drivers/block/rnbd/rnbd-proto.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  * RDMA Network Block Driver
   4  *
   5  * Copyright (c) 2014 - 2018 ProfitBricks GmbH. All rights reserved.
   6  * Copyright (c) 2018 - 2019 1&1 IONOS Cloud GmbH. All rights reserved.
   7  * Copyright (c) 2019 - 2020 1&1 IONOS SE. All rights reserved.
   8  */
   9 #ifndef RNBD_PROTO_H
  10 #define RNBD_PROTO_H
  11
  12 #include <linux/types.h>
  13 #include <linux/blk-mq.h>
  14 #include <linux/limits.h>
  15 #include <linux/inet.h>
  16 #include <linux/in.h>
  17 #include <linux/in6.h>
  18 #include <rdma/ib.h>
  19
  20 #define RNBD_PROTO_VER_MAJOR 2
  21 #define RNBD_PROTO_VER_MINOR 0
  22
  23 /* The default port number the RTRS server is listening on. */
  24 #define RTRS_PORT 1234
  25
  26 /**
  27  * enum rnbd_msg_types - RNBD message types
  28  * @RNBD_MSG_SESS_INFO: initial session info from client to server
  29  * @RNBD_MSG_SESS_INFO_RSP:     initial session info from server to client
  30  * @RNBD_MSG_OPEN:              open (map) device request
  31  * @RNBD_MSG_OPEN_RSP:          response to an @RNBD_MSG_OPEN
  32  * @RNBD_MSG_IO:                block IO request operation
  33  * @RNBD_MSG_CLOSE:             close (unmap) device request
  34  */
  35 enum rnbd_msg_type {
  36         RNBD_MSG_SESS_INFO,
  37         RNBD_MSG_SESS_INFO_RSP,
  38         RNBD_MSG_OPEN,
  39         RNBD_MSG_OPEN_RSP,
  40         RNBD_MSG_IO,
  41         RNBD_MSG_CLOSE,
  42 };
  43
  44 /**
  45  * struct rnbd_msg_hdr - header of RNBD messages
  46  * @type:       Message type, valid values see: enum rnbd_msg_types
  47  */
  48 struct rnbd_msg_hdr {
  49         __le16          type;
  50         __le16          __padding;
  51 };
  52
  53 /**
  54  * We allow to map RO many times and RW only once. We allow to map yet another
  55  * time RW, if MIGRATION is provided (second RW export can be required for
  56  * example for VM migration)
  57  */
  58 enum rnbd_access_mode {
  59         RNBD_ACCESS_RO,
  60         RNBD_ACCESS_RW,
  61         RNBD_ACCESS_MIGRATION,
  62 };
  63
  64 static const __maybe_unused struct {
  65         enum rnbd_access_mode mode;
  66         const char *str;
  67 } rnbd_access_modes[] = {
  68         [RNBD_ACCESS_RO] = {RNBD_ACCESS_RO, "ro"},
  69         [RNBD_ACCESS_RW] = {RNBD_ACCESS_RW, "rw"},
  70         [RNBD_ACCESS_MIGRATION] = {RNBD_ACCESS_MIGRATION, "migration"},
  71 };
  72
  73 /**
  74  * struct rnbd_msg_sess_info - initial session info from client to server
  75  * @hdr:                message header
  76  * @ver:                RNBD protocol version
  77  */
  78 struct rnbd_msg_sess_info {
  79         struct rnbd_msg_hdr hdr;
  80         u8              ver;
  81         u8              reserved[31];
  82 };
  83
  84 /**
  85  * struct rnbd_msg_sess_info_rsp - initial session info from server to client
  86  * @hdr:                message header
  87  * @ver:                RNBD protocol version
  88  */
  89 struct rnbd_msg_sess_info_rsp {
  90         struct rnbd_msg_hdr hdr;
  91         u8              ver;
  92         u8              reserved[31];
  93 };
  94
  95 /**
  96  * struct rnbd_msg_open - request to open a remote device.
  97  * @hdr:                message header
  98  * @access_mode:        the mode to open remote device, valid values see:
  99  *                      enum rnbd_access_mode
 100  * @device_name:        device path on remote side
 101  */
 102 struct rnbd_msg_open {
 103         struct rnbd_msg_hdr hdr;
 104         u8              access_mode;
 105         u8              resv1;
 106         s8              dev_name[NAME_MAX];
 107         u8              reserved[3];
 108 };
 109
 110 /**
 111  * struct rnbd_msg_close - request to close a remote device.
 112  * @hdr:        message header
 113  * @device_id:  device_id on server side to identify the device
 114  */
 115 struct rnbd_msg_close {
 116         struct rnbd_msg_hdr hdr;
 117         __le32          device_id;
 118 };
 119
 120 enum rnbd_cache_policy {
 121         RNBD_FUA = 1 << 0,
 122         RNBD_WRITEBACK = 1 << 1,
 123 };
 124
 125 /**
 126  * struct rnbd_msg_open_rsp - response message to RNBD_MSG_OPEN
 127  * @hdr:                message header
 128  * @device_id:          device_id on server side to identify the device
 129  * @nsectors:           number of sectors in the usual 512b unit
 130  * @max_hw_sectors:     max hardware sectors in the usual 512b unit
 131  * @max_write_zeroes_sectors: max sectors for WRITE ZEROES in the 512b unit
 132  * @max_discard_sectors: max. sectors that can be discarded at once in 512b
 133  * unit.
 134  * @discard_granularity: size of the internal discard allocation unit in bytes
 135  * @discard_alignment: offset from internal allocation assignment in bytes
 136  * @physical_block_size: physical block size device supports in bytes
 137  * @logical_block_size: logical block size device supports in bytes
 138  * @max_segments:       max segments hardware support in one transfer
 139  * @secure_discard:     supports secure discard
 140  * @obsolete_rotational: obsolete, not in used.
 141  * @cache_policy:       support write-back caching or FUA?
 142  */
 143 struct rnbd_msg_open_rsp {
 144         struct rnbd_msg_hdr     hdr;
 145         __le32                  device_id;
 146         __le64                  nsectors;
 147         __le32                  max_hw_sectors;
 148         __le32                  max_write_zeroes_sectors;
 149         __le32                  max_discard_sectors;
 150         __le32                  discard_granularity;
 151         __le32                  discard_alignment;
 152         __le16                  physical_block_size;
 153         __le16                  logical_block_size;
 154         __le16                  max_segments;
 155         __le16                  secure_discard;
 156         u8                      obsolete_rotational;
 157         u8                      cache_policy;
 158         u8                      reserved[10];
 159 };
 160
 161 /**
 162  * struct rnbd_msg_io - message for I/O read/write
 163  * @hdr:        message header
 164  * @device_id:  device_id on server side to find the right device
 165  * @sector:     bi_sector attribute from struct bio
 166  * @rw:         valid values are defined in enum rnbd_io_flags
 167  * @bi_size:    number of bytes for I/O read/write
 168  * @prio:       priority
 169  */
 170 struct rnbd_msg_io {
 171         struct rnbd_msg_hdr hdr;
 172         __le32          device_id;
 173         __le64          sector;
 174         __le32          rw;
 175         __le32          bi_size;
 176         __le16          prio;
 177 };
 178
 179 #define RNBD_OP_BITS  8
 180 #define RNBD_OP_MASK  ((1 << RNBD_OP_BITS) - 1)
 181
 182 /**
 183  * enum rnbd_io_flags - RNBD request types from rq_flag_bits
 184  * @RNBD_OP_READ:            read sectors from the device
 185  * @RNBD_OP_WRITE:           write sectors to the device
 186  * @RNBD_OP_FLUSH:           flush the volatile write cache
 187  * @RNBD_OP_DISCARD:        discard sectors
 188  * @RNBD_OP_SECURE_ERASE:   securely erase sectors
 189  * @RNBD_OP_WRITE_ZEROES:   write zeroes sectors
 190
 191  * @RNBD_F_SYNC:             request is sync (sync write or read)
 192  * @RNBD_F_FUA:             forced unit access
 193  */
 194 enum rnbd_io_flags {
 195
 196         /* Operations */
 197         RNBD_OP_READ            = 0,
 198         RNBD_OP_WRITE           = 1,
 199         RNBD_OP_FLUSH           = 2,
 200         RNBD_OP_DISCARD = 3,
 201         RNBD_OP_SECURE_ERASE    = 4,
 202         RNBD_OP_WRITE_ZEROES    = 5,
 203
 204         /* Flags */
 205         RNBD_F_SYNC  = 1<<(RNBD_OP_BITS + 0),
 206         RNBD_F_FUA   = 1<<(RNBD_OP_BITS + 1),
 207 };
 208
 209 static inline u32 rnbd_op(u32 flags)
 210 {
 211         return flags & RNBD_OP_MASK;
 212 }
 213
 214 static inline u32 rnbd_flags(u32 flags)
 215 {
 216         return flags & ~RNBD_OP_MASK;
 217 }
 218
 219 static inline blk_opf_t rnbd_to_bio_flags(u32 rnbd_opf)
 220 {
 221         blk_opf_t bio_opf;
 222
 223         switch (rnbd_op(rnbd_opf)) {
 224         case RNBD_OP_READ:
 225                 bio_opf = REQ_OP_READ;
 226                 break;
 227         case RNBD_OP_WRITE:
 228                 bio_opf = REQ_OP_WRITE;
 229                 break;
 230         case RNBD_OP_FLUSH:
 231                 bio_opf = REQ_OP_WRITE | REQ_PREFLUSH;
 232                 break;
 233         case RNBD_OP_DISCARD:
 234                 bio_opf = REQ_OP_DISCARD;
 235                 break;
 236         case RNBD_OP_SECURE_ERASE:
 237                 bio_opf = REQ_OP_SECURE_ERASE;
 238                 break;
 239         case RNBD_OP_WRITE_ZEROES:
 240                 bio_opf = REQ_OP_WRITE_ZEROES;
 241                 break;
 242         default:
 243                 WARN(1, "Unknown RNBD type: %d (flags %d)\n",
 244                      rnbd_op(rnbd_opf), rnbd_opf);
 245                 bio_opf = 0;
 246         }
 247
 248         if (rnbd_opf & RNBD_F_SYNC)
 249                 bio_opf |= REQ_SYNC;
 250
 251         if (rnbd_opf & RNBD_F_FUA)
 252                 bio_opf |= REQ_FUA;
 253
 254         return bio_opf;
 255 }
 256
 257 static inline u32 rq_to_rnbd_flags(struct request *rq)
 258 {
 259         u32 rnbd_opf;
 260
 261         switch (req_op(rq)) {
 262         case REQ_OP_READ:
 263                 rnbd_opf = RNBD_OP_READ;
 264                 break;
 265         case REQ_OP_WRITE:
 266                 rnbd_opf = RNBD_OP_WRITE;
 267                 break;
 268         case REQ_OP_DISCARD:
 269                 rnbd_opf = RNBD_OP_DISCARD;
 270                 break;
 271         case REQ_OP_SECURE_ERASE:
 272                 rnbd_opf = RNBD_OP_SECURE_ERASE;
 273                 break;
 274         case REQ_OP_WRITE_ZEROES:
 275                 rnbd_opf = RNBD_OP_WRITE_ZEROES;
 276                 break;
 277         case REQ_OP_FLUSH:
 278                 rnbd_opf = RNBD_OP_FLUSH;
 279                 break;
 280         default:
 281                 WARN(1, "Unknown request type %d (flags %llu)\n",
 282                      (__force u32)req_op(rq),
 283                      (__force unsigned long long)rq->cmd_flags);
 284                 rnbd_opf = 0;
 285         }
 286
 287         if (op_is_sync(rq->cmd_flags))
 288                 rnbd_opf |= RNBD_F_SYNC;
 289
 290         if (op_is_flush(rq->cmd_flags))
 291                 rnbd_opf |= RNBD_F_FUA;
 292
 293         return rnbd_opf;
 294 }
 295
 296 const char *rnbd_access_mode_str(enum rnbd_access_mode mode);
 297
 298 #endif /* RNBD_PROTO_H */