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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Shared Memory Communications over RDMA (SMC-R) and RoCE
4 *
5 * Connection Data Control (CDC)
6 * handles flow control
7 *
8 * Copyright IBM Corp. 2016
9 *
10 * Author(s): Ursula Braun <ubraun@linux.vnet.ibm.com>
11 */
12
13#include <linux/spinlock.h>
14
15#include "smc.h"
16#include "smc_wr.h"
17#include "smc_cdc.h"
18#include "smc_tx.h"
19#include "smc_rx.h"
20#include "smc_close.h"
21#include "smc_ism.h"
22
23/********************************** send *************************************/
24
25/* handler for send/transmission completion of a CDC msg */
26static void smc_cdc_tx_handler(struct smc_wr_tx_pend_priv *pnd_snd,
27 struct smc_link *link,
28 enum ib_wc_status wc_status)
29{
30 struct smc_cdc_tx_pend *cdcpend = (struct smc_cdc_tx_pend *)pnd_snd;
31 struct smc_connection *conn = cdcpend->conn;
32 struct smc_buf_desc *sndbuf_desc;
33 struct smc_sock *smc;
34 int diff;
35
36 sndbuf_desc = conn->sndbuf_desc;
37 smc = container_of(conn, struct smc_sock, conn);
38 bh_lock_sock(&smc->sk);
39 if (!wc_status && sndbuf_desc) {
40 diff = smc_curs_diff(sndbuf_desc->len,
41 &cdcpend->conn->tx_curs_fin,
42 &cdcpend->cursor);
43 /* sndbuf_space is decreased in smc_sendmsg */
44 smp_mb__before_atomic();
45 atomic_add(diff, &cdcpend->conn->sndbuf_space);
46 /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
47 smp_mb__after_atomic();
48 smc_curs_copy(&conn->tx_curs_fin, &cdcpend->cursor, conn);
49 smc_curs_copy(&conn->local_tx_ctrl_fin, &cdcpend->p_cursor,
50 conn);
51 conn->tx_cdc_seq_fin = cdcpend->ctrl_seq;
52 }
53
54 if (atomic_dec_and_test(&conn->cdc_pend_tx_wr)) {
55 /* If user owns the sock_lock, mark the connection need sending.
56 * User context will later try to send when it release sock_lock
57 * in smc_release_cb()
58 */
59 if (sock_owned_by_user(&smc->sk))
60 conn->tx_in_release_sock = true;
61 else
62 smc_tx_pending(conn);
63
64 if (unlikely(wq_has_sleeper(&conn->cdc_pend_tx_wq)))
65 wake_up(&conn->cdc_pend_tx_wq);
66 }
67 WARN_ON(atomic_read(&conn->cdc_pend_tx_wr) < 0);
68
69 smc_tx_sndbuf_nonfull(smc);
70 bh_unlock_sock(&smc->sk);
71}
72
73int smc_cdc_get_free_slot(struct smc_connection *conn,
74 struct smc_link *link,
75 struct smc_wr_buf **wr_buf,
76 struct smc_rdma_wr **wr_rdma_buf,
77 struct smc_cdc_tx_pend **pend)
78{
79 int rc;
80
81 rc = smc_wr_tx_get_free_slot(link, smc_cdc_tx_handler, wr_buf,
82 wr_rdma_buf,
83 (struct smc_wr_tx_pend_priv **)pend);
84 if (conn->killed) {
85 /* abnormal termination */
86 if (!rc)
87 smc_wr_tx_put_slot(link,
88 (struct smc_wr_tx_pend_priv *)(*pend));
89 rc = -EPIPE;
90 }
91 return rc;
92}
93
94static inline void smc_cdc_add_pending_send(struct smc_connection *conn,
95 struct smc_cdc_tx_pend *pend)
96{
97 BUILD_BUG_ON_MSG(
98 sizeof(struct smc_cdc_msg) > SMC_WR_BUF_SIZE,
99 "must increase SMC_WR_BUF_SIZE to at least sizeof(struct smc_cdc_msg)");
100 BUILD_BUG_ON_MSG(
101 offsetofend(struct smc_cdc_msg, reserved) > SMC_WR_TX_SIZE,
102 "must adapt SMC_WR_TX_SIZE to sizeof(struct smc_cdc_msg); if not all smc_wr upper layer protocols use the same message size any more, must start to set link->wr_tx_sges[i].length on each individual smc_wr_tx_send()");
103 BUILD_BUG_ON_MSG(
104 sizeof(struct smc_cdc_tx_pend) > SMC_WR_TX_PEND_PRIV_SIZE,
105 "must increase SMC_WR_TX_PEND_PRIV_SIZE to at least sizeof(struct smc_cdc_tx_pend)");
106 pend->conn = conn;
107 pend->cursor = conn->tx_curs_sent;
108 pend->p_cursor = conn->local_tx_ctrl.prod;
109 pend->ctrl_seq = conn->tx_cdc_seq;
110}
111
112int smc_cdc_msg_send(struct smc_connection *conn,
113 struct smc_wr_buf *wr_buf,
114 struct smc_cdc_tx_pend *pend)
115{
116 struct smc_link *link = conn->lnk;
117 union smc_host_cursor cfed;
118 int rc;
119
120 smc_cdc_add_pending_send(conn, pend);
121
122 conn->tx_cdc_seq++;
123 conn->local_tx_ctrl.seqno = conn->tx_cdc_seq;
124 smc_host_msg_to_cdc((struct smc_cdc_msg *)wr_buf, conn, &cfed);
125
126 atomic_inc(&conn->cdc_pend_tx_wr);
127 smp_mb__after_atomic(); /* Make sure cdc_pend_tx_wr added before post */
128
129 rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend);
130 if (!rc) {
131 smc_curs_copy(&conn->rx_curs_confirmed, &cfed, conn);
132 conn->local_rx_ctrl.prod_flags.cons_curs_upd_req = 0;
133 } else {
134 conn->tx_cdc_seq--;
135 conn->local_tx_ctrl.seqno = conn->tx_cdc_seq;
136 atomic_dec(&conn->cdc_pend_tx_wr);
137 }
138
139 return rc;
140}
141
142/* send a validation msg indicating the move of a conn to an other QP link */
143int smcr_cdc_msg_send_validation(struct smc_connection *conn,
144 struct smc_cdc_tx_pend *pend,
145 struct smc_wr_buf *wr_buf)
146{
147 struct smc_host_cdc_msg *local = &conn->local_tx_ctrl;
148 struct smc_link *link = conn->lnk;
149 struct smc_cdc_msg *peer;
150 int rc;
151
152 peer = (struct smc_cdc_msg *)wr_buf;
153 peer->common.type = local->common.type;
154 peer->len = local->len;
155 peer->seqno = htons(conn->tx_cdc_seq_fin); /* seqno last compl. tx */
156 peer->token = htonl(local->token);
157 peer->prod_flags.failover_validation = 1;
158
159 /* We need to set pend->conn here to make sure smc_cdc_tx_handler()
160 * can handle properly
161 */
162 smc_cdc_add_pending_send(conn, pend);
163
164 atomic_inc(&conn->cdc_pend_tx_wr);
165 smp_mb__after_atomic(); /* Make sure cdc_pend_tx_wr added before post */
166
167 rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend);
168 if (unlikely(rc))
169 atomic_dec(&conn->cdc_pend_tx_wr);
170
171 return rc;
172}
173
174static int smcr_cdc_get_slot_and_msg_send(struct smc_connection *conn)
175{
176 struct smc_cdc_tx_pend *pend;
177 struct smc_wr_buf *wr_buf;
178 struct smc_link *link;
179 bool again = false;
180 int rc;
181
182again:
183 link = conn->lnk;
184 if (!smc_wr_tx_link_hold(link))
185 return -ENOLINK;
186 rc = smc_cdc_get_free_slot(conn, link, &wr_buf, NULL, &pend);
187 if (rc)
188 goto put_out;
189
190 spin_lock_bh(&conn->send_lock);
191 if (link != conn->lnk) {
192 /* link of connection changed, try again one time*/
193 spin_unlock_bh(&conn->send_lock);
194 smc_wr_tx_put_slot(link,
195 (struct smc_wr_tx_pend_priv *)pend);
196 smc_wr_tx_link_put(link);
197 if (again)
198 return -ENOLINK;
199 again = true;
200 goto again;
201 }
202 rc = smc_cdc_msg_send(conn, wr_buf, pend);
203 spin_unlock_bh(&conn->send_lock);
204put_out:
205 smc_wr_tx_link_put(link);
206 return rc;
207}
208
209int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn)
210{
211 int rc;
212
213 if (!smc_conn_lgr_valid(conn) ||
214 (conn->lgr->is_smcd && conn->lgr->peer_shutdown))
215 return -EPIPE;
216
217 if (conn->lgr->is_smcd) {
218 spin_lock_bh(&conn->send_lock);
219 rc = smcd_cdc_msg_send(conn);
220 spin_unlock_bh(&conn->send_lock);
221 } else {
222 rc = smcr_cdc_get_slot_and_msg_send(conn);
223 }
224
225 return rc;
226}
227
228void smc_cdc_wait_pend_tx_wr(struct smc_connection *conn)
229{
230 wait_event(conn->cdc_pend_tx_wq, !atomic_read(&conn->cdc_pend_tx_wr));
231}
232
233/* Send a SMC-D CDC header.
234 * This increments the free space available in our send buffer.
235 * Also update the confirmed receive buffer with what was sent to the peer.
236 */
237int smcd_cdc_msg_send(struct smc_connection *conn)
238{
239 struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
240 union smc_host_cursor curs;
241 struct smcd_cdc_msg cdc;
242 int rc, diff;
243
244 memset(&cdc, 0, sizeof(cdc));
245 cdc.common.type = SMC_CDC_MSG_TYPE;
246 curs.acurs.counter = atomic64_read(&conn->local_tx_ctrl.prod.acurs);
247 cdc.prod.wrap = curs.wrap;
248 cdc.prod.count = curs.count;
249 curs.acurs.counter = atomic64_read(&conn->local_tx_ctrl.cons.acurs);
250 cdc.cons.wrap = curs.wrap;
251 cdc.cons.count = curs.count;
252 cdc.cons.prod_flags = conn->local_tx_ctrl.prod_flags;
253 cdc.cons.conn_state_flags = conn->local_tx_ctrl.conn_state_flags;
254 rc = smcd_tx_ism_write(conn, &cdc, sizeof(cdc), 0, 1);
255 if (rc)
256 return rc;
257 smc_curs_copy(&conn->rx_curs_confirmed, &curs, conn);
258 conn->local_rx_ctrl.prod_flags.cons_curs_upd_req = 0;
259
260 if (smc_ism_support_dmb_nocopy(conn->lgr->smcd))
261 /* if local sndbuf shares the same memory region with
262 * peer DMB, then don't update the tx_curs_fin
263 * and sndbuf_space until peer has consumed the data.
264 */
265 return 0;
266
267 /* Calculate transmitted data and increment free send buffer space */
268 diff = smc_curs_diff(conn->sndbuf_desc->len, &conn->tx_curs_fin,
269 &conn->tx_curs_sent);
270 /* increased by confirmed number of bytes */
271 smp_mb__before_atomic();
272 atomic_add(diff, &conn->sndbuf_space);
273 /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
274 smp_mb__after_atomic();
275 smc_curs_copy(&conn->tx_curs_fin, &conn->tx_curs_sent, conn);
276
277 smc_tx_sndbuf_nonfull(smc);
278 return 0;
279}
280
281/********************************* receive ***********************************/
282
283static inline bool smc_cdc_before(u16 seq1, u16 seq2)
284{
285 return (s16)(seq1 - seq2) < 0;
286}
287
288static void smc_cdc_handle_urg_data_arrival(struct smc_sock *smc,
289 int *diff_prod)
290{
291 struct smc_connection *conn = &smc->conn;
292 char *base;
293
294 /* new data included urgent business */
295 smc_curs_copy(&conn->urg_curs, &conn->local_rx_ctrl.prod, conn);
296 conn->urg_state = SMC_URG_VALID;
297 if (!sock_flag(&smc->sk, SOCK_URGINLINE))
298 /* we'll skip the urgent byte, so don't account for it */
299 (*diff_prod)--;
300 base = (char *)conn->rmb_desc->cpu_addr + conn->rx_off;
301 if (conn->urg_curs.count)
302 conn->urg_rx_byte = *(base + conn->urg_curs.count - 1);
303 else
304 conn->urg_rx_byte = *(base + conn->rmb_desc->len - 1);
305 sk_send_sigurg(&smc->sk);
306}
307
308static void smc_cdc_msg_validate(struct smc_sock *smc, struct smc_cdc_msg *cdc,
309 struct smc_link *link)
310{
311 struct smc_connection *conn = &smc->conn;
312 u16 recv_seq = ntohs(cdc->seqno);
313 s16 diff;
314
315 /* check that seqnum was seen before */
316 diff = conn->local_rx_ctrl.seqno - recv_seq;
317 if (diff < 0) { /* diff larger than 0x7fff */
318 /* drop connection */
319 conn->out_of_sync = 1; /* prevent any further receives */
320 spin_lock_bh(&conn->send_lock);
321 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
322 conn->lnk = link;
323 spin_unlock_bh(&conn->send_lock);
324 sock_hold(&smc->sk); /* sock_put in abort_work */
325 if (!queue_work(smc_close_wq, &conn->abort_work))
326 sock_put(&smc->sk);
327 }
328}
329
330static void smc_cdc_msg_recv_action(struct smc_sock *smc,
331 struct smc_cdc_msg *cdc)
332{
333 union smc_host_cursor cons_old, prod_old;
334 struct smc_connection *conn = &smc->conn;
335 int diff_cons, diff_prod, diff_tx;
336
337 smc_curs_copy(&prod_old, &conn->local_rx_ctrl.prod, conn);
338 smc_curs_copy(&cons_old, &conn->local_rx_ctrl.cons, conn);
339 smc_cdc_msg_to_host(&conn->local_rx_ctrl, cdc, conn);
340
341 diff_cons = smc_curs_diff(conn->peer_rmbe_size, &cons_old,
342 &conn->local_rx_ctrl.cons);
343 if (diff_cons) {
344 /* peer_rmbe_space is decreased during data transfer with RDMA
345 * write
346 */
347 smp_mb__before_atomic();
348 atomic_add(diff_cons, &conn->peer_rmbe_space);
349 /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */
350 smp_mb__after_atomic();
351
352 /* if local sndbuf shares the same memory region with
353 * peer RMB, then update tx_curs_fin and sndbuf_space
354 * here since peer has already consumed the data.
355 */
356 if (conn->lgr->is_smcd &&
357 smc_ism_support_dmb_nocopy(conn->lgr->smcd)) {
358 /* Calculate consumed data and
359 * increment free send buffer space.
360 */
361 diff_tx = smc_curs_diff(conn->sndbuf_desc->len,
362 &conn->tx_curs_fin,
363 &conn->local_rx_ctrl.cons);
364 /* increase local sndbuf space and fin_curs */
365 smp_mb__before_atomic();
366 atomic_add(diff_tx, &conn->sndbuf_space);
367 /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
368 smp_mb__after_atomic();
369 smc_curs_copy(&conn->tx_curs_fin,
370 &conn->local_rx_ctrl.cons, conn);
371
372 smc_tx_sndbuf_nonfull(smc);
373 }
374 }
375
376 diff_prod = smc_curs_diff(conn->rmb_desc->len, &prod_old,
377 &conn->local_rx_ctrl.prod);
378 if (diff_prod) {
379 if (conn->local_rx_ctrl.prod_flags.urg_data_present)
380 smc_cdc_handle_urg_data_arrival(smc, &diff_prod);
381 /* bytes_to_rcv is decreased in smc_recvmsg */
382 smp_mb__before_atomic();
383 atomic_add(diff_prod, &conn->bytes_to_rcv);
384 /* guarantee 0 <= bytes_to_rcv <= rmb_desc->len */
385 smp_mb__after_atomic();
386 smc->sk.sk_data_ready(&smc->sk);
387 } else {
388 if (conn->local_rx_ctrl.prod_flags.write_blocked)
389 smc->sk.sk_data_ready(&smc->sk);
390 if (conn->local_rx_ctrl.prod_flags.urg_data_pending)
391 conn->urg_state = SMC_URG_NOTYET;
392 }
393
394 /* trigger sndbuf consumer: RDMA write into peer RMBE and CDC */
395 if ((diff_cons && smc_tx_prepared_sends(conn)) ||
396 conn->local_rx_ctrl.prod_flags.cons_curs_upd_req ||
397 conn->local_rx_ctrl.prod_flags.urg_data_pending) {
398 if (!sock_owned_by_user(&smc->sk))
399 smc_tx_pending(conn);
400 else
401 conn->tx_in_release_sock = true;
402 }
403
404 if (diff_cons && conn->urg_tx_pend &&
405 atomic_read(&conn->peer_rmbe_space) == conn->peer_rmbe_size) {
406 /* urg data confirmed by peer, indicate we're ready for more */
407 conn->urg_tx_pend = false;
408 smc->sk.sk_write_space(&smc->sk);
409 }
410
411 if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) {
412 smc->sk.sk_err = ECONNRESET;
413 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
414 }
415 if (smc_cdc_rxed_any_close_or_senddone(conn)) {
416 smc->sk.sk_shutdown |= RCV_SHUTDOWN;
417 if (smc->clcsock && smc->clcsock->sk)
418 smc->clcsock->sk->sk_shutdown |= RCV_SHUTDOWN;
419 smc_sock_set_flag(&smc->sk, SOCK_DONE);
420 sock_hold(&smc->sk); /* sock_put in close_work */
421 if (!queue_work(smc_close_wq, &conn->close_work))
422 sock_put(&smc->sk);
423 }
424}
425
426/* called under tasklet context */
427static void smc_cdc_msg_recv(struct smc_sock *smc, struct smc_cdc_msg *cdc)
428{
429 sock_hold(&smc->sk);
430 bh_lock_sock(&smc->sk);
431 smc_cdc_msg_recv_action(smc, cdc);
432 bh_unlock_sock(&smc->sk);
433 sock_put(&smc->sk); /* no free sk in softirq-context */
434}
435
436/* Schedule a tasklet for this connection. Triggered from the ISM device IRQ
437 * handler to indicate update in the DMBE.
438 *
439 * Context:
440 * - tasklet context
441 */
442static void smcd_cdc_rx_tsklet(struct tasklet_struct *t)
443{
444 struct smc_connection *conn = from_tasklet(conn, t, rx_tsklet);
445 struct smcd_cdc_msg *data_cdc;
446 struct smcd_cdc_msg cdc;
447 struct smc_sock *smc;
448
449 if (!conn || conn->killed)
450 return;
451
452 data_cdc = (struct smcd_cdc_msg *)conn->rmb_desc->cpu_addr;
453 smcd_curs_copy(&cdc.prod, &data_cdc->prod, conn);
454 smcd_curs_copy(&cdc.cons, &data_cdc->cons, conn);
455 smc = container_of(conn, struct smc_sock, conn);
456 smc_cdc_msg_recv(smc, (struct smc_cdc_msg *)&cdc);
457}
458
459/* Initialize receive tasklet. Called from ISM device IRQ handler to start
460 * receiver side.
461 */
462void smcd_cdc_rx_init(struct smc_connection *conn)
463{
464 tasklet_setup(&conn->rx_tsklet, smcd_cdc_rx_tsklet);
465}
466
467/***************************** init, exit, misc ******************************/
468
469static void smc_cdc_rx_handler(struct ib_wc *wc, void *buf)
470{
471 struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
472 struct smc_cdc_msg *cdc = buf;
473 struct smc_connection *conn;
474 struct smc_link_group *lgr;
475 struct smc_sock *smc;
476
477 if (wc->byte_len < offsetof(struct smc_cdc_msg, reserved))
478 return; /* short message */
479 if (cdc->len != SMC_WR_TX_SIZE)
480 return; /* invalid message */
481
482 /* lookup connection */
483 lgr = smc_get_lgr(link);
484 read_lock_bh(&lgr->conns_lock);
485 conn = smc_lgr_find_conn(ntohl(cdc->token), lgr);
486 read_unlock_bh(&lgr->conns_lock);
487 if (!conn || conn->out_of_sync)
488 return;
489 smc = container_of(conn, struct smc_sock, conn);
490
491 if (cdc->prod_flags.failover_validation) {
492 smc_cdc_msg_validate(smc, cdc, link);
493 return;
494 }
495 if (smc_cdc_before(ntohs(cdc->seqno),
496 conn->local_rx_ctrl.seqno))
497 /* received seqno is old */
498 return;
499
500 smc_cdc_msg_recv(smc, cdc);
501}
502
503static struct smc_wr_rx_handler smc_cdc_rx_handlers[] = {
504 {
505 .handler = smc_cdc_rx_handler,
506 .type = SMC_CDC_MSG_TYPE
507 },
508 {
509 .handler = NULL,
510 }
511};
512
513int __init smc_cdc_init(void)
514{
515 struct smc_wr_rx_handler *handler;
516 int rc = 0;
517
518 for (handler = smc_cdc_rx_handlers; handler->handler; handler++) {
519 INIT_HLIST_NODE(&handler->list);
520 rc = smc_wr_rx_register_handler(handler);
521 if (rc)
522 break;
523 }
524 return rc;
525}