LXR linux/net/smc/smc

   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 */
  25static 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        }
  51        smc_tx_sndbuf_nonfull(smc);
  52        bh_unlock_sock(&smc->sk);
  53}
  54
  55int smc_cdc_get_free_slot(struct smc_connection *conn,
  56                          struct smc_wr_buf **wr_buf,
  57                          struct smc_rdma_wr **wr_rdma_buf,
  58                          struct smc_cdc_tx_pend **pend)
  59{
  60        struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
  61        int rc;
  62
  63        rc = smc_wr_tx_get_free_slot(link, smc_cdc_tx_handler, wr_buf,
  64                                     wr_rdma_buf,
  65                                     (struct smc_wr_tx_pend_priv **)pend);
  66        if (conn->killed)
  67                /* abnormal termination */
  68                rc = -EPIPE;
  69        return rc;
  70}
  71
  72static inline void smc_cdc_add_pending_send(struct smc_connection *conn,
  73                                            struct smc_cdc_tx_pend *pend)
  74{
  75        BUILD_BUG_ON_MSG(
  76                sizeof(struct smc_cdc_msg) > SMC_WR_BUF_SIZE,
  77                "must increase SMC_WR_BUF_SIZE to at least sizeof(struct smc_cdc_msg)");
  78        BUILD_BUG_ON_MSG(
  79                offsetofend(struct smc_cdc_msg, reserved) > SMC_WR_TX_SIZE,
  80                "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()");
  81        BUILD_BUG_ON_MSG(
  82                sizeof(struct smc_cdc_tx_pend) > SMC_WR_TX_PEND_PRIV_SIZE,
  83                "must increase SMC_WR_TX_PEND_PRIV_SIZE to at least sizeof(struct smc_cdc_tx_pend)");
  84        pend->conn = conn;
  85        pend->cursor = conn->tx_curs_sent;
  86        pend->p_cursor = conn->local_tx_ctrl.prod;
  87        pend->ctrl_seq = conn->tx_cdc_seq;
  88}
  89
  90int smc_cdc_msg_send(struct smc_connection *conn,
  91                     struct smc_wr_buf *wr_buf,
  92                     struct smc_cdc_tx_pend *pend)
  93{
  94        union smc_host_cursor cfed;
  95        struct smc_link *link;
  96        int rc;
  97
  98        link = &conn->lgr->lnk[SMC_SINGLE_LINK];
  99
 100        smc_cdc_add_pending_send(conn, pend);
 101
 102        conn->tx_cdc_seq++;
 103        conn->local_tx_ctrl.seqno = conn->tx_cdc_seq;
 104        smc_host_msg_to_cdc((struct smc_cdc_msg *)wr_buf, conn, &cfed);
 105        rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend);
 106        if (!rc) {
 107                smc_curs_copy(&conn->rx_curs_confirmed, &cfed, conn);
 108                conn->local_rx_ctrl.prod_flags.cons_curs_upd_req = 0;
 109        }
 110
 111        return rc;
 112}
 113
 114static int smcr_cdc_get_slot_and_msg_send(struct smc_connection *conn)
 115{
 116        struct smc_cdc_tx_pend *pend;
 117        struct smc_wr_buf *wr_buf;
 118        int rc;
 119
 120        rc = smc_cdc_get_free_slot(conn, &wr_buf, NULL, &pend);
 121        if (rc)
 122                return rc;
 123
 124        spin_lock_bh(&conn->send_lock);
 125        rc = smc_cdc_msg_send(conn, wr_buf, pend);
 126        spin_unlock_bh(&conn->send_lock);
 127        return rc;
 128}
 129
 130int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn)
 131{
 132        int rc;
 133
 134        if (!conn->lgr || (conn->lgr->is_smcd && conn->lgr->peer_shutdown))
 135                return -EPIPE;
 136
 137        if (conn->lgr->is_smcd) {
 138                spin_lock_bh(&conn->send_lock);
 139                rc = smcd_cdc_msg_send(conn);
 140                spin_unlock_bh(&conn->send_lock);
 141        } else {
 142                rc = smcr_cdc_get_slot_and_msg_send(conn);
 143        }
 144
 145        return rc;
 146}
 147
 148static bool smc_cdc_tx_filter(struct smc_wr_tx_pend_priv *tx_pend,
 149                              unsigned long data)
 150{
 151        struct smc_connection *conn = (struct smc_connection *)data;
 152        struct smc_cdc_tx_pend *cdc_pend =
 153                (struct smc_cdc_tx_pend *)tx_pend;
 154
 155        return cdc_pend->conn == conn;
 156}
 157
 158static void smc_cdc_tx_dismisser(struct smc_wr_tx_pend_priv *tx_pend)
 159{
 160        struct smc_cdc_tx_pend *cdc_pend =
 161                (struct smc_cdc_tx_pend *)tx_pend;
 162
 163        cdc_pend->conn = NULL;
 164}
 165
 166void smc_cdc_tx_dismiss_slots(struct smc_connection *conn)
 167{
 168        struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
 169
 170        smc_wr_tx_dismiss_slots(link, SMC_CDC_MSG_TYPE,
 171                                smc_cdc_tx_filter, smc_cdc_tx_dismisser,
 172                                (unsigned long)conn);
 173}
 174
 175/* Send a SMC-D CDC header.
 176 * This increments the free space available in our send buffer.
 177 * Also update the confirmed receive buffer with what was sent to the peer.
 178 */
 179int smcd_cdc_msg_send(struct smc_connection *conn)
 180{
 181        struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
 182        union smc_host_cursor curs;
 183        struct smcd_cdc_msg cdc;
 184        int rc, diff;
 185
 186        memset(&cdc, 0, sizeof(cdc));
 187        cdc.common.type = SMC_CDC_MSG_TYPE;
 188        curs.acurs.counter = atomic64_read(&conn->local_tx_ctrl.prod.acurs);
 189        cdc.prod.wrap = curs.wrap;
 190        cdc.prod.count = curs.count;
 191        curs.acurs.counter = atomic64_read(&conn->local_tx_ctrl.cons.acurs);
 192        cdc.cons.wrap = curs.wrap;
 193        cdc.cons.count = curs.count;
 194        cdc.cons.prod_flags = conn->local_tx_ctrl.prod_flags;
 195        cdc.cons.conn_state_flags = conn->local_tx_ctrl.conn_state_flags;
 196        rc = smcd_tx_ism_write(conn, &cdc, sizeof(cdc), 0, 1);
 197        if (rc)
 198                return rc;
 199        smc_curs_copy(&conn->rx_curs_confirmed, &curs, conn);
 200        conn->local_rx_ctrl.prod_flags.cons_curs_upd_req = 0;
 201        /* Calculate transmitted data and increment free send buffer space */
 202        diff = smc_curs_diff(conn->sndbuf_desc->len, &conn->tx_curs_fin,
 203                             &conn->tx_curs_sent);
 204        /* increased by confirmed number of bytes */
 205        smp_mb__before_atomic();
 206        atomic_add(diff, &conn->sndbuf_space);
 207        /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
 208        smp_mb__after_atomic();
 209        smc_curs_copy(&conn->tx_curs_fin, &conn->tx_curs_sent, conn);
 210
 211        smc_tx_sndbuf_nonfull(smc);
 212        return rc;
 213}
 214
 215/********************************* receive ***********************************/
 216
 217static inline bool smc_cdc_before(u16 seq1, u16 seq2)
 218{
 219        return (s16)(seq1 - seq2) < 0;
 220}
 221
 222static void smc_cdc_handle_urg_data_arrival(struct smc_sock *smc,
 223                                            int *diff_prod)
 224{
 225        struct smc_connection *conn = &smc->conn;
 226        char *base;
 227
 228        /* new data included urgent business */
 229        smc_curs_copy(&conn->urg_curs, &conn->local_rx_ctrl.prod, conn);
 230        conn->urg_state = SMC_URG_VALID;
 231        if (!sock_flag(&smc->sk, SOCK_URGINLINE))
 232                /* we'll skip the urgent byte, so don't account for it */
 233                (*diff_prod)--;
 234        base = (char *)conn->rmb_desc->cpu_addr + conn->rx_off;
 235        if (conn->urg_curs.count)
 236                conn->urg_rx_byte = *(base + conn->urg_curs.count - 1);
 237        else
 238                conn->urg_rx_byte = *(base + conn->rmb_desc->len - 1);
 239        sk_send_sigurg(&smc->sk);
 240}
 241
 242static void smc_cdc_msg_recv_action(struct smc_sock *smc,
 243                                    struct smc_cdc_msg *cdc)
 244{
 245        union smc_host_cursor cons_old, prod_old;
 246        struct smc_connection *conn = &smc->conn;
 247        int diff_cons, diff_prod;
 248
 249        smc_curs_copy(&prod_old, &conn->local_rx_ctrl.prod, conn);
 250        smc_curs_copy(&cons_old, &conn->local_rx_ctrl.cons, conn);
 251        smc_cdc_msg_to_host(&conn->local_rx_ctrl, cdc, conn);
 252
 253        diff_cons = smc_curs_diff(conn->peer_rmbe_size, &cons_old,
 254                                  &conn->local_rx_ctrl.cons);
 255        if (diff_cons) {
 256                /* peer_rmbe_space is decreased during data transfer with RDMA
 257                 * write
 258                 */
 259                smp_mb__before_atomic();
 260                atomic_add(diff_cons, &conn->peer_rmbe_space);
 261                /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */
 262                smp_mb__after_atomic();
 263        }
 264
 265        diff_prod = smc_curs_diff(conn->rmb_desc->len, &prod_old,
 266                                  &conn->local_rx_ctrl.prod);
 267        if (diff_prod) {
 268                if (conn->local_rx_ctrl.prod_flags.urg_data_present)
 269                        smc_cdc_handle_urg_data_arrival(smc, &diff_prod);
 270                /* bytes_to_rcv is decreased in smc_recvmsg */
 271                smp_mb__before_atomic();
 272                atomic_add(diff_prod, &conn->bytes_to_rcv);
 273                /* guarantee 0 <= bytes_to_rcv <= rmb_desc->len */
 274                smp_mb__after_atomic();
 275                smc->sk.sk_data_ready(&smc->sk);
 276        } else {
 277                if (conn->local_rx_ctrl.prod_flags.write_blocked)
 278                        smc->sk.sk_data_ready(&smc->sk);
 279                if (conn->local_rx_ctrl.prod_flags.urg_data_pending)
 280                        conn->urg_state = SMC_URG_NOTYET;
 281        }
 282
 283        /* trigger sndbuf consumer: RDMA write into peer RMBE and CDC */
 284        if ((diff_cons && smc_tx_prepared_sends(conn)) ||
 285            conn->local_rx_ctrl.prod_flags.cons_curs_upd_req ||
 286            conn->local_rx_ctrl.prod_flags.urg_data_pending)
 287                smc_tx_sndbuf_nonempty(conn);
 288
 289        if (diff_cons && conn->urg_tx_pend &&
 290            atomic_read(&conn->peer_rmbe_space) == conn->peer_rmbe_size) {
 291                /* urg data confirmed by peer, indicate we're ready for more */
 292                conn->urg_tx_pend = false;
 293                smc->sk.sk_write_space(&smc->sk);
 294        }
 295
 296        if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) {
 297                smc->sk.sk_err = ECONNRESET;
 298                conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
 299        }
 300        if (smc_cdc_rxed_any_close_or_senddone(conn)) {
 301                smc->sk.sk_shutdown |= RCV_SHUTDOWN;
 302                if (smc->clcsock && smc->clcsock->sk)
 303                        smc->clcsock->sk->sk_shutdown |= RCV_SHUTDOWN;
 304                sock_set_flag(&smc->sk, SOCK_DONE);
 305                sock_hold(&smc->sk); /* sock_put in close_work */
 306                if (!schedule_work(&conn->close_work))
 307                        sock_put(&smc->sk);
 308        }
 309}
 310
 311/* called under tasklet context */
 312static void smc_cdc_msg_recv(struct smc_sock *smc, struct smc_cdc_msg *cdc)
 313{
 314        sock_hold(&smc->sk);
 315        bh_lock_sock(&smc->sk);
 316        smc_cdc_msg_recv_action(smc, cdc);
 317        bh_unlock_sock(&smc->sk);
 318        sock_put(&smc->sk); /* no free sk in softirq-context */
 319}
 320
 321/* Schedule a tasklet for this connection. Triggered from the ISM device IRQ
 322 * handler to indicate update in the DMBE.
 323 *
 324 * Context:
 325 * - tasklet context
 326 */
 327static void smcd_cdc_rx_tsklet(unsigned long data)
 328{
 329        struct smc_connection *conn = (struct smc_connection *)data;
 330        struct smcd_cdc_msg *data_cdc;
 331        struct smcd_cdc_msg cdc;
 332        struct smc_sock *smc;
 333
 334        if (!conn || conn->killed)
 335                return;
 336
 337        data_cdc = (struct smcd_cdc_msg *)conn->rmb_desc->cpu_addr;
 338        smcd_curs_copy(&cdc.prod, &data_cdc->prod, conn);
 339        smcd_curs_copy(&cdc.cons, &data_cdc->cons, conn);
 340        smc = container_of(conn, struct smc_sock, conn);
 341        smc_cdc_msg_recv(smc, (struct smc_cdc_msg *)&cdc);
 342}
 343
 344/* Initialize receive tasklet. Called from ISM device IRQ handler to start
 345 * receiver side.
 346 */
 347void smcd_cdc_rx_init(struct smc_connection *conn)
 348{
 349        tasklet_init(&conn->rx_tsklet, smcd_cdc_rx_tsklet, (unsigned long)conn);
 350}
 351
 352/***************************** init, exit, misc ******************************/
 353
 354static void smc_cdc_rx_handler(struct ib_wc *wc, void *buf)
 355{
 356        struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
 357        struct smc_cdc_msg *cdc = buf;
 358        struct smc_connection *conn;
 359        struct smc_link_group *lgr;
 360        struct smc_sock *smc;
 361
 362        if (wc->byte_len < offsetof(struct smc_cdc_msg, reserved))
 363                return; /* short message */
 364        if (cdc->len != SMC_WR_TX_SIZE)
 365                return; /* invalid message */
 366
 367        /* lookup connection */
 368        lgr = smc_get_lgr(link);
 369        read_lock_bh(&lgr->conns_lock);
 370        conn = smc_lgr_find_conn(ntohl(cdc->token), lgr);
 371        read_unlock_bh(&lgr->conns_lock);
 372        if (!conn)
 373                return;
 374        smc = container_of(conn, struct smc_sock, conn);
 375
 376        if (!cdc->prod_flags.failover_validation) {
 377                if (smc_cdc_before(ntohs(cdc->seqno),
 378                                   conn->local_rx_ctrl.seqno))
 379                        /* received seqno is old */
 380                        return;
 381        }
 382        smc_cdc_msg_recv(smc, cdc);
 383}
 384
 385static struct smc_wr_rx_handler smc_cdc_rx_handlers[] = {
 386        {
 387                .handler        = smc_cdc_rx_handler,
 388                .type           = SMC_CDC_MSG_TYPE
 389        },
 390        {
 391                .handler        = NULL,
 392        }
 393};
 394
 395int __init smc_cdc_init(void)
 396{
 397        struct smc_wr_rx_handler *handler;
 398        int rc = 0;
 399
 400        for (handler = smc_cdc_rx_handlers; handler->handler; handler++) {
 401                INIT_HLIST_NODE(&handler->list);
 402                rc = smc_wr_rx_register_handler(handler);
 403                if (rc)
 404                        break;
 405        }
 406        return rc;
 407}
 408