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e6727f39 UB |
1 | /* |
2 | * Shared Memory Communications over RDMA (SMC-R) and RoCE | |
3 | * | |
4 | * Manage send buffer. | |
5 | * Producer: | |
6 | * Copy user space data into send buffer, if send buffer space available. | |
7 | * Consumer: | |
8 | * Trigger RDMA write into RMBE of peer and send CDC, if RMBE space available. | |
9 | * | |
10 | * Copyright IBM Corp. 2016 | |
11 | * | |
12 | * Author(s): Ursula Braun <ubraun@linux.vnet.ibm.com> | |
13 | */ | |
14 | ||
15 | #include <linux/net.h> | |
16 | #include <linux/rcupdate.h> | |
17 | #include <linux/workqueue.h> | |
c3edc401 IM |
18 | #include <linux/sched/signal.h> |
19 | ||
e6727f39 UB |
20 | #include <net/sock.h> |
21 | ||
22 | #include "smc.h" | |
23 | #include "smc_wr.h" | |
24 | #include "smc_cdc.h" | |
25 | #include "smc_tx.h" | |
26 | ||
27 | /***************************** sndbuf producer *******************************/ | |
28 | ||
29 | /* callback implementation for sk.sk_write_space() | |
30 | * to wakeup sndbuf producers that blocked with smc_tx_wait_memory(). | |
31 | * called under sk_socket lock. | |
32 | */ | |
33 | static void smc_tx_write_space(struct sock *sk) | |
34 | { | |
35 | struct socket *sock = sk->sk_socket; | |
36 | struct smc_sock *smc = smc_sk(sk); | |
37 | struct socket_wq *wq; | |
38 | ||
39 | /* similar to sk_stream_write_space */ | |
40 | if (atomic_read(&smc->conn.sndbuf_space) && sock) { | |
41 | clear_bit(SOCK_NOSPACE, &sock->flags); | |
42 | rcu_read_lock(); | |
43 | wq = rcu_dereference(sk->sk_wq); | |
44 | if (skwq_has_sleeper(wq)) | |
45 | wake_up_interruptible_poll(&wq->wait, | |
46 | POLLOUT | POLLWRNORM | | |
47 | POLLWRBAND); | |
48 | if (wq && wq->fasync_list && !(sk->sk_shutdown & SEND_SHUTDOWN)) | |
49 | sock_wake_async(wq, SOCK_WAKE_SPACE, POLL_OUT); | |
50 | rcu_read_unlock(); | |
51 | } | |
52 | } | |
53 | ||
54 | /* Wakeup sndbuf producers that blocked with smc_tx_wait_memory(). | |
55 | * Cf. tcp_data_snd_check()=>tcp_check_space()=>tcp_new_space(). | |
56 | */ | |
57 | void smc_tx_sndbuf_nonfull(struct smc_sock *smc) | |
58 | { | |
59 | if (smc->sk.sk_socket && | |
60 | test_bit(SOCK_NOSPACE, &smc->sk.sk_socket->flags)) | |
61 | smc->sk.sk_write_space(&smc->sk); | |
62 | } | |
63 | ||
64 | /* blocks sndbuf producer until at least one byte of free space available */ | |
65 | static int smc_tx_wait_memory(struct smc_sock *smc, int flags) | |
66 | { | |
67 | DEFINE_WAIT_FUNC(wait, woken_wake_function); | |
68 | struct smc_connection *conn = &smc->conn; | |
69 | struct sock *sk = &smc->sk; | |
70 | bool noblock; | |
71 | long timeo; | |
72 | int rc = 0; | |
73 | ||
74 | /* similar to sk_stream_wait_memory */ | |
75 | timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); | |
76 | noblock = timeo ? false : true; | |
77 | add_wait_queue(sk_sleep(sk), &wait); | |
78 | while (1) { | |
79 | sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk); | |
80 | if (sk->sk_err || | |
81 | (sk->sk_shutdown & SEND_SHUTDOWN) || | |
82 | conn->local_tx_ctrl.conn_state_flags.peer_done_writing) { | |
83 | rc = -EPIPE; | |
84 | break; | |
85 | } | |
86 | if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) { | |
87 | rc = -ECONNRESET; | |
88 | break; | |
89 | } | |
90 | if (!timeo) { | |
91 | if (noblock) | |
92 | set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); | |
93 | rc = -EAGAIN; | |
94 | break; | |
95 | } | |
96 | if (signal_pending(current)) { | |
97 | rc = sock_intr_errno(timeo); | |
98 | break; | |
99 | } | |
100 | sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk); | |
101 | if (atomic_read(&conn->sndbuf_space)) | |
102 | break; /* at least 1 byte of free space available */ | |
103 | set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); | |
104 | sk->sk_write_pending++; | |
105 | sk_wait_event(sk, &timeo, | |
106 | sk->sk_err || | |
107 | (sk->sk_shutdown & SEND_SHUTDOWN) || | |
108 | smc_cdc_rxed_any_close_or_senddone(conn) || | |
109 | atomic_read(&conn->sndbuf_space), | |
110 | &wait); | |
111 | sk->sk_write_pending--; | |
112 | } | |
113 | remove_wait_queue(sk_sleep(sk), &wait); | |
114 | return rc; | |
115 | } | |
116 | ||
117 | /* sndbuf producer: main API called by socket layer. | |
118 | * called under sock lock. | |
119 | */ | |
120 | int smc_tx_sendmsg(struct smc_sock *smc, struct msghdr *msg, size_t len) | |
121 | { | |
122 | size_t copylen, send_done = 0, send_remaining = len; | |
123 | size_t chunk_len, chunk_off, chunk_len_sum; | |
124 | struct smc_connection *conn = &smc->conn; | |
125 | union smc_host_cursor prep; | |
126 | struct sock *sk = &smc->sk; | |
127 | char *sndbuf_base; | |
128 | int tx_cnt_prep; | |
129 | int writespace; | |
130 | int rc, chunk; | |
131 | ||
132 | /* This should be in poll */ | |
133 | sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk); | |
134 | ||
135 | if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) { | |
136 | rc = -EPIPE; | |
137 | goto out_err; | |
138 | } | |
139 | ||
140 | while (msg_data_left(msg)) { | |
141 | if (sk->sk_state == SMC_INIT) | |
142 | return -ENOTCONN; | |
143 | if (smc->sk.sk_shutdown & SEND_SHUTDOWN || | |
b38d7324 | 144 | (smc->sk.sk_err == ECONNABORTED) || |
e6727f39 UB |
145 | conn->local_tx_ctrl.conn_state_flags.peer_conn_abort) |
146 | return -EPIPE; | |
147 | if (smc_cdc_rxed_any_close(conn)) | |
148 | return send_done ?: -ECONNRESET; | |
149 | ||
150 | if (!atomic_read(&conn->sndbuf_space)) { | |
151 | rc = smc_tx_wait_memory(smc, msg->msg_flags); | |
152 | if (rc) { | |
153 | if (send_done) | |
154 | return send_done; | |
155 | goto out_err; | |
156 | } | |
157 | continue; | |
158 | } | |
159 | ||
160 | /* initialize variables for 1st iteration of subsequent loop */ | |
161 | /* could be just 1 byte, even after smc_tx_wait_memory above */ | |
162 | writespace = atomic_read(&conn->sndbuf_space); | |
163 | /* not more than what user space asked for */ | |
164 | copylen = min_t(size_t, send_remaining, writespace); | |
165 | /* determine start of sndbuf */ | |
166 | sndbuf_base = conn->sndbuf_desc->cpu_addr; | |
167 | smc_curs_write(&prep, | |
168 | smc_curs_read(&conn->tx_curs_prep, conn), | |
169 | conn); | |
170 | tx_cnt_prep = prep.count; | |
171 | /* determine chunks where to write into sndbuf */ | |
172 | /* either unwrapped case, or 1st chunk of wrapped case */ | |
173 | chunk_len = min_t(size_t, | |
174 | copylen, conn->sndbuf_size - tx_cnt_prep); | |
175 | chunk_len_sum = chunk_len; | |
176 | chunk_off = tx_cnt_prep; | |
177 | for (chunk = 0; chunk < 2; chunk++) { | |
178 | rc = memcpy_from_msg(sndbuf_base + chunk_off, | |
179 | msg, chunk_len); | |
180 | if (rc) { | |
181 | if (send_done) | |
182 | return send_done; | |
183 | goto out_err; | |
184 | } | |
185 | send_done += chunk_len; | |
186 | send_remaining -= chunk_len; | |
187 | ||
188 | if (chunk_len_sum == copylen) | |
189 | break; /* either on 1st or 2nd iteration */ | |
190 | /* prepare next (== 2nd) iteration */ | |
191 | chunk_len = copylen - chunk_len; /* remainder */ | |
192 | chunk_len_sum += chunk_len; | |
193 | chunk_off = 0; /* modulo offset in send ring buffer */ | |
194 | } | |
195 | /* update cursors */ | |
196 | smc_curs_add(conn->sndbuf_size, &prep, copylen); | |
197 | smc_curs_write(&conn->tx_curs_prep, | |
198 | smc_curs_read(&prep, conn), | |
199 | conn); | |
200 | /* increased in send tasklet smc_cdc_tx_handler() */ | |
201 | smp_mb__before_atomic(); | |
202 | atomic_sub(copylen, &conn->sndbuf_space); | |
203 | /* guarantee 0 <= sndbuf_space <= sndbuf_size */ | |
204 | smp_mb__after_atomic(); | |
205 | /* since we just produced more new data into sndbuf, | |
206 | * trigger sndbuf consumer: RDMA write into peer RMBE and CDC | |
207 | */ | |
208 | smc_tx_sndbuf_nonempty(conn); | |
209 | } /* while (msg_data_left(msg)) */ | |
210 | ||
211 | return send_done; | |
212 | ||
213 | out_err: | |
214 | rc = sk_stream_error(sk, msg->msg_flags, rc); | |
215 | /* make sure we wake any epoll edge trigger waiter */ | |
216 | if (unlikely(rc == -EAGAIN)) | |
217 | sk->sk_write_space(sk); | |
218 | return rc; | |
219 | } | |
220 | ||
221 | /***************************** sndbuf consumer *******************************/ | |
222 | ||
223 | /* sndbuf consumer: actual data transfer of one target chunk with RDMA write */ | |
224 | static int smc_tx_rdma_write(struct smc_connection *conn, int peer_rmbe_offset, | |
225 | int num_sges, struct ib_sge sges[]) | |
226 | { | |
227 | struct smc_link_group *lgr = conn->lgr; | |
228 | struct ib_send_wr *failed_wr = NULL; | |
229 | struct ib_rdma_wr rdma_wr; | |
230 | struct smc_link *link; | |
231 | int rc; | |
232 | ||
233 | memset(&rdma_wr, 0, sizeof(rdma_wr)); | |
234 | link = &lgr->lnk[SMC_SINGLE_LINK]; | |
235 | rdma_wr.wr.wr_id = smc_wr_tx_get_next_wr_id(link); | |
236 | rdma_wr.wr.sg_list = sges; | |
237 | rdma_wr.wr.num_sge = num_sges; | |
238 | rdma_wr.wr.opcode = IB_WR_RDMA_WRITE; | |
239 | rdma_wr.remote_addr = | |
240 | lgr->rtokens[conn->rtoken_idx][SMC_SINGLE_LINK].dma_addr + | |
241 | /* RMBE within RMB */ | |
242 | ((conn->peer_conn_idx - 1) * conn->peer_rmbe_size) + | |
243 | /* offset within RMBE */ | |
244 | peer_rmbe_offset; | |
245 | rdma_wr.rkey = lgr->rtokens[conn->rtoken_idx][SMC_SINGLE_LINK].rkey; | |
246 | rc = ib_post_send(link->roce_qp, &rdma_wr.wr, &failed_wr); | |
247 | if (rc) | |
248 | conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1; | |
249 | return rc; | |
250 | } | |
251 | ||
252 | /* sndbuf consumer */ | |
253 | static inline void smc_tx_advance_cursors(struct smc_connection *conn, | |
254 | union smc_host_cursor *prod, | |
255 | union smc_host_cursor *sent, | |
256 | size_t len) | |
257 | { | |
258 | smc_curs_add(conn->peer_rmbe_size, prod, len); | |
259 | /* increased in recv tasklet smc_cdc_msg_rcv() */ | |
260 | smp_mb__before_atomic(); | |
261 | /* data in flight reduces usable snd_wnd */ | |
262 | atomic_sub(len, &conn->peer_rmbe_space); | |
263 | /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */ | |
264 | smp_mb__after_atomic(); | |
265 | smc_curs_add(conn->sndbuf_size, sent, len); | |
266 | } | |
267 | ||
268 | /* sndbuf consumer: prepare all necessary (src&dst) chunks of data transmit; | |
269 | * usable snd_wnd as max transmit | |
270 | */ | |
271 | static int smc_tx_rdma_writes(struct smc_connection *conn) | |
272 | { | |
273 | size_t src_off, src_len, dst_off, dst_len; /* current chunk values */ | |
274 | size_t len, dst_len_sum, src_len_sum, dstchunk, srcchunk; | |
275 | union smc_host_cursor sent, prep, prod, cons; | |
276 | struct ib_sge sges[SMC_IB_MAX_SEND_SGE]; | |
277 | struct smc_link_group *lgr = conn->lgr; | |
278 | int to_send, rmbespace; | |
279 | struct smc_link *link; | |
280 | int num_sges; | |
281 | int rc; | |
282 | ||
283 | /* source: sndbuf */ | |
284 | smc_curs_write(&sent, smc_curs_read(&conn->tx_curs_sent, conn), conn); | |
285 | smc_curs_write(&prep, smc_curs_read(&conn->tx_curs_prep, conn), conn); | |
286 | /* cf. wmem_alloc - (snd_max - snd_una) */ | |
287 | to_send = smc_curs_diff(conn->sndbuf_size, &sent, &prep); | |
288 | if (to_send <= 0) | |
289 | return 0; | |
290 | ||
291 | /* destination: RMBE */ | |
292 | /* cf. snd_wnd */ | |
293 | rmbespace = atomic_read(&conn->peer_rmbe_space); | |
294 | if (rmbespace <= 0) | |
295 | return 0; | |
296 | smc_curs_write(&prod, | |
297 | smc_curs_read(&conn->local_tx_ctrl.prod, conn), | |
298 | conn); | |
299 | smc_curs_write(&cons, | |
300 | smc_curs_read(&conn->local_rx_ctrl.cons, conn), | |
301 | conn); | |
302 | ||
303 | /* if usable snd_wnd closes ask peer to advertise once it opens again */ | |
304 | conn->local_tx_ctrl.prod_flags.write_blocked = (to_send >= rmbespace); | |
305 | /* cf. usable snd_wnd */ | |
306 | len = min(to_send, rmbespace); | |
307 | ||
308 | /* initialize variables for first iteration of subsequent nested loop */ | |
309 | link = &lgr->lnk[SMC_SINGLE_LINK]; | |
310 | dst_off = prod.count; | |
311 | if (prod.wrap == cons.wrap) { | |
312 | /* the filled destination area is unwrapped, | |
313 | * hence the available free destination space is wrapped | |
314 | * and we need 2 destination chunks of sum len; start with 1st | |
315 | * which is limited by what's available in sndbuf | |
316 | */ | |
317 | dst_len = min_t(size_t, | |
318 | conn->peer_rmbe_size - prod.count, len); | |
319 | } else { | |
320 | /* the filled destination area is wrapped, | |
321 | * hence the available free destination space is unwrapped | |
322 | * and we need a single destination chunk of entire len | |
323 | */ | |
324 | dst_len = len; | |
325 | } | |
326 | dst_len_sum = dst_len; | |
327 | src_off = sent.count; | |
328 | /* dst_len determines the maximum src_len */ | |
329 | if (sent.count + dst_len <= conn->sndbuf_size) { | |
330 | /* unwrapped src case: single chunk of entire dst_len */ | |
331 | src_len = dst_len; | |
332 | } else { | |
333 | /* wrapped src case: 2 chunks of sum dst_len; start with 1st: */ | |
334 | src_len = conn->sndbuf_size - sent.count; | |
335 | } | |
336 | src_len_sum = src_len; | |
337 | for (dstchunk = 0; dstchunk < 2; dstchunk++) { | |
338 | num_sges = 0; | |
339 | for (srcchunk = 0; srcchunk < 2; srcchunk++) { | |
340 | sges[srcchunk].addr = | |
341 | conn->sndbuf_desc->dma_addr[SMC_SINGLE_LINK] + | |
342 | src_off; | |
343 | sges[srcchunk].length = src_len; | |
344 | sges[srcchunk].lkey = link->roce_pd->local_dma_lkey; | |
345 | num_sges++; | |
346 | src_off += src_len; | |
347 | if (src_off >= conn->sndbuf_size) | |
348 | src_off -= conn->sndbuf_size; | |
349 | /* modulo in send ring */ | |
350 | if (src_len_sum == dst_len) | |
351 | break; /* either on 1st or 2nd iteration */ | |
352 | /* prepare next (== 2nd) iteration */ | |
353 | src_len = dst_len - src_len; /* remainder */ | |
354 | src_len_sum += src_len; | |
355 | } | |
356 | rc = smc_tx_rdma_write(conn, dst_off, num_sges, sges); | |
357 | if (rc) | |
358 | return rc; | |
359 | if (dst_len_sum == len) | |
360 | break; /* either on 1st or 2nd iteration */ | |
361 | /* prepare next (== 2nd) iteration */ | |
362 | dst_off = 0; /* modulo offset in RMBE ring buffer */ | |
363 | dst_len = len - dst_len; /* remainder */ | |
364 | dst_len_sum += dst_len; | |
365 | src_len = min_t(int, | |
366 | dst_len, conn->sndbuf_size - sent.count); | |
367 | src_len_sum = src_len; | |
368 | } | |
369 | ||
370 | smc_tx_advance_cursors(conn, &prod, &sent, len); | |
371 | /* update connection's cursors with advanced local cursors */ | |
372 | smc_curs_write(&conn->local_tx_ctrl.prod, | |
373 | smc_curs_read(&prod, conn), | |
374 | conn); | |
375 | /* dst: peer RMBE */ | |
376 | smc_curs_write(&conn->tx_curs_sent, | |
377 | smc_curs_read(&sent, conn), | |
378 | conn); | |
379 | /* src: local sndbuf */ | |
380 | ||
381 | return 0; | |
382 | } | |
383 | ||
384 | /* Wakeup sndbuf consumers from any context (IRQ or process) | |
385 | * since there is more data to transmit; usable snd_wnd as max transmit | |
386 | */ | |
387 | int smc_tx_sndbuf_nonempty(struct smc_connection *conn) | |
388 | { | |
389 | struct smc_cdc_tx_pend *pend; | |
390 | struct smc_wr_buf *wr_buf; | |
391 | int rc; | |
392 | ||
393 | spin_lock_bh(&conn->send_lock); | |
394 | rc = smc_cdc_get_free_slot(&conn->lgr->lnk[SMC_SINGLE_LINK], &wr_buf, | |
395 | &pend); | |
396 | if (rc < 0) { | |
397 | if (rc == -EBUSY) { | |
b38d7324 UB |
398 | struct smc_sock *smc = |
399 | container_of(conn, struct smc_sock, conn); | |
400 | ||
401 | if (smc->sk.sk_err == ECONNABORTED) { | |
402 | rc = sock_error(&smc->sk); | |
403 | goto out_unlock; | |
404 | } | |
e6727f39 UB |
405 | rc = 0; |
406 | schedule_work(&conn->tx_work); | |
407 | } | |
408 | goto out_unlock; | |
409 | } | |
410 | ||
411 | rc = smc_tx_rdma_writes(conn); | |
412 | if (rc) { | |
413 | smc_wr_tx_put_slot(&conn->lgr->lnk[SMC_SINGLE_LINK], | |
414 | (struct smc_wr_tx_pend_priv *)pend); | |
415 | goto out_unlock; | |
416 | } | |
417 | ||
418 | rc = smc_cdc_msg_send(conn, wr_buf, pend); | |
419 | ||
420 | out_unlock: | |
421 | spin_unlock_bh(&conn->send_lock); | |
422 | return rc; | |
423 | } | |
424 | ||
425 | /* Wakeup sndbuf consumers from process context | |
426 | * since there is more data to transmit | |
427 | */ | |
428 | static void smc_tx_work(struct work_struct *work) | |
429 | { | |
430 | struct smc_connection *conn = container_of(work, | |
431 | struct smc_connection, | |
432 | tx_work); | |
433 | struct smc_sock *smc = container_of(conn, struct smc_sock, conn); | |
434 | ||
435 | lock_sock(&smc->sk); | |
436 | smc_tx_sndbuf_nonempty(conn); | |
437 | release_sock(&smc->sk); | |
438 | } | |
439 | ||
952310cc UB |
440 | void smc_tx_consumer_update(struct smc_connection *conn) |
441 | { | |
442 | union smc_host_cursor cfed, cons; | |
443 | struct smc_cdc_tx_pend *pend; | |
444 | struct smc_wr_buf *wr_buf; | |
445 | int to_confirm, rc; | |
446 | ||
447 | smc_curs_write(&cons, | |
448 | smc_curs_read(&conn->local_tx_ctrl.cons, conn), | |
449 | conn); | |
450 | smc_curs_write(&cfed, | |
451 | smc_curs_read(&conn->rx_curs_confirmed, conn), | |
452 | conn); | |
453 | to_confirm = smc_curs_diff(conn->rmbe_size, &cfed, &cons); | |
454 | ||
455 | if (conn->local_rx_ctrl.prod_flags.cons_curs_upd_req || | |
456 | ((to_confirm > conn->rmbe_update_limit) && | |
457 | ((to_confirm > (conn->rmbe_size / 2)) || | |
458 | conn->local_rx_ctrl.prod_flags.write_blocked))) { | |
459 | rc = smc_cdc_get_free_slot(&conn->lgr->lnk[SMC_SINGLE_LINK], | |
460 | &wr_buf, &pend); | |
461 | if (!rc) | |
462 | rc = smc_cdc_msg_send(conn, wr_buf, pend); | |
463 | if (rc < 0) { | |
464 | schedule_work(&conn->tx_work); | |
465 | return; | |
466 | } | |
467 | smc_curs_write(&conn->rx_curs_confirmed, | |
468 | smc_curs_read(&conn->local_tx_ctrl.cons, conn), | |
469 | conn); | |
470 | conn->local_rx_ctrl.prod_flags.cons_curs_upd_req = 0; | |
471 | } | |
472 | if (conn->local_rx_ctrl.prod_flags.write_blocked && | |
473 | !atomic_read(&conn->bytes_to_rcv)) | |
474 | conn->local_rx_ctrl.prod_flags.write_blocked = 0; | |
475 | } | |
476 | ||
e6727f39 UB |
477 | /***************************** send initialize *******************************/ |
478 | ||
479 | /* Initialize send properties on connection establishment. NB: not __init! */ | |
480 | void smc_tx_init(struct smc_sock *smc) | |
481 | { | |
482 | smc->sk.sk_write_space = smc_tx_write_space; | |
483 | INIT_WORK(&smc->conn.tx_work, smc_tx_work); | |
484 | spin_lock_init(&smc->conn.send_lock); | |
485 | } |