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