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_sock *smc; 38 int diff; 39 40 if (!cdcpend->conn) 41 /* already dismissed */ 42 return; 43 44 smc = container_of(cdcpend->conn, struct smc_sock, conn); 45 bh_lock_sock(&smc->sk); 46 if (!wc_status) { 47 diff = smc_curs_diff(cdcpend->conn->sndbuf_desc->len, 48 &cdcpend->conn->tx_curs_fin, 49 &cdcpend->cursor); 50 /* sndbuf_space is decreased in smc_sendmsg */ 51 smp_mb__before_atomic(); 52 atomic_add(diff, &cdcpend->conn->sndbuf_space); 53 /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */ 54 smp_mb__after_atomic(); 55 smc_curs_write(&cdcpend->conn->tx_curs_fin, 56 smc_curs_read(&cdcpend->cursor, cdcpend->conn), 57 cdcpend->conn); 58 } 59 smc_tx_sndbuf_nonfull(smc); 60 bh_unlock_sock(&smc->sk); 61 } 62 63 int smc_cdc_get_free_slot(struct smc_connection *conn, 64 struct smc_wr_buf **wr_buf, 65 struct smc_cdc_tx_pend **pend) 66 { 67 struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK]; 68 int rc; 69 70 rc = smc_wr_tx_get_free_slot(link, smc_cdc_tx_handler, wr_buf, 71 (struct smc_wr_tx_pend_priv **)pend); 72 if (!conn->alert_token_local) 73 /* abnormal termination */ 74 rc = -EPIPE; 75 return rc; 76 } 77 78 static inline void smc_cdc_add_pending_send(struct smc_connection *conn, 79 struct smc_cdc_tx_pend *pend) 80 { 81 BUILD_BUG_ON_MSG( 82 sizeof(struct smc_cdc_msg) > SMC_WR_BUF_SIZE, 83 "must increase SMC_WR_BUF_SIZE to at least sizeof(struct smc_cdc_msg)"); 84 BUILD_BUG_ON_MSG( 85 sizeof(struct smc_cdc_msg) != SMC_WR_TX_SIZE, 86 "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()"); 87 BUILD_BUG_ON_MSG( 88 sizeof(struct smc_cdc_tx_pend) > SMC_WR_TX_PEND_PRIV_SIZE, 89 "must increase SMC_WR_TX_PEND_PRIV_SIZE to at least sizeof(struct smc_cdc_tx_pend)"); 90 pend->conn = conn; 91 pend->cursor = conn->tx_curs_sent; 92 pend->p_cursor = conn->local_tx_ctrl.prod; 93 pend->ctrl_seq = conn->tx_cdc_seq; 94 } 95 96 int smc_cdc_msg_send(struct smc_connection *conn, 97 struct smc_wr_buf *wr_buf, 98 struct smc_cdc_tx_pend *pend) 99 { 100 struct smc_link *link; 101 int rc; 102 103 link = &conn->lgr->lnk[SMC_SINGLE_LINK]; 104 105 smc_cdc_add_pending_send(conn, pend); 106 107 conn->tx_cdc_seq++; 108 conn->local_tx_ctrl.seqno = conn->tx_cdc_seq; 109 smc_host_msg_to_cdc((struct smc_cdc_msg *)wr_buf, 110 &conn->local_tx_ctrl, conn); 111 rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend); 112 if (!rc) 113 smc_curs_write(&conn->rx_curs_confirmed, 114 smc_curs_read(&conn->local_tx_ctrl.cons, conn), 115 conn); 116 117 return rc; 118 } 119 120 int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn) 121 { 122 struct smc_cdc_tx_pend *pend; 123 struct smc_wr_buf *wr_buf; 124 int rc; 125 126 rc = smc_cdc_get_free_slot(conn, &wr_buf, &pend); 127 if (rc) 128 return rc; 129 130 return smc_cdc_msg_send(conn, wr_buf, pend); 131 } 132 133 static bool smc_cdc_tx_filter(struct smc_wr_tx_pend_priv *tx_pend, 134 unsigned long data) 135 { 136 struct smc_connection *conn = (struct smc_connection *)data; 137 struct smc_cdc_tx_pend *cdc_pend = 138 (struct smc_cdc_tx_pend *)tx_pend; 139 140 return cdc_pend->conn == conn; 141 } 142 143 static void smc_cdc_tx_dismisser(struct smc_wr_tx_pend_priv *tx_pend) 144 { 145 struct smc_cdc_tx_pend *cdc_pend = 146 (struct smc_cdc_tx_pend *)tx_pend; 147 148 cdc_pend->conn = NULL; 149 } 150 151 void smc_cdc_tx_dismiss_slots(struct smc_connection *conn) 152 { 153 struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK]; 154 155 smc_wr_tx_dismiss_slots(link, SMC_CDC_MSG_TYPE, 156 smc_cdc_tx_filter, smc_cdc_tx_dismisser, 157 (unsigned long)conn); 158 } 159 160 /********************************* receive ***********************************/ 161 162 static inline bool smc_cdc_before(u16 seq1, u16 seq2) 163 { 164 return (s16)(seq1 - seq2) < 0; 165 } 166 167 static void smc_cdc_msg_recv_action(struct smc_sock *smc, 168 struct smc_cdc_msg *cdc) 169 { 170 union smc_host_cursor cons_old, prod_old; 171 struct smc_connection *conn = &smc->conn; 172 int diff_cons, diff_prod; 173 174 smc_curs_write(&prod_old, 175 smc_curs_read(&conn->local_rx_ctrl.prod, conn), 176 conn); 177 smc_curs_write(&cons_old, 178 smc_curs_read(&conn->local_rx_ctrl.cons, conn), 179 conn); 180 smc_cdc_msg_to_host(&conn->local_rx_ctrl, cdc, conn); 181 182 diff_cons = smc_curs_diff(conn->peer_rmbe_size, &cons_old, 183 &conn->local_rx_ctrl.cons); 184 if (diff_cons) { 185 /* peer_rmbe_space is decreased during data transfer with RDMA 186 * write 187 */ 188 smp_mb__before_atomic(); 189 atomic_add(diff_cons, &conn->peer_rmbe_space); 190 /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */ 191 smp_mb__after_atomic(); 192 } 193 194 diff_prod = smc_curs_diff(conn->rmb_desc->len, &prod_old, 195 &conn->local_rx_ctrl.prod); 196 if (diff_prod) { 197 /* bytes_to_rcv is decreased in smc_recvmsg */ 198 smp_mb__before_atomic(); 199 atomic_add(diff_prod, &conn->bytes_to_rcv); 200 /* guarantee 0 <= bytes_to_rcv <= rmb_desc->len */ 201 smp_mb__after_atomic(); 202 smc->sk.sk_data_ready(&smc->sk); 203 } else if ((conn->local_rx_ctrl.prod_flags.write_blocked) || 204 (conn->local_rx_ctrl.prod_flags.cons_curs_upd_req)) { 205 smc->sk.sk_data_ready(&smc->sk); 206 } 207 208 /* piggy backed tx info */ 209 /* trigger sndbuf consumer: RDMA write into peer RMBE and CDC */ 210 if (diff_cons && smc_tx_prepared_sends(conn)) { 211 smc_tx_sndbuf_nonempty(conn); 212 /* trigger socket release if connection closed */ 213 smc_close_wake_tx_prepared(smc); 214 } 215 216 if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) { 217 smc->sk.sk_err = ECONNRESET; 218 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1; 219 } 220 if (smc_cdc_rxed_any_close_or_senddone(conn)) { 221 smc->sk.sk_shutdown |= RCV_SHUTDOWN; 222 if (smc->clcsock && smc->clcsock->sk) 223 smc->clcsock->sk->sk_shutdown |= RCV_SHUTDOWN; 224 sock_set_flag(&smc->sk, SOCK_DONE); 225 sock_hold(&smc->sk); /* sock_put in close_work */ 226 if (!schedule_work(&conn->close_work)) 227 sock_put(&smc->sk); 228 } 229 } 230 231 /* called under tasklet context */ 232 static void smc_cdc_msg_recv(struct smc_sock *smc, struct smc_cdc_msg *cdc) 233 { 234 sock_hold(&smc->sk); 235 bh_lock_sock(&smc->sk); 236 smc_cdc_msg_recv_action(smc, cdc); 237 bh_unlock_sock(&smc->sk); 238 sock_put(&smc->sk); /* no free sk in softirq-context */ 239 } 240 241 /***************************** init, exit, misc ******************************/ 242 243 static void smc_cdc_rx_handler(struct ib_wc *wc, void *buf) 244 { 245 struct smc_link *link = (struct smc_link *)wc->qp->qp_context; 246 struct smc_cdc_msg *cdc = buf; 247 struct smc_connection *conn; 248 struct smc_link_group *lgr; 249 struct smc_sock *smc; 250 251 if (wc->byte_len < offsetof(struct smc_cdc_msg, reserved)) 252 return; /* short message */ 253 if (cdc->len != SMC_WR_TX_SIZE) 254 return; /* invalid message */ 255 256 /* lookup connection */ 257 lgr = container_of(link, struct smc_link_group, lnk[SMC_SINGLE_LINK]); 258 read_lock_bh(&lgr->conns_lock); 259 conn = smc_lgr_find_conn(ntohl(cdc->token), lgr); 260 read_unlock_bh(&lgr->conns_lock); 261 if (!conn) 262 return; 263 smc = container_of(conn, struct smc_sock, conn); 264 265 if (!cdc->prod_flags.failover_validation) { 266 if (smc_cdc_before(ntohs(cdc->seqno), 267 conn->local_rx_ctrl.seqno)) 268 /* received seqno is old */ 269 return; 270 } 271 smc_cdc_msg_recv(smc, cdc); 272 } 273 274 static struct smc_wr_rx_handler smc_cdc_rx_handlers[] = { 275 { 276 .handler = smc_cdc_rx_handler, 277 .type = SMC_CDC_MSG_TYPE 278 }, 279 { 280 .handler = NULL, 281 } 282 }; 283 284 int __init smc_cdc_init(void) 285 { 286 struct smc_wr_rx_handler *handler; 287 int rc = 0; 288 289 for (handler = smc_cdc_rx_handlers; handler->handler; handler++) { 290 INIT_HLIST_NODE(&handler->list); 291 rc = smc_wr_rx_register_handler(handler); 292 if (rc) 293 break; 294 } 295 return rc; 296 } 297