1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2 #ifndef USER_BLK_DRV_CMD_INC_H
3 #define USER_BLK_DRV_CMD_INC_H
4
5 #include <linux/types.h>
6
7 /* ublk server command definition */
8
9 /*
10 * Admin commands, issued by ublk server, and handled by ublk driver.
11 *
12 * Legacy command definition, don't use in new application, and don't
13 * add new such definition any more
14 */
15 #define UBLK_CMD_GET_QUEUE_AFFINITY 0x01
16 #define UBLK_CMD_GET_DEV_INFO 0x02
17 #define UBLK_CMD_ADD_DEV 0x04
18 #define UBLK_CMD_DEL_DEV 0x05
19 #define UBLK_CMD_START_DEV 0x06
20 #define UBLK_CMD_STOP_DEV 0x07
21 #define UBLK_CMD_SET_PARAMS 0x08
22 #define UBLK_CMD_GET_PARAMS 0x09
23 #define UBLK_CMD_START_USER_RECOVERY 0x10
24 #define UBLK_CMD_END_USER_RECOVERY 0x11
25 #define UBLK_CMD_GET_DEV_INFO2 0x12
26
27 /* Any new ctrl command should encode by __IO*() */
28 #define UBLK_U_CMD_GET_QUEUE_AFFINITY \
29 _IOR('u', UBLK_CMD_GET_QUEUE_AFFINITY, struct ublksrv_ctrl_cmd)
30 #define UBLK_U_CMD_GET_DEV_INFO \
31 _IOR('u', UBLK_CMD_GET_DEV_INFO, struct ublksrv_ctrl_cmd)
32 #define UBLK_U_CMD_ADD_DEV \
33 _IOWR('u', UBLK_CMD_ADD_DEV, struct ublksrv_ctrl_cmd)
34 #define UBLK_U_CMD_DEL_DEV \
35 _IOWR('u', UBLK_CMD_DEL_DEV, struct ublksrv_ctrl_cmd)
36 #define UBLK_U_CMD_START_DEV \
37 _IOWR('u', UBLK_CMD_START_DEV, struct ublksrv_ctrl_cmd)
38 #define UBLK_U_CMD_STOP_DEV \
39 _IOWR('u', UBLK_CMD_STOP_DEV, struct ublksrv_ctrl_cmd)
40 #define UBLK_U_CMD_SET_PARAMS \
41 _IOWR('u', UBLK_CMD_SET_PARAMS, struct ublksrv_ctrl_cmd)
42 #define UBLK_U_CMD_GET_PARAMS \
43 _IOR('u', UBLK_CMD_GET_PARAMS, struct ublksrv_ctrl_cmd)
44 #define UBLK_U_CMD_START_USER_RECOVERY \
45 _IOWR('u', UBLK_CMD_START_USER_RECOVERY, struct ublksrv_ctrl_cmd)
46 #define UBLK_U_CMD_END_USER_RECOVERY \
47 _IOWR('u', UBLK_CMD_END_USER_RECOVERY, struct ublksrv_ctrl_cmd)
48 #define UBLK_U_CMD_GET_DEV_INFO2 \
49 _IOR('u', UBLK_CMD_GET_DEV_INFO2, struct ublksrv_ctrl_cmd)
50 #define UBLK_U_CMD_GET_FEATURES \
51 _IOR('u', 0x13, struct ublksrv_ctrl_cmd)
52 #define UBLK_U_CMD_DEL_DEV_ASYNC \
53 _IOR('u', 0x14, struct ublksrv_ctrl_cmd)
54 #define UBLK_U_CMD_UPDATE_SIZE \
55 _IOWR('u', 0x15, struct ublksrv_ctrl_cmd)
56 #define UBLK_U_CMD_QUIESCE_DEV \
57 _IOWR('u', 0x16, struct ublksrv_ctrl_cmd)
58
59 /*
60 * 64bits are enough now, and it should be easy to extend in case of
61 * running out of feature flags
62 */
63 #define UBLK_FEATURES_LEN 8
64
65 /*
66 * IO commands, issued by ublk server, and handled by ublk driver.
67 *
68 * FETCH_REQ: issued via sqe(URING_CMD) beforehand for fetching IO request
69 * from ublk driver, should be issued only when starting device. After
70 * the associated cqe is returned, request's tag can be retrieved via
71 * cqe->userdata.
72 *
73 * COMMIT_AND_FETCH_REQ: issued via sqe(URING_CMD) after ublkserver handled
74 * this IO request, request's handling result is committed to ublk
75 * driver, meantime FETCH_REQ is piggyback, and FETCH_REQ has to be
76 * handled before completing io request.
77 *
78 * NEED_GET_DATA: only used for write requests to set io addr and copy data
79 * When NEED_GET_DATA is set, ublksrv has to issue UBLK_IO_NEED_GET_DATA
80 * command after ublk driver returns UBLK_IO_RES_NEED_GET_DATA.
81 *
82 * It is only used if ublksrv set UBLK_F_NEED_GET_DATA flag
83 * while starting a ublk device.
84 */
85
86 /*
87 * Legacy IO command definition, don't use in new application, and don't
88 * add new such definition any more
89 */
90 #define UBLK_IO_FETCH_REQ 0x20
91 #define UBLK_IO_COMMIT_AND_FETCH_REQ 0x21
92 #define UBLK_IO_NEED_GET_DATA 0x22
93
94 /* Any new IO command should encode by __IOWR() */
95 #define UBLK_U_IO_FETCH_REQ \
96 _IOWR('u', UBLK_IO_FETCH_REQ, struct ublksrv_io_cmd)
97 #define UBLK_U_IO_COMMIT_AND_FETCH_REQ \
98 _IOWR('u', UBLK_IO_COMMIT_AND_FETCH_REQ, struct ublksrv_io_cmd)
99 #define UBLK_U_IO_NEED_GET_DATA \
100 _IOWR('u', UBLK_IO_NEED_GET_DATA, struct ublksrv_io_cmd)
101 #define UBLK_U_IO_REGISTER_IO_BUF \
102 _IOWR('u', 0x23, struct ublksrv_io_cmd)
103 #define UBLK_U_IO_UNREGISTER_IO_BUF \
104 _IOWR('u', 0x24, struct ublksrv_io_cmd)
105
106 /* only ABORT means that no re-fetch */
107 #define UBLK_IO_RES_OK 0
108 #define UBLK_IO_RES_NEED_GET_DATA 1
109 #define UBLK_IO_RES_ABORT (-ENODEV)
110
111 #define UBLKSRV_CMD_BUF_OFFSET 0
112 #define UBLKSRV_IO_BUF_OFFSET 0x80000000
113
114 /* tag bit is 16bit, so far limit at most 4096 IOs for each queue */
115 #define UBLK_MAX_QUEUE_DEPTH 4096
116
117 /* single IO buffer max size is 32MB */
118 #define UBLK_IO_BUF_OFF 0
119 #define UBLK_IO_BUF_BITS 25
120 #define UBLK_IO_BUF_BITS_MASK ((1ULL << UBLK_IO_BUF_BITS) - 1)
121
122 /* so at most 64K IOs for each queue */
123 #define UBLK_TAG_OFF UBLK_IO_BUF_BITS
124 #define UBLK_TAG_BITS 16
125 #define UBLK_TAG_BITS_MASK ((1ULL << UBLK_TAG_BITS) - 1)
126
127 /* max 4096 queues */
128 #define UBLK_QID_OFF (UBLK_TAG_OFF + UBLK_TAG_BITS)
129 #define UBLK_QID_BITS 12
130 #define UBLK_QID_BITS_MASK ((1ULL << UBLK_QID_BITS) - 1)
131
132 #define UBLK_MAX_NR_QUEUES (1U << UBLK_QID_BITS)
133
134 #define UBLKSRV_IO_BUF_TOTAL_BITS (UBLK_QID_OFF + UBLK_QID_BITS)
135 #define UBLKSRV_IO_BUF_TOTAL_SIZE (1ULL << UBLKSRV_IO_BUF_TOTAL_BITS)
136
137 /*
138 * ublk server can register data buffers for incoming I/O requests with a sparse
139 * io_uring buffer table. The request buffer can then be used as the data buffer
140 * for io_uring operations via the fixed buffer index.
141 * Note that the ublk server can never directly access the request data memory.
142 *
143 * To use this feature, the ublk server must first register a sparse buffer
144 * table on an io_uring instance.
145 * When an incoming ublk request is received, the ublk server submits a
146 * UBLK_U_IO_REGISTER_IO_BUF command to that io_uring instance. The
147 * ublksrv_io_cmd's q_id and tag specify the request whose buffer to register
148 * and addr is the index in the io_uring's buffer table to install the buffer.
149 * SQEs can now be submitted to the io_uring to read/write the request's buffer
150 * by enabling fixed buffers (e.g. using IORING_OP_{READ,WRITE}_FIXED or
151 * IORING_URING_CMD_FIXED) and passing the registered buffer index in buf_index.
152 * Once the last io_uring operation using the request's buffer has completed,
153 * the ublk server submits a UBLK_U_IO_UNREGISTER_IO_BUF command with q_id, tag,
154 * and addr again specifying the request buffer to unregister.
155 * The ublk request is completed when its buffer is unregistered from all
156 * io_uring instances and the ublk server issues UBLK_U_IO_COMMIT_AND_FETCH_REQ.
157 *
158 * Not available for UBLK_F_UNPRIVILEGED_DEV, as a ublk server can leak
159 * uninitialized kernel memory by not reading into the full request buffer.
160 */
161 #define UBLK_F_SUPPORT_ZERO_COPY (1ULL << 0)
162
163 /*
164 * Force to complete io cmd via io_uring_cmd_complete_in_task so that
165 * performance comparison is done easily with using task_work_add
166 */
167 #define UBLK_F_URING_CMD_COMP_IN_TASK (1ULL << 1)
168
169 /*
170 * User should issue io cmd again for write requests to
171 * set io buffer address and copy data from bio vectors
172 * to the userspace io buffer.
173 *
174 * In this mode, task_work is not used.
175 */
176 #define UBLK_F_NEED_GET_DATA (1UL << 2)
177
178 /*
179 * - Block devices are recoverable if ublk server exits and restarts
180 * - Outstanding I/O when ublk server exits is met with errors
181 * - I/O issued while there is no ublk server queues
182 */
183 #define UBLK_F_USER_RECOVERY (1UL << 3)
184
185 /*
186 * - Block devices are recoverable if ublk server exits and restarts
187 * - Outstanding I/O when ublk server exits is reissued
188 * - I/O issued while there is no ublk server queues
189 */
190 #define UBLK_F_USER_RECOVERY_REISSUE (1UL << 4)
191
192 /*
193 * Unprivileged user can create /dev/ublkcN and /dev/ublkbN.
194 *
195 * /dev/ublk-control needs to be available for unprivileged user, and it
196 * can be done via udev rule to make all control commands available to
197 * unprivileged user. Except for the command of UBLK_CMD_ADD_DEV, all
198 * other commands are only allowed for the owner of the specified device.
199 *
200 * When userspace sends UBLK_CMD_ADD_DEV, the device pair's owner_uid and
201 * owner_gid are stored to ublksrv_ctrl_dev_info by kernel, so far only
202 * the current user's uid/gid is stored, that said owner of the created
203 * device is always the current user.
204 *
205 * We still need udev rule to apply OWNER/GROUP with the stored owner_uid
206 * and owner_gid.
207 *
208 * Then ublk server can be run as unprivileged user, and /dev/ublkbN can
209 * be accessed and managed by its owner represented by owner_uid/owner_gid.
210 */
211 #define UBLK_F_UNPRIVILEGED_DEV (1UL << 5)
212
213 /* use ioctl encoding for uring command */
214 #define UBLK_F_CMD_IOCTL_ENCODE (1UL << 6)
215
216 /*
217 * Copy between request and user buffer by pread()/pwrite()
218 *
219 * Not available for UBLK_F_UNPRIVILEGED_DEV, otherwise userspace may
220 * deceive us by not filling request buffer, then kernel uninitialized
221 * data may be leaked.
222 */
223 #define UBLK_F_USER_COPY (1UL << 7)
224
225 /*
226 * User space sets this flag when setting up the device to request zoned storage support. Kernel may
227 * deny the request by returning an error.
228 */
229 #define UBLK_F_ZONED (1ULL << 8)
230
231 /*
232 * - Block devices are recoverable if ublk server exits and restarts
233 * - Outstanding I/O when ublk server exits is met with errors
234 * - I/O issued while there is no ublk server is met with errors
235 */
236 #define UBLK_F_USER_RECOVERY_FAIL_IO (1ULL << 9)
237
238 /*
239 * Resizing a block device is possible with UBLK_U_CMD_UPDATE_SIZE
240 * New size is passed in cmd->data[0] and is in units of sectors
241 */
242 #define UBLK_F_UPDATE_SIZE (1ULL << 10)
243
244 /*
245 * request buffer is registered automatically to uring_cmd's io_uring
246 * context before delivering this io command to ublk server, meantime
247 * it is un-registered automatically when completing this io command.
248 *
249 * For using this feature:
250 *
251 * - ublk server has to create sparse buffer table on the same `io_ring_ctx`
252 * for issuing `UBLK_IO_FETCH_REQ` and `UBLK_IO_COMMIT_AND_FETCH_REQ`.
253 * If uring_cmd isn't issued on same `io_ring_ctx`, it is ublk server's
254 * responsibility to unregister the buffer by issuing `IO_UNREGISTER_IO_BUF`
255 * manually, otherwise this ublk request won't complete.
256 *
257 * - ublk server passes auto buf register data via uring_cmd's sqe->addr,
258 * `struct ublk_auto_buf_reg` is populated from sqe->addr, please see
259 * the definition of ublk_sqe_addr_to_auto_buf_reg()
260 *
261 * - pass buffer index from `ublk_auto_buf_reg.index`
262 *
263 * - all reserved fields in `ublk_auto_buf_reg` need to be zeroed
264 *
265 * - pass flags from `ublk_auto_buf_reg.flags` if needed
266 *
267 * This way avoids extra cost from two uring_cmd, but also simplifies backend
268 * implementation, such as, the dependency on IO_REGISTER_IO_BUF and
269 * IO_UNREGISTER_IO_BUF becomes not necessary.
270 *
271 * If wrong data or flags are provided, both IO_FETCH_REQ and
272 * IO_COMMIT_AND_FETCH_REQ are failed, for the latter, the ublk IO request
273 * won't be completed until new IO_COMMIT_AND_FETCH_REQ command is issued
274 * successfully
275 */
276 #define UBLK_F_AUTO_BUF_REG (1ULL << 11)
277
278 /*
279 * Control command `UBLK_U_CMD_QUIESCE_DEV` is added for quiescing device,
280 * which state can be transitioned to `UBLK_S_DEV_QUIESCED` or
281 * `UBLK_S_DEV_FAIL_IO` finally, and it needs ublk server cooperation for
282 * handling `UBLK_IO_RES_ABORT` correctly.
283 *
284 * Typical use case is for supporting to upgrade ublk server application,
285 * meantime keep ublk block device persistent during the period.
286 *
287 * This feature is only available when UBLK_F_USER_RECOVERY is enabled.
288 *
289 * Note, this command returns -EBUSY in case that all IO commands are being
290 * handled by ublk server and not completed in specified time period which
291 * is passed from the control command parameter.
292 */
293 #define UBLK_F_QUIESCE (1ULL << 12)
294
295 /*
296 * If this feature is set, ublk_drv supports each (qid,tag) pair having
297 * its own independent daemon task that is responsible for handling it.
298 * If it is not set, daemons are per-queue instead, so for two pairs
299 * (qid1,tag1) and (qid2,tag2), if qid1 == qid2, then the same task must
300 * be responsible for handling (qid1,tag1) and (qid2,tag2).
301 */
302 #define UBLK_F_PER_IO_DAEMON (1ULL << 13)
303
304 /* device state */
305 #define UBLK_S_DEV_DEAD 0
306 #define UBLK_S_DEV_LIVE 1
307 #define UBLK_S_DEV_QUIESCED 2
308 #define UBLK_S_DEV_FAIL_IO 3
309
310 /* shipped via sqe->cmd of io_uring command */
311 struct ublksrv_ctrl_cmd {
312 /* sent to which device, must be valid */
313 __u32 dev_id;
314
315 /* sent to which queue, must be -1 if the cmd isn't for queue */
316 __u16 queue_id;
317 /*
318 * cmd specific buffer, can be IN or OUT.
319 */
320 __u16 len;
321 __u64 addr;
322
323 /* inline data */
324 __u64 data[1];
325
326 /*
327 * Used for UBLK_F_UNPRIVILEGED_DEV and UBLK_CMD_GET_DEV_INFO2
328 * only, include null char
329 */
330 __u16 dev_path_len;
331 __u16 pad;
332 __u32 reserved;
333 };
334
335 struct ublksrv_ctrl_dev_info {
336 __u16 nr_hw_queues;
337 __u16 queue_depth;
338 __u16 state;
339 __u16 pad0;
340
341 __u32 max_io_buf_bytes;
342 __u32 dev_id;
343
344 __s32 ublksrv_pid;
345 __u32 pad1;
346
347 __u64 flags;
348
349 /* For ublksrv internal use, invisible to ublk driver */
350 __u64 ublksrv_flags;
351
352 __u32 owner_uid; /* store by kernel */
353 __u32 owner_gid; /* store by kernel */
354 __u64 reserved1;
355 __u64 reserved2;
356 };
357
358 #define UBLK_IO_OP_READ 0
359 #define UBLK_IO_OP_WRITE 1
360 #define UBLK_IO_OP_FLUSH 2
361 #define UBLK_IO_OP_DISCARD 3
362 #define UBLK_IO_OP_WRITE_SAME 4
363 #define UBLK_IO_OP_WRITE_ZEROES 5
364 #define UBLK_IO_OP_ZONE_OPEN 10
365 #define UBLK_IO_OP_ZONE_CLOSE 11
366 #define UBLK_IO_OP_ZONE_FINISH 12
367 #define UBLK_IO_OP_ZONE_APPEND 13
368 #define UBLK_IO_OP_ZONE_RESET_ALL 14
369 #define UBLK_IO_OP_ZONE_RESET 15
370 /*
371 * Construct a zone report. The report request is carried in `struct
372 * ublksrv_io_desc`. The `start_sector` field must be the first sector of a zone
373 * and shall indicate the first zone of the report. The `nr_zones` shall
374 * indicate how many zones should be reported at most. The report shall be
375 * delivered as a `struct blk_zone` array. To report fewer zones than requested,
376 * zero the last entry of the returned array.
377 *
378 * Related definitions(blk_zone, blk_zone_cond, blk_zone_type, ...) in
379 * include/uapi/linux/blkzoned.h are part of ublk UAPI.
380 */
381 #define UBLK_IO_OP_REPORT_ZONES 18
382
383 #define UBLK_IO_F_FAILFAST_DEV (1U << 8)
384 #define UBLK_IO_F_FAILFAST_TRANSPORT (1U << 9)
385 #define UBLK_IO_F_FAILFAST_DRIVER (1U << 10)
386 #define UBLK_IO_F_META (1U << 11)
387 #define UBLK_IO_F_FUA (1U << 13)
388 #define UBLK_IO_F_NOUNMAP (1U << 15)
389 #define UBLK_IO_F_SWAP (1U << 16)
390 /*
391 * For UBLK_F_AUTO_BUF_REG & UBLK_AUTO_BUF_REG_FALLBACK only.
392 *
393 * This flag is set if auto buffer register is failed & ublk server passes
394 * UBLK_AUTO_BUF_REG_FALLBACK, and ublk server need to register buffer
395 * manually for handling the delivered IO command if this flag is observed
396 *
397 * ublk server has to check this flag if UBLK_AUTO_BUF_REG_FALLBACK is
398 * passed in.
399 */
400 #define UBLK_IO_F_NEED_REG_BUF (1U << 17)
401
402 /*
403 * io cmd is described by this structure, and stored in share memory, indexed
404 * by request tag.
405 *
406 * The data is stored by ublk driver, and read by ublksrv after one fetch command
407 * returns.
408 */
409 struct ublksrv_io_desc {
410 /* op: bit 0-7, flags: bit 8-31 */
411 __u32 op_flags;
412
413 union {
414 __u32 nr_sectors;
415 __u32 nr_zones; /* for UBLK_IO_OP_REPORT_ZONES */
416 };
417
418 /* start sector for this io */
419 __u64 start_sector;
420
421 /* buffer address in ublksrv daemon vm space, from ublk driver */
422 __u64 addr;
423 };
424
ublksrv_get_op(const struct ublksrv_io_desc * iod)425 static inline __u8 ublksrv_get_op(const struct ublksrv_io_desc *iod)
426 {
427 return iod->op_flags & 0xff;
428 }
429
ublksrv_get_flags(const struct ublksrv_io_desc * iod)430 static inline __u32 ublksrv_get_flags(const struct ublksrv_io_desc *iod)
431 {
432 return iod->op_flags >> 8;
433 }
434
435 /*
436 * If this flag is set, fallback by completing the uring_cmd and setting
437 * `UBLK_IO_F_NEED_REG_BUF` in case of auto-buf-register failure;
438 * otherwise the client ublk request is failed silently
439 *
440 * If ublk server passes this flag, it has to check if UBLK_IO_F_NEED_REG_BUF
441 * is set in `ublksrv_io_desc.op_flags`. If UBLK_IO_F_NEED_REG_BUF is set,
442 * ublk server needs to register io buffer manually for handling IO command.
443 */
444 #define UBLK_AUTO_BUF_REG_FALLBACK (1 << 0)
445 #define UBLK_AUTO_BUF_REG_F_MASK UBLK_AUTO_BUF_REG_FALLBACK
446
447 struct ublk_auto_buf_reg {
448 /* index for registering the delivered request buffer */
449 __u16 index;
450 __u8 flags;
451 __u8 reserved0;
452
453 /*
454 * io_ring FD can be passed via the reserve field in future for
455 * supporting to register io buffer to external io_uring
456 */
457 __u32 reserved1;
458 };
459
460 /*
461 * For UBLK_F_AUTO_BUF_REG, auto buffer register data is carried via
462 * uring_cmd's sqe->addr:
463 *
464 * - bit0 ~ bit15: buffer index
465 * - bit16 ~ bit23: flags
466 * - bit24 ~ bit31: reserved0
467 * - bit32 ~ bit63: reserved1
468 */
ublk_sqe_addr_to_auto_buf_reg(__u64 sqe_addr)469 static inline struct ublk_auto_buf_reg ublk_sqe_addr_to_auto_buf_reg(
470 __u64 sqe_addr)
471 {
472 struct ublk_auto_buf_reg reg = {
473 .index = (__u16)sqe_addr,
474 .flags = (__u8)(sqe_addr >> 16),
475 .reserved0 = (__u8)(sqe_addr >> 24),
476 .reserved1 = (__u32)(sqe_addr >> 32),
477 };
478
479 return reg;
480 }
481
482 static inline __u64
ublk_auto_buf_reg_to_sqe_addr(const struct ublk_auto_buf_reg * buf)483 ublk_auto_buf_reg_to_sqe_addr(const struct ublk_auto_buf_reg *buf)
484 {
485 __u64 addr = buf->index | (__u64)buf->flags << 16 | (__u64)buf->reserved0 << 24 |
486 (__u64)buf->reserved1 << 32;
487
488 return addr;
489 }
490
491 /* issued to ublk driver via /dev/ublkcN */
492 struct ublksrv_io_cmd {
493 __u16 q_id;
494
495 /* for fetch/commit which result */
496 __u16 tag;
497
498 /* io result, it is valid for COMMIT* command only */
499 __s32 result;
500
501 union {
502 /*
503 * userspace buffer address in ublksrv daemon process, valid for
504 * FETCH* command only
505 *
506 * `addr` should not be used when UBLK_F_USER_COPY is enabled,
507 * because userspace handles data copy by pread()/pwrite() over
508 * /dev/ublkcN. But in case of UBLK_F_ZONED, this union is
509 * re-used to pass back the allocated LBA for
510 * UBLK_IO_OP_ZONE_APPEND which actually depends on
511 * UBLK_F_USER_COPY
512 */
513 __u64 addr;
514 __u64 zone_append_lba;
515 };
516 };
517
518 struct ublk_param_basic {
519 #define UBLK_ATTR_READ_ONLY (1 << 0)
520 #define UBLK_ATTR_ROTATIONAL (1 << 1)
521 #define UBLK_ATTR_VOLATILE_CACHE (1 << 2)
522 #define UBLK_ATTR_FUA (1 << 3)
523 __u32 attrs;
524 __u8 logical_bs_shift;
525 __u8 physical_bs_shift;
526 __u8 io_opt_shift;
527 __u8 io_min_shift;
528
529 __u32 max_sectors;
530 __u32 chunk_sectors;
531
532 __u64 dev_sectors;
533 __u64 virt_boundary_mask;
534 };
535
536 struct ublk_param_discard {
537 __u32 discard_alignment;
538
539 __u32 discard_granularity;
540 __u32 max_discard_sectors;
541
542 __u32 max_write_zeroes_sectors;
543 __u16 max_discard_segments;
544 __u16 reserved0;
545 };
546
547 /*
548 * read-only, can't set via UBLK_CMD_SET_PARAMS, disk_devt is available
549 * after device is started
550 */
551 struct ublk_param_devt {
552 __u32 char_major;
553 __u32 char_minor;
554 __u32 disk_major;
555 __u32 disk_minor;
556 };
557
558 struct ublk_param_zoned {
559 __u32 max_open_zones;
560 __u32 max_active_zones;
561 __u32 max_zone_append_sectors;
562 __u8 reserved[20];
563 };
564
565 struct ublk_param_dma_align {
566 __u32 alignment;
567 __u8 pad[4];
568 };
569
570 #define UBLK_MIN_SEGMENT_SIZE 4096
571 /*
572 * If any one of the three segment parameter is set as 0, the behavior is
573 * undefined.
574 */
575 struct ublk_param_segment {
576 /*
577 * seg_boundary_mask + 1 needs to be power_of_2(), and the sum has
578 * to be >= UBLK_MIN_SEGMENT_SIZE(4096)
579 */
580 __u64 seg_boundary_mask;
581
582 /*
583 * max_segment_size could be override by virt_boundary_mask, so be
584 * careful when setting both.
585 *
586 * max_segment_size has to be >= UBLK_MIN_SEGMENT_SIZE(4096)
587 */
588 __u32 max_segment_size;
589 __u16 max_segments;
590 __u8 pad[2];
591 };
592
593 struct ublk_params {
594 /*
595 * Total length of parameters, userspace has to set 'len' for both
596 * SET_PARAMS and GET_PARAMS command, and driver may update len
597 * if two sides use different version of 'ublk_params', same with
598 * 'types' fields.
599 */
600 __u32 len;
601 #define UBLK_PARAM_TYPE_BASIC (1 << 0)
602 #define UBLK_PARAM_TYPE_DISCARD (1 << 1)
603 #define UBLK_PARAM_TYPE_DEVT (1 << 2)
604 #define UBLK_PARAM_TYPE_ZONED (1 << 3)
605 #define UBLK_PARAM_TYPE_DMA_ALIGN (1 << 4)
606 #define UBLK_PARAM_TYPE_SEGMENT (1 << 5)
607 __u32 types; /* types of parameter included */
608
609 struct ublk_param_basic basic;
610 struct ublk_param_discard discard;
611 struct ublk_param_devt devt;
612 struct ublk_param_zoned zoned;
613 struct ublk_param_dma_align dma;
614 struct ublk_param_segment seg;
615 };
616
617 #endif
618