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_sock *smc;
  38         int diff;
  39
  40         if (!cdcpend->conn)
  41                 /* already dismissed */
  42                 return;
  43
  44         smc = container_of(cdcpend->conn, struct smc_sock, conn);
  45         bh_lock_sock(&smc->sk);
  46         if (!wc_status) {
  47                 diff = smc_curs_diff(cdcpend->conn->sndbuf_desc->len,
  48                                      &cdcpend->conn->tx_curs_fin,
  49                                      &cdcpend->cursor);
  50                 /* sndbuf_space is decreased in smc_sendmsg */
  51                 smp_mb__before_atomic();
  52                 atomic_add(diff, &cdcpend->conn->sndbuf_space);
  53                 /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
  54                 smp_mb__after_atomic();
  55                 smc_curs_write(&cdcpend->conn->tx_curs_fin,
  56                                smc_curs_read(&cdcpend->cursor, cdcpend->conn),
  57                                cdcpend->conn);
  58         }
  59         smc_tx_sndbuf_nonfull(smc);
  60         bh_unlock_sock(&smc->sk);
  61 }
  62
  63 int smc_cdc_get_free_slot(struct smc_connection *conn,
  64                           struct smc_wr_buf **wr_buf,
  65                           struct smc_cdc_tx_pend **pend)
  66 {
  67         struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
  68         int rc;
  69
  70         rc = smc_wr_tx_get_free_slot(link, smc_cdc_tx_handler, wr_buf,
  71                                      (struct smc_wr_tx_pend_priv **)pend);
  72         if (!conn->alert_token_local)
  73                 /* abnormal termination */
  74                 rc = -EPIPE;
  75         return rc;
  76 }
  77
  78 static inline void smc_cdc_add_pending_send(struct smc_connection *conn,
  79                                             struct smc_cdc_tx_pend *pend)
  80 {
  81         BUILD_BUG_ON_MSG(
  82                 sizeof(struct smc_cdc_msg) > SMC_WR_BUF_SIZE,
  83                 "must increase SMC_WR_BUF_SIZE to at least sizeof(struct smc_cdc_msg)");
  84         BUILD_BUG_ON_MSG(
  85                 sizeof(struct smc_cdc_msg) != SMC_WR_TX_SIZE,
  86                 "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()");
  87         BUILD_BUG_ON_MSG(
  88                 sizeof(struct smc_cdc_tx_pend) > SMC_WR_TX_PEND_PRIV_SIZE,
  89                 "must increase SMC_WR_TX_PEND_PRIV_SIZE to at least sizeof(struct smc_cdc_tx_pend)");
  90         pend->conn = conn;
  91         pend->cursor = conn->tx_curs_sent;
  92         pend->p_cursor = conn->local_tx_ctrl.prod;
  93         pend->ctrl_seq = conn->tx_cdc_seq;
  94 }
  95
  96 int smc_cdc_msg_send(struct smc_connection *conn,
  97                      struct smc_wr_buf *wr_buf,
  98                      struct smc_cdc_tx_pend *pend)
  99 {
 100         struct smc_link *link;
 101         int rc;
 102
 103         link = &conn->lgr->lnk[SMC_SINGLE_LINK];
 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,
 110                             &conn->local_tx_ctrl, conn);
 111         rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend);
 112         if (!rc)
 113                 smc_curs_write(&conn->rx_curs_confirmed,
 114                                smc_curs_read(&conn->local_tx_ctrl.cons, conn),
 115                                conn);
 116
 117         return rc;
 118 }
 119
 120 int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn)
 121 {
 122         struct smc_cdc_tx_pend *pend;
 123         struct smc_wr_buf *wr_buf;
 124         int rc;
 125
 126         rc = smc_cdc_get_free_slot(conn, &wr_buf, &pend);
 127         if (rc)
 128                 return rc;
 129
 130         return smc_cdc_msg_send(conn, wr_buf, pend);
 131 }
 132
 133 static bool smc_cdc_tx_filter(struct smc_wr_tx_pend_priv *tx_pend,
 134                               unsigned long data)
 135 {
 136         struct smc_connection *conn = (struct smc_connection *)data;
 137         struct smc_cdc_tx_pend *cdc_pend =
 138                 (struct smc_cdc_tx_pend *)tx_pend;
 139
 140         return cdc_pend->conn == conn;
 141 }
 142
 143 static void smc_cdc_tx_dismisser(struct smc_wr_tx_pend_priv *tx_pend)
 144 {
 145         struct smc_cdc_tx_pend *cdc_pend =
 146                 (struct smc_cdc_tx_pend *)tx_pend;
 147
 148         cdc_pend->conn = NULL;
 149 }
 150
 151 void smc_cdc_tx_dismiss_slots(struct smc_connection *conn)
 152 {
 153         struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
 154
 155         smc_wr_tx_dismiss_slots(link, SMC_CDC_MSG_TYPE,
 156                                 smc_cdc_tx_filter, smc_cdc_tx_dismisser,
 157                                 (unsigned long)conn);
 158 }
 159
 160 /********************************* receive ***********************************/
 161
 162 static inline bool smc_cdc_before(u16 seq1, u16 seq2)
 163 {
 164         return (s16)(seq1 - seq2) < 0;
 165 }
 166
 167 static void smc_cdc_handle_urg_data_arrival(struct smc_sock *smc,
 168                                             int *diff_prod)
 169 {
 170         struct smc_connection *conn = &smc->conn;
 171         char *base;
 172
 173         /* new data included urgent business */
 174         smc_curs_write(&conn->urg_curs,
 175                        smc_curs_read(&conn->local_rx_ctrl.prod, conn),
 176                        conn);
 177         conn->urg_state = SMC_URG_VALID;
 178         if (!sock_flag(&smc->sk, SOCK_URGINLINE))
 179                 /* we'll skip the urgent byte, so don't account for it */
 180                 (*diff_prod)--;
 181         base = (char *)conn->rmb_desc->cpu_addr;
 182         if (conn->urg_curs.count)
 183                 conn->urg_rx_byte = *(base + conn->urg_curs.count - 1);
 184         else
 185                 conn->urg_rx_byte = *(base + conn->rmb_desc->len - 1);
 186         sk_send_sigurg(&smc->sk);
 187 }
 188
 189 static void smc_cdc_msg_recv_action(struct smc_sock *smc,
 190                                     struct smc_cdc_msg *cdc)
 191 {
 192         union smc_host_cursor cons_old, prod_old;
 193         struct smc_connection *conn = &smc->conn;
 194         int diff_cons, diff_prod;
 195
 196         smc_curs_write(&prod_old,
 197                        smc_curs_read(&conn->local_rx_ctrl.prod, conn),
 198                        conn);
 199         smc_curs_write(&cons_old,
 200                        smc_curs_read(&conn->local_rx_ctrl.cons, conn),
 201                        conn);
 202         smc_cdc_msg_to_host(&conn->local_rx_ctrl, cdc, conn);
 203
 204         diff_cons = smc_curs_diff(conn->peer_rmbe_size, &cons_old,
 205                                   &conn->local_rx_ctrl.cons);
 206         if (diff_cons) {
 207                 /* peer_rmbe_space is decreased during data transfer with RDMA
 208                  * write
 209                  */
 210                 smp_mb__before_atomic();
 211                 atomic_add(diff_cons, &conn->peer_rmbe_space);
 212                 /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */
 213                 smp_mb__after_atomic();
 214         }
 215
 216         diff_prod = smc_curs_diff(conn->rmb_desc->len, &prod_old,
 217                                   &conn->local_rx_ctrl.prod);
 218         if (diff_prod) {
 219                 if (conn->local_rx_ctrl.prod_flags.urg_data_present)
 220                         smc_cdc_handle_urg_data_arrival(smc, &diff_prod);
 221                 /* bytes_to_rcv is decreased in smc_recvmsg */
 222                 smp_mb__before_atomic();
 223                 atomic_add(diff_prod, &conn->bytes_to_rcv);
 224                 /* guarantee 0 <= bytes_to_rcv <= rmb_desc->len */
 225                 smp_mb__after_atomic();
 226                 smc->sk.sk_data_ready(&smc->sk);
 227         } else {
 228                 if (conn->local_rx_ctrl.prod_flags.write_blocked ||
 229                     conn->local_rx_ctrl.prod_flags.cons_curs_upd_req ||
 230                     conn->local_rx_ctrl.prod_flags.urg_data_pending) {
 231                         if (conn->local_rx_ctrl.prod_flags.urg_data_pending)
 232                                 conn->urg_state = SMC_URG_NOTYET;
 233                         /* force immediate tx of current consumer cursor, but
 234                          * under send_lock to guarantee arrival in seqno-order
 235                          */
 236                         smc_tx_sndbuf_nonempty(conn);
 237                 }
 238         }
 239
 240         /* piggy backed tx info */
 241         /* trigger sndbuf consumer: RDMA write into peer RMBE and CDC */
 242         if (diff_cons && smc_tx_prepared_sends(conn)) {
 243                 smc_tx_sndbuf_nonempty(conn);
 244                 /* trigger socket release if connection closed */
 245                 smc_close_wake_tx_prepared(smc);
 246         }
 247         if (diff_cons && conn->urg_tx_pend &&
 248             atomic_read(&conn->peer_rmbe_space) == conn->peer_rmbe_size) {
 249                 /* urg data confirmed by peer, indicate we're ready for more */
 250                 conn->urg_tx_pend = false;
 251                 smc->sk.sk_write_space(&smc->sk);
 252         }
 253
 254         if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) {
 255                 smc->sk.sk_err = ECONNRESET;
 256                 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
 257         }
 258         if (smc_cdc_rxed_any_close_or_senddone(conn)) {
 259                 smc->sk.sk_shutdown |= RCV_SHUTDOWN;
 260                 if (smc->clcsock && smc->clcsock->sk)
 261                         smc->clcsock->sk->sk_shutdown |= RCV_SHUTDOWN;
 262                 sock_set_flag(&smc->sk, SOCK_DONE);
 263                 sock_hold(&smc->sk); /* sock_put in close_work */
 264                 if (!schedule_work(&conn->close_work))
 265                         sock_put(&smc->sk);
 266         }
 267 }
 268
 269 /* called under tasklet context */
 270 static void smc_cdc_msg_recv(struct smc_sock *smc, struct smc_cdc_msg *cdc)
 271 {
 272         sock_hold(&smc->sk);
 273         bh_lock_sock(&smc->sk);
 274         smc_cdc_msg_recv_action(smc, cdc);
 275         bh_unlock_sock(&smc->sk);
 276         sock_put(&smc->sk); /* no free sk in softirq-context */
 277 }
 278
 279 /***************************** init, exit, misc ******************************/
 280
 281 static void smc_cdc_rx_handler(struct ib_wc *wc, void *buf)
 282 {
 283         struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
 284         struct smc_cdc_msg *cdc = buf;
 285         struct smc_connection *conn;
 286         struct smc_link_group *lgr;
 287         struct smc_sock *smc;
 288
 289         if (wc->byte_len < offsetof(struct smc_cdc_msg, reserved))
 290                 return; /* short message */
 291         if (cdc->len != SMC_WR_TX_SIZE)
 292                 return; /* invalid message */
 293
 294         /* lookup connection */
 295         lgr = container_of(link, struct smc_link_group, lnk[SMC_SINGLE_LINK]);
 296         read_lock_bh(&lgr->conns_lock);
 297         conn = smc_lgr_find_conn(ntohl(cdc->token), lgr);
 298         read_unlock_bh(&lgr->conns_lock);
 299         if (!conn)
 300                 return;
 301         smc = container_of(conn, struct smc_sock, conn);
 302
 303         if (!cdc->prod_flags.failover_validation) {
 304                 if (smc_cdc_before(ntohs(cdc->seqno),
 305                                    conn->local_rx_ctrl.seqno))
 306                         /* received seqno is old */
 307                         return;
 308         }
 309         smc_cdc_msg_recv(smc, cdc);
 310 }
 311
 312 static struct smc_wr_rx_handler smc_cdc_rx_handlers[] = {
 313         {
 314                 .handler        = smc_cdc_rx_handler,
 315                 .type           = SMC_CDC_MSG_TYPE
 316         },
 317         {
 318                 .handler        = NULL,
 319         }
 320 };
 321
 322 int __init smc_cdc_init(void)
 323 {
 324         struct smc_wr_rx_handler *handler;
 325         int rc = 0;
 326
 327         for (handler = smc_cdc_rx_handlers; handler->handler; handler++) {
 328                 INIT_HLIST_NODE(&handler->list);
 329                 rc = smc_wr_rx_register_handler(handler);
 330                 if (rc)
 331                         break;
 332         }
 333         return rc;
 334 }