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 /* Copy cursor src into tgt */
 101 static inline void smc_curs_copy(union smc_host_cursor *tgt,
 102                                  union smc_host_cursor *src,
 103                                  struct smc_connection *conn)
 104 {
 105 #ifndef KERNEL_HAS_ATOMIC64
 106         unsigned long flags;
 107
 108         spin_lock_irqsave(&conn->acurs_lock, flags);
 109         tgt->acurs = src->acurs;
 110         spin_unlock_irqrestore(&conn->acurs_lock, flags);
 111 #else
 112         atomic64_set(&tgt->acurs, atomic64_read(&src->acurs));
 113 #endif
 114 }
 115
 116 static inline void smc_curs_copy_net(union smc_cdc_cursor *tgt,
 117                                      union smc_cdc_cursor *src,
 118                                      struct smc_connection *conn)
 119 {
 120 #ifndef KERNEL_HAS_ATOMIC64
 121         unsigned long flags;
 122
 123         spin_lock_irqsave(&conn->acurs_lock, flags);
 124         tgt->acurs = src->acurs;
 125         spin_unlock_irqrestore(&conn->acurs_lock, flags);
 126 #else
 127         atomic64_set(&tgt->acurs, atomic64_read(&src->acurs));
 128 #endif
 129 }
 130
 131 static inline void smcd_curs_copy(union smcd_cdc_cursor *tgt,
 132                                   union smcd_cdc_cursor *src,
 133                                   struct smc_connection *conn)
 134 {
 135 #ifndef KERNEL_HAS_ATOMIC64
 136         unsigned long flags;
 137
 138         spin_lock_irqsave(&conn->acurs_lock, flags);
 139         tgt->acurs = src->acurs;
 140         spin_unlock_irqrestore(&conn->acurs_lock, flags);
 141 #else
 142         atomic64_set(&tgt->acurs, atomic64_read(&src->acurs));
 143 #endif
 144 }
 145
 146 /* calculate cursor difference between old and new, where old <= new and
 147  * difference cannot exceed size
 148  */
 149 static inline int smc_curs_diff(unsigned int size,
 150                                 union smc_host_cursor *old,
 151                                 union smc_host_cursor *new)
 152 {
 153         if (old->wrap != new->wrap)
 154                 return max_t(int, 0,
 155                              ((size - old->count) + new->count));
 156
 157         return max_t(int, 0, (new->count - old->count));
 158 }
 159
 160 /* calculate cursor difference between old and new - returns negative
 161  * value in case old > new
 162  */
 163 static inline int smc_curs_comp(unsigned int size,
 164                                 union smc_host_cursor *old,
 165                                 union smc_host_cursor *new)
 166 {
 167         if (old->wrap > new->wrap ||
 168             (old->wrap == new->wrap && old->count > new->count))
 169                 return -smc_curs_diff(size, new, old);
 170         return smc_curs_diff(size, old, new);
 171 }
 172
 173 /* calculate cursor difference between old and new, where old <= new and
 174  * difference may exceed size
 175  */
 176 static inline int smc_curs_diff_large(unsigned int size,
 177                                       union smc_host_cursor *old,
 178                                       union smc_host_cursor *new)
 179 {
 180         if (old->wrap < new->wrap)
 181                 return min_t(int,
 182                              (size - old->count) + new->count +
 183                              (new->wrap - old->wrap - 1) * size,
 184                              size);
 185
 186         if (old->wrap > new->wrap) /* wrap has switched from 0xffff to 0x0000 */
 187                 return min_t(int,
 188                              (size - old->count) + new->count +
 189                              (new->wrap + 0xffff - old->wrap) * size,
 190                              size);
 191
 192         return max_t(int, 0, (new->count - old->count));
 193 }
 194
 195 static inline void smc_host_cursor_to_cdc(union smc_cdc_cursor *peer,
 196                                           union smc_host_cursor *local,
 197                                           union smc_host_cursor *save,
 198                                           struct smc_connection *conn)
 199 {
 200         smc_curs_copy(save, local, conn);
 201         peer->count = htonl(save->count);
 202         peer->wrap = htons(save->wrap);
 203         /* peer->reserved = htons(0); must be ensured by caller */
 204 }
 205
 206 static inline void smc_host_msg_to_cdc(struct smc_cdc_msg *peer,
 207                                        struct smc_connection *conn,
 208                                        union smc_host_cursor *save)
 209 {
 210         struct smc_host_cdc_msg *local = &conn->local_tx_ctrl;
 211
 212         peer->common.type = local->common.type;
 213         peer->len = local->len;
 214         peer->seqno = htons(local->seqno);
 215         peer->token = htonl(local->token);
 216         smc_host_cursor_to_cdc(&peer->prod, &local->prod, save, conn);
 217         smc_host_cursor_to_cdc(&peer->cons, &local->cons, save, conn);
 218         peer->prod_flags = local->prod_flags;
 219         peer->conn_state_flags = local->conn_state_flags;
 220 }
 221
 222 static inline void smc_cdc_cursor_to_host(union smc_host_cursor *local,
 223                                           union smc_cdc_cursor *peer,
 224                                           struct smc_connection *conn)
 225 {
 226         union smc_host_cursor temp, old;
 227         union smc_cdc_cursor net;
 228
 229         smc_curs_copy(&old, local, conn);
 230         smc_curs_copy_net(&net, peer, conn);
 231         temp.count = ntohl(net.count);
 232         temp.wrap = ntohs(net.wrap);
 233         if ((old.wrap > temp.wrap) && temp.wrap)
 234                 return;
 235         if ((old.wrap == temp.wrap) &&
 236             (old.count > temp.count))
 237                 return;
 238         smc_curs_copy(local, &temp, conn);
 239 }
 240
 241 static inline void smcr_cdc_msg_to_host(struct smc_host_cdc_msg *local,
 242                                         struct smc_cdc_msg *peer,
 243                                         struct smc_connection *conn)
 244 {
 245         local->common.type = peer->common.type;
 246         local->len = peer->len;
 247         local->seqno = ntohs(peer->seqno);
 248         local->token = ntohl(peer->token);
 249         smc_cdc_cursor_to_host(&local->prod, &peer->prod, conn);
 250         smc_cdc_cursor_to_host(&local->cons, &peer->cons, conn);
 251         local->prod_flags = peer->prod_flags;
 252         local->conn_state_flags = peer->conn_state_flags;
 253 }
 254
 255 static inline void smcd_cdc_msg_to_host(struct smc_host_cdc_msg *local,
 256                                         struct smcd_cdc_msg *peer,
 257                                         struct smc_connection *conn)
 258 {
 259         union smc_host_cursor temp;
 260
 261         temp.wrap = peer->prod.wrap;
 262         temp.count = peer->prod.count;
 263         smc_curs_copy(&local->prod, &temp, conn);
 264
 265         temp.wrap = peer->cons.wrap;
 266         temp.count = peer->cons.count;
 267         smc_curs_copy(&local->cons, &temp, conn);
 268         local->prod_flags = peer->cons.prod_flags;
 269         local->conn_state_flags = peer->cons.conn_state_flags;
 270 }
 271
 272 static inline void smc_cdc_msg_to_host(struct smc_host_cdc_msg *local,
 273                                        struct smc_cdc_msg *peer,
 274                                        struct smc_connection *conn)
 275 {
 276         if (conn->lgr->is_smcd)
 277                 smcd_cdc_msg_to_host(local, (struct smcd_cdc_msg *)peer, conn);
 278         else
 279                 smcr_cdc_msg_to_host(local, peer, conn);
 280 }
 281
 282 struct smc_cdc_tx_pend {
 283         struct smc_connection   *conn;          /* socket connection */
 284         union smc_host_cursor   cursor;         /* tx sndbuf cursor sent */
 285         union smc_host_cursor   p_cursor;       /* rx RMBE cursor produced */
 286         u16                     ctrl_seq;       /* conn. tx sequence # */
 287 };
 288
 289 int smc_cdc_get_free_slot(struct smc_connection *conn,
 290                           struct smc_link *link,
 291                           struct smc_wr_buf **wr_buf,
 292                           struct smc_rdma_wr **wr_rdma_buf,
 293                           struct smc_cdc_tx_pend **pend);
 294 void smc_cdc_tx_dismiss_slots(struct smc_connection *conn);
 295 int smc_cdc_msg_send(struct smc_connection *conn, struct smc_wr_buf *wr_buf,
 296                      struct smc_cdc_tx_pend *pend);
 297 int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn);
 298 int smcd_cdc_msg_send(struct smc_connection *conn);
 299 int smcr_cdc_msg_send_validation(struct smc_connection *conn,
 300                                  struct smc_cdc_tx_pend *pend,
 301                                  struct smc_wr_buf *wr_buf);
 302 int smc_cdc_init(void) __init;
 303 void smcd_cdc_rx_init(struct smc_connection *conn);
 304
 305 #endif /* SMC_CDC_H */