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