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