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             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 (!conn->lgr || (conn->lgr->is_smcd && conn->lgr->peer_shutdown))
 201                 return -EPIPE;
 202
 203         if (conn->lgr->is_smcd) {
 204                 spin_lock_bh(&conn->send_lock);
 205                 rc = smcd_cdc_msg_send(conn);
 206                 spin_unlock_bh(&conn->send_lock);
 207         } else {
 208                 rc = smcr_cdc_get_slot_and_msg_send(conn);
 209         }
 210
 211         return rc;
 212 }
 213
 214 void smc_cdc_wait_pend_tx_wr(struct smc_connection *conn)
 215 {
 216         wait_event(conn->cdc_pend_tx_wq, !atomic_read(&conn->cdc_pend_tx_wr));
 217 }
 218
 219 /* Send a SMC-D CDC header.
 220  * This increments the free space available in our send buffer.
 221  * Also update the confirmed receive buffer with what was sent to the peer.
 222  */
 223 int smcd_cdc_msg_send(struct smc_connection *conn)
 224 {
 225         struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
 226         union smc_host_cursor curs;
 227         struct smcd_cdc_msg cdc;
 228         int rc, diff;
 229
 230         memset(&cdc, 0, sizeof(cdc));
 231         cdc.common.type = SMC_CDC_MSG_TYPE;
 232         curs.acurs.counter = atomic64_read(&conn->local_tx_ctrl.prod.acurs);
 233         cdc.prod.wrap = curs.wrap;
 234         cdc.prod.count = curs.count;
 235         curs.acurs.counter = atomic64_read(&conn->local_tx_ctrl.cons.acurs);
 236         cdc.cons.wrap = curs.wrap;
 237         cdc.cons.count = curs.count;
 238         cdc.cons.prod_flags = conn->local_tx_ctrl.prod_flags;
 239         cdc.cons.conn_state_flags = conn->local_tx_ctrl.conn_state_flags;
 240         rc = smcd_tx_ism_write(conn, &cdc, sizeof(cdc), 0, 1);
 241         if (rc)
 242                 return rc;
 243         smc_curs_copy(&conn->rx_curs_confirmed, &curs, conn);
 244         conn->local_rx_ctrl.prod_flags.cons_curs_upd_req = 0;
 245         /* Calculate transmitted data and increment free send buffer space */
 246         diff = smc_curs_diff(conn->sndbuf_desc->len, &conn->tx_curs_fin,
 247                              &conn->tx_curs_sent);
 248         /* increased by confirmed number of bytes */
 249         smp_mb__before_atomic();
 250         atomic_add(diff, &conn->sndbuf_space);
 251         /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
 252         smp_mb__after_atomic();
 253         smc_curs_copy(&conn->tx_curs_fin, &conn->tx_curs_sent, conn);
 254
 255         smc_tx_sndbuf_nonfull(smc);
 256         return rc;
 257 }
 258
 259 /********************************* receive ***********************************/
 260
 261 static inline bool smc_cdc_before(u16 seq1, u16 seq2)
 262 {
 263         return (s16)(seq1 - seq2) < 0;
 264 }
 265
 266 static void smc_cdc_handle_urg_data_arrival(struct smc_sock *smc,
 267                                             int *diff_prod)
 268 {
 269         struct smc_connection *conn = &smc->conn;
 270         char *base;
 271
 272         /* new data included urgent business */
 273         smc_curs_copy(&conn->urg_curs, &conn->local_rx_ctrl.prod, conn);
 274         conn->urg_state = SMC_URG_VALID;
 275         if (!sock_flag(&smc->sk, SOCK_URGINLINE))
 276                 /* we'll skip the urgent byte, so don't account for it */
 277                 (*diff_prod)--;
 278         base = (char *)conn->rmb_desc->cpu_addr + conn->rx_off;
 279         if (conn->urg_curs.count)
 280                 conn->urg_rx_byte = *(base + conn->urg_curs.count - 1);
 281         else
 282                 conn->urg_rx_byte = *(base + conn->rmb_desc->len - 1);
 283         sk_send_sigurg(&smc->sk);
 284 }
 285
 286 static void smc_cdc_msg_validate(struct smc_sock *smc, struct smc_cdc_msg *cdc,
 287                                  struct smc_link *link)
 288 {
 289         struct smc_connection *conn = &smc->conn;
 290         u16 recv_seq = ntohs(cdc->seqno);
 291         s16 diff;
 292
 293         /* check that seqnum was seen before */
 294         diff = conn->local_rx_ctrl.seqno - recv_seq;
 295         if (diff < 0) { /* diff larger than 0x7fff */
 296                 /* drop connection */
 297                 conn->out_of_sync = 1;  /* prevent any further receives */
 298                 spin_lock_bh(&conn->send_lock);
 299                 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
 300                 conn->lnk = link;
 301                 spin_unlock_bh(&conn->send_lock);
 302                 sock_hold(&smc->sk); /* sock_put in abort_work */
 303                 if (!queue_work(smc_close_wq, &conn->abort_work))
 304                         sock_put(&smc->sk);
 305         }
 306 }
 307
 308 static void smc_cdc_msg_recv_action(struct smc_sock *smc,
 309                                     struct smc_cdc_msg *cdc)
 310 {
 311         union smc_host_cursor cons_old, prod_old;
 312         struct smc_connection *conn = &smc->conn;
 313         int diff_cons, diff_prod;
 314
 315         smc_curs_copy(&prod_old, &conn->local_rx_ctrl.prod, conn);
 316         smc_curs_copy(&cons_old, &conn->local_rx_ctrl.cons, conn);
 317         smc_cdc_msg_to_host(&conn->local_rx_ctrl, cdc, conn);
 318
 319         diff_cons = smc_curs_diff(conn->peer_rmbe_size, &cons_old,
 320                                   &conn->local_rx_ctrl.cons);
 321         if (diff_cons) {
 322                 /* peer_rmbe_space is decreased during data transfer with RDMA
 323                  * write
 324                  */
 325                 smp_mb__before_atomic();
 326                 atomic_add(diff_cons, &conn->peer_rmbe_space);
 327                 /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */
 328                 smp_mb__after_atomic();
 329         }
 330
 331         diff_prod = smc_curs_diff(conn->rmb_desc->len, &prod_old,
 332                                   &conn->local_rx_ctrl.prod);
 333         if (diff_prod) {
 334                 if (conn->local_rx_ctrl.prod_flags.urg_data_present)
 335                         smc_cdc_handle_urg_data_arrival(smc, &diff_prod);
 336                 /* bytes_to_rcv is decreased in smc_recvmsg */
 337                 smp_mb__before_atomic();
 338                 atomic_add(diff_prod, &conn->bytes_to_rcv);
 339                 /* guarantee 0 <= bytes_to_rcv <= rmb_desc->len */
 340                 smp_mb__after_atomic();
 341                 smc->sk.sk_data_ready(&smc->sk);
 342         } else {
 343                 if (conn->local_rx_ctrl.prod_flags.write_blocked)
 344                         smc->sk.sk_data_ready(&smc->sk);
 345                 if (conn->local_rx_ctrl.prod_flags.urg_data_pending)
 346                         conn->urg_state = SMC_URG_NOTYET;
 347         }
 348
 349         /* trigger sndbuf consumer: RDMA write into peer RMBE and CDC */
 350         if ((diff_cons && smc_tx_prepared_sends(conn)) ||
 351             conn->local_rx_ctrl.prod_flags.cons_curs_upd_req ||
 352             conn->local_rx_ctrl.prod_flags.urg_data_pending)
 353                 smc_tx_sndbuf_nonempty(conn);
 354
 355         if (diff_cons && conn->urg_tx_pend &&
 356             atomic_read(&conn->peer_rmbe_space) == conn->peer_rmbe_size) {
 357                 /* urg data confirmed by peer, indicate we're ready for more */
 358                 conn->urg_tx_pend = false;
 359                 smc->sk.sk_write_space(&smc->sk);
 360         }
 361
 362         if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) {
 363                 smc->sk.sk_err = ECONNRESET;
 364                 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
 365         }
 366         if (smc_cdc_rxed_any_close_or_senddone(conn)) {
 367                 smc->sk.sk_shutdown |= RCV_SHUTDOWN;
 368                 if (smc->clcsock && smc->clcsock->sk)
 369                         smc->clcsock->sk->sk_shutdown |= RCV_SHUTDOWN;
 370                 sock_set_flag(&smc->sk, SOCK_DONE);
 371                 sock_hold(&smc->sk); /* sock_put in close_work */
 372                 if (!queue_work(smc_close_wq, &conn->close_work))
 373                         sock_put(&smc->sk);
 374         }
 375 }
 376
 377 /* called under tasklet context */
 378 static void smc_cdc_msg_recv(struct smc_sock *smc, struct smc_cdc_msg *cdc)
 379 {
 380         sock_hold(&smc->sk);
 381         bh_lock_sock(&smc->sk);
 382         smc_cdc_msg_recv_action(smc, cdc);
 383         bh_unlock_sock(&smc->sk);
 384         sock_put(&smc->sk); /* no free sk in softirq-context */
 385 }
 386
 387 /* Schedule a tasklet for this connection. Triggered from the ISM device IRQ
 388  * handler to indicate update in the DMBE.
 389  *
 390  * Context:
 391  * - tasklet context
 392  */
 393 static void smcd_cdc_rx_tsklet(struct tasklet_struct *t)
 394 {
 395         struct smc_connection *conn = from_tasklet(conn, t, rx_tsklet);
 396         struct smcd_cdc_msg *data_cdc;
 397         struct smcd_cdc_msg cdc;
 398         struct smc_sock *smc;
 399
 400         if (!conn || conn->killed)
 401                 return;
 402
 403         data_cdc = (struct smcd_cdc_msg *)conn->rmb_desc->cpu_addr;
 404         smcd_curs_copy(&cdc.prod, &data_cdc->prod, conn);
 405         smcd_curs_copy(&cdc.cons, &data_cdc->cons, conn);
 406         smc = container_of(conn, struct smc_sock, conn);
 407         smc_cdc_msg_recv(smc, (struct smc_cdc_msg *)&cdc);
 408 }
 409
 410 /* Initialize receive tasklet. Called from ISM device IRQ handler to start
 411  * receiver side.
 412  */
 413 void smcd_cdc_rx_init(struct smc_connection *conn)
 414 {
 415         tasklet_setup(&conn->rx_tsklet, smcd_cdc_rx_tsklet);
 416 }
 417
 418 /***************************** init, exit, misc ******************************/
 419
 420 static void smc_cdc_rx_handler(struct ib_wc *wc, void *buf)
 421 {
 422         struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
 423         struct smc_cdc_msg *cdc = buf;
 424         struct smc_connection *conn;
 425         struct smc_link_group *lgr;
 426         struct smc_sock *smc;
 427
 428         if (wc->byte_len < offsetof(struct smc_cdc_msg, reserved))
 429                 return; /* short message */
 430         if (cdc->len != SMC_WR_TX_SIZE)
 431                 return; /* invalid message */
 432
 433         /* lookup connection */
 434         lgr = smc_get_lgr(link);
 435         read_lock_bh(&lgr->conns_lock);
 436         conn = smc_lgr_find_conn(ntohl(cdc->token), lgr);
 437         read_unlock_bh(&lgr->conns_lock);
 438         if (!conn || conn->out_of_sync)
 439                 return;
 440         smc = container_of(conn, struct smc_sock, conn);
 441
 442         if (cdc->prod_flags.failover_validation) {
 443                 smc_cdc_msg_validate(smc, cdc, link);
 444                 return;
 445         }
 446         if (smc_cdc_before(ntohs(cdc->seqno),
 447                            conn->local_rx_ctrl.seqno))
 448                 /* received seqno is old */
 449                 return;
 450
 451         smc_cdc_msg_recv(smc, cdc);
 452 }
 453
 454 static struct smc_wr_rx_handler smc_cdc_rx_handlers[] = {
 455         {
 456                 .handler        = smc_cdc_rx_handler,
 457                 .type           = SMC_CDC_MSG_TYPE
 458         },
 459         {
 460                 .handler        = NULL,
 461         }
 462 };
 463
 464 int __init smc_cdc_init(void)
 465 {
 466         struct smc_wr_rx_handler *handler;
 467         int rc = 0;
 468
 469         for (handler = smc_cdc_rx_handlers; handler->handler; handler++) {
 470                 INIT_HLIST_NODE(&handler->list);
 471                 rc = smc_wr_rx_register_handler(handler);
 472                 if (rc)
 473                         break;
 474         }
 475         return rc;
 476 }