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