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         if (smc->sk.sk_state != SMC_ACTIVE)
  61                 /* wake up smc_close_wait_tx_pends() */
  62                 smc->sk.sk_state_change(&smc->sk);
  63         bh_unlock_sock(&smc->sk);
  64 }
  65
  66 int smc_cdc_get_free_slot(struct smc_link *link,
  67                           struct smc_wr_buf **wr_buf,
  68                           struct smc_cdc_tx_pend **pend)
  69 {
  70         return smc_wr_tx_get_free_slot(link, smc_cdc_tx_handler, wr_buf,
  71                                        (struct smc_wr_tx_pend_priv **)pend);
  72 }
  73
  74 static inline void smc_cdc_add_pending_send(struct smc_connection *conn,
  75                                             struct smc_cdc_tx_pend *pend)
  76 {
  77         BUILD_BUG_ON_MSG(
  78                 sizeof(struct smc_cdc_msg) > SMC_WR_BUF_SIZE,
  79                 "must increase SMC_WR_BUF_SIZE to at least sizeof(struct smc_cdc_msg)");
  80         BUILD_BUG_ON_MSG(
  81                 offsetof(struct smc_cdc_msg, reserved) > SMC_WR_TX_SIZE,
  82                 "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()");
  83         BUILD_BUG_ON_MSG(
  84                 sizeof(struct smc_cdc_tx_pend) > SMC_WR_TX_PEND_PRIV_SIZE,
  85                 "must increase SMC_WR_TX_PEND_PRIV_SIZE to at least sizeof(struct smc_cdc_tx_pend)");
  86         pend->conn = conn;
  87         pend->cursor = conn->tx_curs_sent;
  88         pend->p_cursor = conn->local_tx_ctrl.prod;
  89         pend->ctrl_seq = conn->tx_cdc_seq;
  90 }
  91
  92 int smc_cdc_msg_send(struct smc_connection *conn,
  93                      struct smc_wr_buf *wr_buf,
  94                      struct smc_cdc_tx_pend *pend)
  95 {
  96         struct smc_link *link;
  97         int rc;
  98
  99         link = &conn->lgr->lnk[SMC_SINGLE_LINK];
 100
 101         smc_cdc_add_pending_send(conn, pend);
 102
 103         conn->tx_cdc_seq++;
 104         conn->local_tx_ctrl.seqno = conn->tx_cdc_seq;
 105         smc_host_msg_to_cdc((struct smc_cdc_msg *)wr_buf,
 106                             &conn->local_tx_ctrl, conn);
 107         rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend);
 108         if (!rc)
 109                 smc_curs_write(&conn->rx_curs_confirmed,
 110                                smc_curs_read(&conn->local_tx_ctrl.cons, conn),
 111                                conn);
 112
 113         return rc;
 114 }
 115
 116 int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn)
 117 {
 118         struct smc_cdc_tx_pend *pend;
 119         struct smc_wr_buf *wr_buf;
 120         int rc;
 121
 122         rc = smc_cdc_get_free_slot(&conn->lgr->lnk[SMC_SINGLE_LINK], &wr_buf,
 123                                    &pend);
 124         if (rc)
 125                 return rc;
 126
 127         return smc_cdc_msg_send(conn, wr_buf, pend);
 128 }
 129
 130 static bool smc_cdc_tx_filter(struct smc_wr_tx_pend_priv *tx_pend,
 131                               unsigned long data)
 132 {
 133         struct smc_connection *conn = (struct smc_connection *)data;
 134         struct smc_cdc_tx_pend *cdc_pend =
 135                 (struct smc_cdc_tx_pend *)tx_pend;
 136
 137         return cdc_pend->conn == conn;
 138 }
 139
 140 static void smc_cdc_tx_dismisser(struct smc_wr_tx_pend_priv *tx_pend)
 141 {
 142         struct smc_cdc_tx_pend *cdc_pend =
 143                 (struct smc_cdc_tx_pend *)tx_pend;
 144
 145         cdc_pend->conn = NULL;
 146 }
 147
 148 void smc_cdc_tx_dismiss_slots(struct smc_connection *conn)
 149 {
 150         struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
 151
 152         smc_wr_tx_dismiss_slots(link, SMC_CDC_MSG_TYPE,
 153                                 smc_cdc_tx_filter, smc_cdc_tx_dismisser,
 154                                 (unsigned long)conn);
 155 }
 156
 157 bool smc_cdc_tx_has_pending(struct smc_connection *conn)
 158 {
 159         struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
 160
 161         return smc_wr_tx_has_pending(link, SMC_CDC_MSG_TYPE,
 162                                      smc_cdc_tx_filter, (unsigned long)conn);
 163 }
 164
 165 /********************************* receive ***********************************/
 166
 167 static inline bool smc_cdc_before(u16 seq1, u16 seq2)
 168 {
 169         return (s16)(seq1 - seq2) < 0;
 170 }
 171
 172 static void smc_cdc_msg_recv_action(struct smc_sock *smc,
 173                                     struct smc_link *link,
 174                                     struct smc_cdc_msg *cdc)
 175 {
 176         union smc_host_cursor cons_old, prod_old;
 177         struct smc_connection *conn = &smc->conn;
 178         int diff_cons, diff_prod;
 179
 180         if (!cdc->prod_flags.failover_validation) {
 181                 if (smc_cdc_before(ntohs(cdc->seqno),
 182                                    conn->local_rx_ctrl.seqno))
 183                         /* received seqno is old */
 184                         return;
 185         }
 186         smc_curs_write(&prod_old,
 187                        smc_curs_read(&conn->local_rx_ctrl.prod, conn),
 188                        conn);
 189         smc_curs_write(&cons_old,
 190                        smc_curs_read(&conn->local_rx_ctrl.cons, conn),
 191                        conn);
 192         smc_cdc_msg_to_host(&conn->local_rx_ctrl, cdc, conn);
 193
 194         diff_cons = smc_curs_diff(conn->peer_rmbe_size, &cons_old,
 195                                   &conn->local_rx_ctrl.cons);
 196         if (diff_cons) {
 197                 /* peer_rmbe_space is decreased during data transfer with RDMA
 198                  * write
 199                  */
 200                 smp_mb__before_atomic();
 201                 atomic_add(diff_cons, &conn->peer_rmbe_space);
 202                 /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */
 203                 smp_mb__after_atomic();
 204         }
 205
 206         diff_prod = smc_curs_diff(conn->rmbe_size, &prod_old,
 207                                   &conn->local_rx_ctrl.prod);
 208         if (diff_prod) {
 209                 /* bytes_to_rcv is decreased in smc_recvmsg */
 210                 smp_mb__before_atomic();
 211                 atomic_add(diff_prod, &conn->bytes_to_rcv);
 212                 /* guarantee 0 <= bytes_to_rcv <= rmbe_size */
 213                 smp_mb__after_atomic();
 214                 smc->sk.sk_data_ready(&smc->sk);
 215         }
 216
 217         if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) {
 218                 smc->sk.sk_err = ECONNRESET;
 219                 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
 220         }
 221         if (smc_cdc_rxed_any_close_or_senddone(conn)) {
 222                 smc->sk.sk_shutdown |= RCV_SHUTDOWN;
 223                 if (smc->clcsock && smc->clcsock->sk)
 224                         smc->clcsock->sk->sk_shutdown |= RCV_SHUTDOWN;
 225                 sock_set_flag(&smc->sk, SOCK_DONE);
 226                 schedule_work(&conn->close_work);
 227         }
 228
 229         /* piggy backed tx info */
 230         /* trigger sndbuf consumer: RDMA write into peer RMBE and CDC */
 231         if (diff_cons && smc_tx_prepared_sends(conn)) {
 232                 smc_tx_sndbuf_nonempty(conn);
 233                 /* trigger socket release if connection closed */
 234                 smc_close_wake_tx_prepared(smc);
 235         }
 236
 237         /* socket connected but not accepted */
 238         if (!smc->sk.sk_socket)
 239                 return;
 240
 241         /* data available */
 242         if ((conn->local_rx_ctrl.prod_flags.write_blocked) ||
 243             (conn->local_rx_ctrl.prod_flags.cons_curs_upd_req))
 244                 smc_tx_consumer_update(conn);
 245 }
 246
 247 /* called under tasklet context */
 248 static inline void smc_cdc_msg_recv(struct smc_cdc_msg *cdc,
 249                                     struct smc_link *link, u64 wr_id)
 250 {
 251         struct smc_link_group *lgr = container_of(link, struct smc_link_group,
 252                                                   lnk[SMC_SINGLE_LINK]);
 253         struct smc_connection *connection;
 254         struct smc_sock *smc;
 255
 256         /* lookup connection */
 257         read_lock_bh(&lgr->conns_lock);
 258         connection = smc_lgr_find_conn(ntohl(cdc->token), lgr);
 259         if (!connection) {
 260                 read_unlock_bh(&lgr->conns_lock);
 261                 return;
 262         }
 263         smc = container_of(connection, struct smc_sock, conn);
 264         sock_hold(&smc->sk);
 265         read_unlock_bh(&lgr->conns_lock);
 266         bh_lock_sock(&smc->sk);
 267         smc_cdc_msg_recv_action(smc, link, cdc);
 268         bh_unlock_sock(&smc->sk);
 269         sock_put(&smc->sk); /* no free sk in softirq-context */
 270 }
 271
 272 /***************************** init, exit, misc ******************************/
 273
 274 static void smc_cdc_rx_handler(struct ib_wc *wc, void *buf)
 275 {
 276         struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
 277         struct smc_cdc_msg *cdc = buf;
 278
 279         if (wc->byte_len < offsetof(struct smc_cdc_msg, reserved))
 280                 return; /* short message */
 281         if (cdc->len != sizeof(*cdc))
 282                 return; /* invalid message */
 283         smc_cdc_msg_recv(cdc, link, wc->wr_id);
 284 }
 285
 286 static struct smc_wr_rx_handler smc_cdc_rx_handlers[] = {
 287         {
 288                 .handler        = smc_cdc_rx_handler,
 289                 .type           = SMC_CDC_MSG_TYPE
 290         },
 291         {
 292                 .handler        = NULL,
 293         }
 294 };
 295
 296 int __init smc_cdc_init(void)
 297 {
 298         struct smc_wr_rx_handler *handler;
 299         int rc = 0;
 300
 301         for (handler = smc_cdc_rx_handlers; handler->handler; handler++) {
 302                 INIT_HLIST_NODE(&handler->list);
 303                 rc = smc_wr_rx_register_handler(handler);
 304                 if (rc)
 305                         break;
 306         }
 307         return rc;
 308 }