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 */
 164 static inline int smc_curs_diff(unsigned int size,
 165                                 union smc_host_cursor *old,
 166                                 union smc_host_cursor *new)
 167 {
 168         if (old->wrap != new->wrap)
 169                 return max_t(int, 0,
 170                              ((size - old->count) + new->count));
 171
 172         return max_t(int, 0, (new->count - old->count));
 173 }
 174
 175 /* calculate cursor difference between old and new - returns negative
 176  * value in case old > new
 177  */
 178 static inline int smc_curs_comp(unsigned int size,
 179                                 union smc_host_cursor *old,
 180                                 union smc_host_cursor *new)
 181 {
 182         if (old->wrap > new->wrap ||
 183             (old->wrap == new->wrap && old->count > new->count))
 184                 return -smc_curs_diff(size, new, old);
 185         return smc_curs_diff(size, old, new);
 186 }
 187
 188 static inline void smc_host_cursor_to_cdc(union smc_cdc_cursor *peer,
 189                                           union smc_host_cursor *local,
 190                                           struct smc_connection *conn)
 191 {
 192         union smc_host_cursor temp;
 193
 194         smc_curs_copy(&temp, local, conn);
 195         peer->count = htonl(temp.count);
 196         peer->wrap = htons(temp.wrap);
 197         /* peer->reserved = htons(0); must be ensured by caller */
 198 }
 199
 200 static inline void smc_host_msg_to_cdc(struct smc_cdc_msg *peer,
 201                                        struct smc_host_cdc_msg *local,
 202                                        struct smc_connection *conn)
 203 {
 204         peer->common.type = local->common.type;
 205         peer->len = local->len;
 206         peer->seqno = htons(local->seqno);
 207         peer->token = htonl(local->token);
 208         smc_host_cursor_to_cdc(&peer->prod, &local->prod, conn);
 209         smc_host_cursor_to_cdc(&peer->cons, &local->cons, conn);
 210         peer->prod_flags = local->prod_flags;
 211         peer->conn_state_flags = local->conn_state_flags;
 212 }
 213
 214 static inline void smc_cdc_cursor_to_host(union smc_host_cursor *local,
 215                                           union smc_cdc_cursor *peer,
 216                                           struct smc_connection *conn)
 217 {
 218         union smc_host_cursor temp, old;
 219         union smc_cdc_cursor net;
 220
 221         smc_curs_copy(&old, local, conn);
 222         smc_curs_copy_net(&net, peer, conn);
 223         temp.count = ntohl(net.count);
 224         temp.wrap = ntohs(net.wrap);
 225         if ((old.wrap > temp.wrap) && temp.wrap)
 226                 return;
 227         if ((old.wrap == temp.wrap) &&
 228             (old.count > temp.count))
 229                 return;
 230         smc_curs_copy(local, &temp, conn);
 231 }
 232
 233 static inline void smcr_cdc_msg_to_host(struct smc_host_cdc_msg *local,
 234                                         struct smc_cdc_msg *peer,
 235                                         struct smc_connection *conn)
 236 {
 237         local->common.type = peer->common.type;
 238         local->len = peer->len;
 239         local->seqno = ntohs(peer->seqno);
 240         local->token = ntohl(peer->token);
 241         smc_cdc_cursor_to_host(&local->prod, &peer->prod, conn);
 242         smc_cdc_cursor_to_host(&local->cons, &peer->cons, conn);
 243         local->prod_flags = peer->prod_flags;
 244         local->conn_state_flags = peer->conn_state_flags;
 245 }
 246
 247 static inline void smcd_cdc_msg_to_host(struct smc_host_cdc_msg *local,
 248                                         struct smcd_cdc_msg *peer)
 249 {
 250         union smc_host_cursor temp;
 251
 252         temp.wrap = peer->prod.wrap;
 253         temp.count = peer->prod.count;
 254         atomic64_set(&local->prod.acurs, atomic64_read(&temp.acurs));
 255
 256         temp.wrap = peer->cons.wrap;
 257         temp.count = peer->cons.count;
 258         atomic64_set(&local->cons.acurs, atomic64_read(&temp.acurs));
 259         local->prod_flags = peer->cons.prod_flags;
 260         local->conn_state_flags = peer->cons.conn_state_flags;
 261 }
 262
 263 static inline void smc_cdc_msg_to_host(struct smc_host_cdc_msg *local,
 264                                        struct smc_cdc_msg *peer,
 265                                        struct smc_connection *conn)
 266 {
 267         if (conn->lgr->is_smcd)
 268                 smcd_cdc_msg_to_host(local, (struct smcd_cdc_msg *)peer);
 269         else
 270                 smcr_cdc_msg_to_host(local, peer, conn);
 271 }
 272
 273 struct smc_cdc_tx_pend;
 274
 275 int smc_cdc_get_free_slot(struct smc_connection *conn,
 276                           struct smc_wr_buf **wr_buf,
 277                           struct smc_cdc_tx_pend **pend);
 278 void smc_cdc_tx_dismiss_slots(struct smc_connection *conn);
 279 int smc_cdc_msg_send(struct smc_connection *conn, struct smc_wr_buf *wr_buf,
 280                      struct smc_cdc_tx_pend *pend);
 281 int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn);
 282 int smcd_cdc_msg_send(struct smc_connection *conn);
 283 int smc_cdc_init(void) __init;
 284 void smcd_cdc_rx_init(struct smc_connection *conn);
 285
 286 #endif /* SMC_CDC_H */