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 if (!smc_wr_tx_link_hold(link)) 154 return -ENOLINK; 155 rc = smc_cdc_get_free_slot(conn, link, &wr_buf, NULL, &pend); 156 if (rc) 157 goto put_out; 158 159 spin_lock_bh(&conn->send_lock); 160 if (link != conn->lnk) { 161 /* link of connection changed, try again one time*/ 162 spin_unlock_bh(&conn->send_lock); 163 smc_wr_tx_put_slot(link, 164 (struct smc_wr_tx_pend_priv *)pend); 165 smc_wr_tx_link_put(link); 166 if (again) 167 return -ENOLINK; 168 again = true; 169 goto again; 170 } 171 rc = smc_cdc_msg_send(conn, wr_buf, pend); 172 spin_unlock_bh(&conn->send_lock); 173 put_out: 174 smc_wr_tx_link_put(link); 175 return rc; 176 } 177 178 int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn) 179 { 180 int rc; 181 182 if (!conn->lgr || (conn->lgr->is_smcd && conn->lgr->peer_shutdown)) 183 return -EPIPE; 184 185 if (conn->lgr->is_smcd) { 186 spin_lock_bh(&conn->send_lock); 187 rc = smcd_cdc_msg_send(conn); 188 spin_unlock_bh(&conn->send_lock); 189 } else { 190 rc = smcr_cdc_get_slot_and_msg_send(conn); 191 } 192 193 return rc; 194 } 195 196 static bool smc_cdc_tx_filter(struct smc_wr_tx_pend_priv *tx_pend, 197 unsigned long data) 198 { 199 struct smc_connection *conn = (struct smc_connection *)data; 200 struct smc_cdc_tx_pend *cdc_pend = 201 (struct smc_cdc_tx_pend *)tx_pend; 202 203 return cdc_pend->conn == conn; 204 } 205 206 static void smc_cdc_tx_dismisser(struct smc_wr_tx_pend_priv *tx_pend) 207 { 208 struct smc_cdc_tx_pend *cdc_pend = 209 (struct smc_cdc_tx_pend *)tx_pend; 210 211 cdc_pend->conn = NULL; 212 } 213 214 void smc_cdc_tx_dismiss_slots(struct smc_connection *conn) 215 { 216 struct smc_link *link = conn->lnk; 217 218 smc_wr_tx_dismiss_slots(link, SMC_CDC_MSG_TYPE, 219 smc_cdc_tx_filter, smc_cdc_tx_dismisser, 220 (unsigned long)conn); 221 } 222 223 /* Send a SMC-D CDC header. 224 * This increments the free space available in our send buffer. 225 * Also update the confirmed receive buffer with what was sent to the peer. 226 */ 227 int smcd_cdc_msg_send(struct smc_connection *conn) 228 { 229 struct smc_sock *smc = container_of(conn, struct smc_sock, conn); 230 union smc_host_cursor curs; 231 struct smcd_cdc_msg cdc; 232 int rc, diff; 233 234 memset(&cdc, 0, sizeof(cdc)); 235 cdc.common.type = SMC_CDC_MSG_TYPE; 236 curs.acurs.counter = atomic64_read(&conn->local_tx_ctrl.prod.acurs); 237 cdc.prod.wrap = curs.wrap; 238 cdc.prod.count = curs.count; 239 curs.acurs.counter = atomic64_read(&conn->local_tx_ctrl.cons.acurs); 240 cdc.cons.wrap = curs.wrap; 241 cdc.cons.count = curs.count; 242 cdc.cons.prod_flags = conn->local_tx_ctrl.prod_flags; 243 cdc.cons.conn_state_flags = conn->local_tx_ctrl.conn_state_flags; 244 rc = smcd_tx_ism_write(conn, &cdc, sizeof(cdc), 0, 1); 245 if (rc) 246 return rc; 247 smc_curs_copy(&conn->rx_curs_confirmed, &curs, conn); 248 conn->local_rx_ctrl.prod_flags.cons_curs_upd_req = 0; 249 /* Calculate transmitted data and increment free send buffer space */ 250 diff = smc_curs_diff(conn->sndbuf_desc->len, &conn->tx_curs_fin, 251 &conn->tx_curs_sent); 252 /* increased by confirmed number of bytes */ 253 smp_mb__before_atomic(); 254 atomic_add(diff, &conn->sndbuf_space); 255 /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */ 256 smp_mb__after_atomic(); 257 smc_curs_copy(&conn->tx_curs_fin, &conn->tx_curs_sent, conn); 258 259 smc_tx_sndbuf_nonfull(smc); 260 return rc; 261 } 262 263 /********************************* receive ***********************************/ 264 265 static inline bool smc_cdc_before(u16 seq1, u16 seq2) 266 { 267 return (s16)(seq1 - seq2) < 0; 268 } 269 270 static void smc_cdc_handle_urg_data_arrival(struct smc_sock *smc, 271 int *diff_prod) 272 { 273 struct smc_connection *conn = &smc->conn; 274 char *base; 275 276 /* new data included urgent business */ 277 smc_curs_copy(&conn->urg_curs, &conn->local_rx_ctrl.prod, conn); 278 conn->urg_state = SMC_URG_VALID; 279 if (!sock_flag(&smc->sk, SOCK_URGINLINE)) 280 /* we'll skip the urgent byte, so don't account for it */ 281 (*diff_prod)--; 282 base = (char *)conn->rmb_desc->cpu_addr + conn->rx_off; 283 if (conn->urg_curs.count) 284 conn->urg_rx_byte = *(base + conn->urg_curs.count - 1); 285 else 286 conn->urg_rx_byte = *(base + conn->rmb_desc->len - 1); 287 sk_send_sigurg(&smc->sk); 288 } 289 290 static void smc_cdc_msg_validate(struct smc_sock *smc, struct smc_cdc_msg *cdc, 291 struct smc_link *link) 292 { 293 struct smc_connection *conn = &smc->conn; 294 u16 recv_seq = ntohs(cdc->seqno); 295 s16 diff; 296 297 /* check that seqnum was seen before */ 298 diff = conn->local_rx_ctrl.seqno - recv_seq; 299 if (diff < 0) { /* diff larger than 0x7fff */ 300 /* drop connection */ 301 conn->out_of_sync = 1; /* prevent any further receives */ 302 spin_lock_bh(&conn->send_lock); 303 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1; 304 conn->lnk = link; 305 spin_unlock_bh(&conn->send_lock); 306 sock_hold(&smc->sk); /* sock_put in abort_work */ 307 if (!queue_work(smc_close_wq, &conn->abort_work)) 308 sock_put(&smc->sk); 309 } 310 } 311 312 static void smc_cdc_msg_recv_action(struct smc_sock *smc, 313 struct smc_cdc_msg *cdc) 314 { 315 union smc_host_cursor cons_old, prod_old; 316 struct smc_connection *conn = &smc->conn; 317 int diff_cons, diff_prod; 318 319 smc_curs_copy(&prod_old, &conn->local_rx_ctrl.prod, conn); 320 smc_curs_copy(&cons_old, &conn->local_rx_ctrl.cons, conn); 321 smc_cdc_msg_to_host(&conn->local_rx_ctrl, cdc, conn); 322 323 diff_cons = smc_curs_diff(conn->peer_rmbe_size, &cons_old, 324 &conn->local_rx_ctrl.cons); 325 if (diff_cons) { 326 /* peer_rmbe_space is decreased during data transfer with RDMA 327 * write 328 */ 329 smp_mb__before_atomic(); 330 atomic_add(diff_cons, &conn->peer_rmbe_space); 331 /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */ 332 smp_mb__after_atomic(); 333 } 334 335 diff_prod = smc_curs_diff(conn->rmb_desc->len, &prod_old, 336 &conn->local_rx_ctrl.prod); 337 if (diff_prod) { 338 if (conn->local_rx_ctrl.prod_flags.urg_data_present) 339 smc_cdc_handle_urg_data_arrival(smc, &diff_prod); 340 /* bytes_to_rcv is decreased in smc_recvmsg */ 341 smp_mb__before_atomic(); 342 atomic_add(diff_prod, &conn->bytes_to_rcv); 343 /* guarantee 0 <= bytes_to_rcv <= rmb_desc->len */ 344 smp_mb__after_atomic(); 345 smc->sk.sk_data_ready(&smc->sk); 346 } else { 347 if (conn->local_rx_ctrl.prod_flags.write_blocked) 348 smc->sk.sk_data_ready(&smc->sk); 349 if (conn->local_rx_ctrl.prod_flags.urg_data_pending) 350 conn->urg_state = SMC_URG_NOTYET; 351 } 352 353 /* trigger sndbuf consumer: RDMA write into peer RMBE and CDC */ 354 if ((diff_cons && smc_tx_prepared_sends(conn)) || 355 conn->local_rx_ctrl.prod_flags.cons_curs_upd_req || 356 conn->local_rx_ctrl.prod_flags.urg_data_pending) 357 smc_tx_sndbuf_nonempty(conn); 358 359 if (diff_cons && conn->urg_tx_pend && 360 atomic_read(&conn->peer_rmbe_space) == conn->peer_rmbe_size) { 361 /* urg data confirmed by peer, indicate we're ready for more */ 362 conn->urg_tx_pend = false; 363 smc->sk.sk_write_space(&smc->sk); 364 } 365 366 if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) { 367 smc->sk.sk_err = ECONNRESET; 368 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1; 369 } 370 if (smc_cdc_rxed_any_close_or_senddone(conn)) { 371 smc->sk.sk_shutdown |= RCV_SHUTDOWN; 372 if (smc->clcsock && smc->clcsock->sk) 373 smc->clcsock->sk->sk_shutdown |= RCV_SHUTDOWN; 374 sock_set_flag(&smc->sk, SOCK_DONE); 375 sock_hold(&smc->sk); /* sock_put in close_work */ 376 if (!queue_work(smc_close_wq, &conn->close_work)) 377 sock_put(&smc->sk); 378 } 379 } 380 381 /* called under tasklet context */ 382 static void smc_cdc_msg_recv(struct smc_sock *smc, struct smc_cdc_msg *cdc) 383 { 384 sock_hold(&smc->sk); 385 bh_lock_sock(&smc->sk); 386 smc_cdc_msg_recv_action(smc, cdc); 387 bh_unlock_sock(&smc->sk); 388 sock_put(&smc->sk); /* no free sk in softirq-context */ 389 } 390 391 /* Schedule a tasklet for this connection. Triggered from the ISM device IRQ 392 * handler to indicate update in the DMBE. 393 * 394 * Context: 395 * - tasklet context 396 */ 397 static void smcd_cdc_rx_tsklet(struct tasklet_struct *t) 398 { 399 struct smc_connection *conn = from_tasklet(conn, t, rx_tsklet); 400 struct smcd_cdc_msg *data_cdc; 401 struct smcd_cdc_msg cdc; 402 struct smc_sock *smc; 403 404 if (!conn || conn->killed) 405 return; 406 407 data_cdc = (struct smcd_cdc_msg *)conn->rmb_desc->cpu_addr; 408 smcd_curs_copy(&cdc.prod, &data_cdc->prod, conn); 409 smcd_curs_copy(&cdc.cons, &data_cdc->cons, conn); 410 smc = container_of(conn, struct smc_sock, conn); 411 smc_cdc_msg_recv(smc, (struct smc_cdc_msg *)&cdc); 412 } 413 414 /* Initialize receive tasklet. Called from ISM device IRQ handler to start 415 * receiver side. 416 */ 417 void smcd_cdc_rx_init(struct smc_connection *conn) 418 { 419 tasklet_setup(&conn->rx_tsklet, smcd_cdc_rx_tsklet); 420 } 421 422 /***************************** init, exit, misc ******************************/ 423 424 static void smc_cdc_rx_handler(struct ib_wc *wc, void *buf) 425 { 426 struct smc_link *link = (struct smc_link *)wc->qp->qp_context; 427 struct smc_cdc_msg *cdc = buf; 428 struct smc_connection *conn; 429 struct smc_link_group *lgr; 430 struct smc_sock *smc; 431 432 if (wc->byte_len < offsetof(struct smc_cdc_msg, reserved)) 433 return; /* short message */ 434 if (cdc->len != SMC_WR_TX_SIZE) 435 return; /* invalid message */ 436 437 /* lookup connection */ 438 lgr = smc_get_lgr(link); 439 read_lock_bh(&lgr->conns_lock); 440 conn = smc_lgr_find_conn(ntohl(cdc->token), lgr); 441 read_unlock_bh(&lgr->conns_lock); 442 if (!conn || conn->out_of_sync) 443 return; 444 smc = container_of(conn, struct smc_sock, conn); 445 446 if (cdc->prod_flags.failover_validation) { 447 smc_cdc_msg_validate(smc, cdc, link); 448 return; 449 } 450 if (smc_cdc_before(ntohs(cdc->seqno), 451 conn->local_rx_ctrl.seqno)) 452 /* received seqno is old */ 453 return; 454 455 smc_cdc_msg_recv(smc, cdc); 456 } 457 458 static struct smc_wr_rx_handler smc_cdc_rx_handlers[] = { 459 { 460 .handler = smc_cdc_rx_handler, 461 .type = SMC_CDC_MSG_TYPE 462 }, 463 { 464 .handler = NULL, 465 } 466 }; 467 468 int __init smc_cdc_init(void) 469 { 470 struct smc_wr_rx_handler *handler; 471 int rc = 0; 472 473 for (handler = smc_cdc_rx_handlers; handler->handler; handler++) { 474 INIT_HLIST_NODE(&handler->list); 475 rc = smc_wr_rx_register_handler(handler); 476 if (rc) 477 break; 478 } 479 return rc; 480 } 481