net/smc/smc_cdc.c

   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                 offsetofend(struct smc_cdc_msg, reserved) > 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         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         /* Calculate transmitted data and increment free send buffer space */
 199         diff = smc_curs_diff(conn->sndbuf_desc->len, &conn->tx_curs_fin,
 200                              &conn->tx_curs_sent);
 201         /* increased by confirmed number of bytes */
 202         smp_mb__before_atomic();
 203         atomic_add(diff, &conn->sndbuf_space);
 204         /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
 205         smp_mb__after_atomic();
 206         smc_curs_copy(&conn->tx_curs_fin, &conn->tx_curs_sent, conn);
 207
 208         smc_tx_sndbuf_nonfull(smc);
 209         return rc;
 210 }
 211
 212 /********************************* receive ***********************************/
 213
 214 static inline bool smc_cdc_before(u16 seq1, u16 seq2)
 215 {
 216         return (s16)(seq1 - seq2) < 0;
 217 }
 218
 219 static void smc_cdc_handle_urg_data_arrival(struct smc_sock *smc,
 220                                             int *diff_prod)
 221 {
 222         struct smc_connection *conn = &smc->conn;
 223         char *base;
 224
 225         /* new data included urgent business */
 226         smc_curs_copy(&conn->urg_curs, &conn->local_rx_ctrl.prod, conn);
 227         conn->urg_state = SMC_URG_VALID;
 228         if (!sock_flag(&smc->sk, SOCK_URGINLINE))
 229                 /* we'll skip the urgent byte, so don't account for it */
 230                 (*diff_prod)--;
 231         base = (char *)conn->rmb_desc->cpu_addr + conn->rx_off;
 232         if (conn->urg_curs.count)
 233                 conn->urg_rx_byte = *(base + conn->urg_curs.count - 1);
 234         else
 235                 conn->urg_rx_byte = *(base + conn->rmb_desc->len - 1);
 236         sk_send_sigurg(&smc->sk);
 237 }
 238
 239 static void smc_cdc_msg_recv_action(struct smc_sock *smc,
 240                                     struct smc_cdc_msg *cdc)
 241 {
 242         union smc_host_cursor cons_old, prod_old;
 243         struct smc_connection *conn = &smc->conn;
 244         int diff_cons, diff_prod;
 245
 246         smc_curs_copy(&prod_old, &conn->local_rx_ctrl.prod, conn);
 247         smc_curs_copy(&cons_old, &conn->local_rx_ctrl.cons, conn);
 248         smc_cdc_msg_to_host(&conn->local_rx_ctrl, cdc, conn);
 249
 250         diff_cons = smc_curs_diff(conn->peer_rmbe_size, &cons_old,
 251                                   &conn->local_rx_ctrl.cons);
 252         if (diff_cons) {
 253                 /* peer_rmbe_space is decreased during data transfer with RDMA
 254                  * write
 255                  */
 256                 smp_mb__before_atomic();
 257                 atomic_add(diff_cons, &conn->peer_rmbe_space);
 258                 /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */
 259                 smp_mb__after_atomic();
 260         }
 261
 262         diff_prod = smc_curs_diff(conn->rmb_desc->len, &prod_old,
 263                                   &conn->local_rx_ctrl.prod);
 264         if (diff_prod) {
 265                 if (conn->local_rx_ctrl.prod_flags.urg_data_present)
 266                         smc_cdc_handle_urg_data_arrival(smc, &diff_prod);
 267                 /* bytes_to_rcv is decreased in smc_recvmsg */
 268                 smp_mb__before_atomic();
 269                 atomic_add(diff_prod, &conn->bytes_to_rcv);
 270                 /* guarantee 0 <= bytes_to_rcv <= rmb_desc->len */
 271                 smp_mb__after_atomic();
 272                 smc->sk.sk_data_ready(&smc->sk);
 273         } else {
 274                 if (conn->local_rx_ctrl.prod_flags.write_blocked ||
 275                     conn->local_rx_ctrl.prod_flags.cons_curs_upd_req ||
 276                     conn->local_rx_ctrl.prod_flags.urg_data_pending) {
 277                         if (conn->local_rx_ctrl.prod_flags.urg_data_pending)
 278                                 conn->urg_state = SMC_URG_NOTYET;
 279                         /* force immediate tx of current consumer cursor, but
 280                          * under send_lock to guarantee arrival in seqno-order
 281                          */
 282                         if (smc->sk.sk_state != SMC_INIT)
 283                                 smc_tx_sndbuf_nonempty(conn);
 284                 }
 285         }
 286
 287         /* piggy backed tx info */
 288         /* trigger sndbuf consumer: RDMA write into peer RMBE and CDC */
 289         if (diff_cons && smc_tx_prepared_sends(conn)) {
 290                 smc_tx_sndbuf_nonempty(conn);
 291                 /* trigger socket release if connection closed */
 292                 smc_close_wake_tx_prepared(smc);
 293         }
 294         if (diff_cons && conn->urg_tx_pend &&
 295             atomic_read(&conn->peer_rmbe_space) == conn->peer_rmbe_size) {
 296                 /* urg data confirmed by peer, indicate we're ready for more */
 297                 conn->urg_tx_pend = false;
 298                 smc->sk.sk_write_space(&smc->sk);
 299         }
 300
 301         if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) {
 302                 smc->sk.sk_err = ECONNRESET;
 303                 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
 304         }
 305         if (smc_cdc_rxed_any_close_or_senddone(conn)) {
 306                 smc->sk.sk_shutdown |= RCV_SHUTDOWN;
 307                 if (smc->clcsock && smc->clcsock->sk)
 308                         smc->clcsock->sk->sk_shutdown |= RCV_SHUTDOWN;
 309                 sock_set_flag(&smc->sk, SOCK_DONE);
 310                 sock_hold(&smc->sk); /* sock_put in close_work */
 311                 if (!schedule_work(&conn->close_work))
 312                         sock_put(&smc->sk);
 313         }
 314 }
 315
 316 /* called under tasklet context */
 317 static void smc_cdc_msg_recv(struct smc_sock *smc, struct smc_cdc_msg *cdc)
 318 {
 319         sock_hold(&smc->sk);
 320         bh_lock_sock(&smc->sk);
 321         smc_cdc_msg_recv_action(smc, cdc);
 322         bh_unlock_sock(&smc->sk);
 323         sock_put(&smc->sk); /* no free sk in softirq-context */
 324 }
 325
 326 /* Schedule a tasklet for this connection. Triggered from the ISM device IRQ
 327  * handler to indicate update in the DMBE.
 328  *
 329  * Context:
 330  * - tasklet context
 331  */
 332 static void smcd_cdc_rx_tsklet(unsigned long data)
 333 {
 334         struct smc_connection *conn = (struct smc_connection *)data;
 335         struct smcd_cdc_msg *data_cdc;
 336         struct smcd_cdc_msg cdc;
 337         struct smc_sock *smc;
 338
 339         if (!conn)
 340                 return;
 341
 342         data_cdc = (struct smcd_cdc_msg *)conn->rmb_desc->cpu_addr;
 343         smcd_curs_copy(&cdc.prod, &data_cdc->prod, conn);
 344         smcd_curs_copy(&cdc.cons, &data_cdc->cons, conn);
 345         smc = container_of(conn, struct smc_sock, conn);
 346         smc_cdc_msg_recv(smc, (struct smc_cdc_msg *)&cdc);
 347 }
 348
 349 /* Initialize receive tasklet. Called from ISM device IRQ handler to start
 350  * receiver side.
 351  */
 352 void smcd_cdc_rx_init(struct smc_connection *conn)
 353 {
 354         tasklet_init(&conn->rx_tsklet, smcd_cdc_rx_tsklet, (unsigned long)conn);
 355 }
 356
 357 /***************************** init, exit, misc ******************************/
 358
 359 static void smc_cdc_rx_handler(struct ib_wc *wc, void *buf)
 360 {
 361         struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
 362         struct smc_cdc_msg *cdc = buf;
 363         struct smc_connection *conn;
 364         struct smc_link_group *lgr;
 365         struct smc_sock *smc;
 366
 367         if (wc->byte_len < offsetof(struct smc_cdc_msg, reserved))
 368                 return; /* short message */
 369         if (cdc->len != SMC_WR_TX_SIZE)
 370                 return; /* invalid message */
 371
 372         /* lookup connection */
 373         lgr = smc_get_lgr(link);
 374         read_lock_bh(&lgr->conns_lock);
 375         conn = smc_lgr_find_conn(ntohl(cdc->token), lgr);
 376         read_unlock_bh(&lgr->conns_lock);
 377         if (!conn)
 378                 return;
 379         smc = container_of(conn, struct smc_sock, conn);
 380
 381         if (!cdc->prod_flags.failover_validation) {
 382                 if (smc_cdc_before(ntohs(cdc->seqno),
 383                                    conn->local_rx_ctrl.seqno))
 384                         /* received seqno is old */
 385                         return;
 386         }
 387         smc_cdc_msg_recv(smc, cdc);
 388 }
 389
 390 static struct smc_wr_rx_handler smc_cdc_rx_handlers[] = {
 391         {
 392                 .handler        = smc_cdc_rx_handler,
 393                 .type           = SMC_CDC_MSG_TYPE
 394         },
 395         {
 396                 .handler        = NULL,
 397         }
 398 };
 399
 400 int __init smc_cdc_init(void)
 401 {
 402         struct smc_wr_rx_handler *handler;
 403         int rc = 0;
 404
 405         for (handler = smc_cdc_rx_handlers; handler->handler; handler++) {
 406                 INIT_HLIST_NODE(&handler->list);
 407                 rc = smc_wr_rx_register_handler(handler);
 408                 if (rc)
 409                         break;
 410         }
 411         return rc;
 412 }