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