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 <[email protected]>
  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         smc = container_of(conn, struct smc_sock, conn);
  35         bh_lock_sock(&smc->sk);
  36         if (!wc_status) {
  37                 diff = smc_curs_diff(cdcpend->conn->sndbuf_desc->len,
  38                                      &cdcpend->conn->tx_curs_fin,
  39                                      &cdcpend->cursor);
  40                 /* sndbuf_space is decreased in smc_sendmsg */
  41                 smp_mb__before_atomic();
  42                 atomic_add(diff, &cdcpend->conn->sndbuf_space);
  43                 /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
  44                 smp_mb__after_atomic();
  45                 smc_curs_copy(&conn->tx_curs_fin, &cdcpend->cursor, conn);
  46                 smc_curs_copy(&conn->local_tx_ctrl_fin, &cdcpend->p_cursor,
  47                               conn);
  48                 conn->tx_cdc_seq_fin = cdcpend->ctrl_seq;
  49         }
  50
  51         if (atomic_dec_and_test(&conn->cdc_pend_tx_wr) &&
  52             unlikely(wq_has_sleeper(&conn->cdc_pend_tx_wq)))
  53                 wake_up(&conn->cdc_pend_tx_wq);
  54         WARN_ON(atomic_read(&conn->cdc_pend_tx_wr) < 0);
  55
  56         smc_tx_sndbuf_nonfull(smc);
  57         bh_unlock_sock(&smc->sk);
  58 }
  59
  60 int smc_cdc_get_free_slot(struct smc_connection *conn,
  61                           struct smc_link *link,
  62                           struct smc_wr_buf **wr_buf,
  63                           struct smc_rdma_wr **wr_rdma_buf,
  64                           struct smc_cdc_tx_pend **pend)
  65 {
  66         int rc;
  67
  68         rc = smc_wr_tx_get_free_slot(link, smc_cdc_tx_handler, wr_buf,
  69                                      wr_rdma_buf,
  70                                      (struct smc_wr_tx_pend_priv **)pend);
  71         if (conn->killed) {
  72                 /* abnormal termination */
  73                 if (!rc)
  74                         smc_wr_tx_put_slot(link,
  75                                            (struct smc_wr_tx_pend_priv *)pend);
  76                 rc = -EPIPE;
  77         }
  78         return rc;
  79 }
  80
  81 static inline void smc_cdc_add_pending_send(struct smc_connection *conn,
  82                                             struct smc_cdc_tx_pend *pend)
  83 {
  84         BUILD_BUG_ON_MSG(
  85                 sizeof(struct smc_cdc_msg) > SMC_WR_BUF_SIZE,
  86                 "must increase SMC_WR_BUF_SIZE to at least sizeof(struct smc_cdc_msg)");
  87         BUILD_BUG_ON_MSG(
  88                 offsetofend(struct smc_cdc_msg, reserved) > SMC_WR_TX_SIZE,
  89                 "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()");
  90         BUILD_BUG_ON_MSG(
  91                 sizeof(struct smc_cdc_tx_pend) > SMC_WR_TX_PEND_PRIV_SIZE,
  92                 "must increase SMC_WR_TX_PEND_PRIV_SIZE to at least sizeof(struct smc_cdc_tx_pend)");
  93         pend->conn = conn;
  94         pend->cursor = conn->tx_curs_sent;
  95         pend->p_cursor = conn->local_tx_ctrl.prod;
  96         pend->ctrl_seq = conn->tx_cdc_seq;
  97 }
  98
  99 int smc_cdc_msg_send(struct smc_connection *conn,
 100                      struct smc_wr_buf *wr_buf,
 101                      struct smc_cdc_tx_pend *pend)
 102 {
 103         struct smc_link *link = conn->lnk;
 104         union smc_host_cursor cfed;
 105         int rc;
 106
 107         smc_cdc_add_pending_send(conn, pend);
 108
 109         conn->tx_cdc_seq++;
 110         conn->local_tx_ctrl.seqno = conn->tx_cdc_seq;
 111         smc_host_msg_to_cdc((struct smc_cdc_msg *)wr_buf, conn, &cfed);
 112
 113         atomic_inc(&conn->cdc_pend_tx_wr);
 114         smp_mb__after_atomic(); /* Make sure cdc_pend_tx_wr added before post */
 115
 116         rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend);
 117         if (!rc) {
 118                 smc_curs_copy(&conn->rx_curs_confirmed, &cfed, conn);
 119                 conn->local_rx_ctrl.prod_flags.cons_curs_upd_req = 0;
 120         } else {
 121                 conn->tx_cdc_seq--;
 122                 conn->local_tx_ctrl.seqno = conn->tx_cdc_seq;
 123                 atomic_dec(&conn->cdc_pend_tx_wr);
 124         }
 125
 126         return rc;
 127 }
 128
 129 /* send a validation msg indicating the move of a conn to an other QP link */
 130 int smcr_cdc_msg_send_validation(struct smc_connection *conn,
 131                                  struct smc_cdc_tx_pend *pend,
 132                                  struct smc_wr_buf *wr_buf)
 133 {
 134         struct smc_host_cdc_msg *local = &conn->local_tx_ctrl;
 135         struct smc_link *link = conn->lnk;
 136         struct smc_cdc_msg *peer;
 137         int rc;
 138
 139         peer = (struct smc_cdc_msg *)wr_buf;
 140         peer->common.type = local->common.type;
 141         peer->len = local->len;
 142         peer->seqno = htons(conn->tx_cdc_seq_fin); /* seqno last compl. tx */
 143         peer->token = htonl(local->token);
 144         peer->prod_flags.failover_validation = 1;
 145
 146         /* We need to set pend->conn here to make sure smc_cdc_tx_handler()
 147          * can handle properly
 148          */
 149         smc_cdc_add_pending_send(conn, pend);
 150
 151         atomic_inc(&conn->cdc_pend_tx_wr);
 152         smp_mb__after_atomic(); /* Make sure cdc_pend_tx_wr added before post */
 153
 154         rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend);
 155         if (unlikely(rc))
 156                 atomic_dec(&conn->cdc_pend_tx_wr);
 157
 158         return rc;
 159 }
 160
 161 static int smcr_cdc_get_slot_and_msg_send(struct smc_connection *conn)
 162 {
 163         struct smc_cdc_tx_pend *pend;
 164         struct smc_wr_buf *wr_buf;
 165         struct smc_link *link;
 166         bool again = false;
 167         int rc;
 168
 169 again:
 170         link = conn->lnk;
 171         if (!smc_wr_tx_link_hold(link))
 172                 return -ENOLINK;
 173         rc = smc_cdc_get_free_slot(conn, link, &wr_buf, NULL, &pend);
 174         if (rc)
 175                 goto put_out;
 176
 177         spin_lock_bh(&conn->send_lock);
 178         if (link != conn->lnk) {
 179                 /* link of connection changed, try again one time*/
 180                 spin_unlock_bh(&conn->send_lock);
 181                 smc_wr_tx_put_slot(link,
 182                                    (struct smc_wr_tx_pend_priv *)pend);
 183                 smc_wr_tx_link_put(link);
 184                 if (again)
 185                         return -ENOLINK;
 186                 again = true;
 187                 goto again;
 188         }
 189         rc = smc_cdc_msg_send(conn, wr_buf, pend);
 190         spin_unlock_bh(&conn->send_lock);
 191 put_out:
 192         smc_wr_tx_link_put(link);
 193         return rc;
 194 }
 195
 196 int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn)
 197 {
 198         int rc;
 199
 200         if (!smc_conn_lgr_valid(conn) ||
 201             (conn->lgr->is_smcd && conn->lgr->peer_shutdown))
 202                 return -EPIPE;
 203
 204         if (conn->lgr->is_smcd) {
 205                 spin_lock_bh(&conn->send_lock);
 206                 rc = smcd_cdc_msg_send(conn);
 207                 spin_unlock_bh(&conn->send_lock);
 208         } else {
 209                 rc = smcr_cdc_get_slot_and_msg_send(conn);
 210         }
 211
 212         return rc;
 213 }
 214
 215 void smc_cdc_wait_pend_tx_wr(struct smc_connection *conn)
 216 {
 217         wait_event(conn->cdc_pend_tx_wq, !atomic_read(&conn->cdc_pend_tx_wr));
 218 }
 219
 220 /* Send a SMC-D CDC header.
 221  * This increments the free space available in our send buffer.
 222  * Also update the confirmed receive buffer with what was sent to the peer.
 223  */
 224 int smcd_cdc_msg_send(struct smc_connection *conn)
 225 {
 226         struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
 227         union smc_host_cursor curs;
 228         struct smcd_cdc_msg cdc;
 229         int rc, diff;
 230
 231         memset(&cdc, 0, sizeof(cdc));
 232         cdc.common.type = SMC_CDC_MSG_TYPE;
 233         curs.acurs.counter = atomic64_read(&conn->local_tx_ctrl.prod.acurs);
 234         cdc.prod.wrap = curs.wrap;
 235         cdc.prod.count = curs.count;
 236         curs.acurs.counter = atomic64_read(&conn->local_tx_ctrl.cons.acurs);
 237         cdc.cons.wrap = curs.wrap;
 238         cdc.cons.count = curs.count;
 239         cdc.cons.prod_flags = conn->local_tx_ctrl.prod_flags;
 240         cdc.cons.conn_state_flags = conn->local_tx_ctrl.conn_state_flags;
 241         rc = smcd_tx_ism_write(conn, &cdc, sizeof(cdc), 0, 1);
 242         if (rc)
 243                 return rc;
 244         smc_curs_copy(&conn->rx_curs_confirmed, &curs, conn);
 245         conn->local_rx_ctrl.prod_flags.cons_curs_upd_req = 0;
 246         /* Calculate transmitted data and increment free send buffer space */
 247         diff = smc_curs_diff(conn->sndbuf_desc->len, &conn->tx_curs_fin,
 248                              &conn->tx_curs_sent);
 249         /* increased by confirmed number of bytes */
 250         smp_mb__before_atomic();
 251         atomic_add(diff, &conn->sndbuf_space);
 252         /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
 253         smp_mb__after_atomic();
 254         smc_curs_copy(&conn->tx_curs_fin, &conn->tx_curs_sent, conn);
 255
 256         smc_tx_sndbuf_nonfull(smc);
 257         return rc;
 258 }
 259
 260 /********************************* receive ***********************************/
 261
 262 static inline bool smc_cdc_before(u16 seq1, u16 seq2)
 263 {
 264         return (s16)(seq1 - seq2) < 0;
 265 }
 266
 267 static void smc_cdc_handle_urg_data_arrival(struct smc_sock *smc,
 268                                             int *diff_prod)
 269 {
 270         struct smc_connection *conn = &smc->conn;
 271         char *base;
 272
 273         /* new data included urgent business */
 274         smc_curs_copy(&conn->urg_curs, &conn->local_rx_ctrl.prod, conn);
 275         conn->urg_state = SMC_URG_VALID;
 276         if (!sock_flag(&smc->sk, SOCK_URGINLINE))
 277                 /* we'll skip the urgent byte, so don't account for it */
 278                 (*diff_prod)--;
 279         base = (char *)conn->rmb_desc->cpu_addr + conn->rx_off;
 280         if (conn->urg_curs.count)
 281                 conn->urg_rx_byte = *(base + conn->urg_curs.count - 1);
 282         else
 283                 conn->urg_rx_byte = *(base + conn->rmb_desc->len - 1);
 284         sk_send_sigurg(&smc->sk);
 285 }
 286
 287 static void smc_cdc_msg_validate(struct smc_sock *smc, struct smc_cdc_msg *cdc,
 288                                  struct smc_link *link)
 289 {
 290         struct smc_connection *conn = &smc->conn;
 291         u16 recv_seq = ntohs(cdc->seqno);
 292         s16 diff;
 293
 294         /* check that seqnum was seen before */
 295         diff = conn->local_rx_ctrl.seqno - recv_seq;
 296         if (diff < 0) { /* diff larger than 0x7fff */
 297                 /* drop connection */
 298                 conn->out_of_sync = 1;  /* prevent any further receives */
 299                 spin_lock_bh(&conn->send_lock);
 300                 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
 301                 conn->lnk = link;
 302                 spin_unlock_bh(&conn->send_lock);
 303                 sock_hold(&smc->sk); /* sock_put in abort_work */
 304                 if (!queue_work(smc_close_wq, &conn->abort_work))
 305                         sock_put(&smc->sk);
 306         }
 307 }
 308
 309 static void smc_cdc_msg_recv_action(struct smc_sock *smc,
 310                                     struct smc_cdc_msg *cdc)
 311 {
 312         union smc_host_cursor cons_old, prod_old;
 313         struct smc_connection *conn = &smc->conn;
 314         int diff_cons, diff_prod;
 315
 316         smc_curs_copy(&prod_old, &conn->local_rx_ctrl.prod, conn);
 317         smc_curs_copy(&cons_old, &conn->local_rx_ctrl.cons, conn);
 318         smc_cdc_msg_to_host(&conn->local_rx_ctrl, cdc, conn);
 319
 320         diff_cons = smc_curs_diff(conn->peer_rmbe_size, &cons_old,
 321                                   &conn->local_rx_ctrl.cons);
 322         if (diff_cons) {
 323                 /* peer_rmbe_space is decreased during data transfer with RDMA
 324                  * write
 325                  */
 326                 smp_mb__before_atomic();
 327                 atomic_add(diff_cons, &conn->peer_rmbe_space);
 328                 /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */
 329                 smp_mb__after_atomic();
 330         }
 331
 332         diff_prod = smc_curs_diff(conn->rmb_desc->len, &prod_old,
 333                                   &conn->local_rx_ctrl.prod);
 334         if (diff_prod) {
 335                 if (conn->local_rx_ctrl.prod_flags.urg_data_present)
 336                         smc_cdc_handle_urg_data_arrival(smc, &diff_prod);
 337                 /* bytes_to_rcv is decreased in smc_recvmsg */
 338                 smp_mb__before_atomic();
 339                 atomic_add(diff_prod, &conn->bytes_to_rcv);
 340                 /* guarantee 0 <= bytes_to_rcv <= rmb_desc->len */
 341                 smp_mb__after_atomic();
 342                 smc->sk.sk_data_ready(&smc->sk);
 343         } else {
 344                 if (conn->local_rx_ctrl.prod_flags.write_blocked)
 345                         smc->sk.sk_data_ready(&smc->sk);
 346                 if (conn->local_rx_ctrl.prod_flags.urg_data_pending)
 347                         conn->urg_state = SMC_URG_NOTYET;
 348         }
 349
 350         /* trigger sndbuf consumer: RDMA write into peer RMBE and CDC */
 351         if ((diff_cons && smc_tx_prepared_sends(conn)) ||
 352             conn->local_rx_ctrl.prod_flags.cons_curs_upd_req ||
 353             conn->local_rx_ctrl.prod_flags.urg_data_pending)
 354                 smc_tx_sndbuf_nonempty(conn);
 355
 356         if (diff_cons && conn->urg_tx_pend &&
 357             atomic_read(&conn->peer_rmbe_space) == conn->peer_rmbe_size) {
 358                 /* urg data confirmed by peer, indicate we're ready for more */
 359                 conn->urg_tx_pend = false;
 360                 smc->sk.sk_write_space(&smc->sk);
 361         }
 362
 363         if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) {
 364                 smc->sk.sk_err = ECONNRESET;
 365                 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
 366         }
 367         if (smc_cdc_rxed_any_close_or_senddone(conn)) {
 368                 smc->sk.sk_shutdown |= RCV_SHUTDOWN;
 369                 if (smc->clcsock && smc->clcsock->sk)
 370                         smc->clcsock->sk->sk_shutdown |= RCV_SHUTDOWN;
 371                 sock_set_flag(&smc->sk, SOCK_DONE);
 372                 sock_hold(&smc->sk); /* sock_put in close_work */
 373                 if (!queue_work(smc_close_wq, &conn->close_work))
 374                         sock_put(&smc->sk);
 375         }
 376 }
 377
 378 /* called under tasklet context */
 379 static void smc_cdc_msg_recv(struct smc_sock *smc, struct smc_cdc_msg *cdc)
 380 {
 381         sock_hold(&smc->sk);
 382         bh_lock_sock(&smc->sk);
 383         smc_cdc_msg_recv_action(smc, cdc);
 384         bh_unlock_sock(&smc->sk);
 385         sock_put(&smc->sk); /* no free sk in softirq-context */
 386 }
 387
 388 /* Schedule a tasklet for this connection. Triggered from the ISM device IRQ
 389  * handler to indicate update in the DMBE.
 390  *
 391  * Context:
 392  * - tasklet context
 393  */
 394 static void smcd_cdc_rx_tsklet(struct tasklet_struct *t)
 395 {
 396         struct smc_connection *conn = from_tasklet(conn, t, rx_tsklet);
 397         struct smcd_cdc_msg *data_cdc;
 398         struct smcd_cdc_msg cdc;
 399         struct smc_sock *smc;
 400
 401         if (!conn || conn->killed)
 402                 return;
 403
 404         data_cdc = (struct smcd_cdc_msg *)conn->rmb_desc->cpu_addr;
 405         smcd_curs_copy(&cdc.prod, &data_cdc->prod, conn);
 406         smcd_curs_copy(&cdc.cons, &data_cdc->cons, conn);
 407         smc = container_of(conn, struct smc_sock, conn);
 408         smc_cdc_msg_recv(smc, (struct smc_cdc_msg *)&cdc);
 409 }
 410
 411 /* Initialize receive tasklet. Called from ISM device IRQ handler to start
 412  * receiver side.
 413  */
 414 void smcd_cdc_rx_init(struct smc_connection *conn)
 415 {
 416         tasklet_setup(&conn->rx_tsklet, smcd_cdc_rx_tsklet);
 417 }
 418
 419 /***************************** init, exit, misc ******************************/
 420
 421 static void smc_cdc_rx_handler(struct ib_wc *wc, void *buf)
 422 {
 423         struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
 424         struct smc_cdc_msg *cdc = buf;
 425         struct smc_connection *conn;
 426         struct smc_link_group *lgr;
 427         struct smc_sock *smc;
 428
 429         if (wc->byte_len < offsetof(struct smc_cdc_msg, reserved))
 430                 return; /* short message */
 431         if (cdc->len != SMC_WR_TX_SIZE)
 432                 return; /* invalid message */
 433
 434         /* lookup connection */
 435         lgr = smc_get_lgr(link);
 436         read_lock_bh(&lgr->conns_lock);
 437         conn = smc_lgr_find_conn(ntohl(cdc->token), lgr);
 438         read_unlock_bh(&lgr->conns_lock);
 439         if (!conn || conn->out_of_sync)
 440                 return;
 441         smc = container_of(conn, struct smc_sock, conn);
 442
 443         if (cdc->prod_flags.failover_validation) {
 444                 smc_cdc_msg_validate(smc, cdc, link);
 445                 return;
 446         }
 447         if (smc_cdc_before(ntohs(cdc->seqno),
 448                            conn->local_rx_ctrl.seqno))
 449                 /* received seqno is old */
 450                 return;
 451
 452         smc_cdc_msg_recv(smc, cdc);
 453 }
 454
 455 static struct smc_wr_rx_handler smc_cdc_rx_handlers[] = {
 456         {
 457                 .handler        = smc_cdc_rx_handler,
 458                 .type           = SMC_CDC_MSG_TYPE
 459         },
 460         {
 461                 .handler        = NULL,
 462         }
 463 };
 464
 465 int __init smc_cdc_init(void)
 466 {
 467         struct smc_wr_rx_handler *handler;
 468         int rc = 0;
 469
 470         for (handler = smc_cdc_rx_handlers; handler->handler; handler++) {
 471                 INIT_HLIST_NODE(&handler->list);
 472                 rc = smc_wr_rx_register_handler(handler);
 473                 if (rc)
 474                         break;
 475         }
 476         return rc;
 477 }