS(credits), &ic->i_credits);
415         if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags))
416                 queue_delayed_work(rds_wq, &conn->c_send_w, 0);
417
418         WARN_ON(IB_GET_SEND_CREDITS(credits) >= 16384);
419
420         rds_iw_stats_inc(s_iw_rx_credit_updates);
421 }
422
423 void rds_iw_advertise_credits(struct rds_connection *conn, unsigned int posted)
424 {
425         struct rds_iw_connection *ic = conn->c_transport_data;
426
427         if (posted == 0)
428                 return;
429
430         atomic_add(IB_SET_POST_CREDITS(posted), &ic->i_credits);
431
432         /* Decide whether to send an update to the peer now.
433          * If we would send a credit update for every single buffer we
434          * post, we would end up with an ACK storm (ACK arrives,
435          * consumes buffer, we refill the ring, send ACK to remote
436          * advertising the newly posted buffer... ad inf)
437          *
438          * Performance pretty much depends on how often we send
439          * credit updates - too frequent updates mean lots of ACKs.
440          * Too infrequent updates, and the peer will run out of
441          * credits and has to throttle.
442          * For the time being, 16 seems to be a good compromise.
443          */
444         if (IB_GET_POST_CREDITS(atomic_read(&ic->i_credits)) >= 16)
445                 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
446 }
447
448 static inline void
449 rds_iw_xmit_populate_wr(struct rds_iw_connection *ic,
450                 struct rds_iw_send_work *send, unsigned int pos,
451                 unsigned long buffer, unsigned int length,
452                 int send_flags)
453 {
454         struct ib_sge *sge;
455
456         WARN_ON(pos != send - ic->i_sends);
457
458         send->s_wr.send_flags = send_flags;
459         send->s_wr.opcode = IB_WR_SEND;
460         send->s_wr.num_sge = 2;
461         send->s_wr.next = NULL;
462         send->s_queued = jiffies;
463         send->s_op = NULL;
464
465         if (length != 0) {
466                 sge = rds_iw_data_sge(ic, send->s_sge);
467                 sge->addr = buffer;
468                 sge->length = length;
469                 sge->lkey = rds_iw_local_dma_lkey(ic);
470
471                 sge = rds_iw_header_sge(ic, send->s_sge);
472         } else {
473                 /* We're sending a packet with no payload. There is only
474                  * one SGE */
475                 send->s_wr.num_sge = 1;
476                 sge = &send->s_sge[0];
477         }
478
479         sge->addr = ic->i_send_hdrs_dma + (pos * sizeof(struct rds_header));
480         sge->length = sizeof(struct rds_header);
481         sge->lkey = rds_iw_local_dma_lkey(ic);
482 }
483
484 /*
485  * This can be called multiple times for a given message.  The first time
486  * we see a message we map its scatterlist into the IB device so that
487  * we can provide that mapped address to the IB scatter gather entries
488  * in the IB work requests.  We translate the scatterlist into a series
489  * of work requests that fragment the message.  These work requests complete
490  * in order so we pass ownership of the message to the completion handler
491  * once we send the final fragment.
492  *
493  * The RDS core uses the c_send_lock to only enter this function once
494  * per connection.  This makes sure that the tx ring alloc/unalloc pairs
495  * don't get out of sync and confuse the ring.
496  */
497 int rds_iw_xmit(struct rds_connection *conn, struct rds_message *rm,
498                 unsigned int hdr_off, unsigned int sg, unsigned int off)
499 {
500         struct rds_iw_connection *ic = conn->c_transport_data;
501         struct ib_device *dev = ic->i_cm_id->device;
502         struct rds_iw_send_work *send = NULL;
503         struct rds_iw_send_work *first;
504         struct rds_iw_send_work *prev;
505         struct ib_send_wr *failed_wr;
506         struct scatterlist *scat;
507         u32 pos;
508         u32 i;
509         u32 work_alloc;
510         u32 credit_alloc;
511         u32 posted;
512         u32 adv_credits = 0;
513         int send_flags = 0;
514         int sent;
515         int ret;
516         int flow_controlled = 0;
517
518         BUG_ON(off % RDS_FRAG_SIZE);
519         BUG_ON(hdr_off != 0 && hdr_off != sizeof(struct rds_header));
520
521         /* Fastreg support */
522         if (rds_rdma_cookie_key(rm->m_rdma_cookie)
523          && !ic->i_fastreg_posted) {
524                 ret = -EAGAIN;
525                 goto out;
526         }
527
528         /* FIXME we may overallocate here */
529         if (be32_to_cpu(rm->m_inc.i_hdr.h_len) == 0)
530                 i = 1;
531         else
532                 i = ceil(be32_to_cpu(rm->m_inc.i_hdr.h_len), RDS_FRAG_SIZE);
533
534         work_alloc = rds_iw_ring_alloc(&ic->i_send_ring, i, &pos);
535         if (work_alloc == 0) {
536                 set_bit(RDS_LL_SEND_FULL, &conn->c_flags);
537                 rds_iw_stats_inc(s_iw_tx_ring_full);
538                 ret = -ENOMEM;
539                 goto out;
540         }
541
542         credit_alloc = work_alloc;
543         if (ic->i_flowctl) {
544                 credit_alloc = rds_iw_send_grab_credits(ic, work_alloc, &posted, 0);
545                 adv_credits += posted;
546                 if (credit_alloc < work_alloc) {
547                         rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc - credit_alloc);
548                         work_alloc = credit_alloc;
549                         flow_controlled++;
550                 }
551                 if (work_alloc == 0) {
552                         rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc);
553                         rds_iw_stats_inc(s_iw_tx_throttle);
554                         ret = -ENOMEM;
555                         goto out;
556                 }
557         }
558
559         /* map the message the first time we see it */
560         if (ic->i_rm == NULL) {
561                 /*
562                 printk(KERN_NOTICE "rds_iw_xmit prep msg dport=%u flags=0x%x len=%d\n",
563                                 be16_to_cpu(rm->m_inc.i_hdr.h_dport),
564                                 rm->m_inc.i_hdr.h_flags,
565                                 be32_to_cpu(rm->m_inc.i_hdr.h_len));
566                    */
567                 if (rm->m_nents) {
568                         rm->m_count = ib_dma_map_sg(dev,
569                                          rm->m_sg, rm->m_nents, DMA_TO_DEVICE);
570                         rdsdebug("ic %p mapping rm %p: %d\n", ic, rm, rm->m_count);
571                         if (rm->m_count == 0) {
572                                 rds_iw_stats_inc(s_iw_tx_sg_mapping_failure);
573                                 rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc);
574                                 ret = -ENOMEM; /* XXX ? */
575                                 goto out;
576                         }
577                 } else {
578                         rm->m_count = 0;
579                 }
580
581                 ic->i_unsignaled_wrs = rds_iw_sysctl_max_unsig_wrs;
582                 ic->i_unsignaled_bytes = rds_iw_sysctl_max_unsig_bytes;
583                 rds_message_addref(rm);
584                 ic->i_rm = rm;
585
586                 /* Finalize the header */
587                 if (test_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags))
588                         rm->m_inc.i_hdr.h_flags |= RDS_FLAG_ACK_REQUIRED;
589                 if (test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags))
590                         rm->m_inc.i_hdr.h_flags |= RDS_FLAG_RETRANSMITTED;
591
592                 /* If it has a RDMA op, tell the peer we did it. This is
593                  * used by the peer to release use-once RDMA MRs. */
594                 if (rm->m_rdma_op) {
595                         struct rds_ext_header_rdma ext_hdr;
596
597                         ext_hdr.h_rdma_rkey = cpu_to_be32(rm->m_rdma_op->r_key);
598                         rds_message_add_extension(&rm->m_inc.i_hdr,
599                                         RDS_EXTHDR_RDMA, &ext_hdr, sizeof(ext_hdr));
600                 }
601                 if (rm->m_rdma_cookie) {
602                         rds_message_add_rdma_dest_extension(&rm->m_inc.i_hdr,
603                                         rds_rdma_cookie_key(rm->m_rdma_cookie),
604                                         rds_rdma_cookie_offset(rm->m_rdma_cookie));
605                 }
606
607                 /* Note - rds_iw_piggyb_ack clears the ACK_REQUIRED bit, so
608                  * we should not do this unless we have a chance of at least
609                  * sticking the header into the send ring. Which is why we
610                  * should call rds_iw_ring_alloc first. */
611                 rm->m_inc.i_hdr.h_ack = cpu_to_be64(rds_iw_piggyb_ack(ic));
612                 rds_message_make_checksum(&rm->m_inc.i_hdr);
613
614                 /*
615                  * Update adv_credits since we reset the ACK_REQUIRED bit.
616                  */
617                 rds_iw_send_grab_credits(ic, 0, &posted, 1);
618                 adv_credits += posted;
619                 BUG_ON(adv_credits > 255);
620         } else if (ic->i_rm != rm)
621                 BUG();
622
623         send = &ic->i_sends[pos];
624         first = send;
625         prev = NULL;
626         scat = &rm->m_sg[sg];
627         sent = 0;
628         i = 0;
629
630         /* Sometimes you want to put a fence between an RDMA
631          * READ and the following SEND.
632          * We could either do this all the time
633          * or when requested by the user. Right now, we let
634          * the application choose.
635          */
636         if (rm->m_rdma_op && rm->m_rdma_op->r_fence)
637                 send_flags = IB_SEND_FENCE;
638
639         /*
640          * We could be copying the header into the unused tail of the page.
641          * That would need to be changed in the future when those pages might
642          * be mapped userspace pages or page cache pages.  So instead we always
643          * use a second sge and our long-lived ring of mapped headers.  We send
644          * the header after the data so that the data payload can be aligned on
645          * the receiver.
646          */
647
648         /* handle a 0-len message */
649         if (be32_to_cpu(rm->m_inc.i_hdr.h_len) == 0) {
650                 rds_iw_xmit_populate_wr(ic, send, pos, 0, 0, send_flags);
651                 goto add_header;
652         }
653
654         /* if there's data reference it with a chain of work reqs */
655         for (; i < work_alloc && scat != &rm->m_sg[rm->m_count]; i++) {
656                 unsigned int len;
657
658                 send = &ic->i_sends[pos];
659
660                 len = min(RDS_FRAG_SIZE, ib_sg_dma_len(dev, scat) - off);
661                 rds_iw_xmit_populate_wr(ic, send, pos,
662                                 ib_sg_dma_address(dev, scat) + off, len,
663                                 send_flags);
664
665                 /*
666                  * We want to delay signaling completions just enough to get
667                  * the batching benefits but not so much that we create dead time
668                  * on the wire.
669                  */
670                 if (ic->i_unsignaled_wrs-- == 0) {
671                         ic->i_unsignaled_wrs = rds_iw_sysctl_max_unsig_wrs;
672                         send->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED;
673                 }
674
675                 ic->i_unsignaled_bytes -= len;
676                 if (ic->i_unsignaled_bytes <= 0) {
677                         ic->i_unsignaled_bytes = rds_iw_sysctl_max_unsig_bytes;
678                         send->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED;
679                 }
680
681                 /*
682                  * Always signal the last one if we're stopping due to flow control.
683                  */
684                 if (flow_controlled && i == (work_alloc-1))
685                         send->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED;
686
687                 rdsdebug("send %p wr %p num_sge %u next %p\n", send,
688                          &send->s_wr, send->s_wr.num_sge, send->s_wr.next);
689
690                 sent += len;
691                 off += len;
692                 if (off == ib_sg_dma_len(dev, scat)) {
693                         scat++;
694                         off = 0;
695                 }
696
697 add_header:
698                 /* Tack on the header after the data. The header SGE should already
699                  * have been set up to point to the right header buffer. */
700                 memcpy(&ic->i_send_hdrs[pos], &rm->m_inc.i_hdr, sizeof(struct rds_header));
701
702                 if (0) {
703                         struct rds_header *hdr = &ic->i_send_hdrs[pos];
704
705                         printk(KERN_NOTICE "send WR dport=%u flags=0x%x len=%d\n",
706                                 be16_to_cpu(hdr->h_dport),
707                                 hdr->h_flags,
708                                 be32_to_cpu(hdr->h_len));
709                 }
710                 if (adv_credits) {
711                         struct rds_header *hdr = &ic->i_send_hdrs[pos];
712
713                         /* add credit and redo the header checksum */
714                         hdr->h_credit = adv_credits;
715                         rds_message_make_checksum(hdr);
716                         adv_credits = 0;
717                         rds_iw_stats_inc(s_iw_tx_credit_updates);
718                 }
719
720                 if (prev)
721                         prev->s_wr.next = &send->s_wr;
722                 prev = send;
723
724                 pos = (pos + 1) % ic->i_send_ring.w_nr;
725         }
726
727         /* Account the RDS header in the number of bytes we sent, but just once.
728          * The caller has no concept of fragmentation. */
729         if (hdr_off == 0)
730                 sent += sizeof(struct rds_header);
731
732         /* if we finished the message then send completion owns it */
733         if (scat == &rm->m_sg[rm->m_count]) {
734                 prev->s_rm = ic->i_rm;
735                 prev->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED;
736                 ic->i_rm = NULL;
737         }
738
739         if (i < work_alloc) {
740                 rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc - i);
741                 work_alloc = i;
742         }
743         if (ic->i_flowctl && i < credit_alloc)
744                 rds_iw_send_add_credits(conn, credit_alloc - i);
745
746         /* XXX need to worry about failed_wr and partial sends. */
747         failed_wr = &first->s_wr;
748         ret = ib_post_send(ic->i_cm_id->qp, &first->s_wr, &failed_wr);
749         rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic,
750                  first, &first->s_wr, ret, failed_wr);
751         BUG_ON(failed_wr != &first->s_wr);
752         if (ret) {
753                 printk(KERN_WARNING "RDS/IW: ib_post_send to %pI4 "
754                        "returned %d\n", &conn->c_faddr, ret);
755                 rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc);
756                 if (prev->s_rm) {
757                         ic->i_rm = prev->s_rm;
758                         prev->s_rm = NULL;
759                 }
760                 goto out;
761         }
762
763         ret = sent;
764 out:
765         BUG_ON(adv_credits);
766         return ret;
767 }
768
769 static void rds_iw_build_send_fastreg(struct rds_iw_device *rds_iwdev, struct rds_iw_connection *ic, struct rds_iw_send_work *send, int nent, int len, u64 sg_addr)
770 {
771         BUG_ON(nent > send->s_page_list->max_page_list_len);
772         /*
773          * Perform a WR for the fast_reg_mr. Each individual page
774          * in the sg list is added to the fast reg page list and placed
775          * inside the fast_reg_mr WR.
776          */
777         send->s_wr.opcode = IB_WR_FAST_REG_MR;
778         send->s_wr.wr.fast_reg.length = len;
779         send->s_wr.wr.fast_reg.rkey = send->s_mr->rkey;
780         send->s_wr.wr.fast_reg.page_list = send->s_page_list;
781         send->s_wr.wr.fast_reg.page_list_len = nent;
782         send->s_wr.wr.fast_reg.page_shift = rds_iwdev->page_shift;
783         send->s_wr.wr.fast_reg.access_flags = IB_ACCESS_REMOTE_WRITE;
784         send->s_wr.wr.fast_reg.iova_start = sg_addr;
785
786         ib_update_fast_reg_key(send->s_mr, send->s_remap_count++);
787 }
788
789 int rds_iw_xmit_rdma(struct rds_connection *conn, struct rds_rdma_op *op)
790 {
791         struct rds_iw_connection *ic = conn->c_transport_data;
792         struct rds_iw_send_work *send = NULL;
793         struct rds_iw_send_work *first;
794         struct rds_iw_send_work *prev;
795         struct ib_send_wr *failed_wr;
796         struct rds_iw_device *rds_iwdev;
797         struct scatterlist *scat;
798         unsigned long len;
799         u64 remote_addr = op->r_remote_addr;
800         u32 pos, fr_pos;
801         u32 work_alloc;
802         u32 i;
803         u32 j;
804         int sent;
805         int ret;
806         int num_sge;
807
808         rds_iwdev = ib_get_client_data(ic->i_cm_id->device, &rds_iw_client);
809
810         /* map the message the first time we see it */
811         if (!op->r_mapped) {
812                 op->r_count = ib_dma_map_sg(ic->i_cm_id->device,
813                                         op->r_sg, op->r_nents, (op->r_write) ?
814                                         DMA_TO_DEVICE : DMA_FROM_DEVICE);
815                 rdsdebug("ic %p mapping op %p: %d\n", ic, op, op->r_count);
816                 if (op->r_count == 0) {
817                         rds_iw_stats_inc(s_iw_tx_sg_mapping_failure);
818                         ret = -ENOMEM; /* XXX ? */
819                         goto out;
820                 }
821
822                 op->r_mapped = 1;
823         }
824
825         if (!op->r_write) {
826                 /* Alloc space on the send queue for the fastreg */
827                 work_alloc = rds_iw_ring_alloc(&ic->i_send_ring, 1, &fr_pos);
828                 if (work_alloc != 1) {
829                         rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc);
830                         rds_iw_stats_inc(s_iw_tx_ring_full);
831                         ret = -ENOMEM;
832                         goto out;
833                 }
834         }
835
836         /*
837          * Instead of knowing how to return a partial rdma read/write we insist that there
838          * be enough work requests to send the entire message.
839          */
840         i = ceil(op->r_count, rds_iwdev->max_sge);
841
842         work_alloc = rds_iw_ring_alloc(&ic->i_send_ring, i, &pos);
843         if (work_alloc != i) {
844                 rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc);
845                 rds_iw_stats_inc(s_iw_tx_ring_full);
846                 ret = -ENOMEM;
847                 goto out;
848         }
849
850         send = &ic->i_sends[pos];
851         if (!op->r_write) {
852                 first = prev = &ic->i_sends[fr_pos];
853         } else {
854                 first = send;
855                 prev = NULL;
856         }
857         scat = &op->r_sg[0];
858         sent = 0;
859         num_sge = op->r_count;
860
861         for (i = 0; i < work_alloc && scat != &op->r_sg[op->r_count]; i++) {
862                 send->s_wr.send_flags = 0;
863                 send->s_queued = jiffies;
864
865                 /*
866                  * We want to delay signaling completions just enough to get
867                  * the batching benefits but not so much that we create dead time on the wire.
868                  */
869                 if (ic->i_unsignaled_wrs-- == 0) {
870                         ic->i_unsignaled_wrs = rds_iw_sysctl_max_unsig_wrs;
871                         send->s_wr.send_flags = IB_SEND_SIGNALED;
872                 }
873
874                 /* To avoid the need to have the plumbing to invalidate the fastreg_mr used
875                  * for local access after RDS is finished with it, using
876                  * IB_WR_RDMA_READ_WITH_INV will invalidate it after the read has completed.
877                  */
878                 if (op->r_write)
879                         send->s_wr.opcode = IB_WR_RDMA_WRITE;
880                 else
881                         send->s_wr.opcode = IB_WR_RDMA_READ_WITH_INV;
882
883                 send->s_wr.wr.rdma.remote_addr = remote_addr;
884                 send->s_wr.wr.rdma.rkey = op->r_key;
885                 send->s_op = op;
886
887                 if (num_sge > rds_iwdev->max_sge) {
888                         send->s_wr.num_sge = rds_iwdev->max_sge;
889                         num_sge -= rds_iwdev->max_sge;
890                 } else
891                         send->s_wr.num_sge = num_sge;
892
893                 send->s_wr.next = NULL;
894
895                 if (prev)
896                         prev->s_wr.next = &send->s_wr;
897
898                 for (j = 0; j < send->s_wr.num_sge && scat != &op->r_sg[op->r_count]; j++) {
899                         len = ib_sg_dma_len(ic->i_cm_id->device, scat);
900
901                         if (send->s_wr.opcode == IB_WR_RDMA_READ_WITH_INV)
902                                 send->s_page_list->page_list[j] = ib_sg_dma_address(ic->i_cm_id->device, scat);
903                         else {
904                                 send->s_sge[j].addr = ib_sg_dma_address(ic->i_cm_id->device, scat);
905                                 send->s_sge[j].length = len;
906                                 send->s_sge[j].lkey = rds_iw_local_dma_lkey(ic);
907                         }
908
909                         sent += len;
910                         rdsdebug("ic %p sent %d remote_addr %llu\n", ic, sent, remote_addr);
911                         remote_addr += len;
912
913                         scat++;
914                 }
915
916                 if (send->s_wr.opcode == IB_WR_RDMA_READ_WITH_INV) {
917                         send->s_wr.num_sge = 1;
918                         send->s_sge[0].addr = conn->c_xmit_rm->m_rs->rs_user_addr;
919                         send->s_sge[0].length = conn->c_xmit_rm->m_rs->rs_user_bytes;
920                         send->s_sge[0].lkey = ic->i_sends[fr_pos].s_mr->lkey;
921                 }
922
923                 rdsdebug("send %p wr %p num_sge %u next %p\n", send,
924                         &send->s_wr, send->s_wr.num_sge, send->s_wr.next);
925
926                 prev = send;
927                 if (++send == &ic->i_sends[ic->i_send_ring.w_nr])
928                         send = ic->i_sends;
929         }
930
931         /* if we finished the message then send completion owns it */
932         if (scat == &op->r_sg[op->r_count])
933                 first->s_wr.send_flags = IB_SEND_SIGNALED;
934
935         if (i < work_alloc) {
936                 rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc - i);
937                 work_alloc = i;
938         }
939
940         /* On iWARP, local memory access by a remote system (ie, RDMA Read) is not
941          * recommended.  Putting the lkey on the wire is a security hole, as it can
942          * allow for memory access to all of memory on the remote system.  Some
943          * adapters do not allow using the lkey for this at all.  To bypass this use a
944          * fastreg_mr (or possibly a dma_mr)
945          */
946         if (!op->r_write) {
947                 rds_iw_build_send_fastreg(rds_iwdev, ic, &ic->i_sends[fr_pos],
948                         op->r_count, sent, conn->c_xmit_rm->m_rs->rs_user_addr);
949                 work_alloc++;
950         }
951
952         failed_wr = &first->s_wr;
953         ret = ib_post_send(ic->i_cm_id->qp, &first->s_wr, &failed_wr);
954         rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic,
955                  first, &first->s_wr, ret, failed_wr);
956         BUG_ON(failed_wr != &first->s_wr);
957         if (ret) {
958                 printk(KERN_WARNING "RDS/IW: rdma ib_post_send to %pI4 "
959                        "returned %d\n", &conn->c_faddr, ret);
960                 rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc);
961                 goto out;
962         }
963
964 out:
965         return ret;
966 }
967
968 void rds_iw_xmit_complete(struct rds_connection *conn)
969 {
970         struct rds_iw_connection *ic = conn->c_transport_data;
971
972         /* We may have a pending ACK or window update we were unable
973          * to send previously (due to flow control). Try again. */
974         rds_iw_attempt_ack(ic);
975 }