blob: 545d8ee3efb19b9295f812c0b382efe9cdd6b572 [file] [log] [blame]
Andy Groverfcd8b7c2009-02-24 15:30:36 +00001/*
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"
Andy Groverfcd8b7c2009-02-24 15:30:36 +000039#include "iw.h"
40
41static void rds_iw_send_rdma_complete(struct rds_message *rm,
42 int wc_status)
43{
44 int notify_status;
45
46 switch (wc_status) {
47 case IB_WC_WR_FLUSH_ERR:
48 return;
49
50 case IB_WC_SUCCESS:
51 notify_status = RDS_RDMA_SUCCESS;
52 break;
53
54 case IB_WC_REM_ACCESS_ERR:
55 notify_status = RDS_RDMA_REMOTE_ERROR;
56 break;
57
58 default:
59 notify_status = RDS_RDMA_OTHER_ERROR;
60 break;
61 }
62 rds_rdma_send_complete(rm, notify_status);
63}
64
65static void rds_iw_send_unmap_rdma(struct rds_iw_connection *ic,
Andy Groverf8b3aaf2010-03-01 14:11:53 -080066 struct rm_rdma_op *op)
Andy Groverfcd8b7c2009-02-24 15:30:36 +000067{
Andy Groverf8b3aaf2010-03-01 14:11:53 -080068 if (op->op_mapped) {
Andy Groverfcd8b7c2009-02-24 15:30:36 +000069 ib_dma_unmap_sg(ic->i_cm_id->device,
Andy Groverf8b3aaf2010-03-01 14:11:53 -080070 op->op_sg, op->op_nents,
71 op->op_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
72 op->op_mapped = 0;
Andy Groverfcd8b7c2009-02-24 15:30:36 +000073 }
74}
75
76static void rds_iw_send_unmap_rm(struct rds_iw_connection *ic,
77 struct rds_iw_send_work *send,
78 int wc_status)
79{
80 struct rds_message *rm = send->s_rm;
81
82 rdsdebug("ic %p send %p rm %p\n", ic, send, rm);
83
84 ib_dma_unmap_sg(ic->i_cm_id->device,
Andy Grover6c7cc6e2010-01-27 18:04:18 -080085 rm->data.op_sg, rm->data.op_nents,
Andy Groverfcd8b7c2009-02-24 15:30:36 +000086 DMA_TO_DEVICE);
87
Andy Groverf8b3aaf2010-03-01 14:11:53 -080088 if (rm->rdma.op_active) {
89 rds_iw_send_unmap_rdma(ic, &rm->rdma);
Andy Groverfcd8b7c2009-02-24 15:30:36 +000090
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 * call rds_rdma_send_complete from the cq_handler. 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_iw_send_rdma_complete(rm, wc_status);
112
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800113 if (rm->rdma.op_write)
114 rds_stats_add(s_send_rdma_bytes, rm->rdma.op_bytes);
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000115 else
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800116 rds_stats_add(s_recv_rdma_bytes, rm->rdma.op_bytes);
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000117 }
118
119 /* If anyone waited for this message to get flushed out, wake
120 * them up now */
121 rds_message_unmapped(rm);
122
123 rds_message_put(rm);
124 send->s_rm = NULL;
125}
126
127void rds_iw_send_init_ring(struct rds_iw_connection *ic)
128{
129 struct rds_iw_send_work *send;
130 u32 i;
131
132 for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) {
133 struct ib_sge *sge;
134
135 send->s_rm = NULL;
136 send->s_op = NULL;
137 send->s_mapping = NULL;
138
139 send->s_wr.next = NULL;
140 send->s_wr.wr_id = i;
141 send->s_wr.sg_list = send->s_sge;
142 send->s_wr.num_sge = 1;
143 send->s_wr.opcode = IB_WR_SEND;
144 send->s_wr.send_flags = 0;
145 send->s_wr.ex.imm_data = 0;
146
147 sge = rds_iw_data_sge(ic, send->s_sge);
148 sge->lkey = 0;
149
150 sge = rds_iw_header_sge(ic, send->s_sge);
151 sge->addr = ic->i_send_hdrs_dma + (i * sizeof(struct rds_header));
152 sge->length = sizeof(struct rds_header);
153 sge->lkey = 0;
154
155 send->s_mr = ib_alloc_fast_reg_mr(ic->i_pd, fastreg_message_size);
156 if (IS_ERR(send->s_mr)) {
157 printk(KERN_WARNING "RDS/IW: ib_alloc_fast_reg_mr failed\n");
158 break;
159 }
160
161 send->s_page_list = ib_alloc_fast_reg_page_list(
162 ic->i_cm_id->device, fastreg_message_size);
163 if (IS_ERR(send->s_page_list)) {
164 printk(KERN_WARNING "RDS/IW: ib_alloc_fast_reg_page_list failed\n");
165 break;
166 }
167 }
168}
169
170void rds_iw_send_clear_ring(struct rds_iw_connection *ic)
171{
172 struct rds_iw_send_work *send;
173 u32 i;
174
175 for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) {
176 BUG_ON(!send->s_mr);
177 ib_dereg_mr(send->s_mr);
178 BUG_ON(!send->s_page_list);
179 ib_free_fast_reg_page_list(send->s_page_list);
180 if (send->s_wr.opcode == 0xdead)
181 continue;
182 if (send->s_rm)
183 rds_iw_send_unmap_rm(ic, send, IB_WC_WR_FLUSH_ERR);
184 if (send->s_op)
185 rds_iw_send_unmap_rdma(ic, send->s_op);
186 }
187}
188
189/*
190 * The _oldest/_free ring operations here race cleanly with the alloc/unalloc
191 * operations performed in the send path. As the sender allocs and potentially
192 * unallocs the next free entry in the ring it doesn't alter which is
193 * the next to be freed, which is what this is concerned with.
194 */
195void rds_iw_send_cq_comp_handler(struct ib_cq *cq, void *context)
196{
197 struct rds_connection *conn = context;
198 struct rds_iw_connection *ic = conn->c_transport_data;
199 struct ib_wc wc;
200 struct rds_iw_send_work *send;
201 u32 completed;
202 u32 oldest;
203 u32 i;
204 int ret;
205
206 rdsdebug("cq %p conn %p\n", cq, conn);
207 rds_iw_stats_inc(s_iw_tx_cq_call);
208 ret = ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
209 if (ret)
210 rdsdebug("ib_req_notify_cq send failed: %d\n", ret);
211
212 while (ib_poll_cq(cq, 1, &wc) > 0) {
213 rdsdebug("wc wr_id 0x%llx status %u byte_len %u imm_data %u\n",
214 (unsigned long long)wc.wr_id, wc.status, wc.byte_len,
215 be32_to_cpu(wc.ex.imm_data));
216 rds_iw_stats_inc(s_iw_tx_cq_event);
217
218 if (wc.status != IB_WC_SUCCESS) {
219 printk(KERN_ERR "WC Error: status = %d opcode = %d\n", wc.status, wc.opcode);
220 break;
221 }
222
223 if (wc.opcode == IB_WC_LOCAL_INV && wc.wr_id == RDS_IW_LOCAL_INV_WR_ID) {
224 ic->i_fastreg_posted = 0;
225 continue;
226 }
227
228 if (wc.opcode == IB_WC_FAST_REG_MR && wc.wr_id == RDS_IW_FAST_REG_WR_ID) {
229 ic->i_fastreg_posted = 1;
230 continue;
231 }
232
233 if (wc.wr_id == RDS_IW_ACK_WR_ID) {
234 if (ic->i_ack_queued + HZ/2 < jiffies)
235 rds_iw_stats_inc(s_iw_tx_stalled);
236 rds_iw_ack_send_complete(ic);
237 continue;
238 }
239
240 oldest = rds_iw_ring_oldest(&ic->i_send_ring);
241
242 completed = rds_iw_ring_completed(&ic->i_send_ring, wc.wr_id, oldest);
243
244 for (i = 0; i < completed; i++) {
245 send = &ic->i_sends[oldest];
246
247 /* In the error case, wc.opcode sometimes contains garbage */
248 switch (send->s_wr.opcode) {
249 case IB_WR_SEND:
250 if (send->s_rm)
251 rds_iw_send_unmap_rm(ic, send, wc.status);
252 break;
253 case IB_WR_FAST_REG_MR:
254 case IB_WR_RDMA_WRITE:
255 case IB_WR_RDMA_READ:
256 case IB_WR_RDMA_READ_WITH_INV:
257 /* Nothing to be done - the SG list will be unmapped
258 * when the SEND completes. */
259 break;
260 default:
261 if (printk_ratelimit())
262 printk(KERN_NOTICE
263 "RDS/IW: %s: unexpected opcode 0x%x in WR!\n",
264 __func__, send->s_wr.opcode);
265 break;
266 }
267
268 send->s_wr.opcode = 0xdead;
269 send->s_wr.num_sge = 1;
270 if (send->s_queued + HZ/2 < jiffies)
271 rds_iw_stats_inc(s_iw_tx_stalled);
272
273 /* If a RDMA operation produced an error, signal this right
274 * away. If we don't, the subsequent SEND that goes with this
275 * RDMA will be canceled with ERR_WFLUSH, and the application
276 * never learn that the RDMA failed. */
277 if (unlikely(wc.status == IB_WC_REM_ACCESS_ERR && send->s_op)) {
278 struct rds_message *rm;
279
280 rm = rds_send_get_message(conn, send->s_op);
281 if (rm)
282 rds_iw_send_rdma_complete(rm, wc.status);
283 }
284
285 oldest = (oldest + 1) % ic->i_send_ring.w_nr;
286 }
287
288 rds_iw_ring_free(&ic->i_send_ring, completed);
289
Joe Perchesf64f9e72009-11-29 16:55:45 -0800290 if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags) ||
291 test_bit(0, &conn->c_map_queued))
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000292 queue_delayed_work(rds_wq, &conn->c_send_w, 0);
293
294 /* We expect errors as the qp is drained during shutdown */
295 if (wc.status != IB_WC_SUCCESS && rds_conn_up(conn)) {
296 rds_iw_conn_error(conn,
297 "send completion on %pI4 "
298 "had status %u, disconnecting and reconnecting\n",
299 &conn->c_faddr, wc.status);
300 }
301 }
302}
303
304/*
305 * This is the main function for allocating credits when sending
306 * messages.
307 *
308 * Conceptually, we have two counters:
309 * - send credits: this tells us how many WRs we're allowed
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300310 * to submit without overruning the receiver's queue. For
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000311 * each SEND WR we post, we decrement this by one.
312 *
313 * - posted credits: this tells us how many WRs we recently
314 * posted to the receive queue. This value is transferred
315 * to the peer as a "credit update" in a RDS header field.
316 * Every time we transmit credits to the peer, we subtract
317 * the amount of transferred credits from this counter.
318 *
319 * It is essential that we avoid situations where both sides have
320 * exhausted their send credits, and are unable to send new credits
321 * to the peer. We achieve this by requiring that we send at least
322 * one credit update to the peer before exhausting our credits.
323 * When new credits arrive, we subtract one credit that is withheld
324 * until we've posted new buffers and are ready to transmit these
325 * credits (see rds_iw_send_add_credits below).
326 *
327 * The RDS send code is essentially single-threaded; rds_send_xmit
328 * grabs c_send_lock to ensure exclusive access to the send ring.
329 * However, the ACK sending code is independent and can race with
330 * message SENDs.
331 *
332 * In the send path, we need to update the counters for send credits
333 * and the counter of posted buffers atomically - when we use the
334 * last available credit, we cannot allow another thread to race us
335 * and grab the posted credits counter. Hence, we have to use a
336 * spinlock to protect the credit counter, or use atomics.
337 *
338 * Spinlocks shared between the send and the receive path are bad,
339 * because they create unnecessary delays. An early implementation
340 * using a spinlock showed a 5% degradation in throughput at some
341 * loads.
342 *
343 * This implementation avoids spinlocks completely, putting both
344 * counters into a single atomic, and updating that atomic using
345 * atomic_add (in the receive path, when receiving fresh credits),
346 * and using atomic_cmpxchg when updating the two counters.
347 */
348int rds_iw_send_grab_credits(struct rds_iw_connection *ic,
Steve Wise7b70d032009-04-09 14:09:39 +0000349 u32 wanted, u32 *adv_credits, int need_posted, int max_posted)
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000350{
351 unsigned int avail, posted, got = 0, advertise;
352 long oldval, newval;
353
354 *adv_credits = 0;
355 if (!ic->i_flowctl)
356 return wanted;
357
358try_again:
359 advertise = 0;
360 oldval = newval = atomic_read(&ic->i_credits);
361 posted = IB_GET_POST_CREDITS(oldval);
362 avail = IB_GET_SEND_CREDITS(oldval);
363
364 rdsdebug("rds_iw_send_grab_credits(%u): credits=%u posted=%u\n",
365 wanted, avail, posted);
366
367 /* The last credit must be used to send a credit update. */
368 if (avail && !posted)
369 avail--;
370
371 if (avail < wanted) {
372 struct rds_connection *conn = ic->i_cm_id->context;
373
374 /* Oops, there aren't that many credits left! */
375 set_bit(RDS_LL_SEND_FULL, &conn->c_flags);
376 got = avail;
377 } else {
378 /* Sometimes you get what you want, lalala. */
379 got = wanted;
380 }
381 newval -= IB_SET_SEND_CREDITS(got);
382
383 /*
384 * If need_posted is non-zero, then the caller wants
385 * the posted regardless of whether any send credits are
386 * available.
387 */
388 if (posted && (got || need_posted)) {
Steve Wise7b70d032009-04-09 14:09:39 +0000389 advertise = min_t(unsigned int, posted, max_posted);
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000390 newval -= IB_SET_POST_CREDITS(advertise);
391 }
392
393 /* Finally bill everything */
394 if (atomic_cmpxchg(&ic->i_credits, oldval, newval) != oldval)
395 goto try_again;
396
397 *adv_credits = advertise;
398 return got;
399}
400
401void rds_iw_send_add_credits(struct rds_connection *conn, unsigned int credits)
402{
403 struct rds_iw_connection *ic = conn->c_transport_data;
404
405 if (credits == 0)
406 return;
407
408 rdsdebug("rds_iw_send_add_credits(%u): current=%u%s\n",
409 credits,
410 IB_GET_SEND_CREDITS(atomic_read(&ic->i_credits)),
411 test_bit(RDS_LL_SEND_FULL, &conn->c_flags) ? ", ll_send_full" : "");
412
413 atomic_add(IB_SET_SEND_CREDITS(credits), &ic->i_credits);
414 if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags))
415 queue_delayed_work(rds_wq, &conn->c_send_w, 0);
416
417 WARN_ON(IB_GET_SEND_CREDITS(credits) >= 16384);
418
419 rds_iw_stats_inc(s_iw_rx_credit_updates);
420}
421
422void rds_iw_advertise_credits(struct rds_connection *conn, unsigned int posted)
423{
424 struct rds_iw_connection *ic = conn->c_transport_data;
425
426 if (posted == 0)
427 return;
428
429 atomic_add(IB_SET_POST_CREDITS(posted), &ic->i_credits);
430
431 /* Decide whether to send an update to the peer now.
432 * If we would send a credit update for every single buffer we
433 * post, we would end up with an ACK storm (ACK arrives,
434 * consumes buffer, we refill the ring, send ACK to remote
435 * advertising the newly posted buffer... ad inf)
436 *
437 * Performance pretty much depends on how often we send
438 * credit updates - too frequent updates mean lots of ACKs.
439 * Too infrequent updates, and the peer will run out of
440 * credits and has to throttle.
441 * For the time being, 16 seems to be a good compromise.
442 */
443 if (IB_GET_POST_CREDITS(atomic_read(&ic->i_credits)) >= 16)
444 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
445}
446
447static inline void
448rds_iw_xmit_populate_wr(struct rds_iw_connection *ic,
449 struct rds_iw_send_work *send, unsigned int pos,
450 unsigned long buffer, unsigned int length,
451 int send_flags)
452{
453 struct ib_sge *sge;
454
455 WARN_ON(pos != send - ic->i_sends);
456
457 send->s_wr.send_flags = send_flags;
458 send->s_wr.opcode = IB_WR_SEND;
459 send->s_wr.num_sge = 2;
460 send->s_wr.next = NULL;
461 send->s_queued = jiffies;
462 send->s_op = NULL;
463
464 if (length != 0) {
465 sge = rds_iw_data_sge(ic, send->s_sge);
466 sge->addr = buffer;
467 sge->length = length;
468 sge->lkey = rds_iw_local_dma_lkey(ic);
469
470 sge = rds_iw_header_sge(ic, send->s_sge);
471 } else {
472 /* We're sending a packet with no payload. There is only
473 * one SGE */
474 send->s_wr.num_sge = 1;
475 sge = &send->s_sge[0];
476 }
477
478 sge->addr = ic->i_send_hdrs_dma + (pos * sizeof(struct rds_header));
479 sge->length = sizeof(struct rds_header);
480 sge->lkey = rds_iw_local_dma_lkey(ic);
481}
482
483/*
484 * This can be called multiple times for a given message. The first time
485 * we see a message we map its scatterlist into the IB device so that
486 * we can provide that mapped address to the IB scatter gather entries
487 * in the IB work requests. We translate the scatterlist into a series
488 * of work requests that fragment the message. These work requests complete
489 * in order so we pass ownership of the message to the completion handler
490 * once we send the final fragment.
491 *
492 * The RDS core uses the c_send_lock to only enter this function once
493 * per connection. This makes sure that the tx ring alloc/unalloc pairs
494 * don't get out of sync and confuse the ring.
495 */
496int rds_iw_xmit(struct rds_connection *conn, struct rds_message *rm,
497 unsigned int hdr_off, unsigned int sg, unsigned int off)
498{
499 struct rds_iw_connection *ic = conn->c_transport_data;
500 struct ib_device *dev = ic->i_cm_id->device;
501 struct rds_iw_send_work *send = NULL;
502 struct rds_iw_send_work *first;
503 struct rds_iw_send_work *prev;
504 struct ib_send_wr *failed_wr;
505 struct scatterlist *scat;
506 u32 pos;
507 u32 i;
508 u32 work_alloc;
509 u32 credit_alloc;
510 u32 posted;
511 u32 adv_credits = 0;
512 int send_flags = 0;
513 int sent;
514 int ret;
515 int flow_controlled = 0;
516
517 BUG_ON(off % RDS_FRAG_SIZE);
518 BUG_ON(hdr_off != 0 && hdr_off != sizeof(struct rds_header));
519
520 /* Fastreg support */
Joe Perchesf64f9e72009-11-29 16:55:45 -0800521 if (rds_rdma_cookie_key(rm->m_rdma_cookie) && !ic->i_fastreg_posted) {
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000522 ret = -EAGAIN;
523 goto out;
524 }
525
526 /* FIXME we may overallocate here */
527 if (be32_to_cpu(rm->m_inc.i_hdr.h_len) == 0)
528 i = 1;
529 else
530 i = ceil(be32_to_cpu(rm->m_inc.i_hdr.h_len), RDS_FRAG_SIZE);
531
532 work_alloc = rds_iw_ring_alloc(&ic->i_send_ring, i, &pos);
533 if (work_alloc == 0) {
534 set_bit(RDS_LL_SEND_FULL, &conn->c_flags);
535 rds_iw_stats_inc(s_iw_tx_ring_full);
536 ret = -ENOMEM;
537 goto out;
538 }
539
540 credit_alloc = work_alloc;
541 if (ic->i_flowctl) {
Steve Wise7b70d032009-04-09 14:09:39 +0000542 credit_alloc = rds_iw_send_grab_credits(ic, work_alloc, &posted, 0, RDS_MAX_ADV_CREDIT);
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000543 adv_credits += posted;
544 if (credit_alloc < work_alloc) {
545 rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc - credit_alloc);
546 work_alloc = credit_alloc;
547 flow_controlled++;
548 }
549 if (work_alloc == 0) {
Steve Wised39e0602009-04-09 14:09:38 +0000550 set_bit(RDS_LL_SEND_FULL, &conn->c_flags);
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000551 rds_iw_stats_inc(s_iw_tx_throttle);
552 ret = -ENOMEM;
553 goto out;
554 }
555 }
556
557 /* map the message the first time we see it */
Andy Grover8690bfa2010-01-12 11:56:44 -0800558 if (!ic->i_rm) {
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000559 /*
560 printk(KERN_NOTICE "rds_iw_xmit prep msg dport=%u flags=0x%x len=%d\n",
561 be16_to_cpu(rm->m_inc.i_hdr.h_dport),
562 rm->m_inc.i_hdr.h_flags,
563 be32_to_cpu(rm->m_inc.i_hdr.h_len));
564 */
Andy Grover6c7cc6e2010-01-27 18:04:18 -0800565 if (rm->data.op_nents) {
566 rm->data.op_count = ib_dma_map_sg(dev,
567 rm->data.op_sg,
568 rm->data.op_nents,
569 DMA_TO_DEVICE);
570 rdsdebug("ic %p mapping rm %p: %d\n", ic, rm, rm->data.op_count);
571 if (rm->data.op_count == 0) {
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000572 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 {
Andy Grover6c7cc6e2010-01-27 18:04:18 -0800578 rm->data.op_count = 0;
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000579 }
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. */
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800594 if (rm->rdma.op_active) {
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000595 struct rds_ext_header_rdma ext_hdr;
596
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800597 ext_hdr.h_rdma_rkey = cpu_to_be32(rm->rdma.op_rkey);
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000598 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 */
Steve Wise7b70d032009-04-09 14:09:39 +0000617 rds_iw_send_grab_credits(ic, 0, &posted, 1, RDS_MAX_ADV_CREDIT - adv_credits);
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000618 adv_credits += posted;
619 BUG_ON(adv_credits > 255);
Andy Grover735f61e2010-03-11 13:49:55 +0000620 }
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000621
622 send = &ic->i_sends[pos];
623 first = send;
624 prev = NULL;
Andy Grover6c7cc6e2010-01-27 18:04:18 -0800625 scat = &rm->data.op_sg[sg];
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000626 sent = 0;
627 i = 0;
628
629 /* Sometimes you want to put a fence between an RDMA
630 * READ and the following SEND.
631 * We could either do this all the time
632 * or when requested by the user. Right now, we let
633 * the application choose.
634 */
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800635 if (rm->rdma.op_active && rm->rdma.op_fence)
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000636 send_flags = IB_SEND_FENCE;
637
638 /*
639 * We could be copying the header into the unused tail of the page.
640 * That would need to be changed in the future when those pages might
641 * be mapped userspace pages or page cache pages. So instead we always
642 * use a second sge and our long-lived ring of mapped headers. We send
643 * the header after the data so that the data payload can be aligned on
644 * the receiver.
645 */
646
647 /* handle a 0-len message */
648 if (be32_to_cpu(rm->m_inc.i_hdr.h_len) == 0) {
649 rds_iw_xmit_populate_wr(ic, send, pos, 0, 0, send_flags);
650 goto add_header;
651 }
652
653 /* if there's data reference it with a chain of work reqs */
Andy Grover6c7cc6e2010-01-27 18:04:18 -0800654 for (; i < work_alloc && scat != &rm->data.op_sg[rm->data.op_count]; i++) {
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000655 unsigned int len;
656
657 send = &ic->i_sends[pos];
658
659 len = min(RDS_FRAG_SIZE, ib_sg_dma_len(dev, scat) - off);
660 rds_iw_xmit_populate_wr(ic, send, pos,
661 ib_sg_dma_address(dev, scat) + off, len,
662 send_flags);
663
664 /*
665 * We want to delay signaling completions just enough to get
666 * the batching benefits but not so much that we create dead time
667 * on the wire.
668 */
669 if (ic->i_unsignaled_wrs-- == 0) {
670 ic->i_unsignaled_wrs = rds_iw_sysctl_max_unsig_wrs;
671 send->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED;
672 }
673
674 ic->i_unsignaled_bytes -= len;
675 if (ic->i_unsignaled_bytes <= 0) {
676 ic->i_unsignaled_bytes = rds_iw_sysctl_max_unsig_bytes;
677 send->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED;
678 }
679
680 /*
681 * Always signal the last one if we're stopping due to flow control.
682 */
683 if (flow_controlled && i == (work_alloc-1))
684 send->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED;
685
686 rdsdebug("send %p wr %p num_sge %u next %p\n", send,
687 &send->s_wr, send->s_wr.num_sge, send->s_wr.next);
688
689 sent += len;
690 off += len;
691 if (off == ib_sg_dma_len(dev, scat)) {
692 scat++;
693 off = 0;
694 }
695
696add_header:
697 /* Tack on the header after the data. The header SGE should already
698 * have been set up to point to the right header buffer. */
699 memcpy(&ic->i_send_hdrs[pos], &rm->m_inc.i_hdr, sizeof(struct rds_header));
700
701 if (0) {
702 struct rds_header *hdr = &ic->i_send_hdrs[pos];
703
704 printk(KERN_NOTICE "send WR dport=%u flags=0x%x len=%d\n",
705 be16_to_cpu(hdr->h_dport),
706 hdr->h_flags,
707 be32_to_cpu(hdr->h_len));
708 }
709 if (adv_credits) {
710 struct rds_header *hdr = &ic->i_send_hdrs[pos];
711
712 /* add credit and redo the header checksum */
713 hdr->h_credit = adv_credits;
714 rds_message_make_checksum(hdr);
715 adv_credits = 0;
716 rds_iw_stats_inc(s_iw_tx_credit_updates);
717 }
718
719 if (prev)
720 prev->s_wr.next = &send->s_wr;
721 prev = send;
722
723 pos = (pos + 1) % ic->i_send_ring.w_nr;
724 }
725
726 /* Account the RDS header in the number of bytes we sent, but just once.
727 * The caller has no concept of fragmentation. */
728 if (hdr_off == 0)
729 sent += sizeof(struct rds_header);
730
731 /* if we finished the message then send completion owns it */
Andy Grover6c7cc6e2010-01-27 18:04:18 -0800732 if (scat == &rm->data.op_sg[rm->data.op_count]) {
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000733 prev->s_rm = ic->i_rm;
734 prev->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED;
735 ic->i_rm = NULL;
736 }
737
738 if (i < work_alloc) {
739 rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc - i);
740 work_alloc = i;
741 }
742 if (ic->i_flowctl && i < credit_alloc)
743 rds_iw_send_add_credits(conn, credit_alloc - i);
744
745 /* XXX need to worry about failed_wr and partial sends. */
746 failed_wr = &first->s_wr;
747 ret = ib_post_send(ic->i_cm_id->qp, &first->s_wr, &failed_wr);
748 rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic,
749 first, &first->s_wr, ret, failed_wr);
750 BUG_ON(failed_wr != &first->s_wr);
751 if (ret) {
752 printk(KERN_WARNING "RDS/IW: ib_post_send to %pI4 "
753 "returned %d\n", &conn->c_faddr, ret);
754 rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc);
755 if (prev->s_rm) {
756 ic->i_rm = prev->s_rm;
757 prev->s_rm = NULL;
758 }
759 goto out;
760 }
761
762 ret = sent;
763out:
764 BUG_ON(adv_credits);
765 return ret;
766}
767
768static 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)
769{
770 BUG_ON(nent > send->s_page_list->max_page_list_len);
771 /*
772 * Perform a WR for the fast_reg_mr. Each individual page
773 * in the sg list is added to the fast reg page list and placed
774 * inside the fast_reg_mr WR.
775 */
776 send->s_wr.opcode = IB_WR_FAST_REG_MR;
777 send->s_wr.wr.fast_reg.length = len;
778 send->s_wr.wr.fast_reg.rkey = send->s_mr->rkey;
779 send->s_wr.wr.fast_reg.page_list = send->s_page_list;
780 send->s_wr.wr.fast_reg.page_list_len = nent;
Andy Grover404bb722009-07-17 13:13:34 +0000781 send->s_wr.wr.fast_reg.page_shift = PAGE_SHIFT;
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000782 send->s_wr.wr.fast_reg.access_flags = IB_ACCESS_REMOTE_WRITE;
783 send->s_wr.wr.fast_reg.iova_start = sg_addr;
784
785 ib_update_fast_reg_key(send->s_mr, send->s_remap_count++);
786}
787
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800788int rds_iw_xmit_rdma(struct rds_connection *conn, struct rm_rdma_op *op)
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000789{
790 struct rds_iw_connection *ic = conn->c_transport_data;
791 struct rds_iw_send_work *send = NULL;
792 struct rds_iw_send_work *first;
793 struct rds_iw_send_work *prev;
794 struct ib_send_wr *failed_wr;
795 struct rds_iw_device *rds_iwdev;
796 struct scatterlist *scat;
797 unsigned long len;
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800798 u64 remote_addr = op->op_remote_addr;
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000799 u32 pos, fr_pos;
800 u32 work_alloc;
801 u32 i;
802 u32 j;
803 int sent;
804 int ret;
805 int num_sge;
806
807 rds_iwdev = ib_get_client_data(ic->i_cm_id->device, &rds_iw_client);
808
809 /* map the message the first time we see it */
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800810 if (!op->op_mapped) {
811 op->op_count = ib_dma_map_sg(ic->i_cm_id->device,
812 op->op_sg, op->op_nents, (op->op_write) ?
813 DMA_TO_DEVICE : DMA_FROM_DEVICE);
814 rdsdebug("ic %p mapping op %p: %d\n", ic, op, op->op_count);
815 if (op->op_count == 0) {
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000816 rds_iw_stats_inc(s_iw_tx_sg_mapping_failure);
817 ret = -ENOMEM; /* XXX ? */
818 goto out;
819 }
820
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800821 op->op_mapped = 1;
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000822 }
823
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800824 if (!op->op_write) {
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000825 /* Alloc space on the send queue for the fastreg */
826 work_alloc = rds_iw_ring_alloc(&ic->i_send_ring, 1, &fr_pos);
827 if (work_alloc != 1) {
828 rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc);
829 rds_iw_stats_inc(s_iw_tx_ring_full);
830 ret = -ENOMEM;
831 goto out;
832 }
833 }
834
835 /*
836 * Instead of knowing how to return a partial rdma read/write we insist that there
837 * be enough work requests to send the entire message.
838 */
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800839 i = ceil(op->op_count, rds_iwdev->max_sge);
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000840
841 work_alloc = rds_iw_ring_alloc(&ic->i_send_ring, i, &pos);
842 if (work_alloc != i) {
843 rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc);
844 rds_iw_stats_inc(s_iw_tx_ring_full);
845 ret = -ENOMEM;
846 goto out;
847 }
848
849 send = &ic->i_sends[pos];
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800850 if (!op->op_write) {
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000851 first = prev = &ic->i_sends[fr_pos];
852 } else {
853 first = send;
854 prev = NULL;
855 }
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800856 scat = &op->op_sg[0];
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000857 sent = 0;
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800858 num_sge = op->op_count;
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000859
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800860 for (i = 0; i < work_alloc && scat != &op->op_sg[op->op_count]; i++) {
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000861 send->s_wr.send_flags = 0;
862 send->s_queued = jiffies;
863
864 /*
865 * We want to delay signaling completions just enough to get
866 * the batching benefits but not so much that we create dead time on the wire.
867 */
868 if (ic->i_unsignaled_wrs-- == 0) {
869 ic->i_unsignaled_wrs = rds_iw_sysctl_max_unsig_wrs;
870 send->s_wr.send_flags = IB_SEND_SIGNALED;
871 }
872
873 /* To avoid the need to have the plumbing to invalidate the fastreg_mr used
874 * for local access after RDS is finished with it, using
875 * IB_WR_RDMA_READ_WITH_INV will invalidate it after the read has completed.
876 */
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800877 if (op->op_write)
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000878 send->s_wr.opcode = IB_WR_RDMA_WRITE;
879 else
880 send->s_wr.opcode = IB_WR_RDMA_READ_WITH_INV;
881
882 send->s_wr.wr.rdma.remote_addr = remote_addr;
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800883 send->s_wr.wr.rdma.rkey = op->op_rkey;
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000884 send->s_op = op;
885
886 if (num_sge > rds_iwdev->max_sge) {
887 send->s_wr.num_sge = rds_iwdev->max_sge;
888 num_sge -= rds_iwdev->max_sge;
889 } else
890 send->s_wr.num_sge = num_sge;
891
892 send->s_wr.next = NULL;
893
894 if (prev)
895 prev->s_wr.next = &send->s_wr;
896
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800897 for (j = 0; j < send->s_wr.num_sge && scat != &op->op_sg[op->op_count]; j++) {
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000898 len = ib_sg_dma_len(ic->i_cm_id->device, scat);
899
900 if (send->s_wr.opcode == IB_WR_RDMA_READ_WITH_INV)
901 send->s_page_list->page_list[j] = ib_sg_dma_address(ic->i_cm_id->device, scat);
902 else {
903 send->s_sge[j].addr = ib_sg_dma_address(ic->i_cm_id->device, scat);
904 send->s_sge[j].length = len;
905 send->s_sge[j].lkey = rds_iw_local_dma_lkey(ic);
906 }
907
908 sent += len;
909 rdsdebug("ic %p sent %d remote_addr %llu\n", ic, sent, remote_addr);
910 remote_addr += len;
911
912 scat++;
913 }
914
915 if (send->s_wr.opcode == IB_WR_RDMA_READ_WITH_INV) {
916 send->s_wr.num_sge = 1;
917 send->s_sge[0].addr = conn->c_xmit_rm->m_rs->rs_user_addr;
918 send->s_sge[0].length = conn->c_xmit_rm->m_rs->rs_user_bytes;
919 send->s_sge[0].lkey = ic->i_sends[fr_pos].s_mr->lkey;
920 }
921
922 rdsdebug("send %p wr %p num_sge %u next %p\n", send,
923 &send->s_wr, send->s_wr.num_sge, send->s_wr.next);
924
925 prev = send;
926 if (++send == &ic->i_sends[ic->i_send_ring.w_nr])
927 send = ic->i_sends;
928 }
929
930 /* if we finished the message then send completion owns it */
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800931 if (scat == &op->op_sg[op->op_count])
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000932 first->s_wr.send_flags = IB_SEND_SIGNALED;
933
934 if (i < work_alloc) {
935 rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc - i);
936 work_alloc = i;
937 }
938
939 /* On iWARP, local memory access by a remote system (ie, RDMA Read) is not
940 * recommended. Putting the lkey on the wire is a security hole, as it can
941 * allow for memory access to all of memory on the remote system. Some
942 * adapters do not allow using the lkey for this at all. To bypass this use a
943 * fastreg_mr (or possibly a dma_mr)
944 */
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800945 if (!op->op_write) {
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000946 rds_iw_build_send_fastreg(rds_iwdev, ic, &ic->i_sends[fr_pos],
Andy Groverf8b3aaf2010-03-01 14:11:53 -0800947 op->op_count, sent, conn->c_xmit_rm->m_rs->rs_user_addr);
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000948 work_alloc++;
949 }
950
951 failed_wr = &first->s_wr;
952 ret = ib_post_send(ic->i_cm_id->qp, &first->s_wr, &failed_wr);
953 rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic,
954 first, &first->s_wr, ret, failed_wr);
955 BUG_ON(failed_wr != &first->s_wr);
956 if (ret) {
957 printk(KERN_WARNING "RDS/IW: rdma ib_post_send to %pI4 "
958 "returned %d\n", &conn->c_faddr, ret);
959 rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc);
960 goto out;
961 }
962
963out:
964 return ret;
965}
966
967void rds_iw_xmit_complete(struct rds_connection *conn)
968{
969 struct rds_iw_connection *ic = conn->c_transport_data;
970
971 /* We may have a pending ACK or window update we were unable
972 * to send previously (due to flow control). Try again. */
973 rds_iw_attempt_ack(ic);
974}