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/blkdev.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 /**
  65  * struct rnbd_msg_sess_info - initial session info from client to server
  66  * @hdr:                message header
  67  * @ver:                RNBD protocol version
  68  */
  69 struct rnbd_msg_sess_info {
  70         struct rnbd_msg_hdr hdr;
  71         u8              ver;
  72         u8              reserved[31];
  73 };
  74
  75 /**
  76  * struct rnbd_msg_sess_info_rsp - initial session info from server to client
  77  * @hdr:                message header
  78  * @ver:                RNBD protocol version
  79  */
  80 struct rnbd_msg_sess_info_rsp {
  81         struct rnbd_msg_hdr hdr;
  82         u8              ver;
  83         u8              reserved[31];
  84 };
  85
  86 /**
  87  * struct rnbd_msg_open - request to open a remote device.
  88  * @hdr:                message header
  89  * @access_mode:        the mode to open remote device, valid values see:
  90  *                      enum rnbd_access_mode
  91  * @device_name:        device path on remote side
  92  */
  93 struct rnbd_msg_open {
  94         struct rnbd_msg_hdr hdr;
  95         u8              access_mode;
  96         u8              resv1;
  97         s8              dev_name[NAME_MAX];
  98         u8              reserved[3];
  99 };
 100
 101 /**
 102  * struct rnbd_msg_close - request to close a remote device.
 103  * @hdr:        message header
 104  * @device_id:  device_id on server side to identify the device
 105  */
 106 struct rnbd_msg_close {
 107         struct rnbd_msg_hdr hdr;
 108         __le32          device_id;
 109 };
 110
 111 enum rnbd_cache_policy {
 112         RNBD_FUA = 1 << 0,
 113         RNBD_WRITEBACK = 1 << 1,
 114 };
 115
 116 /**
 117  * struct rnbd_msg_open_rsp - response message to RNBD_MSG_OPEN
 118  * @hdr:                message header
 119  * @device_id:          device_id on server side to identify the device
 120  * @nsectors:           number of sectors in the usual 512b unit
 121  * @max_hw_sectors:     max hardware sectors in the usual 512b unit
 122  * @max_write_same_sectors: max sectors for WRITE SAME in the 512b unit
 123  * @max_discard_sectors: max. sectors that can be discarded at once in 512b
 124  * unit.
 125  * @discard_granularity: size of the internal discard allocation unit in bytes
 126  * @discard_alignment: offset from internal allocation assignment in bytes
 127  * @physical_block_size: physical block size device supports in bytes
 128  * @logical_block_size: logical block size device supports in bytes
 129  * @max_segments:       max segments hardware support in one transfer
 130  * @secure_discard:     supports secure discard
 131  * @rotation:           is a rotational disc?
 132  * @cache_policy:       support write-back caching or FUA?
 133  */
 134 struct rnbd_msg_open_rsp {
 135         struct rnbd_msg_hdr     hdr;
 136         __le32                  device_id;
 137         __le64                  nsectors;
 138         __le32                  max_hw_sectors;
 139         __le32                  max_write_same_sectors;
 140         __le32                  max_discard_sectors;
 141         __le32                  discard_granularity;
 142         __le32                  discard_alignment;
 143         __le16                  physical_block_size;
 144         __le16                  logical_block_size;
 145         __le16                  max_segments;
 146         __le16                  secure_discard;
 147         u8                      rotational;
 148         u8                      cache_policy;
 149         u8                      reserved[10];
 150 };
 151
 152 /**
 153  * struct rnbd_msg_io - message for I/O read/write
 154  * @hdr:        message header
 155  * @device_id:  device_id on server side to find the right device
 156  * @sector:     bi_sector attribute from struct bio
 157  * @rw:         valid values are defined in enum rnbd_io_flags
 158  * @bi_size:    number of bytes for I/O read/write
 159  * @prio:       priority
 160  */
 161 struct rnbd_msg_io {
 162         struct rnbd_msg_hdr hdr;
 163         __le32          device_id;
 164         __le64          sector;
 165         __le32          rw;
 166         __le32          bi_size;
 167         __le16          prio;
 168 };
 169
 170 #define RNBD_OP_BITS  8
 171 #define RNBD_OP_MASK  ((1 << RNBD_OP_BITS) - 1)
 172
 173 /**
 174  * enum rnbd_io_flags - RNBD request types from rq_flag_bits
 175  * @RNBD_OP_READ:            read sectors from the device
 176  * @RNBD_OP_WRITE:           write sectors to the device
 177  * @RNBD_OP_FLUSH:           flush the volatile write cache
 178  * @RNBD_OP_DISCARD:        discard sectors
 179  * @RNBD_OP_SECURE_ERASE:   securely erase sectors
 180  * @RNBD_OP_WRITE_SAME:     write the same sectors many times
 181
 182  * @RNBD_F_SYNC:             request is sync (sync write or read)
 183  * @RNBD_F_FUA:             forced unit access
 184  */
 185 enum rnbd_io_flags {
 186
 187         /* Operations */
 188
 189         RNBD_OP_READ            = 0,
 190         RNBD_OP_WRITE           = 1,
 191         RNBD_OP_FLUSH           = 2,
 192         RNBD_OP_DISCARD = 3,
 193         RNBD_OP_SECURE_ERASE    = 4,
 194         RNBD_OP_WRITE_SAME      = 5,
 195
 196         RNBD_OP_LAST,
 197
 198         /* Flags */
 199
 200         RNBD_F_SYNC  = 1<<(RNBD_OP_BITS + 0),
 201         RNBD_F_FUA   = 1<<(RNBD_OP_BITS + 1),
 202
 203         RNBD_F_ALL   = (RNBD_F_SYNC | RNBD_F_FUA)
 204
 205 };
 206
 207 static inline u32 rnbd_op(u32 flags)
 208 {
 209         return flags & RNBD_OP_MASK;
 210 }
 211
 212 static inline u32 rnbd_flags(u32 flags)
 213 {
 214         return flags & ~RNBD_OP_MASK;
 215 }
 216
 217 static inline bool rnbd_flags_supported(u32 flags)
 218 {
 219         u32 op;
 220
 221         op = rnbd_op(flags);
 222         flags = rnbd_flags(flags);
 223
 224         if (op >= RNBD_OP_LAST)
 225                 return false;
 226         if (flags & ~RNBD_F_ALL)
 227                 return false;
 228
 229         return true;
 230 }
 231
 232 static inline u32 rnbd_to_bio_flags(u32 rnbd_opf)
 233 {
 234         u32 bio_opf;
 235
 236         switch (rnbd_op(rnbd_opf)) {
 237         case RNBD_OP_READ:
 238                 bio_opf = REQ_OP_READ;
 239                 break;
 240         case RNBD_OP_WRITE:
 241                 bio_opf = REQ_OP_WRITE;
 242                 break;
 243         case RNBD_OP_FLUSH:
 244                 bio_opf = REQ_OP_FLUSH | REQ_PREFLUSH;
 245                 break;
 246         case RNBD_OP_DISCARD:
 247                 bio_opf = REQ_OP_DISCARD;
 248                 break;
 249         case RNBD_OP_SECURE_ERASE:
 250                 bio_opf = REQ_OP_SECURE_ERASE;
 251                 break;
 252         case RNBD_OP_WRITE_SAME:
 253                 bio_opf = REQ_OP_WRITE_SAME;
 254                 break;
 255         default:
 256                 WARN(1, "Unknown RNBD type: %d (flags %d)\n",
 257                      rnbd_op(rnbd_opf), rnbd_opf);
 258                 bio_opf = 0;
 259         }
 260
 261         if (rnbd_opf & RNBD_F_SYNC)
 262                 bio_opf |= REQ_SYNC;
 263
 264         if (rnbd_opf & RNBD_F_FUA)
 265                 bio_opf |= REQ_FUA;
 266
 267         return bio_opf;
 268 }
 269
 270 static inline u32 rq_to_rnbd_flags(struct request *rq)
 271 {
 272         u32 rnbd_opf;
 273
 274         switch (req_op(rq)) {
 275         case REQ_OP_READ:
 276                 rnbd_opf = RNBD_OP_READ;
 277                 break;
 278         case REQ_OP_WRITE:
 279                 rnbd_opf = RNBD_OP_WRITE;
 280                 break;
 281         case REQ_OP_DISCARD:
 282                 rnbd_opf = RNBD_OP_DISCARD;
 283                 break;
 284         case REQ_OP_SECURE_ERASE:
 285                 rnbd_opf = RNBD_OP_SECURE_ERASE;
 286                 break;
 287         case REQ_OP_WRITE_SAME:
 288                 rnbd_opf = RNBD_OP_WRITE_SAME;
 289                 break;
 290         case REQ_OP_FLUSH:
 291                 rnbd_opf = RNBD_OP_FLUSH;
 292                 break;
 293         default:
 294                 WARN(1, "Unknown request type %d (flags %llu)\n",
 295                      req_op(rq), (unsigned long long)rq->cmd_flags);
 296                 rnbd_opf = 0;
 297         }
 298
 299         if (op_is_sync(rq->cmd_flags))
 300                 rnbd_opf |= RNBD_F_SYNC;
 301
 302         if (op_is_flush(rq->cmd_flags))
 303                 rnbd_opf |= RNBD_F_FUA;
 304
 305         return rnbd_opf;
 306 }
 307
 308 const char *rnbd_access_mode_str(enum rnbd_access_mode mode);
 309
 310 #endif /* RNBD_PROTO_H */