]>
Commit | Line | Data |
---|---|---|
6a0979df AG |
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 "ib.h" | |
41 | ||
42 | static void rds_ib_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_ib_send_unmap_rdma(struct rds_ib_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_ib_send_unmap_rm(struct rds_ib_connection *ic, | |
78 | struct rds_ib_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 | ||
8690bfa1 | 89 | if (rm->m_rdma_op) { |
6a0979df AG |
90 | rds_ib_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_ib_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_ib_send_init_ring(struct rds_ib_connection *ic) | |
129 | { | |
130 | struct rds_ib_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 | ||
139 | send->s_wr.wr_id = i; | |
140 | send->s_wr.sg_list = send->s_sge; | |
141 | send->s_wr.num_sge = 1; | |
142 | send->s_wr.opcode = IB_WR_SEND; | |
143 | send->s_wr.send_flags = 0; | |
144 | send->s_wr.ex.imm_data = 0; | |
145 | ||
146 | sge = rds_ib_data_sge(ic, send->s_sge); | |
147 | sge->lkey = ic->i_mr->lkey; | |
148 | ||
149 | sge = rds_ib_header_sge(ic, send->s_sge); | |
150 | sge->addr = ic->i_send_hdrs_dma + (i * sizeof(struct rds_header)); | |
151 | sge->length = sizeof(struct rds_header); | |
152 | sge->lkey = ic->i_mr->lkey; | |
153 | } | |
154 | } | |
155 | ||
156 | void rds_ib_send_clear_ring(struct rds_ib_connection *ic) | |
157 | { | |
158 | struct rds_ib_send_work *send; | |
159 | u32 i; | |
160 | ||
161 | for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) { | |
162 | if (send->s_wr.opcode == 0xdead) | |
163 | continue; | |
164 | if (send->s_rm) | |
165 | rds_ib_send_unmap_rm(ic, send, IB_WC_WR_FLUSH_ERR); | |
166 | if (send->s_op) | |
167 | rds_ib_send_unmap_rdma(ic, send->s_op); | |
168 | } | |
169 | } | |
170 | ||
171 | /* | |
172 | * The _oldest/_free ring operations here race cleanly with the alloc/unalloc | |
173 | * operations performed in the send path. As the sender allocs and potentially | |
174 | * unallocs the next free entry in the ring it doesn't alter which is | |
175 | * the next to be freed, which is what this is concerned with. | |
176 | */ | |
177 | void rds_ib_send_cq_comp_handler(struct ib_cq *cq, void *context) | |
178 | { | |
179 | struct rds_connection *conn = context; | |
180 | struct rds_ib_connection *ic = conn->c_transport_data; | |
181 | struct ib_wc wc; | |
182 | struct rds_ib_send_work *send; | |
183 | u32 completed; | |
184 | u32 oldest; | |
185 | u32 i = 0; | |
186 | int ret; | |
187 | ||
188 | rdsdebug("cq %p conn %p\n", cq, conn); | |
189 | rds_ib_stats_inc(s_ib_tx_cq_call); | |
190 | ret = ib_req_notify_cq(cq, IB_CQ_NEXT_COMP); | |
191 | if (ret) | |
192 | rdsdebug("ib_req_notify_cq send failed: %d\n", ret); | |
193 | ||
194 | while (ib_poll_cq(cq, 1, &wc) > 0) { | |
195 | rdsdebug("wc wr_id 0x%llx status %u byte_len %u imm_data %u\n", | |
196 | (unsigned long long)wc.wr_id, wc.status, wc.byte_len, | |
197 | be32_to_cpu(wc.ex.imm_data)); | |
198 | rds_ib_stats_inc(s_ib_tx_cq_event); | |
199 | ||
200 | if (wc.wr_id == RDS_IB_ACK_WR_ID) { | |
201 | if (ic->i_ack_queued + HZ/2 < jiffies) | |
202 | rds_ib_stats_inc(s_ib_tx_stalled); | |
203 | rds_ib_ack_send_complete(ic); | |
204 | continue; | |
205 | } | |
206 | ||
207 | oldest = rds_ib_ring_oldest(&ic->i_send_ring); | |
208 | ||
209 | completed = rds_ib_ring_completed(&ic->i_send_ring, wc.wr_id, oldest); | |
210 | ||
211 | for (i = 0; i < completed; i++) { | |
212 | send = &ic->i_sends[oldest]; | |
213 | ||
214 | /* In the error case, wc.opcode sometimes contains garbage */ | |
215 | switch (send->s_wr.opcode) { | |
216 | case IB_WR_SEND: | |
217 | if (send->s_rm) | |
218 | rds_ib_send_unmap_rm(ic, send, wc.status); | |
219 | break; | |
220 | case IB_WR_RDMA_WRITE: | |
221 | case IB_WR_RDMA_READ: | |
222 | /* Nothing to be done - the SG list will be unmapped | |
223 | * when the SEND completes. */ | |
224 | break; | |
225 | default: | |
226 | if (printk_ratelimit()) | |
227 | printk(KERN_NOTICE | |
228 | "RDS/IB: %s: unexpected opcode 0x%x in WR!\n", | |
229 | __func__, send->s_wr.opcode); | |
230 | break; | |
231 | } | |
232 | ||
233 | send->s_wr.opcode = 0xdead; | |
234 | send->s_wr.num_sge = 1; | |
235 | if (send->s_queued + HZ/2 < jiffies) | |
236 | rds_ib_stats_inc(s_ib_tx_stalled); | |
237 | ||
238 | /* If a RDMA operation produced an error, signal this right | |
239 | * away. If we don't, the subsequent SEND that goes with this | |
240 | * RDMA will be canceled with ERR_WFLUSH, and the application | |
241 | * never learn that the RDMA failed. */ | |
242 | if (unlikely(wc.status == IB_WC_REM_ACCESS_ERR && send->s_op)) { | |
243 | struct rds_message *rm; | |
244 | ||
245 | rm = rds_send_get_message(conn, send->s_op); | |
450d06c0 SP |
246 | if (rm) { |
247 | if (rm->m_rdma_op) | |
248 | rds_ib_send_unmap_rdma(ic, rm->m_rdma_op); | |
6a0979df | 249 | rds_ib_send_rdma_complete(rm, wc.status); |
450d06c0 SP |
250 | rds_message_put(rm); |
251 | } | |
6a0979df AG |
252 | } |
253 | ||
254 | oldest = (oldest + 1) % ic->i_send_ring.w_nr; | |
255 | } | |
256 | ||
257 | rds_ib_ring_free(&ic->i_send_ring, completed); | |
258 | ||
f64f9e71 JP |
259 | if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags) || |
260 | test_bit(0, &conn->c_map_queued)) | |
6a0979df AG |
261 | queue_delayed_work(rds_wq, &conn->c_send_w, 0); |
262 | ||
263 | /* We expect errors as the qp is drained during shutdown */ | |
264 | if (wc.status != IB_WC_SUCCESS && rds_conn_up(conn)) { | |
265 | rds_ib_conn_error(conn, | |
266 | "send completion on %pI4 " | |
267 | "had status %u, disconnecting and reconnecting\n", | |
268 | &conn->c_faddr, wc.status); | |
269 | } | |
270 | } | |
271 | } | |
272 | ||
273 | /* | |
274 | * This is the main function for allocating credits when sending | |
275 | * messages. | |
276 | * | |
277 | * Conceptually, we have two counters: | |
278 | * - send credits: this tells us how many WRs we're allowed | |
279 | * to submit without overruning the reciever's queue. For | |
280 | * each SEND WR we post, we decrement this by one. | |
281 | * | |
282 | * - posted credits: this tells us how many WRs we recently | |
283 | * posted to the receive queue. This value is transferred | |
284 | * to the peer as a "credit update" in a RDS header field. | |
285 | * Every time we transmit credits to the peer, we subtract | |
286 | * the amount of transferred credits from this counter. | |
287 | * | |
288 | * It is essential that we avoid situations where both sides have | |
289 | * exhausted their send credits, and are unable to send new credits | |
290 | * to the peer. We achieve this by requiring that we send at least | |
291 | * one credit update to the peer before exhausting our credits. | |
292 | * When new credits arrive, we subtract one credit that is withheld | |
293 | * until we've posted new buffers and are ready to transmit these | |
294 | * credits (see rds_ib_send_add_credits below). | |
295 | * | |
296 | * The RDS send code is essentially single-threaded; rds_send_xmit | |
297 | * grabs c_send_lock to ensure exclusive access to the send ring. | |
298 | * However, the ACK sending code is independent and can race with | |
299 | * message SENDs. | |
300 | * | |
301 | * In the send path, we need to update the counters for send credits | |
302 | * and the counter of posted buffers atomically - when we use the | |
303 | * last available credit, we cannot allow another thread to race us | |
304 | * and grab the posted credits counter. Hence, we have to use a | |
305 | * spinlock to protect the credit counter, or use atomics. | |
306 | * | |
307 | * Spinlocks shared between the send and the receive path are bad, | |
308 | * because they create unnecessary delays. An early implementation | |
309 | * using a spinlock showed a 5% degradation in throughput at some | |
310 | * loads. | |
311 | * | |
312 | * This implementation avoids spinlocks completely, putting both | |
313 | * counters into a single atomic, and updating that atomic using | |
314 | * atomic_add (in the receive path, when receiving fresh credits), | |
315 | * and using atomic_cmpxchg when updating the two counters. | |
316 | */ | |
317 | int rds_ib_send_grab_credits(struct rds_ib_connection *ic, | |
7b70d033 | 318 | u32 wanted, u32 *adv_credits, int need_posted, int max_posted) |
6a0979df AG |
319 | { |
320 | unsigned int avail, posted, got = 0, advertise; | |
321 | long oldval, newval; | |
322 | ||
323 | *adv_credits = 0; | |
324 | if (!ic->i_flowctl) | |
325 | return wanted; | |
326 | ||
327 | try_again: | |
328 | advertise = 0; | |
329 | oldval = newval = atomic_read(&ic->i_credits); | |
330 | posted = IB_GET_POST_CREDITS(oldval); | |
331 | avail = IB_GET_SEND_CREDITS(oldval); | |
332 | ||
333 | rdsdebug("rds_ib_send_grab_credits(%u): credits=%u posted=%u\n", | |
334 | wanted, avail, posted); | |
335 | ||
336 | /* The last credit must be used to send a credit update. */ | |
337 | if (avail && !posted) | |
338 | avail--; | |
339 | ||
340 | if (avail < wanted) { | |
341 | struct rds_connection *conn = ic->i_cm_id->context; | |
342 | ||
343 | /* Oops, there aren't that many credits left! */ | |
344 | set_bit(RDS_LL_SEND_FULL, &conn->c_flags); | |
345 | got = avail; | |
346 | } else { | |
347 | /* Sometimes you get what you want, lalala. */ | |
348 | got = wanted; | |
349 | } | |
350 | newval -= IB_SET_SEND_CREDITS(got); | |
351 | ||
352 | /* | |
353 | * If need_posted is non-zero, then the caller wants | |
354 | * the posted regardless of whether any send credits are | |
355 | * available. | |
356 | */ | |
357 | if (posted && (got || need_posted)) { | |
7b70d033 | 358 | advertise = min_t(unsigned int, posted, max_posted); |
6a0979df AG |
359 | newval -= IB_SET_POST_CREDITS(advertise); |
360 | } | |
361 | ||
362 | /* Finally bill everything */ | |
363 | if (atomic_cmpxchg(&ic->i_credits, oldval, newval) != oldval) | |
364 | goto try_again; | |
365 | ||
366 | *adv_credits = advertise; | |
367 | return got; | |
368 | } | |
369 | ||
370 | void rds_ib_send_add_credits(struct rds_connection *conn, unsigned int credits) | |
371 | { | |
372 | struct rds_ib_connection *ic = conn->c_transport_data; | |
373 | ||
374 | if (credits == 0) | |
375 | return; | |
376 | ||
377 | rdsdebug("rds_ib_send_add_credits(%u): current=%u%s\n", | |
378 | credits, | |
379 | IB_GET_SEND_CREDITS(atomic_read(&ic->i_credits)), | |
380 | test_bit(RDS_LL_SEND_FULL, &conn->c_flags) ? ", ll_send_full" : ""); | |
381 | ||
382 | atomic_add(IB_SET_SEND_CREDITS(credits), &ic->i_credits); | |
383 | if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags)) | |
384 | queue_delayed_work(rds_wq, &conn->c_send_w, 0); | |
385 | ||
386 | WARN_ON(IB_GET_SEND_CREDITS(credits) >= 16384); | |
387 | ||
388 | rds_ib_stats_inc(s_ib_rx_credit_updates); | |
389 | } | |
390 | ||
391 | void rds_ib_advertise_credits(struct rds_connection *conn, unsigned int posted) | |
392 | { | |
393 | struct rds_ib_connection *ic = conn->c_transport_data; | |
394 | ||
395 | if (posted == 0) | |
396 | return; | |
397 | ||
398 | atomic_add(IB_SET_POST_CREDITS(posted), &ic->i_credits); | |
399 | ||
400 | /* Decide whether to send an update to the peer now. | |
401 | * If we would send a credit update for every single buffer we | |
402 | * post, we would end up with an ACK storm (ACK arrives, | |
403 | * consumes buffer, we refill the ring, send ACK to remote | |
404 | * advertising the newly posted buffer... ad inf) | |
405 | * | |
406 | * Performance pretty much depends on how often we send | |
407 | * credit updates - too frequent updates mean lots of ACKs. | |
408 | * Too infrequent updates, and the peer will run out of | |
409 | * credits and has to throttle. | |
410 | * For the time being, 16 seems to be a good compromise. | |
411 | */ | |
412 | if (IB_GET_POST_CREDITS(atomic_read(&ic->i_credits)) >= 16) | |
413 | set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); | |
414 | } | |
415 | ||
416 | static inline void | |
417 | rds_ib_xmit_populate_wr(struct rds_ib_connection *ic, | |
418 | struct rds_ib_send_work *send, unsigned int pos, | |
419 | unsigned long buffer, unsigned int length, | |
420 | int send_flags) | |
421 | { | |
422 | struct ib_sge *sge; | |
423 | ||
424 | WARN_ON(pos != send - ic->i_sends); | |
425 | ||
426 | send->s_wr.send_flags = send_flags; | |
427 | send->s_wr.opcode = IB_WR_SEND; | |
428 | send->s_wr.num_sge = 2; | |
429 | send->s_wr.next = NULL; | |
430 | send->s_queued = jiffies; | |
431 | send->s_op = NULL; | |
432 | ||
433 | if (length != 0) { | |
434 | sge = rds_ib_data_sge(ic, send->s_sge); | |
435 | sge->addr = buffer; | |
436 | sge->length = length; | |
437 | sge->lkey = ic->i_mr->lkey; | |
438 | ||
439 | sge = rds_ib_header_sge(ic, send->s_sge); | |
440 | } else { | |
441 | /* We're sending a packet with no payload. There is only | |
442 | * one SGE */ | |
443 | send->s_wr.num_sge = 1; | |
444 | sge = &send->s_sge[0]; | |
445 | } | |
446 | ||
447 | sge->addr = ic->i_send_hdrs_dma + (pos * sizeof(struct rds_header)); | |
448 | sge->length = sizeof(struct rds_header); | |
449 | sge->lkey = ic->i_mr->lkey; | |
450 | } | |
451 | ||
452 | /* | |
453 | * This can be called multiple times for a given message. The first time | |
454 | * we see a message we map its scatterlist into the IB device so that | |
455 | * we can provide that mapped address to the IB scatter gather entries | |
456 | * in the IB work requests. We translate the scatterlist into a series | |
457 | * of work requests that fragment the message. These work requests complete | |
458 | * in order so we pass ownership of the message to the completion handler | |
459 | * once we send the final fragment. | |
460 | * | |
461 | * The RDS core uses the c_send_lock to only enter this function once | |
462 | * per connection. This makes sure that the tx ring alloc/unalloc pairs | |
463 | * don't get out of sync and confuse the ring. | |
464 | */ | |
465 | int rds_ib_xmit(struct rds_connection *conn, struct rds_message *rm, | |
466 | unsigned int hdr_off, unsigned int sg, unsigned int off) | |
467 | { | |
468 | struct rds_ib_connection *ic = conn->c_transport_data; | |
469 | struct ib_device *dev = ic->i_cm_id->device; | |
470 | struct rds_ib_send_work *send = NULL; | |
471 | struct rds_ib_send_work *first; | |
472 | struct rds_ib_send_work *prev; | |
473 | struct ib_send_wr *failed_wr; | |
474 | struct scatterlist *scat; | |
475 | u32 pos; | |
476 | u32 i; | |
477 | u32 work_alloc; | |
478 | u32 credit_alloc; | |
479 | u32 posted; | |
480 | u32 adv_credits = 0; | |
481 | int send_flags = 0; | |
482 | int sent; | |
483 | int ret; | |
484 | int flow_controlled = 0; | |
485 | ||
486 | BUG_ON(off % RDS_FRAG_SIZE); | |
487 | BUG_ON(hdr_off != 0 && hdr_off != sizeof(struct rds_header)); | |
488 | ||
2e7b3b99 AG |
489 | /* Do not send cong updates to IB loopback */ |
490 | if (conn->c_loopback | |
491 | && rm->m_inc.i_hdr.h_flags & RDS_FLAG_CONG_BITMAP) { | |
492 | rds_cong_map_updated(conn->c_fcong, ~(u64) 0); | |
493 | return sizeof(struct rds_header) + RDS_CONG_MAP_BYTES; | |
494 | } | |
495 | ||
6a0979df AG |
496 | /* FIXME we may overallocate here */ |
497 | if (be32_to_cpu(rm->m_inc.i_hdr.h_len) == 0) | |
498 | i = 1; | |
499 | else | |
500 | i = ceil(be32_to_cpu(rm->m_inc.i_hdr.h_len), RDS_FRAG_SIZE); | |
501 | ||
502 | work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos); | |
503 | if (work_alloc == 0) { | |
504 | set_bit(RDS_LL_SEND_FULL, &conn->c_flags); | |
505 | rds_ib_stats_inc(s_ib_tx_ring_full); | |
506 | ret = -ENOMEM; | |
507 | goto out; | |
508 | } | |
509 | ||
510 | credit_alloc = work_alloc; | |
511 | if (ic->i_flowctl) { | |
7b70d033 | 512 | credit_alloc = rds_ib_send_grab_credits(ic, work_alloc, &posted, 0, RDS_MAX_ADV_CREDIT); |
6a0979df AG |
513 | adv_credits += posted; |
514 | if (credit_alloc < work_alloc) { | |
515 | rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - credit_alloc); | |
516 | work_alloc = credit_alloc; | |
517 | flow_controlled++; | |
518 | } | |
519 | if (work_alloc == 0) { | |
d39e0602 | 520 | set_bit(RDS_LL_SEND_FULL, &conn->c_flags); |
6a0979df AG |
521 | rds_ib_stats_inc(s_ib_tx_throttle); |
522 | ret = -ENOMEM; | |
523 | goto out; | |
524 | } | |
525 | } | |
526 | ||
527 | /* map the message the first time we see it */ | |
8690bfa1 | 528 | if (!ic->i_rm) { |
6a0979df AG |
529 | /* |
530 | printk(KERN_NOTICE "rds_ib_xmit prep msg dport=%u flags=0x%x len=%d\n", | |
531 | be16_to_cpu(rm->m_inc.i_hdr.h_dport), | |
532 | rm->m_inc.i_hdr.h_flags, | |
533 | be32_to_cpu(rm->m_inc.i_hdr.h_len)); | |
534 | */ | |
535 | if (rm->m_nents) { | |
536 | rm->m_count = ib_dma_map_sg(dev, | |
537 | rm->m_sg, rm->m_nents, DMA_TO_DEVICE); | |
538 | rdsdebug("ic %p mapping rm %p: %d\n", ic, rm, rm->m_count); | |
539 | if (rm->m_count == 0) { | |
540 | rds_ib_stats_inc(s_ib_tx_sg_mapping_failure); | |
541 | rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); | |
542 | ret = -ENOMEM; /* XXX ? */ | |
543 | goto out; | |
544 | } | |
545 | } else { | |
546 | rm->m_count = 0; | |
547 | } | |
548 | ||
549 | ic->i_unsignaled_wrs = rds_ib_sysctl_max_unsig_wrs; | |
550 | ic->i_unsignaled_bytes = rds_ib_sysctl_max_unsig_bytes; | |
551 | rds_message_addref(rm); | |
552 | ic->i_rm = rm; | |
553 | ||
554 | /* Finalize the header */ | |
555 | if (test_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags)) | |
556 | rm->m_inc.i_hdr.h_flags |= RDS_FLAG_ACK_REQUIRED; | |
557 | if (test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) | |
558 | rm->m_inc.i_hdr.h_flags |= RDS_FLAG_RETRANSMITTED; | |
559 | ||
560 | /* If it has a RDMA op, tell the peer we did it. This is | |
561 | * used by the peer to release use-once RDMA MRs. */ | |
562 | if (rm->m_rdma_op) { | |
563 | struct rds_ext_header_rdma ext_hdr; | |
564 | ||
565 | ext_hdr.h_rdma_rkey = cpu_to_be32(rm->m_rdma_op->r_key); | |
566 | rds_message_add_extension(&rm->m_inc.i_hdr, | |
567 | RDS_EXTHDR_RDMA, &ext_hdr, sizeof(ext_hdr)); | |
568 | } | |
569 | if (rm->m_rdma_cookie) { | |
570 | rds_message_add_rdma_dest_extension(&rm->m_inc.i_hdr, | |
571 | rds_rdma_cookie_key(rm->m_rdma_cookie), | |
572 | rds_rdma_cookie_offset(rm->m_rdma_cookie)); | |
573 | } | |
574 | ||
575 | /* Note - rds_ib_piggyb_ack clears the ACK_REQUIRED bit, so | |
576 | * we should not do this unless we have a chance of at least | |
577 | * sticking the header into the send ring. Which is why we | |
578 | * should call rds_ib_ring_alloc first. */ | |
579 | rm->m_inc.i_hdr.h_ack = cpu_to_be64(rds_ib_piggyb_ack(ic)); | |
580 | rds_message_make_checksum(&rm->m_inc.i_hdr); | |
581 | ||
582 | /* | |
583 | * Update adv_credits since we reset the ACK_REQUIRED bit. | |
584 | */ | |
7b70d033 | 585 | rds_ib_send_grab_credits(ic, 0, &posted, 1, RDS_MAX_ADV_CREDIT - adv_credits); |
6a0979df AG |
586 | adv_credits += posted; |
587 | BUG_ON(adv_credits > 255); | |
735f61e6 | 588 | } |
6a0979df AG |
589 | |
590 | send = &ic->i_sends[pos]; | |
591 | first = send; | |
592 | prev = NULL; | |
593 | scat = &rm->m_sg[sg]; | |
594 | sent = 0; | |
595 | i = 0; | |
596 | ||
597 | /* Sometimes you want to put a fence between an RDMA | |
598 | * READ and the following SEND. | |
599 | * We could either do this all the time | |
600 | * or when requested by the user. Right now, we let | |
601 | * the application choose. | |
602 | */ | |
603 | if (rm->m_rdma_op && rm->m_rdma_op->r_fence) | |
604 | send_flags = IB_SEND_FENCE; | |
605 | ||
606 | /* | |
607 | * We could be copying the header into the unused tail of the page. | |
608 | * That would need to be changed in the future when those pages might | |
609 | * be mapped userspace pages or page cache pages. So instead we always | |
610 | * use a second sge and our long-lived ring of mapped headers. We send | |
611 | * the header after the data so that the data payload can be aligned on | |
612 | * the receiver. | |
613 | */ | |
614 | ||
615 | /* handle a 0-len message */ | |
616 | if (be32_to_cpu(rm->m_inc.i_hdr.h_len) == 0) { | |
617 | rds_ib_xmit_populate_wr(ic, send, pos, 0, 0, send_flags); | |
618 | goto add_header; | |
619 | } | |
620 | ||
621 | /* if there's data reference it with a chain of work reqs */ | |
622 | for (; i < work_alloc && scat != &rm->m_sg[rm->m_count]; i++) { | |
623 | unsigned int len; | |
624 | ||
625 | send = &ic->i_sends[pos]; | |
626 | ||
627 | len = min(RDS_FRAG_SIZE, ib_sg_dma_len(dev, scat) - off); | |
628 | rds_ib_xmit_populate_wr(ic, send, pos, | |
629 | ib_sg_dma_address(dev, scat) + off, len, | |
630 | send_flags); | |
631 | ||
632 | /* | |
633 | * We want to delay signaling completions just enough to get | |
634 | * the batching benefits but not so much that we create dead time | |
635 | * on the wire. | |
636 | */ | |
637 | if (ic->i_unsignaled_wrs-- == 0) { | |
638 | ic->i_unsignaled_wrs = rds_ib_sysctl_max_unsig_wrs; | |
639 | send->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED; | |
640 | } | |
641 | ||
642 | ic->i_unsignaled_bytes -= len; | |
643 | if (ic->i_unsignaled_bytes <= 0) { | |
644 | ic->i_unsignaled_bytes = rds_ib_sysctl_max_unsig_bytes; | |
645 | send->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED; | |
646 | } | |
647 | ||
648 | /* | |
649 | * Always signal the last one if we're stopping due to flow control. | |
650 | */ | |
651 | if (flow_controlled && i == (work_alloc-1)) | |
652 | send->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED; | |
653 | ||
654 | rdsdebug("send %p wr %p num_sge %u next %p\n", send, | |
655 | &send->s_wr, send->s_wr.num_sge, send->s_wr.next); | |
656 | ||
657 | sent += len; | |
658 | off += len; | |
659 | if (off == ib_sg_dma_len(dev, scat)) { | |
660 | scat++; | |
661 | off = 0; | |
662 | } | |
663 | ||
664 | add_header: | |
665 | /* Tack on the header after the data. The header SGE should already | |
666 | * have been set up to point to the right header buffer. */ | |
667 | memcpy(&ic->i_send_hdrs[pos], &rm->m_inc.i_hdr, sizeof(struct rds_header)); | |
668 | ||
669 | if (0) { | |
670 | struct rds_header *hdr = &ic->i_send_hdrs[pos]; | |
671 | ||
672 | printk(KERN_NOTICE "send WR dport=%u flags=0x%x len=%d\n", | |
673 | be16_to_cpu(hdr->h_dport), | |
674 | hdr->h_flags, | |
675 | be32_to_cpu(hdr->h_len)); | |
676 | } | |
677 | if (adv_credits) { | |
678 | struct rds_header *hdr = &ic->i_send_hdrs[pos]; | |
679 | ||
680 | /* add credit and redo the header checksum */ | |
681 | hdr->h_credit = adv_credits; | |
682 | rds_message_make_checksum(hdr); | |
683 | adv_credits = 0; | |
684 | rds_ib_stats_inc(s_ib_tx_credit_updates); | |
685 | } | |
686 | ||
687 | if (prev) | |
688 | prev->s_wr.next = &send->s_wr; | |
689 | prev = send; | |
690 | ||
691 | pos = (pos + 1) % ic->i_send_ring.w_nr; | |
692 | } | |
693 | ||
694 | /* Account the RDS header in the number of bytes we sent, but just once. | |
695 | * The caller has no concept of fragmentation. */ | |
696 | if (hdr_off == 0) | |
697 | sent += sizeof(struct rds_header); | |
698 | ||
699 | /* if we finished the message then send completion owns it */ | |
700 | if (scat == &rm->m_sg[rm->m_count]) { | |
701 | prev->s_rm = ic->i_rm; | |
702 | prev->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED; | |
703 | ic->i_rm = NULL; | |
704 | } | |
705 | ||
706 | if (i < work_alloc) { | |
707 | rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - i); | |
708 | work_alloc = i; | |
709 | } | |
710 | if (ic->i_flowctl && i < credit_alloc) | |
711 | rds_ib_send_add_credits(conn, credit_alloc - i); | |
712 | ||
713 | /* XXX need to worry about failed_wr and partial sends. */ | |
714 | failed_wr = &first->s_wr; | |
715 | ret = ib_post_send(ic->i_cm_id->qp, &first->s_wr, &failed_wr); | |
716 | rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic, | |
717 | first, &first->s_wr, ret, failed_wr); | |
718 | BUG_ON(failed_wr != &first->s_wr); | |
719 | if (ret) { | |
720 | printk(KERN_WARNING "RDS/IB: ib_post_send to %pI4 " | |
721 | "returned %d\n", &conn->c_faddr, ret); | |
722 | rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); | |
723 | if (prev->s_rm) { | |
724 | ic->i_rm = prev->s_rm; | |
725 | prev->s_rm = NULL; | |
726 | } | |
735f61e6 AG |
727 | |
728 | rds_ib_conn_error(ic->conn, "ib_post_send failed\n"); | |
6a0979df AG |
729 | goto out; |
730 | } | |
731 | ||
732 | ret = sent; | |
733 | out: | |
734 | BUG_ON(adv_credits); | |
735 | return ret; | |
736 | } | |
737 | ||
738 | int rds_ib_xmit_rdma(struct rds_connection *conn, struct rds_rdma_op *op) | |
739 | { | |
740 | struct rds_ib_connection *ic = conn->c_transport_data; | |
741 | struct rds_ib_send_work *send = NULL; | |
742 | struct rds_ib_send_work *first; | |
743 | struct rds_ib_send_work *prev; | |
744 | struct ib_send_wr *failed_wr; | |
745 | struct rds_ib_device *rds_ibdev; | |
746 | struct scatterlist *scat; | |
747 | unsigned long len; | |
748 | u64 remote_addr = op->r_remote_addr; | |
749 | u32 pos; | |
750 | u32 work_alloc; | |
751 | u32 i; | |
752 | u32 j; | |
753 | int sent; | |
754 | int ret; | |
755 | int num_sge; | |
756 | ||
757 | rds_ibdev = ib_get_client_data(ic->i_cm_id->device, &rds_ib_client); | |
758 | ||
759 | /* map the message the first time we see it */ | |
760 | if (!op->r_mapped) { | |
761 | op->r_count = ib_dma_map_sg(ic->i_cm_id->device, | |
762 | op->r_sg, op->r_nents, (op->r_write) ? | |
763 | DMA_TO_DEVICE : DMA_FROM_DEVICE); | |
764 | rdsdebug("ic %p mapping op %p: %d\n", ic, op, op->r_count); | |
765 | if (op->r_count == 0) { | |
766 | rds_ib_stats_inc(s_ib_tx_sg_mapping_failure); | |
767 | ret = -ENOMEM; /* XXX ? */ | |
768 | goto out; | |
769 | } | |
770 | ||
771 | op->r_mapped = 1; | |
772 | } | |
773 | ||
774 | /* | |
775 | * Instead of knowing how to return a partial rdma read/write we insist that there | |
776 | * be enough work requests to send the entire message. | |
777 | */ | |
778 | i = ceil(op->r_count, rds_ibdev->max_sge); | |
779 | ||
780 | work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos); | |
781 | if (work_alloc != i) { | |
782 | rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); | |
783 | rds_ib_stats_inc(s_ib_tx_ring_full); | |
784 | ret = -ENOMEM; | |
785 | goto out; | |
786 | } | |
787 | ||
788 | send = &ic->i_sends[pos]; | |
789 | first = send; | |
790 | prev = NULL; | |
791 | scat = &op->r_sg[0]; | |
792 | sent = 0; | |
793 | num_sge = op->r_count; | |
794 | ||
795 | for (i = 0; i < work_alloc && scat != &op->r_sg[op->r_count]; i++) { | |
796 | send->s_wr.send_flags = 0; | |
797 | send->s_queued = jiffies; | |
798 | /* | |
799 | * We want to delay signaling completions just enough to get | |
800 | * the batching benefits but not so much that we create dead time on the wire. | |
801 | */ | |
802 | if (ic->i_unsignaled_wrs-- == 0) { | |
803 | ic->i_unsignaled_wrs = rds_ib_sysctl_max_unsig_wrs; | |
804 | send->s_wr.send_flags = IB_SEND_SIGNALED; | |
805 | } | |
806 | ||
807 | send->s_wr.opcode = op->r_write ? IB_WR_RDMA_WRITE : IB_WR_RDMA_READ; | |
808 | send->s_wr.wr.rdma.remote_addr = remote_addr; | |
809 | send->s_wr.wr.rdma.rkey = op->r_key; | |
810 | send->s_op = op; | |
811 | ||
812 | if (num_sge > rds_ibdev->max_sge) { | |
813 | send->s_wr.num_sge = rds_ibdev->max_sge; | |
814 | num_sge -= rds_ibdev->max_sge; | |
815 | } else { | |
816 | send->s_wr.num_sge = num_sge; | |
817 | } | |
818 | ||
819 | send->s_wr.next = NULL; | |
820 | ||
821 | if (prev) | |
822 | prev->s_wr.next = &send->s_wr; | |
823 | ||
824 | for (j = 0; j < send->s_wr.num_sge && scat != &op->r_sg[op->r_count]; j++) { | |
825 | len = ib_sg_dma_len(ic->i_cm_id->device, scat); | |
826 | send->s_sge[j].addr = | |
827 | ib_sg_dma_address(ic->i_cm_id->device, scat); | |
828 | send->s_sge[j].length = len; | |
829 | send->s_sge[j].lkey = ic->i_mr->lkey; | |
830 | ||
831 | sent += len; | |
832 | rdsdebug("ic %p sent %d remote_addr %llu\n", ic, sent, remote_addr); | |
833 | ||
834 | remote_addr += len; | |
835 | scat++; | |
836 | } | |
837 | ||
838 | rdsdebug("send %p wr %p num_sge %u next %p\n", send, | |
839 | &send->s_wr, send->s_wr.num_sge, send->s_wr.next); | |
840 | ||
841 | prev = send; | |
842 | if (++send == &ic->i_sends[ic->i_send_ring.w_nr]) | |
843 | send = ic->i_sends; | |
844 | } | |
845 | ||
846 | /* if we finished the message then send completion owns it */ | |
847 | if (scat == &op->r_sg[op->r_count]) | |
848 | prev->s_wr.send_flags = IB_SEND_SIGNALED; | |
849 | ||
850 | if (i < work_alloc) { | |
851 | rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - i); | |
852 | work_alloc = i; | |
853 | } | |
854 | ||
855 | failed_wr = &first->s_wr; | |
856 | ret = ib_post_send(ic->i_cm_id->qp, &first->s_wr, &failed_wr); | |
857 | rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic, | |
858 | first, &first->s_wr, ret, failed_wr); | |
859 | BUG_ON(failed_wr != &first->s_wr); | |
860 | if (ret) { | |
861 | printk(KERN_WARNING "RDS/IB: rdma ib_post_send to %pI4 " | |
862 | "returned %d\n", &conn->c_faddr, ret); | |
863 | rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); | |
864 | goto out; | |
865 | } | |
866 | ||
867 | if (unlikely(failed_wr != &first->s_wr)) { | |
868 | printk(KERN_WARNING "RDS/IB: ib_post_send() rc=%d, but failed_wqe updated!\n", ret); | |
869 | BUG_ON(failed_wr != &first->s_wr); | |
870 | } | |
871 | ||
872 | ||
873 | out: | |
874 | return ret; | |
875 | } | |
876 | ||
877 | void rds_ib_xmit_complete(struct rds_connection *conn) | |
878 | { | |
879 | struct rds_ib_connection *ic = conn->c_transport_data; | |
880 | ||
881 | /* We may have a pending ACK or window update we were unable | |
882 | * to send previously (due to flow control). Try again. */ | |
883 | rds_ib_attempt_ack(ic); | |
884 | } |