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