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_connection *conn,
  67                           struct smc_wr_buf **wr_buf,
  68                           struct smc_cdc_tx_pend **pend)
  69 {
  70         struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
  71
  72         return smc_wr_tx_get_free_slot(link, smc_cdc_tx_handler, wr_buf,
  73                                        (struct smc_wr_tx_pend_priv **)pend);
  74 }
  75
  76 static inline void smc_cdc_add_pending_send(struct smc_connection *conn,
  77                                             struct smc_cdc_tx_pend *pend)
  78 {
  79         BUILD_BUG_ON_MSG(
  80                 sizeof(struct smc_cdc_msg) > SMC_WR_BUF_SIZE,
  81                 "must increase SMC_WR_BUF_SIZE to at least sizeof(struct smc_cdc_msg)");
  82         BUILD_BUG_ON_MSG(
  83                 offsetof(struct smc_cdc_msg, reserved) > SMC_WR_TX_SIZE,
  84                 "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()");
  85         BUILD_BUG_ON_MSG(
  86                 sizeof(struct smc_cdc_tx_pend) > SMC_WR_TX_PEND_PRIV_SIZE,
  87                 "must increase SMC_WR_TX_PEND_PRIV_SIZE to at least sizeof(struct smc_cdc_tx_pend)");
  88         pend->conn = conn;
  89         pend->cursor = conn->tx_curs_sent;
  90         pend->p_cursor = conn->local_tx_ctrl.prod;
  91         pend->ctrl_seq = conn->tx_cdc_seq;
  92 }
  93
  94 int smc_cdc_msg_send(struct smc_connection *conn,
  95                      struct smc_wr_buf *wr_buf,
  96                      struct smc_cdc_tx_pend *pend)
  97 {
  98         struct smc_link *link;
  99         int rc;
 100
 101         link = &conn->lgr->lnk[SMC_SINGLE_LINK];
 102
 103         smc_cdc_add_pending_send(conn, pend);
 104
 105         conn->tx_cdc_seq++;
 106         conn->local_tx_ctrl.seqno = conn->tx_cdc_seq;
 107         smc_host_msg_to_cdc((struct smc_cdc_msg *)wr_buf,
 108                             &conn->local_tx_ctrl, conn);
 109         rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend);
 110         if (!rc)
 111                 smc_curs_write(&conn->rx_curs_confirmed,
 112                                smc_curs_read(&conn->local_tx_ctrl.cons, conn),
 113                                conn);
 114
 115         return rc;
 116 }
 117
 118 int smc_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 static bool smc_cdc_tx_filter(struct smc_wr_tx_pend_priv *tx_pend,
 132                               unsigned long data)
 133 {
 134         struct smc_connection *conn = (struct smc_connection *)data;
 135         struct smc_cdc_tx_pend *cdc_pend =
 136                 (struct smc_cdc_tx_pend *)tx_pend;
 137
 138         return cdc_pend->conn == conn;
 139 }
 140
 141 static void smc_cdc_tx_dismisser(struct smc_wr_tx_pend_priv *tx_pend)
 142 {
 143         struct smc_cdc_tx_pend *cdc_pend =
 144                 (struct smc_cdc_tx_pend *)tx_pend;
 145
 146         cdc_pend->conn = NULL;
 147 }
 148
 149 void smc_cdc_tx_dismiss_slots(struct smc_connection *conn)
 150 {
 151         struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
 152
 153         smc_wr_tx_dismiss_slots(link, SMC_CDC_MSG_TYPE,
 154                                 smc_cdc_tx_filter, smc_cdc_tx_dismisser,
 155                                 (unsigned long)conn);
 156 }
 157
 158 bool smc_cdc_tx_has_pending(struct smc_connection *conn)
 159 {
 160         struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
 161
 162         return smc_wr_tx_has_pending(link, SMC_CDC_MSG_TYPE,
 163                                      smc_cdc_tx_filter, (unsigned long)conn);
 164 }
 165
 166 /********************************* receive ***********************************/
 167
 168 static inline bool smc_cdc_before(u16 seq1, u16 seq2)
 169 {
 170         return (s16)(seq1 - seq2) < 0;
 171 }
 172
 173 static void smc_cdc_msg_recv_action(struct smc_sock *smc,
 174                                     struct smc_link *link,
 175                                     struct smc_cdc_msg *cdc)
 176 {
 177         union smc_host_cursor cons_old, prod_old;
 178         struct smc_connection *conn = &smc->conn;
 179         int diff_cons, diff_prod;
 180
 181         if (!cdc->prod_flags.failover_validation) {
 182                 if (smc_cdc_before(ntohs(cdc->seqno),
 183                                    conn->local_rx_ctrl.seqno))
 184                         /* received seqno is old */
 185                         return;
 186         }
 187         smc_curs_write(&prod_old,
 188                        smc_curs_read(&conn->local_rx_ctrl.prod, conn),
 189                        conn);
 190         smc_curs_write(&cons_old,
 191                        smc_curs_read(&conn->local_rx_ctrl.cons, conn),
 192                        conn);
 193         smc_cdc_msg_to_host(&conn->local_rx_ctrl, cdc, conn);
 194
 195         diff_cons = smc_curs_diff(conn->peer_rmbe_size, &cons_old,
 196                                   &conn->local_rx_ctrl.cons);
 197         if (diff_cons) {
 198                 /* peer_rmbe_space is decreased during data transfer with RDMA
 199                  * write
 200                  */
 201                 smp_mb__before_atomic();
 202                 atomic_add(diff_cons, &conn->peer_rmbe_space);
 203                 /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */
 204                 smp_mb__after_atomic();
 205         }
 206
 207         diff_prod = smc_curs_diff(conn->rmbe_size, &prod_old,
 208                                   &conn->local_rx_ctrl.prod);
 209         if (diff_prod) {
 210                 /* bytes_to_rcv is decreased in smc_recvmsg */
 211                 smp_mb__before_atomic();
 212                 atomic_add(diff_prod, &conn->bytes_to_rcv);
 213                 /* guarantee 0 <= bytes_to_rcv <= rmbe_size */
 214                 smp_mb__after_atomic();
 215                 smc->sk.sk_data_ready(&smc->sk);
 216         }
 217
 218         if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) {
 219                 smc->sk.sk_err = ECONNRESET;
 220                 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
 221         }
 222         if (smc_cdc_rxed_any_close_or_senddone(conn)) {
 223                 smc->sk.sk_shutdown |= RCV_SHUTDOWN;
 224                 if (smc->clcsock && smc->clcsock->sk)
 225                         smc->clcsock->sk->sk_shutdown |= RCV_SHUTDOWN;
 226                 sock_set_flag(&smc->sk, SOCK_DONE);
 227                 schedule_work(&conn->close_work);
 228         }
 229
 230         /* piggy backed tx info */
 231         /* trigger sndbuf consumer: RDMA write into peer RMBE and CDC */
 232         if (diff_cons && smc_tx_prepared_sends(conn)) {
 233                 smc_tx_sndbuf_nonempty(conn);
 234                 /* trigger socket release if connection closed */
 235                 smc_close_wake_tx_prepared(smc);
 236         }
 237
 238         /* socket connected but not accepted */
 239         if (!smc->sk.sk_socket)
 240                 return;
 241
 242         /* data available */
 243         if ((conn->local_rx_ctrl.prod_flags.write_blocked) ||
 244             (conn->local_rx_ctrl.prod_flags.cons_curs_upd_req))
 245                 smc_tx_consumer_update(conn);
 246 }
 247
 248 /* called under tasklet context */
 249 static inline void smc_cdc_msg_recv(struct smc_cdc_msg *cdc,
 250                                     struct smc_link *link, u64 wr_id)
 251 {
 252         struct smc_link_group *lgr = container_of(link, struct smc_link_group,
 253                                                   lnk[SMC_SINGLE_LINK]);
 254         struct smc_connection *connection;
 255         struct smc_sock *smc;
 256
 257         /* lookup connection */
 258         read_lock_bh(&lgr->conns_lock);
 259         connection = smc_lgr_find_conn(ntohl(cdc->token), lgr);
 260         if (!connection) {
 261                 read_unlock_bh(&lgr->conns_lock);
 262                 return;
 263         }
 264         smc = container_of(connection, struct smc_sock, conn);
 265         sock_hold(&smc->sk);
 266         read_unlock_bh(&lgr->conns_lock);
 267         bh_lock_sock(&smc->sk);
 268         smc_cdc_msg_recv_action(smc, link, cdc);
 269         bh_unlock_sock(&smc->sk);
 270         sock_put(&smc->sk); /* no free sk in softirq-context */
 271 }
 272
 273 /***************************** init, exit, misc ******************************/
 274
 275 static void smc_cdc_rx_handler(struct ib_wc *wc, void *buf)
 276 {
 277         struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
 278         struct smc_cdc_msg *cdc = buf;
 279
 280         if (wc->byte_len < offsetof(struct smc_cdc_msg, reserved))
 281                 return; /* short message */
 282         if (cdc->len != sizeof(*cdc))
 283                 return; /* invalid message */
 284         smc_cdc_msg_recv(cdc, link, wc->wr_id);
 285 }
 286
 287 static struct smc_wr_rx_handler smc_cdc_rx_handlers[] = {
 288         {
 289                 .handler        = smc_cdc_rx_handler,
 290                 .type           = SMC_CDC_MSG_TYPE
 291         },
 292         {
 293                 .handler        = NULL,
 294         }
 295 };
 296
 297 int __init smc_cdc_init(void)
 298 {
 299         struct smc_wr_rx_handler *handler;
 300         int rc = 0;
 301
 302         for (handler = smc_cdc_rx_handlers; handler->handler; handler++) {
 303                 INIT_HLIST_NODE(&handler->list);
 304                 rc = smc_wr_rx_register_handler(handler);
 305                 if (rc)
 306                         break;
 307         }
 308         return rc;
 309 }