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