net/smc/smc_cdc.h

   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  *
   7  * Copyright IBM Corp. 2016
   8  *
   9  * Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
  10  */
  11
  12 #ifndef SMC_CDC_H
  13 #define SMC_CDC_H
  14
  15 #include <linux/kernel.h> /* max_t */
  16 #include <linux/atomic.h>
  17 #include <linux/in.h>
  18 #include <linux/compiler.h>
  19
  20 #include "smc.h"
  21 #include "smc_core.h"
  22 #include "smc_wr.h"
  23
  24 #define SMC_CDC_MSG_TYPE                0xFE
  25
  26 /* in network byte order */
  27 union smc_cdc_cursor {          /* SMC cursor */
  28         struct {
  29                 __be16  reserved;
  30                 __be16  wrap;
  31                 __be32  count;
  32         };
  33 #ifdef KERNEL_HAS_ATOMIC64
  34         atomic64_t      acurs;          /* for atomic processing */
  35 #else
  36         u64             acurs;          /* for atomic processing */
  37 #endif
  38 } __aligned(8);
  39
  40 /* in network byte order */
  41 struct smc_cdc_msg {
  42         struct smc_wr_rx_hdr            common; /* .type = 0xFE */
  43         u8                              len;    /* 44 */
  44         __be16                          seqno;
  45         __be32                          token;
  46         union smc_cdc_cursor            prod;
  47         union smc_cdc_cursor            cons;   /* piggy backed "ack" */
  48         struct smc_cdc_producer_flags   prod_flags;
  49         struct smc_cdc_conn_state_flags conn_state_flags;
  50         u8                              reserved[18];
  51 };
  52
  53 /* SMC-D cursor format */
  54 union smcd_cdc_cursor {
  55         struct {
  56                 u16     wrap;
  57                 u32     count;
  58                 struct smc_cdc_producer_flags   prod_flags;
  59                 struct smc_cdc_conn_state_flags conn_state_flags;
  60         } __packed;
  61 #ifdef KERNEL_HAS_ATOMIC64
  62         atomic64_t              acurs;          /* for atomic processing */
  63 #else
  64         u64                     acurs;          /* for atomic processing */
  65 #endif
  66 } __aligned(8);
  67
  68 /* CDC message for SMC-D */
  69 struct smcd_cdc_msg {
  70         struct smc_wr_rx_hdr common;    /* Type = 0xFE */
  71         u8 res1[7];
  72         union smcd_cdc_cursor   prod;
  73         union smcd_cdc_cursor   cons;
  74         u8 res3[8];
  75 } __aligned(8);
  76
  77 static inline bool smc_cdc_rxed_any_close(struct smc_connection *conn)
  78 {
  79         return conn->local_rx_ctrl.conn_state_flags.peer_conn_abort ||
  80                conn->local_rx_ctrl.conn_state_flags.peer_conn_closed;
  81 }
  82
  83 static inline bool smc_cdc_rxed_any_close_or_senddone(
  84         struct smc_connection *conn)
  85 {
  86         return smc_cdc_rxed_any_close(conn) ||
  87                conn->local_rx_ctrl.conn_state_flags.peer_done_writing;
  88 }
  89
  90 static inline void smc_curs_add(int size, union smc_host_cursor *curs,
  91                                 int value)
  92 {
  93         curs->count += value;
  94         if (curs->count >= size) {
  95                 curs->wrap++;
  96                 curs->count -= size;
  97         }
  98 }
  99
 100 /* SMC cursors are 8 bytes long and require atomic reading and writing */
 101 static inline u64 smc_curs_read(union smc_host_cursor *curs,
 102                                 struct smc_connection *conn)
 103 {
 104 #ifndef KERNEL_HAS_ATOMIC64
 105         unsigned long flags;
 106         u64 ret;
 107
 108         spin_lock_irqsave(&conn->acurs_lock, flags);
 109         ret = curs->acurs;
 110         spin_unlock_irqrestore(&conn->acurs_lock, flags);
 111         return ret;
 112 #else
 113         return atomic64_read(&curs->acurs);
 114 #endif
 115 }
 116
 117 /* Copy cursor src into tgt */
 118 static inline void smc_curs_copy(union smc_host_cursor *tgt,
 119                                  union smc_host_cursor *src,
 120                                  struct smc_connection *conn)
 121 {
 122 #ifndef KERNEL_HAS_ATOMIC64
 123         unsigned long flags;
 124
 125         spin_lock_irqsave(&conn->acurs_lock, flags);
 126         tgt->acurs = src->acurs;
 127         spin_unlock_irqrestore(&conn->acurs_lock, flags);
 128 #else
 129         atomic64_set(&tgt->acurs, atomic64_read(&src->acurs));
 130 #endif
 131 }
 132
 133 static inline void smc_curs_copy_net(union smc_cdc_cursor *tgt,
 134                                      union smc_cdc_cursor *src,
 135                                      struct smc_connection *conn)
 136 {
 137 #ifndef KERNEL_HAS_ATOMIC64
 138         unsigned long flags;
 139
 140         spin_lock_irqsave(&conn->acurs_lock, flags);
 141         tgt->acurs = src->acurs;
 142         spin_unlock_irqrestore(&conn->acurs_lock, flags);
 143 #else
 144         atomic64_set(&tgt->acurs, atomic64_read(&src->acurs));
 145 #endif
 146 }
 147
 148 static inline void smcd_curs_copy(union smcd_cdc_cursor *tgt,
 149                                   union smcd_cdc_cursor *src,
 150                                   struct smc_connection *conn)
 151 {
 152 #ifndef KERNEL_HAS_ATOMIC64
 153         unsigned long flags;
 154
 155         spin_lock_irqsave(&conn->acurs_lock, flags);
 156         tgt->acurs = src->acurs;
 157         spin_unlock_irqrestore(&conn->acurs_lock, flags);
 158 #else
 159         atomic64_set(&tgt->acurs, atomic64_read(&src->acurs));
 160 #endif
 161 }
 162
 163 /* calculate cursor difference between old and new, where old <= new and
 164  * difference cannot exceed size
 165  */
 166 static inline int smc_curs_diff(unsigned int size,
 167                                 union smc_host_cursor *old,
 168                                 union smc_host_cursor *new)
 169 {
 170         if (old->wrap != new->wrap)
 171                 return max_t(int, 0,
 172                              ((size - old->count) + new->count));
 173
 174         return max_t(int, 0, (new->count - old->count));
 175 }
 176
 177 /* calculate cursor difference between old and new - returns negative
 178  * value in case old > new
 179  */
 180 static inline int smc_curs_comp(unsigned int size,
 181                                 union smc_host_cursor *old,
 182                                 union smc_host_cursor *new)
 183 {
 184         if (old->wrap > new->wrap ||
 185             (old->wrap == new->wrap && old->count > new->count))
 186                 return -smc_curs_diff(size, new, old);
 187         return smc_curs_diff(size, old, new);
 188 }
 189
 190 /* calculate cursor difference between old and new, where old <= new and
 191  * difference may exceed size
 192  */
 193 static inline int smc_curs_diff_large(unsigned int size,
 194                                       union smc_host_cursor *old,
 195                                       union smc_host_cursor *new)
 196 {
 197         if (old->wrap < new->wrap)
 198                 return min_t(int,
 199                              (size - old->count) + new->count +
 200                              (new->wrap - old->wrap - 1) * size,
 201                              size);
 202
 203         if (old->wrap > new->wrap) /* wrap has switched from 0xffff to 0x0000 */
 204                 return min_t(int,
 205                              (size - old->count) + new->count +
 206                              (new->wrap + 0xffff - old->wrap) * size,
 207                              size);
 208
 209         return max_t(int, 0, (new->count - old->count));
 210 }
 211
 212 static inline void smc_host_cursor_to_cdc(union smc_cdc_cursor *peer,
 213                                           union smc_host_cursor *local,
 214                                           union smc_host_cursor *save,
 215                                           struct smc_connection *conn)
 216 {
 217         smc_curs_copy(save, local, conn);
 218         peer->count = htonl(save->count);
 219         peer->wrap = htons(save->wrap);
 220         /* peer->reserved = htons(0); must be ensured by caller */
 221 }
 222
 223 static inline void smc_host_msg_to_cdc(struct smc_cdc_msg *peer,
 224                                        struct smc_connection *conn,
 225                                        union smc_host_cursor *save)
 226 {
 227         struct smc_host_cdc_msg *local = &conn->local_tx_ctrl;
 228
 229         peer->common.type = local->common.type;
 230         peer->len = local->len;
 231         peer->seqno = htons(local->seqno);
 232         peer->token = htonl(local->token);
 233         smc_host_cursor_to_cdc(&peer->prod, &local->prod, save, conn);
 234         smc_host_cursor_to_cdc(&peer->cons, &local->cons, save, conn);
 235         peer->prod_flags = local->prod_flags;
 236         peer->conn_state_flags = local->conn_state_flags;
 237 }
 238
 239 static inline void smc_cdc_cursor_to_host(union smc_host_cursor *local,
 240                                           union smc_cdc_cursor *peer,
 241                                           struct smc_connection *conn)
 242 {
 243         union smc_host_cursor temp, old;
 244         union smc_cdc_cursor net;
 245
 246         smc_curs_copy(&old, local, conn);
 247         smc_curs_copy_net(&net, peer, conn);
 248         temp.count = ntohl(net.count);
 249         temp.wrap = ntohs(net.wrap);
 250         if ((old.wrap > temp.wrap) && temp.wrap)
 251                 return;
 252         if ((old.wrap == temp.wrap) &&
 253             (old.count > temp.count))
 254                 return;
 255         smc_curs_copy(local, &temp, conn);
 256 }
 257
 258 static inline void smcr_cdc_msg_to_host(struct smc_host_cdc_msg *local,
 259                                         struct smc_cdc_msg *peer,
 260                                         struct smc_connection *conn)
 261 {
 262         local->common.type = peer->common.type;
 263         local->len = peer->len;
 264         local->seqno = ntohs(peer->seqno);
 265         local->token = ntohl(peer->token);
 266         smc_cdc_cursor_to_host(&local->prod, &peer->prod, conn);
 267         smc_cdc_cursor_to_host(&local->cons, &peer->cons, conn);
 268         local->prod_flags = peer->prod_flags;
 269         local->conn_state_flags = peer->conn_state_flags;
 270 }
 271
 272 static inline void smcd_cdc_msg_to_host(struct smc_host_cdc_msg *local,
 273                                         struct smcd_cdc_msg *peer,
 274                                         struct smc_connection *conn)
 275 {
 276         union smc_host_cursor temp;
 277
 278         temp.wrap = peer->prod.wrap;
 279         temp.count = peer->prod.count;
 280         smc_curs_copy(&local->prod, &temp, conn);
 281
 282         temp.wrap = peer->cons.wrap;
 283         temp.count = peer->cons.count;
 284         smc_curs_copy(&local->cons, &temp, conn);
 285         local->prod_flags = peer->cons.prod_flags;
 286         local->conn_state_flags = peer->cons.conn_state_flags;
 287 }
 288
 289 static inline void smc_cdc_msg_to_host(struct smc_host_cdc_msg *local,
 290                                        struct smc_cdc_msg *peer,
 291                                        struct smc_connection *conn)
 292 {
 293         if (conn->lgr->is_smcd)
 294                 smcd_cdc_msg_to_host(local, (struct smcd_cdc_msg *)peer, conn);
 295         else
 296                 smcr_cdc_msg_to_host(local, peer, conn);
 297 }
 298
 299 struct smc_cdc_tx_pend {
 300         struct smc_connection   *conn;          /* socket connection */
 301         union smc_host_cursor   cursor;         /* tx sndbuf cursor sent */
 302         union smc_host_cursor   p_cursor;       /* rx RMBE cursor produced */
 303         u16                     ctrl_seq;       /* conn. tx sequence # */
 304 };
 305
 306 int smc_cdc_get_free_slot(struct smc_connection *conn,
 307                           struct smc_wr_buf **wr_buf,
 308                           struct smc_rdma_wr **wr_rdma_buf,
 309                           struct smc_cdc_tx_pend **pend);
 310 void smc_cdc_tx_dismiss_slots(struct smc_connection *conn);
 311 int smc_cdc_msg_send(struct smc_connection *conn, struct smc_wr_buf *wr_buf,
 312                      struct smc_cdc_tx_pend *pend);
 313 int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn);
 314 int smcd_cdc_msg_send(struct smc_connection *conn);
 315 int smc_cdc_init(void) __init;
 316 void smcd_cdc_rx_init(struct smc_connection *conn);
 317
 318 #endif /* SMC_CDC_H */