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 struct smc_cdc_tx_pend { 25 struct smc_connection *conn; /* socket connection */ 26 union smc_host_cursor cursor; /* tx sndbuf cursor sent */ 27 union smc_host_cursor p_cursor; /* rx RMBE cursor produced */ 28 u16 ctrl_seq; /* conn. tx sequence # */ 29 }; 30 31 /* handler for send/transmission completion of a CDC msg */ 32 static void smc_cdc_tx_handler(struct smc_wr_tx_pend_priv *pnd_snd, 33 struct smc_link *link, 34 enum ib_wc_status wc_status) 35 { 36 struct smc_cdc_tx_pend *cdcpend = (struct smc_cdc_tx_pend *)pnd_snd; 37 struct smc_connection *conn = cdcpend->conn; 38 struct smc_sock *smc; 39 int diff; 40 41 if (!conn) 42 /* already dismissed */ 43 return; 44 45 smc = container_of(conn, struct smc_sock, conn); 46 bh_lock_sock(&smc->sk); 47 if (!wc_status) { 48 diff = smc_curs_diff(cdcpend->conn->sndbuf_desc->len, 49 &cdcpend->conn->tx_curs_fin, 50 &cdcpend->cursor); 51 /* sndbuf_space is decreased in smc_sendmsg */ 52 smp_mb__before_atomic(); 53 atomic_add(diff, &cdcpend->conn->sndbuf_space); 54 /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */ 55 smp_mb__after_atomic(); 56 smc_curs_copy(&conn->tx_curs_fin, &cdcpend->cursor, conn); 57 } 58 smc_tx_sndbuf_nonfull(smc); 59 bh_unlock_sock(&smc->sk); 60 } 61 62 int smc_cdc_get_free_slot(struct smc_connection *conn, 63 struct smc_wr_buf **wr_buf, 64 struct smc_cdc_tx_pend **pend) 65 { 66 struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK]; 67 int rc; 68 69 rc = smc_wr_tx_get_free_slot(link, smc_cdc_tx_handler, wr_buf, 70 (struct smc_wr_tx_pend_priv **)pend); 71 if (!conn->alert_token_local) 72 /* abnormal termination */ 73 rc = -EPIPE; 74 return rc; 75 } 76 77 static inline void smc_cdc_add_pending_send(struct smc_connection *conn, 78 struct smc_cdc_tx_pend *pend) 79 { 80 BUILD_BUG_ON_MSG( 81 sizeof(struct smc_cdc_msg) > SMC_WR_BUF_SIZE, 82 "must increase SMC_WR_BUF_SIZE to at least sizeof(struct smc_cdc_msg)"); 83 BUILD_BUG_ON_MSG( 84 sizeof(struct smc_cdc_msg) != SMC_WR_TX_SIZE, 85 "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()"); 86 BUILD_BUG_ON_MSG( 87 sizeof(struct smc_cdc_tx_pend) > SMC_WR_TX_PEND_PRIV_SIZE, 88 "must increase SMC_WR_TX_PEND_PRIV_SIZE to at least sizeof(struct smc_cdc_tx_pend)"); 89 pend->conn = conn; 90 pend->cursor = conn->tx_curs_sent; 91 pend->p_cursor = conn->local_tx_ctrl.prod; 92 pend->ctrl_seq = conn->tx_cdc_seq; 93 } 94 95 int smc_cdc_msg_send(struct smc_connection *conn, 96 struct smc_wr_buf *wr_buf, 97 struct smc_cdc_tx_pend *pend) 98 { 99 struct smc_link *link; 100 int rc; 101 102 link = &conn->lgr->lnk[SMC_SINGLE_LINK]; 103 104 smc_cdc_add_pending_send(conn, pend); 105 106 conn->tx_cdc_seq++; 107 conn->local_tx_ctrl.seqno = conn->tx_cdc_seq; 108 smc_host_msg_to_cdc((struct smc_cdc_msg *)wr_buf, 109 &conn->local_tx_ctrl, conn); 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, 113 &conn->local_tx_ctrl.cons, conn); 114 115 return rc; 116 } 117 118 static int smcr_cdc_get_slot_and_msg_send(struct smc_connection *conn) 119 { 120 struct smc_cdc_tx_pend *pend; 121 struct smc_wr_buf *wr_buf; 122 int rc; 123 124 rc = smc_cdc_get_free_slot(conn, &wr_buf, &pend); 125 if (rc) 126 return rc; 127 128 return smc_cdc_msg_send(conn, wr_buf, pend); 129 } 130 131 int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn) 132 { 133 int rc; 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->lgr->lnk[SMC_SINGLE_LINK]; 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 struct smcd_cdc_msg cdc; 181 int rc, diff; 182 183 memset(&cdc, 0, sizeof(cdc)); 184 cdc.common.type = SMC_CDC_MSG_TYPE; 185 cdc.prod_wrap = conn->local_tx_ctrl.prod.wrap; 186 cdc.prod_count = conn->local_tx_ctrl.prod.count; 187 188 cdc.cons_wrap = conn->local_tx_ctrl.cons.wrap; 189 cdc.cons_count = conn->local_tx_ctrl.cons.count; 190 cdc.prod_flags = conn->local_tx_ctrl.prod_flags; 191 cdc.conn_state_flags = conn->local_tx_ctrl.conn_state_flags; 192 rc = smcd_tx_ism_write(conn, &cdc, sizeof(cdc), 0, 1); 193 if (rc) 194 return rc; 195 smc_curs_copy(&conn->rx_curs_confirmed, &conn->local_tx_ctrl.cons, 196 conn); 197 /* Calculate transmitted data and increment free send buffer space */ 198 diff = smc_curs_diff(conn->sndbuf_desc->len, &conn->tx_curs_fin, 199 &conn->tx_curs_sent); 200 /* increased by confirmed number of bytes */ 201 smp_mb__before_atomic(); 202 atomic_add(diff, &conn->sndbuf_space); 203 /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */ 204 smp_mb__after_atomic(); 205 smc_curs_copy(&conn->tx_curs_fin, &conn->tx_curs_sent, conn); 206 207 smc_tx_sndbuf_nonfull(smc); 208 return rc; 209 } 210 211 /********************************* receive ***********************************/ 212 213 static inline bool smc_cdc_before(u16 seq1, u16 seq2) 214 { 215 return (s16)(seq1 - seq2) < 0; 216 } 217 218 static void smc_cdc_handle_urg_data_arrival(struct smc_sock *smc, 219 int *diff_prod) 220 { 221 struct smc_connection *conn = &smc->conn; 222 char *base; 223 224 /* new data included urgent business */ 225 smc_curs_copy(&conn->urg_curs, &conn->local_rx_ctrl.prod, conn); 226 conn->urg_state = SMC_URG_VALID; 227 if (!sock_flag(&smc->sk, SOCK_URGINLINE)) 228 /* we'll skip the urgent byte, so don't account for it */ 229 (*diff_prod)--; 230 base = (char *)conn->rmb_desc->cpu_addr + conn->rx_off; 231 if (conn->urg_curs.count) 232 conn->urg_rx_byte = *(base + conn->urg_curs.count - 1); 233 else 234 conn->urg_rx_byte = *(base + conn->rmb_desc->len - 1); 235 sk_send_sigurg(&smc->sk); 236 } 237 238 static void smc_cdc_msg_recv_action(struct smc_sock *smc, 239 struct smc_cdc_msg *cdc) 240 { 241 union smc_host_cursor cons_old, prod_old; 242 struct smc_connection *conn = &smc->conn; 243 int diff_cons, diff_prod; 244 245 smc_curs_copy(&prod_old, &conn->local_rx_ctrl.prod, conn); 246 smc_curs_copy(&cons_old, &conn->local_rx_ctrl.cons, conn); 247 smc_cdc_msg_to_host(&conn->local_rx_ctrl, cdc, conn); 248 249 diff_cons = smc_curs_diff(conn->peer_rmbe_size, &cons_old, 250 &conn->local_rx_ctrl.cons); 251 if (diff_cons) { 252 /* peer_rmbe_space is decreased during data transfer with RDMA 253 * write 254 */ 255 smp_mb__before_atomic(); 256 atomic_add(diff_cons, &conn->peer_rmbe_space); 257 /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */ 258 smp_mb__after_atomic(); 259 } 260 261 diff_prod = smc_curs_diff(conn->rmb_desc->len, &prod_old, 262 &conn->local_rx_ctrl.prod); 263 if (diff_prod) { 264 if (conn->local_rx_ctrl.prod_flags.urg_data_present) 265 smc_cdc_handle_urg_data_arrival(smc, &diff_prod); 266 /* bytes_to_rcv is decreased in smc_recvmsg */ 267 smp_mb__before_atomic(); 268 atomic_add(diff_prod, &conn->bytes_to_rcv); 269 /* guarantee 0 <= bytes_to_rcv <= rmb_desc->len */ 270 smp_mb__after_atomic(); 271 smc->sk.sk_data_ready(&smc->sk); 272 } else { 273 if (conn->local_rx_ctrl.prod_flags.write_blocked || 274 conn->local_rx_ctrl.prod_flags.cons_curs_upd_req || 275 conn->local_rx_ctrl.prod_flags.urg_data_pending) { 276 if (conn->local_rx_ctrl.prod_flags.urg_data_pending) 277 conn->urg_state = SMC_URG_NOTYET; 278 /* force immediate tx of current consumer cursor, but 279 * under send_lock to guarantee arrival in seqno-order 280 */ 281 smc_tx_sndbuf_nonempty(conn); 282 } 283 } 284 285 /* piggy backed tx info */ 286 /* trigger sndbuf consumer: RDMA write into peer RMBE and CDC */ 287 if (diff_cons && smc_tx_prepared_sends(conn)) { 288 smc_tx_sndbuf_nonempty(conn); 289 /* trigger socket release if connection closed */ 290 smc_close_wake_tx_prepared(smc); 291 } 292 if (diff_cons && conn->urg_tx_pend && 293 atomic_read(&conn->peer_rmbe_space) == conn->peer_rmbe_size) { 294 /* urg data confirmed by peer, indicate we're ready for more */ 295 conn->urg_tx_pend = false; 296 smc->sk.sk_write_space(&smc->sk); 297 } 298 299 if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) { 300 smc->sk.sk_err = ECONNRESET; 301 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1; 302 } 303 if (smc_cdc_rxed_any_close_or_senddone(conn)) { 304 smc->sk.sk_shutdown |= RCV_SHUTDOWN; 305 if (smc->clcsock && smc->clcsock->sk) 306 smc->clcsock->sk->sk_shutdown |= RCV_SHUTDOWN; 307 sock_set_flag(&smc->sk, SOCK_DONE); 308 sock_hold(&smc->sk); /* sock_put in close_work */ 309 if (!schedule_work(&conn->close_work)) 310 sock_put(&smc->sk); 311 } 312 } 313 314 /* called under tasklet context */ 315 static void smc_cdc_msg_recv(struct smc_sock *smc, struct smc_cdc_msg *cdc) 316 { 317 sock_hold(&smc->sk); 318 bh_lock_sock(&smc->sk); 319 smc_cdc_msg_recv_action(smc, cdc); 320 bh_unlock_sock(&smc->sk); 321 sock_put(&smc->sk); /* no free sk in softirq-context */ 322 } 323 324 /* Schedule a tasklet for this connection. Triggered from the ISM device IRQ 325 * handler to indicate update in the DMBE. 326 * 327 * Context: 328 * - tasklet context 329 */ 330 static void smcd_cdc_rx_tsklet(unsigned long data) 331 { 332 struct smc_connection *conn = (struct smc_connection *)data; 333 struct smcd_cdc_msg cdc; 334 struct smc_sock *smc; 335 336 if (!conn) 337 return; 338 339 memcpy(&cdc, conn->rmb_desc->cpu_addr, sizeof(cdc)); 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