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         if (unlikely(!READ_ONCE(conn->sndbuf_desc)))
 118                 return -ENOBUFS;
 119
 120         smc_cdc_add_pending_send(conn, pend);
 121
 122         conn->tx_cdc_seq++;
 123         conn->local_tx_ctrl.seqno = conn->tx_cdc_seq;
 124         smc_host_msg_to_cdc((struct smc_cdc_msg *)wr_buf, conn, &cfed);
 125
 126         atomic_inc(&conn->cdc_pend_tx_wr);
 127         smp_mb__after_atomic(); /* Make sure cdc_pend_tx_wr added before post */
 128
 129         rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend);
 130         if (!rc) {
 131                 smc_curs_copy(&conn->rx_curs_confirmed, &cfed, conn);
 132                 conn->local_rx_ctrl.prod_flags.cons_curs_upd_req = 0;
 133         } else {
 134                 conn->tx_cdc_seq--;
 135                 conn->local_tx_ctrl.seqno = conn->tx_cdc_seq;
 136                 atomic_dec(&conn->cdc_pend_tx_wr);
 137         }
 138
 139         return rc;
 140 }
 141
 142 /* send a validation msg indicating the move of a conn to an other QP link */
 143 int smcr_cdc_msg_send_validation(struct smc_connection *conn,
 144                                  struct smc_cdc_tx_pend *pend,
 145                                  struct smc_wr_buf *wr_buf)
 146 {
 147         struct smc_host_cdc_msg *local = &conn->local_tx_ctrl;
 148         struct smc_link *link = conn->lnk;
 149         struct smc_cdc_msg *peer;
 150         int rc;
 151
 152         peer = (struct smc_cdc_msg *)wr_buf;
 153         peer->common.type = local->common.type;
 154         peer->len = local->len;
 155         peer->seqno = htons(conn->tx_cdc_seq_fin); /* seqno last compl. tx */
 156         peer->token = htonl(local->token);
 157         peer->prod_flags.failover_validation = 1;
 158
 159         /* We need to set pend->conn here to make sure smc_cdc_tx_handler()
 160          * can handle properly
 161          */
 162         smc_cdc_add_pending_send(conn, pend);
 163
 164         atomic_inc(&conn->cdc_pend_tx_wr);
 165         smp_mb__after_atomic(); /* Make sure cdc_pend_tx_wr added before post */
 166
 167         rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend);
 168         if (unlikely(rc))
 169                 atomic_dec(&conn->cdc_pend_tx_wr);
 170
 171         return rc;
 172 }
 173
 174 static int smcr_cdc_get_slot_and_msg_send(struct smc_connection *conn)
 175 {
 176         struct smc_cdc_tx_pend *pend;
 177         struct smc_wr_buf *wr_buf;
 178         struct smc_link *link;
 179         bool again = false;
 180         int rc;
 181
 182 again:
 183         link = conn->lnk;
 184         if (!smc_wr_tx_link_hold(link))
 185                 return -ENOLINK;
 186         rc = smc_cdc_get_free_slot(conn, link, &wr_buf, NULL, &pend);
 187         if (rc)
 188                 goto put_out;
 189
 190         spin_lock_bh(&conn->send_lock);
 191         if (link != conn->lnk) {
 192                 /* link of connection changed, try again one time*/
 193                 spin_unlock_bh(&conn->send_lock);
 194                 smc_wr_tx_put_slot(link,
 195                                    (struct smc_wr_tx_pend_priv *)pend);
 196                 smc_wr_tx_link_put(link);
 197                 if (again)
 198                         return -ENOLINK;
 199                 again = true;
 200                 goto again;
 201         }
 202         rc = smc_cdc_msg_send(conn, wr_buf, pend);
 203         spin_unlock_bh(&conn->send_lock);
 204 put_out:
 205         smc_wr_tx_link_put(link);
 206         return rc;
 207 }
 208
 209 int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn)
 210 {
 211         int rc;
 212
 213         if (!smc_conn_lgr_valid(conn) ||
 214             (conn->lgr->is_smcd && conn->lgr->peer_shutdown))
 215                 return -EPIPE;
 216
 217         if (conn->lgr->is_smcd) {
 218                 spin_lock_bh(&conn->send_lock);
 219                 rc = smcd_cdc_msg_send(conn);
 220                 spin_unlock_bh(&conn->send_lock);
 221         } else {
 222                 rc = smcr_cdc_get_slot_and_msg_send(conn);
 223         }
 224
 225         return rc;
 226 }
 227
 228 void smc_cdc_wait_pend_tx_wr(struct smc_connection *conn)
 229 {
 230         wait_event(conn->cdc_pend_tx_wq, !atomic_read(&conn->cdc_pend_tx_wr));
 231 }
 232
 233 /* Send a SMC-D CDC header.
 234  * This increments the free space available in our send buffer.
 235  * Also update the confirmed receive buffer with what was sent to the peer.
 236  */
 237 int smcd_cdc_msg_send(struct smc_connection *conn)
 238 {
 239         struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
 240         union smc_host_cursor curs;
 241         struct smcd_cdc_msg cdc;
 242         int rc, diff;
 243
 244         memset(&cdc, 0, sizeof(cdc));
 245         cdc.common.type = SMC_CDC_MSG_TYPE;
 246         curs.acurs.counter = atomic64_read(&conn->local_tx_ctrl.prod.acurs);
 247         cdc.prod.wrap = curs.wrap;
 248         cdc.prod.count = curs.count;
 249         curs.acurs.counter = atomic64_read(&conn->local_tx_ctrl.cons.acurs);
 250         cdc.cons.wrap = curs.wrap;
 251         cdc.cons.count = curs.count;
 252         cdc.cons.prod_flags = conn->local_tx_ctrl.prod_flags;
 253         cdc.cons.conn_state_flags = conn->local_tx_ctrl.conn_state_flags;
 254         rc = smcd_tx_ism_write(conn, &cdc, sizeof(cdc), 0, 1);
 255         if (rc)
 256                 return rc;
 257         smc_curs_copy(&conn->rx_curs_confirmed, &curs, conn);
 258         conn->local_rx_ctrl.prod_flags.cons_curs_upd_req = 0;
 259         /* Calculate transmitted data and increment free send buffer space */
 260         diff = smc_curs_diff(conn->sndbuf_desc->len, &conn->tx_curs_fin,
 261                              &conn->tx_curs_sent);
 262         /* increased by confirmed number of bytes */
 263         smp_mb__before_atomic();
 264         atomic_add(diff, &conn->sndbuf_space);
 265         /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
 266         smp_mb__after_atomic();
 267         smc_curs_copy(&conn->tx_curs_fin, &conn->tx_curs_sent, conn);
 268
 269         smc_tx_sndbuf_nonfull(smc);
 270         return rc;
 271 }
 272
 273 /********************************* receive ***********************************/
 274
 275 static inline bool smc_cdc_before(u16 seq1, u16 seq2)
 276 {
 277         return (s16)(seq1 - seq2) < 0;
 278 }
 279
 280 static void smc_cdc_handle_urg_data_arrival(struct smc_sock *smc,
 281                                             int *diff_prod)
 282 {
 283         struct smc_connection *conn = &smc->conn;
 284         char *base;
 285
 286         /* new data included urgent business */
 287         smc_curs_copy(&conn->urg_curs, &conn->local_rx_ctrl.prod, conn);
 288         conn->urg_state = SMC_URG_VALID;
 289         if (!sock_flag(&smc->sk, SOCK_URGINLINE))
 290                 /* we'll skip the urgent byte, so don't account for it */
 291                 (*diff_prod)--;
 292         base = (char *)conn->rmb_desc->cpu_addr + conn->rx_off;
 293         if (conn->urg_curs.count)
 294                 conn->urg_rx_byte = *(base + conn->urg_curs.count - 1);
 295         else
 296                 conn->urg_rx_byte = *(base + conn->rmb_desc->len - 1);
 297         sk_send_sigurg(&smc->sk);
 298 }
 299
 300 static void smc_cdc_msg_validate(struct smc_sock *smc, struct smc_cdc_msg *cdc,
 301                                  struct smc_link *link)
 302 {
 303         struct smc_connection *conn = &smc->conn;
 304         u16 recv_seq = ntohs(cdc->seqno);
 305         s16 diff;
 306
 307         /* check that seqnum was seen before */
 308         diff = conn->local_rx_ctrl.seqno - recv_seq;
 309         if (diff < 0) { /* diff larger than 0x7fff */
 310                 /* drop connection */
 311                 conn->out_of_sync = 1;  /* prevent any further receives */
 312                 spin_lock_bh(&conn->send_lock);
 313                 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
 314                 conn->lnk = link;
 315                 spin_unlock_bh(&conn->send_lock);
 316                 sock_hold(&smc->sk); /* sock_put in abort_work */
 317                 if (!queue_work(smc_close_wq, &conn->abort_work))
 318                         sock_put(&smc->sk);
 319         }
 320 }
 321
 322 static void smc_cdc_msg_recv_action(struct smc_sock *smc,
 323                                     struct smc_cdc_msg *cdc)
 324 {
 325         union smc_host_cursor cons_old, prod_old;
 326         struct smc_connection *conn = &smc->conn;
 327         int diff_cons, diff_prod;
 328
 329         smc_curs_copy(&prod_old, &conn->local_rx_ctrl.prod, conn);
 330         smc_curs_copy(&cons_old, &conn->local_rx_ctrl.cons, conn);
 331         smc_cdc_msg_to_host(&conn->local_rx_ctrl, cdc, conn);
 332
 333         diff_cons = smc_curs_diff(conn->peer_rmbe_size, &cons_old,
 334                                   &conn->local_rx_ctrl.cons);
 335         if (diff_cons) {
 336                 /* peer_rmbe_space is decreased during data transfer with RDMA
 337                  * write
 338                  */
 339                 smp_mb__before_atomic();
 340                 atomic_add(diff_cons, &conn->peer_rmbe_space);
 341                 /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */
 342                 smp_mb__after_atomic();
 343         }
 344
 345         diff_prod = smc_curs_diff(conn->rmb_desc->len, &prod_old,
 346                                   &conn->local_rx_ctrl.prod);
 347         if (diff_prod) {
 348                 if (conn->local_rx_ctrl.prod_flags.urg_data_present)
 349                         smc_cdc_handle_urg_data_arrival(smc, &diff_prod);
 350                 /* bytes_to_rcv is decreased in smc_recvmsg */
 351                 smp_mb__before_atomic();
 352                 atomic_add(diff_prod, &conn->bytes_to_rcv);
 353                 /* guarantee 0 <= bytes_to_rcv <= rmb_desc->len */
 354                 smp_mb__after_atomic();
 355                 smc->sk.sk_data_ready(&smc->sk);
 356         } else {
 357                 if (conn->local_rx_ctrl.prod_flags.write_blocked)
 358                         smc->sk.sk_data_ready(&smc->sk);
 359                 if (conn->local_rx_ctrl.prod_flags.urg_data_pending)
 360                         conn->urg_state = SMC_URG_NOTYET;
 361         }
 362
 363         /* trigger sndbuf consumer: RDMA write into peer RMBE and CDC */
 364         if ((diff_cons && smc_tx_prepared_sends(conn)) ||
 365             conn->local_rx_ctrl.prod_flags.cons_curs_upd_req ||
 366             conn->local_rx_ctrl.prod_flags.urg_data_pending) {
 367                 if (!sock_owned_by_user(&smc->sk))
 368                         smc_tx_pending(conn);
 369                 else
 370                         conn->tx_in_release_sock = true;
 371         }
 372
 373         if (diff_cons && conn->urg_tx_pend &&
 374             atomic_read(&conn->peer_rmbe_space) == conn->peer_rmbe_size) {
 375                 /* urg data confirmed by peer, indicate we're ready for more */
 376                 conn->urg_tx_pend = false;
 377                 smc->sk.sk_write_space(&smc->sk);
 378         }
 379
 380         if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) {
 381                 smc->sk.sk_err = ECONNRESET;
 382                 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
 383         }
 384         if (smc_cdc_rxed_any_close_or_senddone(conn)) {
 385                 smc->sk.sk_shutdown |= RCV_SHUTDOWN;
 386                 if (smc->clcsock && smc->clcsock->sk)
 387                         smc->clcsock->sk->sk_shutdown |= RCV_SHUTDOWN;
 388                 sock_set_flag(&smc->sk, SOCK_DONE);
 389                 sock_hold(&smc->sk); /* sock_put in close_work */
 390                 if (!queue_work(smc_close_wq, &conn->close_work))
 391                         sock_put(&smc->sk);
 392         }
 393 }
 394
 395 /* called under tasklet context */
 396 static void smc_cdc_msg_recv(struct smc_sock *smc, struct smc_cdc_msg *cdc)
 397 {
 398         sock_hold(&smc->sk);
 399         bh_lock_sock(&smc->sk);
 400         smc_cdc_msg_recv_action(smc, cdc);
 401         bh_unlock_sock(&smc->sk);
 402         sock_put(&smc->sk); /* no free sk in softirq-context */
 403 }
 404
 405 /* Schedule a tasklet for this connection. Triggered from the ISM device IRQ
 406  * handler to indicate update in the DMBE.
 407  *
 408  * Context:
 409  * - tasklet context
 410  */
 411 static void smcd_cdc_rx_tsklet(struct tasklet_struct *t)
 412 {
 413         struct smc_connection *conn = from_tasklet(conn, t, rx_tsklet);
 414         struct smcd_cdc_msg *data_cdc;
 415         struct smcd_cdc_msg cdc;
 416         struct smc_sock *smc;
 417
 418         if (!conn || conn->killed)
 419                 return;
 420
 421         data_cdc = (struct smcd_cdc_msg *)conn->rmb_desc->cpu_addr;
 422         smcd_curs_copy(&cdc.prod, &data_cdc->prod, conn);
 423         smcd_curs_copy(&cdc.cons, &data_cdc->cons, conn);
 424         smc = container_of(conn, struct smc_sock, conn);
 425         smc_cdc_msg_recv(smc, (struct smc_cdc_msg *)&cdc);
 426 }
 427
 428 /* Initialize receive tasklet. Called from ISM device IRQ handler to start
 429  * receiver side.
 430  */
 431 void smcd_cdc_rx_init(struct smc_connection *conn)
 432 {
 433         tasklet_setup(&conn->rx_tsklet, smcd_cdc_rx_tsklet);
 434 }
 435
 436 /***************************** init, exit, misc ******************************/
 437
 438 static void smc_cdc_rx_handler(struct ib_wc *wc, void *buf)
 439 {
 440         struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
 441         struct smc_cdc_msg *cdc = buf;
 442         struct smc_connection *conn;
 443         struct smc_link_group *lgr;
 444         struct smc_sock *smc;
 445
 446         if (wc->byte_len < offsetof(struct smc_cdc_msg, reserved))
 447                 return; /* short message */
 448         if (cdc->len != SMC_WR_TX_SIZE)
 449                 return; /* invalid message */
 450
 451         /* lookup connection */
 452         lgr = smc_get_lgr(link);
 453         read_lock_bh(&lgr->conns_lock);
 454         conn = smc_lgr_find_conn(ntohl(cdc->token), lgr);
 455         read_unlock_bh(&lgr->conns_lock);
 456         if (!conn || conn->out_of_sync)
 457                 return;
 458         smc = container_of(conn, struct smc_sock, conn);
 459
 460         if (cdc->prod_flags.failover_validation) {
 461                 smc_cdc_msg_validate(smc, cdc, link);
 462                 return;
 463         }
 464         if (smc_cdc_before(ntohs(cdc->seqno),
 465                            conn->local_rx_ctrl.seqno))
 466                 /* received seqno is old */
 467                 return;
 468
 469         smc_cdc_msg_recv(smc, cdc);
 470 }
 471
 472 static struct smc_wr_rx_handler smc_cdc_rx_handlers[] = {
 473         {
 474                 .handler        = smc_cdc_rx_handler,
 475                 .type           = SMC_CDC_MSG_TYPE
 476         },
 477         {
 478                 .handler        = NULL,
 479         }
 480 };
 481
 482 int __init smc_cdc_init(void)
 483 {
 484         struct smc_wr_rx_handler *handler;
 485         int rc = 0;
 486
 487         for (handler = smc_cdc_rx_handlers; handler->handler; handler++) {
 488                 INIT_HLIST_NODE(&handler->list);
 489                 rc = smc_wr_rx_register_handler(handler);
 490                 if (rc)
 491                         break;
 492         }
 493         return rc;
 494 }