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