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