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 struct smc_cdc_tx_pend {
  25         struct smc_connection   *conn;          /* socket connection */
  26         union smc_host_cursor   cursor; /* tx sndbuf cursor sent */
  27         union smc_host_cursor   p_cursor;       /* rx RMBE cursor produced */
  28         u16                     ctrl_seq;       /* conn. tx sequence # */
  29 };
  30
  31 /* handler for send/transmission completion of a CDC msg */
  32 static void smc_cdc_tx_handler(struct smc_wr_tx_pend_priv *pnd_snd,
  33                                struct smc_link *link,
  34                                enum ib_wc_status wc_status)
  35 {
  36         struct smc_cdc_tx_pend *cdcpend = (struct smc_cdc_tx_pend *)pnd_snd;
  37         struct smc_connection *conn = cdcpend->conn;
  38         struct smc_sock *smc;
  39         int diff;
  40
  41         if (!conn)
  42                 /* already dismissed */
  43                 return;
  44
  45         smc = container_of(conn, struct smc_sock, conn);
  46         bh_lock_sock(&smc->sk);
  47         if (!wc_status) {
  48                 diff = smc_curs_diff(cdcpend->conn->sndbuf_desc->len,
  49                                      &cdcpend->conn->tx_curs_fin,
  50                                      &cdcpend->cursor);
  51                 /* sndbuf_space is decreased in smc_sendmsg */
  52                 smp_mb__before_atomic();
  53                 atomic_add(diff, &cdcpend->conn->sndbuf_space);
  54                 /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
  55                 smp_mb__after_atomic();
  56                 smc_curs_copy(&conn->tx_curs_fin, &cdcpend->cursor, conn);
  57         }
  58         smc_tx_sndbuf_nonfull(smc);
  59         bh_unlock_sock(&smc->sk);
  60 }
  61
  62 int smc_cdc_get_free_slot(struct smc_connection *conn,
  63                           struct smc_wr_buf **wr_buf,
  64                           struct smc_cdc_tx_pend **pend)
  65 {
  66         struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
  67         int rc;
  68
  69         rc = smc_wr_tx_get_free_slot(link, smc_cdc_tx_handler, wr_buf,
  70                                      (struct smc_wr_tx_pend_priv **)pend);
  71         if (!conn->alert_token_local)
  72                 /* abnormal termination */
  73                 rc = -EPIPE;
  74         return rc;
  75 }
  76
  77 static inline void smc_cdc_add_pending_send(struct smc_connection *conn,
  78                                             struct smc_cdc_tx_pend *pend)
  79 {
  80         BUILD_BUG_ON_MSG(
  81                 sizeof(struct smc_cdc_msg) > SMC_WR_BUF_SIZE,
  82                 "must increase SMC_WR_BUF_SIZE to at least sizeof(struct smc_cdc_msg)");
  83         BUILD_BUG_ON_MSG(
  84                 sizeof(struct smc_cdc_msg) != SMC_WR_TX_SIZE,
  85                 "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()");
  86         BUILD_BUG_ON_MSG(
  87                 sizeof(struct smc_cdc_tx_pend) > SMC_WR_TX_PEND_PRIV_SIZE,
  88                 "must increase SMC_WR_TX_PEND_PRIV_SIZE to at least sizeof(struct smc_cdc_tx_pend)");
  89         pend->conn = conn;
  90         pend->cursor = conn->tx_curs_sent;
  91         pend->p_cursor = conn->local_tx_ctrl.prod;
  92         pend->ctrl_seq = conn->tx_cdc_seq;
  93 }
  94
  95 int smc_cdc_msg_send(struct smc_connection *conn,
  96                      struct smc_wr_buf *wr_buf,
  97                      struct smc_cdc_tx_pend *pend)
  98 {
  99         struct smc_link *link;
 100         int rc;
 101
 102         link = &conn->lgr->lnk[SMC_SINGLE_LINK];
 103
 104         smc_cdc_add_pending_send(conn, pend);
 105
 106         conn->tx_cdc_seq++;
 107         conn->local_tx_ctrl.seqno = conn->tx_cdc_seq;
 108         smc_host_msg_to_cdc((struct smc_cdc_msg *)wr_buf,
 109                             &conn->local_tx_ctrl, conn);
 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,
 113                               &conn->local_tx_ctrl.cons, conn);
 114
 115         return rc;
 116 }
 117
 118 static int smcr_cdc_get_slot_and_msg_send(struct smc_connection *conn)
 119 {
 120         struct smc_cdc_tx_pend *pend;
 121         struct smc_wr_buf *wr_buf;
 122         int rc;
 123
 124         rc = smc_cdc_get_free_slot(conn, &wr_buf, &pend);
 125         if (rc)
 126                 return rc;
 127
 128         return smc_cdc_msg_send(conn, wr_buf, pend);
 129 }
 130
 131 int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn)
 132 {
 133         int rc;
 134
 135         if (conn->lgr->is_smcd) {
 136                 spin_lock_bh(&conn->send_lock);
 137                 rc = smcd_cdc_msg_send(conn);
 138                 spin_unlock_bh(&conn->send_lock);
 139         } else {
 140                 rc = smcr_cdc_get_slot_and_msg_send(conn);
 141         }
 142
 143         return rc;
 144 }
 145
 146 static bool smc_cdc_tx_filter(struct smc_wr_tx_pend_priv *tx_pend,
 147                               unsigned long data)
 148 {
 149         struct smc_connection *conn = (struct smc_connection *)data;
 150         struct smc_cdc_tx_pend *cdc_pend =
 151                 (struct smc_cdc_tx_pend *)tx_pend;
 152
 153         return cdc_pend->conn == conn;
 154 }
 155
 156 static void smc_cdc_tx_dismisser(struct smc_wr_tx_pend_priv *tx_pend)
 157 {
 158         struct smc_cdc_tx_pend *cdc_pend =
 159                 (struct smc_cdc_tx_pend *)tx_pend;
 160
 161         cdc_pend->conn = NULL;
 162 }
 163
 164 void smc_cdc_tx_dismiss_slots(struct smc_connection *conn)
 165 {
 166         struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
 167
 168         smc_wr_tx_dismiss_slots(link, SMC_CDC_MSG_TYPE,
 169                                 smc_cdc_tx_filter, smc_cdc_tx_dismisser,
 170                                 (unsigned long)conn);
 171 }
 172
 173 /* Send a SMC-D CDC header.
 174  * This increments the free space available in our send buffer.
 175  * Also update the confirmed receive buffer with what was sent to the peer.
 176  */
 177 int smcd_cdc_msg_send(struct smc_connection *conn)
 178 {
 179         struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
 180         struct smcd_cdc_msg cdc;
 181         int rc, diff;
 182
 183         memset(&cdc, 0, sizeof(cdc));
 184         cdc.common.type = SMC_CDC_MSG_TYPE;
 185         cdc.prod_wrap = conn->local_tx_ctrl.prod.wrap;
 186         cdc.prod_count = conn->local_tx_ctrl.prod.count;
 187
 188         cdc.cons_wrap = conn->local_tx_ctrl.cons.wrap;
 189         cdc.cons_count = conn->local_tx_ctrl.cons.count;
 190         cdc.prod_flags = conn->local_tx_ctrl.prod_flags;
 191         cdc.conn_state_flags = conn->local_tx_ctrl.conn_state_flags;
 192         rc = smcd_tx_ism_write(conn, &cdc, sizeof(cdc), 0, 1);
 193         if (rc)
 194                 return rc;
 195         smc_curs_copy(&conn->rx_curs_confirmed, &conn->local_tx_ctrl.cons,
 196                       conn);
 197         /* Calculate transmitted data and increment free send buffer space */
 198         diff = smc_curs_diff(conn->sndbuf_desc->len, &conn->tx_curs_fin,
 199                              &conn->tx_curs_sent);
 200         /* increased by confirmed number of bytes */
 201         smp_mb__before_atomic();
 202         atomic_add(diff, &conn->sndbuf_space);
 203         /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
 204         smp_mb__after_atomic();
 205         smc_curs_copy(&conn->tx_curs_fin, &conn->tx_curs_sent, conn);
 206
 207         smc_tx_sndbuf_nonfull(smc);
 208         return rc;
 209 }
 210
 211 /********************************* receive ***********************************/
 212
 213 static inline bool smc_cdc_before(u16 seq1, u16 seq2)
 214 {
 215         return (s16)(seq1 - seq2) < 0;
 216 }
 217
 218 static void smc_cdc_handle_urg_data_arrival(struct smc_sock *smc,
 219                                             int *diff_prod)
 220 {
 221         struct smc_connection *conn = &smc->conn;
 222         char *base;
 223
 224         /* new data included urgent business */
 225         smc_curs_copy(&conn->urg_curs, &conn->local_rx_ctrl.prod, conn);
 226         conn->urg_state = SMC_URG_VALID;
 227         if (!sock_flag(&smc->sk, SOCK_URGINLINE))
 228                 /* we'll skip the urgent byte, so don't account for it */
 229                 (*diff_prod)--;
 230         base = (char *)conn->rmb_desc->cpu_addr + conn->rx_off;
 231         if (conn->urg_curs.count)
 232                 conn->urg_rx_byte = *(base + conn->urg_curs.count - 1);
 233         else
 234                 conn->urg_rx_byte = *(base + conn->rmb_desc->len - 1);
 235         sk_send_sigurg(&smc->sk);
 236 }
 237
 238 static void smc_cdc_msg_recv_action(struct smc_sock *smc,
 239                                     struct smc_cdc_msg *cdc)
 240 {
 241         union smc_host_cursor cons_old, prod_old;
 242         struct smc_connection *conn = &smc->conn;
 243         int diff_cons, diff_prod;
 244
 245         smc_curs_copy(&prod_old, &conn->local_rx_ctrl.prod, conn);
 246         smc_curs_copy(&cons_old, &conn->local_rx_ctrl.cons, conn);
 247         smc_cdc_msg_to_host(&conn->local_rx_ctrl, cdc, conn);
 248
 249         diff_cons = smc_curs_diff(conn->peer_rmbe_size, &cons_old,
 250                                   &conn->local_rx_ctrl.cons);
 251         if (diff_cons) {
 252                 /* peer_rmbe_space is decreased during data transfer with RDMA
 253                  * write
 254                  */
 255                 smp_mb__before_atomic();
 256                 atomic_add(diff_cons, &conn->peer_rmbe_space);
 257                 /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */
 258                 smp_mb__after_atomic();
 259         }
 260
 261         diff_prod = smc_curs_diff(conn->rmb_desc->len, &prod_old,
 262                                   &conn->local_rx_ctrl.prod);
 263         if (diff_prod) {
 264                 if (conn->local_rx_ctrl.prod_flags.urg_data_present)
 265                         smc_cdc_handle_urg_data_arrival(smc, &diff_prod);
 266                 /* bytes_to_rcv is decreased in smc_recvmsg */
 267                 smp_mb__before_atomic();
 268                 atomic_add(diff_prod, &conn->bytes_to_rcv);
 269                 /* guarantee 0 <= bytes_to_rcv <= rmb_desc->len */
 270                 smp_mb__after_atomic();
 271                 smc->sk.sk_data_ready(&smc->sk);
 272         } else {
 273                 if (conn->local_rx_ctrl.prod_flags.write_blocked ||
 274                     conn->local_rx_ctrl.prod_flags.cons_curs_upd_req ||
 275                     conn->local_rx_ctrl.prod_flags.urg_data_pending) {
 276                         if (conn->local_rx_ctrl.prod_flags.urg_data_pending)
 277                                 conn->urg_state = SMC_URG_NOTYET;
 278                         /* force immediate tx of current consumer cursor, but
 279                          * under send_lock to guarantee arrival in seqno-order
 280                          */
 281                         if (smc->sk.sk_state != SMC_INIT)
 282                                 smc_tx_sndbuf_nonempty(conn);
 283                 }
 284         }
 285
 286         /* piggy backed tx info */
 287         /* trigger sndbuf consumer: RDMA write into peer RMBE and CDC */
 288         if (diff_cons && smc_tx_prepared_sends(conn)) {
 289                 smc_tx_sndbuf_nonempty(conn);
 290                 /* trigger socket release if connection closed */
 291                 smc_close_wake_tx_prepared(smc);
 292         }
 293         if (diff_cons && conn->urg_tx_pend &&
 294             atomic_read(&conn->peer_rmbe_space) == conn->peer_rmbe_size) {
 295                 /* urg data confirmed by peer, indicate we're ready for more */
 296                 conn->urg_tx_pend = false;
 297                 smc->sk.sk_write_space(&smc->sk);
 298         }
 299
 300         if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) {
 301                 smc->sk.sk_err = ECONNRESET;
 302                 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
 303         }
 304         if (smc_cdc_rxed_any_close_or_senddone(conn)) {
 305                 smc->sk.sk_shutdown |= RCV_SHUTDOWN;
 306                 if (smc->clcsock && smc->clcsock->sk)
 307                         smc->clcsock->sk->sk_shutdown |= RCV_SHUTDOWN;
 308                 sock_set_flag(&smc->sk, SOCK_DONE);
 309                 sock_hold(&smc->sk); /* sock_put in close_work */
 310                 if (!schedule_work(&conn->close_work))
 311                         sock_put(&smc->sk);
 312         }
 313 }
 314
 315 /* called under tasklet context */
 316 static void smc_cdc_msg_recv(struct smc_sock *smc, struct smc_cdc_msg *cdc)
 317 {
 318         sock_hold(&smc->sk);
 319         bh_lock_sock(&smc->sk);
 320         smc_cdc_msg_recv_action(smc, cdc);
 321         bh_unlock_sock(&smc->sk);
 322         sock_put(&smc->sk); /* no free sk in softirq-context */
 323 }
 324
 325 /* Schedule a tasklet for this connection. Triggered from the ISM device IRQ
 326  * handler to indicate update in the DMBE.
 327  *
 328  * Context:
 329  * - tasklet context
 330  */
 331 static void smcd_cdc_rx_tsklet(unsigned long data)
 332 {
 333         struct smc_connection *conn = (struct smc_connection *)data;
 334         struct smcd_cdc_msg cdc;
 335         struct smc_sock *smc;
 336
 337         if (!conn)
 338                 return;
 339
 340         memcpy(&cdc, conn->rmb_desc->cpu_addr, sizeof(cdc));
 341         smc = container_of(conn, struct smc_sock, conn);
 342         smc_cdc_msg_recv(smc, (struct smc_cdc_msg *)&cdc);
 343 }
 344
 345 /* Initialize receive tasklet. Called from ISM device IRQ handler to start
 346  * receiver side.
 347  */
 348 void smcd_cdc_rx_init(struct smc_connection *conn)
 349 {
 350         tasklet_init(&conn->rx_tsklet, smcd_cdc_rx_tsklet, (unsigned long)conn);
 351 }
 352
 353 /***************************** init, exit, misc ******************************/
 354
 355 static void smc_cdc_rx_handler(struct ib_wc *wc, void *buf)
 356 {
 357         struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
 358         struct smc_cdc_msg *cdc = buf;
 359         struct smc_connection *conn;
 360         struct smc_link_group *lgr;
 361         struct smc_sock *smc;
 362
 363         if (wc->byte_len < offsetof(struct smc_cdc_msg, reserved))
 364                 return; /* short message */
 365         if (cdc->len != SMC_WR_TX_SIZE)
 366                 return; /* invalid message */
 367
 368         /* lookup connection */
 369         lgr = smc_get_lgr(link);
 370         read_lock_bh(&lgr->conns_lock);
 371         conn = smc_lgr_find_conn(ntohl(cdc->token), lgr);
 372         read_unlock_bh(&lgr->conns_lock);
 373         if (!conn)
 374                 return;
 375         smc = container_of(conn, struct smc_sock, conn);
 376
 377         if (!cdc->prod_flags.failover_validation) {
 378                 if (smc_cdc_before(ntohs(cdc->seqno),
 379                                    conn->local_rx_ctrl.seqno))
 380                         /* received seqno is old */
 381                         return;
 382         }
 383         smc_cdc_msg_recv(smc, cdc);
 384 }
 385
 386 static struct smc_wr_rx_handler smc_cdc_rx_handlers[] = {
 387         {
 388                 .handler        = smc_cdc_rx_handler,
 389                 .type           = SMC_CDC_MSG_TYPE
 390         },
 391         {
 392                 .handler        = NULL,
 393         }
 394 };
 395
 396 int __init smc_cdc_init(void)
 397 {
 398         struct smc_wr_rx_handler *handler;
 399         int rc = 0;
 400
 401         for (handler = smc_cdc_rx_handlers; handler->handler; handler++) {
 402                 INIT_HLIST_NODE(&handler->list);
 403                 rc = smc_wr_rx_register_handler(handler);
 404                 if (rc)
 405                         break;
 406         }
 407         return rc;
 408 }