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_size,
  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_size */
  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                 offsetof(struct smc_cdc_msg, reserved) > 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_msg_recv_action(struct smc_sock *smc,
 168                                     struct smc_link *link,
 169                                     struct smc_cdc_msg *cdc)
 170 {
 171         union smc_host_cursor cons_old, prod_old;
 172         struct smc_connection *conn = &smc->conn;
 173         int diff_cons, diff_prod;
 174
 175         if (!cdc->prod_flags.failover_validation) {
 176                 if (smc_cdc_before(ntohs(cdc->seqno),
 177                                    conn->local_rx_ctrl.seqno))
 178                         /* received seqno is old */
 179                         return;
 180         }
 181         smc_curs_write(&prod_old,
 182                        smc_curs_read(&conn->local_rx_ctrl.prod, conn),
 183                        conn);
 184         smc_curs_write(&cons_old,
 185                        smc_curs_read(&conn->local_rx_ctrl.cons, conn),
 186                        conn);
 187         smc_cdc_msg_to_host(&conn->local_rx_ctrl, cdc, conn);
 188
 189         diff_cons = smc_curs_diff(conn->peer_rmbe_size, &cons_old,
 190                                   &conn->local_rx_ctrl.cons);
 191         if (diff_cons) {
 192                 /* peer_rmbe_space is decreased during data transfer with RDMA
 193                  * write
 194                  */
 195                 smp_mb__before_atomic();
 196                 atomic_add(diff_cons, &conn->peer_rmbe_space);
 197                 /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */
 198                 smp_mb__after_atomic();
 199         }
 200
 201         diff_prod = smc_curs_diff(conn->rmbe_size, &prod_old,
 202                                   &conn->local_rx_ctrl.prod);
 203         if (diff_prod) {
 204                 /* bytes_to_rcv is decreased in smc_recvmsg */
 205                 smp_mb__before_atomic();
 206                 atomic_add(diff_prod, &conn->bytes_to_rcv);
 207                 /* guarantee 0 <= bytes_to_rcv <= rmbe_size */
 208                 smp_mb__after_atomic();
 209                 smc->sk.sk_data_ready(&smc->sk);
 210         } else if ((conn->local_rx_ctrl.prod_flags.write_blocked) ||
 211                    (conn->local_rx_ctrl.prod_flags.cons_curs_upd_req)) {
 212                 smc->sk.sk_data_ready(&smc->sk);
 213         }
 214
 215         /* piggy backed tx info */
 216         /* trigger sndbuf consumer: RDMA write into peer RMBE and CDC */
 217         if (diff_cons && smc_tx_prepared_sends(conn)) {
 218                 smc_tx_sndbuf_nonempty(conn);
 219                 /* trigger socket release if connection closed */
 220                 smc_close_wake_tx_prepared(smc);
 221         }
 222
 223         if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) {
 224                 smc->sk.sk_err = ECONNRESET;
 225                 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
 226         }
 227         if (smc_cdc_rxed_any_close_or_senddone(conn)) {
 228                 smc->sk.sk_shutdown |= RCV_SHUTDOWN;
 229                 if (smc->clcsock && smc->clcsock->sk)
 230                         smc->clcsock->sk->sk_shutdown |= RCV_SHUTDOWN;
 231                 sock_set_flag(&smc->sk, SOCK_DONE);
 232                 sock_hold(&smc->sk); /* sock_put in close_work */
 233                 if (!schedule_work(&conn->close_work))
 234                         sock_put(&smc->sk);
 235         }
 236 }
 237
 238 /* called under tasklet context */
 239 static inline void smc_cdc_msg_recv(struct smc_cdc_msg *cdc,
 240                                     struct smc_link *link, u64 wr_id)
 241 {
 242         struct smc_link_group *lgr = container_of(link, struct smc_link_group,
 243                                                   lnk[SMC_SINGLE_LINK]);
 244         struct smc_connection *connection;
 245         struct smc_sock *smc;
 246
 247         /* lookup connection */
 248         read_lock_bh(&lgr->conns_lock);
 249         connection = smc_lgr_find_conn(ntohl(cdc->token), lgr);
 250         if (!connection) {
 251                 read_unlock_bh(&lgr->conns_lock);
 252                 return;
 253         }
 254         smc = container_of(connection, struct smc_sock, conn);
 255         sock_hold(&smc->sk);
 256         read_unlock_bh(&lgr->conns_lock);
 257         bh_lock_sock(&smc->sk);
 258         smc_cdc_msg_recv_action(smc, link, cdc);
 259         bh_unlock_sock(&smc->sk);
 260         sock_put(&smc->sk); /* no free sk in softirq-context */
 261 }
 262
 263 /***************************** init, exit, misc ******************************/
 264
 265 static void smc_cdc_rx_handler(struct ib_wc *wc, void *buf)
 266 {
 267         struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
 268         struct smc_cdc_msg *cdc = buf;
 269
 270         if (wc->byte_len < offsetof(struct smc_cdc_msg, reserved))
 271                 return; /* short message */
 272         if (cdc->len != sizeof(*cdc))
 273                 return; /* invalid message */
 274         smc_cdc_msg_recv(cdc, link, wc->wr_id);
 275 }
 276
 277 static struct smc_wr_rx_handler smc_cdc_rx_handlers[] = {
 278         {
 279                 .handler        = smc_cdc_rx_handler,
 280                 .type           = SMC_CDC_MSG_TYPE
 281         },
 282         {
 283                 .handler        = NULL,
 284         }
 285 };
 286
 287 int __init smc_cdc_init(void)
 288 {
 289         struct smc_wr_rx_handler *handler;
 290         int rc = 0;
 291
 292         for (handler = smc_cdc_rx_handlers; handler->handler; handler++) {
 293                 INIT_HLIST_NODE(&handler->list);
 294                 rc = smc_wr_rx_register_handler(handler);
 295                 if (rc)
 296                         break;
 297         }
 298         return rc;
 299 }