net/smc/smc_cdc.c

   1 /*
   2  * Shared Memory Communications over RDMA (SMC-R) and RoCE
   3  *
   4  * Connection Data Control (CDC)
   5  * handles flow control
   6  *
   7  * Copyright IBM Corp. 2016
   8  *
   9  * Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
  10  */
  11
  12 #include <linux/spinlock.h>
  13
  14 #include "smc.h"
  15 #include "smc_wr.h"
  16 #include "smc_cdc.h"
  17 #include "smc_tx.h"
  18 #include "smc_rx.h"
  19 #include "smc_close.h"
  20
  21 /********************************** send *************************************/
  22
  23 struct smc_cdc_tx_pend {
  24         struct smc_connection   *conn;          /* socket connection */
  25         union smc_host_cursor   cursor; /* tx sndbuf cursor sent */
  26         union smc_host_cursor   p_cursor;       /* rx RMBE cursor produced */
  27         u16                     ctrl_seq;       /* conn. tx sequence # */
  28 };
  29
  30 /* handler for send/transmission completion of a CDC msg */
  31 static void smc_cdc_tx_handler(struct smc_wr_tx_pend_priv *pnd_snd,
  32                                struct smc_link *link,
  33                                enum ib_wc_status wc_status)
  34 {
  35         struct smc_cdc_tx_pend *cdcpend = (struct smc_cdc_tx_pend *)pnd_snd;
  36         struct smc_sock *smc;
  37         int diff;
  38
  39         if (!cdcpend->conn)
  40                 /* already dismissed */
  41                 return;
  42
  43         smc = container_of(cdcpend->conn, struct smc_sock, conn);
  44         bh_lock_sock(&smc->sk);
  45         if (!wc_status) {
  46                 diff = smc_curs_diff(cdcpend->conn->sndbuf_size,
  47                                      &cdcpend->conn->tx_curs_fin,
  48                                      &cdcpend->cursor);
  49                 /* sndbuf_space is decreased in smc_sendmsg */
  50                 smp_mb__before_atomic();
  51                 atomic_add(diff, &cdcpend->conn->sndbuf_space);
  52                 /* guarantee 0 <= sndbuf_space <= sndbuf_size */
  53                 smp_mb__after_atomic();
  54                 smc_curs_write(&cdcpend->conn->tx_curs_fin,
  55                                smc_curs_read(&cdcpend->cursor, cdcpend->conn),
  56                                cdcpend->conn);
  57         }
  58         smc_tx_sndbuf_nonfull(smc);
  59         if (smc->sk.sk_state != SMC_ACTIVE)
  60                 /* wake up smc_close_wait_tx_pends() */
  61                 smc->sk.sk_state_change(&smc->sk);
  62         bh_unlock_sock(&smc->sk);
  63 }
  64
  65 int smc_cdc_get_free_slot(struct smc_link *link,
  66                           struct smc_wr_buf **wr_buf,
  67                           struct smc_cdc_tx_pend **pend)
  68 {
  69         return smc_wr_tx_get_free_slot(link, smc_cdc_tx_handler, wr_buf,
  70                                        (struct smc_wr_tx_pend_priv **)pend);
  71 }
  72
  73 static inline void smc_cdc_add_pending_send(struct smc_connection *conn,
  74                                             struct smc_cdc_tx_pend *pend)
  75 {
  76         BUILD_BUG_ON_MSG(
  77                 sizeof(struct smc_cdc_msg) > SMC_WR_BUF_SIZE,
  78                 "must increase SMC_WR_BUF_SIZE to at least sizeof(struct smc_cdc_msg)");
  79         BUILD_BUG_ON_MSG(
  80                 offsetof(struct smc_cdc_msg, reserved) > SMC_WR_TX_SIZE,
  81                 "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()");
  82         BUILD_BUG_ON_MSG(
  83                 sizeof(struct smc_cdc_tx_pend) > SMC_WR_TX_PEND_PRIV_SIZE,
  84                 "must increase SMC_WR_TX_PEND_PRIV_SIZE to at least sizeof(struct smc_cdc_tx_pend)");
  85         pend->conn = conn;
  86         pend->cursor = conn->tx_curs_sent;
  87         pend->p_cursor = conn->local_tx_ctrl.prod;
  88         pend->ctrl_seq = conn->tx_cdc_seq;
  89 }
  90
  91 int smc_cdc_msg_send(struct smc_connection *conn,
  92                      struct smc_wr_buf *wr_buf,
  93                      struct smc_cdc_tx_pend *pend)
  94 {
  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,
 105                             &conn->local_tx_ctrl, conn);
 106         rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend);
 107         if (!rc)
 108                 smc_curs_write(&conn->rx_curs_confirmed,
 109                                smc_curs_read(&conn->local_tx_ctrl.cons, conn),
 110                                conn);
 111
 112         return rc;
 113 }
 114
 115 int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn)
 116 {
 117         struct smc_cdc_tx_pend *pend;
 118         struct smc_wr_buf *wr_buf;
 119         int rc;
 120
 121         rc = smc_cdc_get_free_slot(&conn->lgr->lnk[SMC_SINGLE_LINK], &wr_buf,
 122                                    &pend);
 123         if (rc)
 124                 return rc;
 125
 126         return smc_cdc_msg_send(conn, wr_buf, pend);
 127 }
 128
 129 static bool smc_cdc_tx_filter(struct smc_wr_tx_pend_priv *tx_pend,
 130                               unsigned long data)
 131 {
 132         struct smc_connection *conn = (struct smc_connection *)data;
 133         struct smc_cdc_tx_pend *cdc_pend =
 134                 (struct smc_cdc_tx_pend *)tx_pend;
 135
 136         return cdc_pend->conn == conn;
 137 }
 138
 139 static void smc_cdc_tx_dismisser(struct smc_wr_tx_pend_priv *tx_pend)
 140 {
 141         struct smc_cdc_tx_pend *cdc_pend =
 142                 (struct smc_cdc_tx_pend *)tx_pend;
 143
 144         cdc_pend->conn = NULL;
 145 }
 146
 147 void smc_cdc_tx_dismiss_slots(struct smc_connection *conn)
 148 {
 149         struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
 150
 151         smc_wr_tx_dismiss_slots(link, SMC_CDC_MSG_TYPE,
 152                                 smc_cdc_tx_filter, smc_cdc_tx_dismisser,
 153                                 (unsigned long)conn);
 154 }
 155
 156 bool smc_cdc_tx_has_pending(struct smc_connection *conn)
 157 {
 158         struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
 159
 160         return smc_wr_tx_has_pending(link, SMC_CDC_MSG_TYPE,
 161                                      smc_cdc_tx_filter, (unsigned long)conn);
 162 }
 163
 164 /********************************* receive ***********************************/
 165
 166 static inline bool smc_cdc_before(u16 seq1, u16 seq2)
 167 {
 168         return (s16)(seq1 - seq2) < 0;
 169 }
 170
 171 static void smc_cdc_msg_recv_action(struct smc_sock *smc,
 172                                     struct smc_link *link,
 173                                     struct smc_cdc_msg *cdc)
 174 {
 175         union smc_host_cursor cons_old, prod_old;
 176         struct smc_connection *conn = &smc->conn;
 177         int diff_cons, diff_prod;
 178
 179         if (!cdc->prod_flags.failover_validation) {
 180                 if (smc_cdc_before(ntohs(cdc->seqno),
 181                                    conn->local_rx_ctrl.seqno))
 182                         /* received seqno is old */
 183                         return;
 184         }
 185         smc_curs_write(&prod_old,
 186                        smc_curs_read(&conn->local_rx_ctrl.prod, conn),
 187                        conn);
 188         smc_curs_write(&cons_old,
 189                        smc_curs_read(&conn->local_rx_ctrl.cons, conn),
 190                        conn);
 191         smc_cdc_msg_to_host(&conn->local_rx_ctrl, cdc, conn);
 192
 193         diff_cons = smc_curs_diff(conn->peer_rmbe_size, &cons_old,
 194                                   &conn->local_rx_ctrl.cons);
 195         if (diff_cons) {
 196                 /* peer_rmbe_space is decreased during data transfer with RDMA
 197                  * write
 198                  */
 199                 smp_mb__before_atomic();
 200                 atomic_add(diff_cons, &conn->peer_rmbe_space);
 201                 /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */
 202                 smp_mb__after_atomic();
 203         }
 204
 205         diff_prod = smc_curs_diff(conn->rmbe_size, &prod_old,
 206                                   &conn->local_rx_ctrl.prod);
 207         if (diff_prod) {
 208                 /* bytes_to_rcv is decreased in smc_recvmsg */
 209                 smp_mb__before_atomic();
 210                 atomic_add(diff_prod, &conn->bytes_to_rcv);
 211                 /* guarantee 0 <= bytes_to_rcv <= rmbe_size */
 212                 smp_mb__after_atomic();
 213                 smc->sk.sk_data_ready(&smc->sk);
 214         }
 215
 216         if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) {
 217                 smc->sk.sk_err = ECONNRESET;
 218                 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
 219         }
 220         if (smc_cdc_rxed_any_close_or_senddone(conn))
 221                 smc_close_passive_received(smc);
 222
 223         /* piggy backed tx info */
 224         /* trigger sndbuf consumer: RDMA write into peer RMBE and CDC */
 225         if (diff_cons && smc_tx_prepared_sends(conn)) {
 226                 smc_tx_sndbuf_nonempty(conn);
 227                 /* trigger socket release if connection closed */
 228                 smc_close_wake_tx_prepared(smc);
 229         }
 230
 231         /* subsequent patch: trigger socket release if connection closed */
 232
 233         /* socket connected but not accepted */
 234         if (!smc->sk.sk_socket)
 235                 return;
 236
 237         /* data available */
 238         if ((conn->local_rx_ctrl.prod_flags.write_blocked) ||
 239             (conn->local_rx_ctrl.prod_flags.cons_curs_upd_req))
 240                 smc_tx_consumer_update(conn);
 241 }
 242
 243 /* called under tasklet context */
 244 static inline void smc_cdc_msg_recv(struct smc_cdc_msg *cdc,
 245                                     struct smc_link *link, u64 wr_id)
 246 {
 247         struct smc_link_group *lgr = container_of(link, struct smc_link_group,
 248                                                   lnk[SMC_SINGLE_LINK]);
 249         struct smc_connection *connection;
 250         struct smc_sock *smc;
 251
 252         /* lookup connection */
 253         read_lock_bh(&lgr->conns_lock);
 254         connection = smc_lgr_find_conn(ntohl(cdc->token), lgr);
 255         if (!connection) {
 256                 read_unlock_bh(&lgr->conns_lock);
 257                 return;
 258         }
 259         smc = container_of(connection, struct smc_sock, conn);
 260         sock_hold(&smc->sk);
 261         read_unlock_bh(&lgr->conns_lock);
 262         bh_lock_sock(&smc->sk);
 263         smc_cdc_msg_recv_action(smc, link, cdc);
 264         bh_unlock_sock(&smc->sk);
 265         sock_put(&smc->sk); /* no free sk in softirq-context */
 266 }
 267
 268 /***************************** init, exit, misc ******************************/
 269
 270 static void smc_cdc_rx_handler(struct ib_wc *wc, void *buf)
 271 {
 272         struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
 273         struct smc_cdc_msg *cdc = buf;
 274
 275         if (wc->byte_len < offsetof(struct smc_cdc_msg, reserved))
 276                 return; /* short message */
 277         if (cdc->len != sizeof(*cdc))
 278                 return; /* invalid message */
 279         smc_cdc_msg_recv(cdc, link, wc->wr_id);
 280 }
 281
 282 static struct smc_wr_rx_handler smc_cdc_rx_handlers[] = {
 283         {
 284                 .handler        = smc_cdc_rx_handler,
 285                 .type           = SMC_CDC_MSG_TYPE
 286         },
 287         {
 288                 .handler        = NULL,
 289         }
 290 };
 291
 292 int __init smc_cdc_init(void)
 293 {
 294         struct smc_wr_rx_handler *handler;
 295         int rc = 0;
 296
 297         for (handler = smc_cdc_rx_handlers; handler->handler; handler++) {
 298                 INIT_HLIST_NODE(&handler->list);
 299                 rc = smc_wr_rx_register_handler(handler);
 300                 if (rc)
 301                         break;
 302         }
 303         return rc;
 304 }