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 /* 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                 /* If user owns the sock_lock, mark the connection need sending.
  53                  * User context will later try to send when it release sock_lock
  54                  * in smc_release_cb()
  55                  */
  56                 if (sock_owned_by_user(&smc->sk))
  57                         conn->tx_in_release_sock = true;
  58                 else
  59                         smc_tx_pending(conn);
  60
  61                 if (unlikely(wq_has_sleeper(&conn->cdc_pend_tx_wq)))
  62                         wake_up(&conn->cdc_pend_tx_wq);
  63         }
  64         WARN_ON(atomic_read(&conn->cdc_pend_tx_wr) < 0);
  65
  66         smc_tx_sndbuf_nonfull(smc);
  67         bh_unlock_sock(&smc->sk);
  68 }
  69
  70 int smc_cdc_get_free_slot(struct smc_connection *conn,
  71                           struct smc_link *link,
  72                           struct smc_wr_buf **wr_buf,
  73                           struct smc_rdma_wr **wr_rdma_buf,
  74                           struct smc_cdc_tx_pend **pend)
  75 {
  76         int rc;
  77
  78         rc = smc_wr_tx_get_free_slot(link, smc_cdc_tx_handler, wr_buf,
  79                                      wr_rdma_buf,
  80                                      (struct smc_wr_tx_pend_priv **)pend);
  81         if (conn->killed) {
  82                 /* abnormal termination */
  83                 if (!rc)
  84                         smc_wr_tx_put_slot(link,
  85                                            (struct smc_wr_tx_pend_priv *)pend);
  86                 rc = -EPIPE;
  87         }
  88         return rc;
  89 }
  90
  91 static inline void smc_cdc_add_pending_send(struct smc_connection *conn,
  92                                             struct smc_cdc_tx_pend *pend)
  93 {
  94         BUILD_BUG_ON_MSG(
  95                 sizeof(struct smc_cdc_msg) > SMC_WR_BUF_SIZE,
  96                 "must increase SMC_WR_BUF_SIZE to at least sizeof(struct smc_cdc_msg)");
  97         BUILD_BUG_ON_MSG(
  98                 offsetofend(struct smc_cdc_msg, reserved) > SMC_WR_TX_SIZE,
  99                 "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()");
 100         BUILD_BUG_ON_MSG(
 101                 sizeof(struct smc_cdc_tx_pend) > SMC_WR_TX_PEND_PRIV_SIZE,
 102                 "must increase SMC_WR_TX_PEND_PRIV_SIZE to at least sizeof(struct smc_cdc_tx_pend)");
 103         pend->conn = conn;
 104         pend->cursor = conn->tx_curs_sent;
 105         pend->p_cursor = conn->local_tx_ctrl.prod;
 106         pend->ctrl_seq = conn->tx_cdc_seq;
 107 }
 108
 109 int smc_cdc_msg_send(struct smc_connection *conn,
 110                      struct smc_wr_buf *wr_buf,
 111                      struct smc_cdc_tx_pend *pend)
 112 {
 113         struct smc_link *link = conn->lnk;
 114         union smc_host_cursor cfed;
 115         int rc;
 116
 117         smc_cdc_add_pending_send(conn, pend);
 118
 119         conn->tx_cdc_seq++;
 120         conn->local_tx_ctrl.seqno = conn->tx_cdc_seq;
 121         smc_host_msg_to_cdc((struct smc_cdc_msg *)wr_buf, conn, &cfed);
 122
 123         atomic_inc(&conn->cdc_pend_tx_wr);
 124         smp_mb__after_atomic(); /* Make sure cdc_pend_tx_wr added before post */
 125
 126         rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend);
 127         if (!rc) {
 128                 smc_curs_copy(&conn->rx_curs_confirmed, &cfed, conn);
 129                 conn->local_rx_ctrl.prod_flags.cons_curs_upd_req = 0;
 130         } else {
 131                 conn->tx_cdc_seq--;
 132                 conn->local_tx_ctrl.seqno = conn->tx_cdc_seq;
 133                 atomic_dec(&conn->cdc_pend_tx_wr);
 134         }
 135
 136         return rc;
 137 }
 138
 139 /* send a validation msg indicating the move of a conn to an other QP link */
 140 int smcr_cdc_msg_send_validation(struct smc_connection *conn,
 141                                  struct smc_cdc_tx_pend *pend,
 142                                  struct smc_wr_buf *wr_buf)
 143 {
 144         struct smc_host_cdc_msg *local = &conn->local_tx_ctrl;
 145         struct smc_link *link = conn->lnk;
 146         struct smc_cdc_msg *peer;
 147         int rc;
 148
 149         peer = (struct smc_cdc_msg *)wr_buf;
 150         peer->common.type = local->common.type;
 151         peer->len = local->len;
 152         peer->seqno = htons(conn->tx_cdc_seq_fin); /* seqno last compl. tx */
 153         peer->token = htonl(local->token);
 154         peer->prod_flags.failover_validation = 1;
 155
 156         /* We need to set pend->conn here to make sure smc_cdc_tx_handler()
 157          * can handle properly
 158          */
 159         smc_cdc_add_pending_send(conn, pend);
 160
 161         atomic_inc(&conn->cdc_pend_tx_wr);
 162         smp_mb__after_atomic(); /* Make sure cdc_pend_tx_wr added before post */
 163
 164         rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend);
 165         if (unlikely(rc))
 166                 atomic_dec(&conn->cdc_pend_tx_wr);
 167
 168         return rc;
 169 }
 170
 171 static int smcr_cdc_get_slot_and_msg_send(struct smc_connection *conn)
 172 {
 173         struct smc_cdc_tx_pend *pend;
 174         struct smc_wr_buf *wr_buf;
 175         struct smc_link *link;
 176         bool again = false;
 177         int rc;
 178
 179 again:
 180         link = conn->lnk;
 181         if (!smc_wr_tx_link_hold(link))
 182                 return -ENOLINK;
 183         rc = smc_cdc_get_free_slot(conn, link, &wr_buf, NULL, &pend);
 184         if (rc)
 185                 goto put_out;
 186
 187         spin_lock_bh(&conn->send_lock);
 188         if (link != conn->lnk) {
 189                 /* link of connection changed, try again one time*/
 190                 spin_unlock_bh(&conn->send_lock);
 191                 smc_wr_tx_put_slot(link,
 192                                    (struct smc_wr_tx_pend_priv *)pend);
 193                 smc_wr_tx_link_put(link);
 194                 if (again)
 195                         return -ENOLINK;
 196                 again = true;
 197                 goto again;
 198         }
 199         rc = smc_cdc_msg_send(conn, wr_buf, pend);
 200         spin_unlock_bh(&conn->send_lock);
 201 put_out:
 202         smc_wr_tx_link_put(link);
 203         return rc;
 204 }
 205
 206 int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn)
 207 {
 208         int rc;
 209
 210         if (!smc_conn_lgr_valid(conn) ||
 211             (conn->lgr->is_smcd && conn->lgr->peer_shutdown))
 212                 return -EPIPE;
 213
 214         if (conn->lgr->is_smcd) {
 215                 spin_lock_bh(&conn->send_lock);
 216                 rc = smcd_cdc_msg_send(conn);
 217                 spin_unlock_bh(&conn->send_lock);
 218         } else {
 219                 rc = smcr_cdc_get_slot_and_msg_send(conn);
 220         }
 221
 222         return rc;
 223 }
 224
 225 void smc_cdc_wait_pend_tx_wr(struct smc_connection *conn)
 226 {
 227         wait_event(conn->cdc_pend_tx_wq, !atomic_read(&conn->cdc_pend_tx_wr));
 228 }
 229
 230 /* Send a SMC-D CDC header.
 231  * This increments the free space available in our send buffer.
 232  * Also update the confirmed receive buffer with what was sent to the peer.
 233  */
 234 int smcd_cdc_msg_send(struct smc_connection *conn)
 235 {
 236         struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
 237         union smc_host_cursor curs;
 238         struct smcd_cdc_msg cdc;
 239         int rc, diff;
 240
 241         memset(&cdc, 0, sizeof(cdc));
 242         cdc.common.type = SMC_CDC_MSG_TYPE;
 243         curs.acurs.counter = atomic64_read(&conn->local_tx_ctrl.prod.acurs);
 244         cdc.prod.wrap = curs.wrap;
 245         cdc.prod.count = curs.count;
 246         curs.acurs.counter = atomic64_read(&conn->local_tx_ctrl.cons.acurs);
 247         cdc.cons.wrap = curs.wrap;
 248         cdc.cons.count = curs.count;
 249         cdc.cons.prod_flags = conn->local_tx_ctrl.prod_flags;
 250         cdc.cons.conn_state_flags = conn->local_tx_ctrl.conn_state_flags;
 251         rc = smcd_tx_ism_write(conn, &cdc, sizeof(cdc), 0, 1);
 252         if (rc)
 253                 return rc;
 254         smc_curs_copy(&conn->rx_curs_confirmed, &curs, conn);
 255         conn->local_rx_ctrl.prod_flags.cons_curs_upd_req = 0;
 256         /* Calculate transmitted data and increment free send buffer space */
 257         diff = smc_curs_diff(conn->sndbuf_desc->len, &conn->tx_curs_fin,
 258                              &conn->tx_curs_sent);
 259         /* increased by confirmed number of bytes */
 260         smp_mb__before_atomic();
 261         atomic_add(diff, &conn->sndbuf_space);
 262         /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
 263         smp_mb__after_atomic();
 264         smc_curs_copy(&conn->tx_curs_fin, &conn->tx_curs_sent, conn);
 265
 266         smc_tx_sndbuf_nonfull(smc);
 267         return rc;
 268 }
 269
 270 /********************************* receive ***********************************/
 271
 272 static inline bool smc_cdc_before(u16 seq1, u16 seq2)
 273 {
 274         return (s16)(seq1 - seq2) < 0;
 275 }
 276
 277 static void smc_cdc_handle_urg_data_arrival(struct smc_sock *smc,
 278                                             int *diff_prod)
 279 {
 280         struct smc_connection *conn = &smc->conn;
 281         char *base;
 282
 283         /* new data included urgent business */
 284         smc_curs_copy(&conn->urg_curs, &conn->local_rx_ctrl.prod, conn);
 285         conn->urg_state = SMC_URG_VALID;
 286         if (!sock_flag(&smc->sk, SOCK_URGINLINE))
 287                 /* we'll skip the urgent byte, so don't account for it */
 288                 (*diff_prod)--;
 289         base = (char *)conn->rmb_desc->cpu_addr + conn->rx_off;
 290         if (conn->urg_curs.count)
 291                 conn->urg_rx_byte = *(base + conn->urg_curs.count - 1);
 292         else
 293                 conn->urg_rx_byte = *(base + conn->rmb_desc->len - 1);
 294         sk_send_sigurg(&smc->sk);
 295 }
 296
 297 static void smc_cdc_msg_validate(struct smc_sock *smc, struct smc_cdc_msg *cdc,
 298                                  struct smc_link *link)
 299 {
 300         struct smc_connection *conn = &smc->conn;
 301         u16 recv_seq = ntohs(cdc->seqno);
 302         s16 diff;
 303
 304         /* check that seqnum was seen before */
 305         diff = conn->local_rx_ctrl.seqno - recv_seq;
 306         if (diff < 0) { /* diff larger than 0x7fff */
 307                 /* drop connection */
 308                 conn->out_of_sync = 1;  /* prevent any further receives */
 309                 spin_lock_bh(&conn->send_lock);
 310                 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
 311                 conn->lnk = link;
 312                 spin_unlock_bh(&conn->send_lock);
 313                 sock_hold(&smc->sk); /* sock_put in abort_work */
 314                 if (!queue_work(smc_close_wq, &conn->abort_work))
 315                         sock_put(&smc->sk);
 316         }
 317 }
 318
 319 static void smc_cdc_msg_recv_action(struct smc_sock *smc,
 320                                     struct smc_cdc_msg *cdc)
 321 {
 322         union smc_host_cursor cons_old, prod_old;
 323         struct smc_connection *conn = &smc->conn;
 324         int diff_cons, diff_prod;
 325
 326         smc_curs_copy(&prod_old, &conn->local_rx_ctrl.prod, conn);
 327         smc_curs_copy(&cons_old, &conn->local_rx_ctrl.cons, conn);
 328         smc_cdc_msg_to_host(&conn->local_rx_ctrl, cdc, conn);
 329
 330         diff_cons = smc_curs_diff(conn->peer_rmbe_size, &cons_old,
 331                                   &conn->local_rx_ctrl.cons);
 332         if (diff_cons) {
 333                 /* peer_rmbe_space is decreased during data transfer with RDMA
 334                  * write
 335                  */
 336                 smp_mb__before_atomic();
 337                 atomic_add(diff_cons, &conn->peer_rmbe_space);
 338                 /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */
 339                 smp_mb__after_atomic();
 340         }
 341
 342         diff_prod = smc_curs_diff(conn->rmb_desc->len, &prod_old,
 343                                   &conn->local_rx_ctrl.prod);
 344         if (diff_prod) {
 345                 if (conn->local_rx_ctrl.prod_flags.urg_data_present)
 346                         smc_cdc_handle_urg_data_arrival(smc, &diff_prod);
 347                 /* bytes_to_rcv is decreased in smc_recvmsg */
 348                 smp_mb__before_atomic();
 349                 atomic_add(diff_prod, &conn->bytes_to_rcv);
 350                 /* guarantee 0 <= bytes_to_rcv <= rmb_desc->len */
 351                 smp_mb__after_atomic();
 352                 smc->sk.sk_data_ready(&smc->sk);
 353         } else {
 354                 if (conn->local_rx_ctrl.prod_flags.write_blocked)
 355                         smc->sk.sk_data_ready(&smc->sk);
 356                 if (conn->local_rx_ctrl.prod_flags.urg_data_pending)
 357                         conn->urg_state = SMC_URG_NOTYET;
 358         }
 359
 360         /* trigger sndbuf consumer: RDMA write into peer RMBE and CDC */
 361         if ((diff_cons && smc_tx_prepared_sends(conn)) ||
 362             conn->local_rx_ctrl.prod_flags.cons_curs_upd_req ||
 363             conn->local_rx_ctrl.prod_flags.urg_data_pending) {
 364                 if (!sock_owned_by_user(&smc->sk))
 365                         smc_tx_pending(conn);
 366                 else
 367                         conn->tx_in_release_sock = true;
 368         }
 369
 370         if (diff_cons && conn->urg_tx_pend &&
 371             atomic_read(&conn->peer_rmbe_space) == conn->peer_rmbe_size) {
 372                 /* urg data confirmed by peer, indicate we're ready for more */
 373                 conn->urg_tx_pend = false;
 374                 smc->sk.sk_write_space(&smc->sk);
 375         }
 376
 377         if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) {
 378                 smc->sk.sk_err = ECONNRESET;
 379                 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
 380         }
 381         if (smc_cdc_rxed_any_close_or_senddone(conn)) {
 382                 smc->sk.sk_shutdown |= RCV_SHUTDOWN;
 383                 if (smc->clcsock && smc->clcsock->sk)
 384                         smc->clcsock->sk->sk_shutdown |= RCV_SHUTDOWN;
 385                 sock_set_flag(&smc->sk, SOCK_DONE);
 386                 sock_hold(&smc->sk); /* sock_put in close_work */
 387                 if (!queue_work(smc_close_wq, &conn->close_work))
 388                         sock_put(&smc->sk);
 389         }
 390 }
 391
 392 /* called under tasklet context */
 393 static void smc_cdc_msg_recv(struct smc_sock *smc, struct smc_cdc_msg *cdc)
 394 {
 395         sock_hold(&smc->sk);
 396         bh_lock_sock(&smc->sk);
 397         smc_cdc_msg_recv_action(smc, cdc);
 398         bh_unlock_sock(&smc->sk);
 399         sock_put(&smc->sk); /* no free sk in softirq-context */
 400 }
 401
 402 /* Schedule a tasklet for this connection. Triggered from the ISM device IRQ
 403  * handler to indicate update in the DMBE.
 404  *
 405  * Context:
 406  * - tasklet context
 407  */
 408 static void smcd_cdc_rx_tsklet(struct tasklet_struct *t)
 409 {
 410         struct smc_connection *conn = from_tasklet(conn, t, rx_tsklet);
 411         struct smcd_cdc_msg *data_cdc;
 412         struct smcd_cdc_msg cdc;
 413         struct smc_sock *smc;
 414
 415         if (!conn || conn->killed)
 416                 return;
 417
 418         data_cdc = (struct smcd_cdc_msg *)conn->rmb_desc->cpu_addr;
 419         smcd_curs_copy(&cdc.prod, &data_cdc->prod, conn);
 420         smcd_curs_copy(&cdc.cons, &data_cdc->cons, conn);
 421         smc = container_of(conn, struct smc_sock, conn);
 422         smc_cdc_msg_recv(smc, (struct smc_cdc_msg *)&cdc);
 423 }
 424
 425 /* Initialize receive tasklet. Called from ISM device IRQ handler to start
 426  * receiver side.
 427  */
 428 void smcd_cdc_rx_init(struct smc_connection *conn)
 429 {
 430         tasklet_setup(&conn->rx_tsklet, smcd_cdc_rx_tsklet);
 431 }
 432
 433 /***************************** init, exit, misc ******************************/
 434
 435 static void smc_cdc_rx_handler(struct ib_wc *wc, void *buf)
 436 {
 437         struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
 438         struct smc_cdc_msg *cdc = buf;
 439         struct smc_connection *conn;
 440         struct smc_link_group *lgr;
 441         struct smc_sock *smc;
 442
 443         if (wc->byte_len < offsetof(struct smc_cdc_msg, reserved))
 444                 return; /* short message */
 445         if (cdc->len != SMC_WR_TX_SIZE)
 446                 return; /* invalid message */
 447
 448         /* lookup connection */
 449         lgr = smc_get_lgr(link);
 450         read_lock_bh(&lgr->conns_lock);
 451         conn = smc_lgr_find_conn(ntohl(cdc->token), lgr);
 452         read_unlock_bh(&lgr->conns_lock);
 453         if (!conn || conn->out_of_sync)
 454                 return;
 455         smc = container_of(conn, struct smc_sock, conn);
 456
 457         if (cdc->prod_flags.failover_validation) {
 458                 smc_cdc_msg_validate(smc, cdc, link);
 459                 return;
 460         }
 461         if (smc_cdc_before(ntohs(cdc->seqno),
 462                            conn->local_rx_ctrl.seqno))
 463                 /* received seqno is old */
 464                 return;
 465
 466         smc_cdc_msg_recv(smc, cdc);
 467 }
 468
 469 static struct smc_wr_rx_handler smc_cdc_rx_handlers[] = {
 470         {
 471                 .handler        = smc_cdc_rx_handler,
 472                 .type           = SMC_CDC_MSG_TYPE
 473         },
 474         {
 475                 .handler        = NULL,
 476         }
 477 };
 478
 479 int __init smc_cdc_init(void)
 480 {
 481         struct smc_wr_rx_handler *handler;
 482         int rc = 0;
 483
 484         for (handler = smc_cdc_rx_handlers; handler->handler; handler++) {
 485                 INIT_HLIST_NODE(&handler->list);
 486                 rc = smc_wr_rx_register_handler(handler);
 487                 if (rc)
 488                         break;
 489         }
 490         return rc;
 491 }