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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/*
305 * If this feature is set, UBLK_U_IO_REGISTER_IO_BUF/UBLK_U_IO_UNREGISTER_IO_BUF
306 * can be issued for an I/O on any task. q_id and tag are also ignored in
307 * UBLK_U_IO_UNREGISTER_IO_BUF's ublksrv_io_cmd.
308 * If it is unset, zero-copy buffers can only be registered and unregistered by
309 * the I/O's daemon task. The q_id and tag of the registered buffer are required
310 * in UBLK_U_IO_UNREGISTER_IO_BUF's ublksrv_io_cmd.
311 */
312#define UBLK_F_BUF_REG_OFF_DAEMON (1ULL << 14)
313
314/* device state */
315#define UBLK_S_DEV_DEAD 0
316#define UBLK_S_DEV_LIVE 1
317#define UBLK_S_DEV_QUIESCED 2
318#define UBLK_S_DEV_FAIL_IO 3
319
320/* shipped via sqe->cmd of io_uring command */
321struct ublksrv_ctrl_cmd {
322 /* sent to which device, must be valid */
323 __u32 dev_id;
324
325 /* sent to which queue, must be -1 if the cmd isn't for queue */
326 __u16 queue_id;
327 /*
328 * cmd specific buffer, can be IN or OUT.
329 */
330 __u16 len;
331 __u64 addr;
332
333 /* inline data */
334 __u64 data[1];
335
336 /*
337 * Used for UBLK_F_UNPRIVILEGED_DEV and UBLK_CMD_GET_DEV_INFO2
338 * only, include null char
339 */
340 __u16 dev_path_len;
341 __u16 pad;
342 __u32 reserved;
343};
344
345struct ublksrv_ctrl_dev_info {
346 __u16 nr_hw_queues;
347 __u16 queue_depth;
348 __u16 state;
349 __u16 pad0;
350
351 __u32 max_io_buf_bytes;
352 __u32 dev_id;
353
354 __s32 ublksrv_pid;
355 __u32 pad1;
356
357 __u64 flags;
358
359 /* For ublksrv internal use, invisible to ublk driver */
360 __u64 ublksrv_flags;
361
362 __u32 owner_uid; /* store by kernel */
363 __u32 owner_gid; /* store by kernel */
364 __u64 reserved1;
365 __u64 reserved2;
366};
367
368#define UBLK_IO_OP_READ 0
369#define UBLK_IO_OP_WRITE 1
370#define UBLK_IO_OP_FLUSH 2
371#define UBLK_IO_OP_DISCARD 3
372#define UBLK_IO_OP_WRITE_SAME 4
373#define UBLK_IO_OP_WRITE_ZEROES 5
374#define UBLK_IO_OP_ZONE_OPEN 10
375#define UBLK_IO_OP_ZONE_CLOSE 11
376#define UBLK_IO_OP_ZONE_FINISH 12
377#define UBLK_IO_OP_ZONE_APPEND 13
378#define UBLK_IO_OP_ZONE_RESET_ALL 14
379#define UBLK_IO_OP_ZONE_RESET 15
380/*
381 * Construct a zone report. The report request is carried in `struct
382 * ublksrv_io_desc`. The `start_sector` field must be the first sector of a zone
383 * and shall indicate the first zone of the report. The `nr_zones` shall
384 * indicate how many zones should be reported at most. The report shall be
385 * delivered as a `struct blk_zone` array. To report fewer zones than requested,
386 * zero the last entry of the returned array.
387 *
388 * Related definitions(blk_zone, blk_zone_cond, blk_zone_type, ...) in
389 * include/uapi/linux/blkzoned.h are part of ublk UAPI.
390 */
391#define UBLK_IO_OP_REPORT_ZONES 18
392
393#define UBLK_IO_F_FAILFAST_DEV (1U << 8)
394#define UBLK_IO_F_FAILFAST_TRANSPORT (1U << 9)
395#define UBLK_IO_F_FAILFAST_DRIVER (1U << 10)
396#define UBLK_IO_F_META (1U << 11)
397#define UBLK_IO_F_FUA (1U << 13)
398#define UBLK_IO_F_NOUNMAP (1U << 15)
399#define UBLK_IO_F_SWAP (1U << 16)
400/*
401 * For UBLK_F_AUTO_BUF_REG & UBLK_AUTO_BUF_REG_FALLBACK only.
402 *
403 * This flag is set if auto buffer register is failed & ublk server passes
404 * UBLK_AUTO_BUF_REG_FALLBACK, and ublk server need to register buffer
405 * manually for handling the delivered IO command if this flag is observed
406 *
407 * ublk server has to check this flag if UBLK_AUTO_BUF_REG_FALLBACK is
408 * passed in.
409 */
410#define UBLK_IO_F_NEED_REG_BUF (1U << 17)
411
412/*
413 * io cmd is described by this structure, and stored in share memory, indexed
414 * by request tag.
415 *
416 * The data is stored by ublk driver, and read by ublksrv after one fetch command
417 * returns.
418 */
419struct ublksrv_io_desc {
420 /* op: bit 0-7, flags: bit 8-31 */
421 __u32 op_flags;
422
423 union {
424 __u32 nr_sectors;
425 __u32 nr_zones; /* for UBLK_IO_OP_REPORT_ZONES */
426 };
427
428 /* start sector for this io */
429 __u64 start_sector;
430
431 /* buffer address in ublksrv daemon vm space, from ublk driver */
432 __u64 addr;
433};
434
435static inline __u8 ublksrv_get_op(const struct ublksrv_io_desc *iod)
436{
437 return iod->op_flags & 0xff;
438}
439
440static inline __u32 ublksrv_get_flags(const struct ublksrv_io_desc *iod)
441{
442 return iod->op_flags >> 8;
443}
444
445/*
446 * If this flag is set, fallback by completing the uring_cmd and setting
447 * `UBLK_IO_F_NEED_REG_BUF` in case of auto-buf-register failure;
448 * otherwise the client ublk request is failed silently
449 *
450 * If ublk server passes this flag, it has to check if UBLK_IO_F_NEED_REG_BUF
451 * is set in `ublksrv_io_desc.op_flags`. If UBLK_IO_F_NEED_REG_BUF is set,
452 * ublk server needs to register io buffer manually for handling IO command.
453 */
454#define UBLK_AUTO_BUF_REG_FALLBACK (1 << 0)
455#define UBLK_AUTO_BUF_REG_F_MASK UBLK_AUTO_BUF_REG_FALLBACK
456
457struct ublk_auto_buf_reg {
458 /* index for registering the delivered request buffer */
459 __u16 index;
460 __u8 flags;
461 __u8 reserved0;
462
463 /*
464 * io_ring FD can be passed via the reserve field in future for
465 * supporting to register io buffer to external io_uring
466 */
467 __u32 reserved1;
468};
469
470/*
471 * For UBLK_F_AUTO_BUF_REG, auto buffer register data is carried via
472 * uring_cmd's sqe->addr:
473 *
474 * - bit0 ~ bit15: buffer index
475 * - bit16 ~ bit23: flags
476 * - bit24 ~ bit31: reserved0
477 * - bit32 ~ bit63: reserved1
478 */
479static inline struct ublk_auto_buf_reg ublk_sqe_addr_to_auto_buf_reg(
480 __u64 sqe_addr)
481{
482 struct ublk_auto_buf_reg reg = {
483 .index = (__u16)sqe_addr,
484 .flags = (__u8)(sqe_addr >> 16),
485 .reserved0 = (__u8)(sqe_addr >> 24),
486 .reserved1 = (__u32)(sqe_addr >> 32),
487 };
488
489 return reg;
490}
491
492static inline __u64
493ublk_auto_buf_reg_to_sqe_addr(const struct ublk_auto_buf_reg *buf)
494{
495 __u64 addr = buf->index | (__u64)buf->flags << 16 | (__u64)buf->reserved0 << 24 |
496 (__u64)buf->reserved1 << 32;
497
498 return addr;
499}
500
501/* issued to ublk driver via /dev/ublkcN */
502struct ublksrv_io_cmd {
503 __u16 q_id;
504
505 /* for fetch/commit which result */
506 __u16 tag;
507
508 /* io result, it is valid for COMMIT* command only */
509 __s32 result;
510
511 union {
512 /*
513 * userspace buffer address in ublksrv daemon process, valid for
514 * FETCH* command only
515 *
516 * `addr` should not be used when UBLK_F_USER_COPY is enabled,
517 * because userspace handles data copy by pread()/pwrite() over
518 * /dev/ublkcN. But in case of UBLK_F_ZONED, this union is
519 * re-used to pass back the allocated LBA for
520 * UBLK_IO_OP_ZONE_APPEND which actually depends on
521 * UBLK_F_USER_COPY
522 */
523 __u64 addr;
524 __u64 zone_append_lba;
525 };
526};
527
528struct ublk_param_basic {
529#define UBLK_ATTR_READ_ONLY (1 << 0)
530#define UBLK_ATTR_ROTATIONAL (1 << 1)
531#define UBLK_ATTR_VOLATILE_CACHE (1 << 2)
532#define UBLK_ATTR_FUA (1 << 3)
533 __u32 attrs;
534 __u8 logical_bs_shift;
535 __u8 physical_bs_shift;
536 __u8 io_opt_shift;
537 __u8 io_min_shift;
538
539 __u32 max_sectors;
540 __u32 chunk_sectors;
541
542 __u64 dev_sectors;
543 __u64 virt_boundary_mask;
544};
545
546struct ublk_param_discard {
547 __u32 discard_alignment;
548
549 __u32 discard_granularity;
550 __u32 max_discard_sectors;
551
552 __u32 max_write_zeroes_sectors;
553 __u16 max_discard_segments;
554 __u16 reserved0;
555};
556
557/*
558 * read-only, can't set via UBLK_CMD_SET_PARAMS, disk_devt is available
559 * after device is started
560 */
561struct ublk_param_devt {
562 __u32 char_major;
563 __u32 char_minor;
564 __u32 disk_major;
565 __u32 disk_minor;
566};
567
568struct ublk_param_zoned {
569 __u32 max_open_zones;
570 __u32 max_active_zones;
571 __u32 max_zone_append_sectors;
572 __u8 reserved[20];
573};
574
575struct ublk_param_dma_align {
576 __u32 alignment;
577 __u8 pad[4];
578};
579
580#define UBLK_MIN_SEGMENT_SIZE 4096
581/*
582 * If any one of the three segment parameter is set as 0, the behavior is
583 * undefined.
584 */
585struct ublk_param_segment {
586 /*
587 * seg_boundary_mask + 1 needs to be power_of_2(), and the sum has
588 * to be >= UBLK_MIN_SEGMENT_SIZE(4096)
589 */
590 __u64 seg_boundary_mask;
591
592 /*
593 * max_segment_size could be override by virt_boundary_mask, so be
594 * careful when setting both.
595 *
596 * max_segment_size has to be >= UBLK_MIN_SEGMENT_SIZE(4096)
597 */
598 __u32 max_segment_size;
599 __u16 max_segments;
600 __u8 pad[2];
601};
602
603struct ublk_params {
604 /*
605 * Total length of parameters, userspace has to set 'len' for both
606 * SET_PARAMS and GET_PARAMS command, and driver may update len
607 * if two sides use different version of 'ublk_params', same with
608 * 'types' fields.
609 */
610 __u32 len;
611#define UBLK_PARAM_TYPE_BASIC (1 << 0)
612#define UBLK_PARAM_TYPE_DISCARD (1 << 1)
613#define UBLK_PARAM_TYPE_DEVT (1 << 2)
614#define UBLK_PARAM_TYPE_ZONED (1 << 3)
615#define UBLK_PARAM_TYPE_DMA_ALIGN (1 << 4)
616#define UBLK_PARAM_TYPE_SEGMENT (1 << 5)
617 __u32 types; /* types of parameter included */
618
619 struct ublk_param_basic basic;
620 struct ublk_param_discard discard;
621 struct ublk_param_devt devt;
622 struct ublk_param_zoned zoned;
623 struct ublk_param_dma_align dma;
624 struct ublk_param_segment seg;
625};
626
627#endif
628

source code of linux/include/uapi/linux/ublk_cmd.h