Something went wrong. Try again.
(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
Something went wrong. Try again.
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661662663664665666667668669670671672673674675676677678679680681682683684685686687688689690691692693694695696697698699700701702703704705706707708709710711712713714715716717718719720721722723724725726727728729730731732733734735736737738739740741742743744745746747748749750751752753754755756757758759760761762763764765766767768769770771772773774775776777778779780781782783784785786787788789790791792793794795796797798799800801802803804805806807808809810811812813814815816817818819820821822823824825826827828829830/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */#ifndef USER_BLK_DRV_CMD_INC_H#define USER_BLK_DRV_CMD_INC_H
#include <linux/types.h>
/* ublk server command definition */
/* * Admin commands, issued by ublk server, and handled by ublk driver. * * Legacy command definition, don't use in new application, and don't * add new such definition any more */#define UBLK_CMD_GET_QUEUE_AFFINITY 0x01#define UBLK_CMD_GET_DEV_INFO 0x02#define UBLK_CMD_ADD_DEV 0x04#define UBLK_CMD_DEL_DEV 0x05#define UBLK_CMD_START_DEV 0x06#define UBLK_CMD_STOP_DEV 0x07#define UBLK_CMD_SET_PARAMS 0x08#define UBLK_CMD_GET_PARAMS 0x09#define UBLK_CMD_START_USER_RECOVERY 0x10#define UBLK_CMD_END_USER_RECOVERY 0x11#define UBLK_CMD_GET_DEV_INFO2 0x12
/* Any new ctrl command should encode by __IO*() */#define UBLK_U_CMD_GET_QUEUE_AFFINITY \ _IOR('u', UBLK_CMD_GET_QUEUE_AFFINITY, struct ublksrv_ctrl_cmd)#define UBLK_U_CMD_GET_DEV_INFO \ _IOR('u', UBLK_CMD_GET_DEV_INFO, struct ublksrv_ctrl_cmd)#define UBLK_U_CMD_ADD_DEV \ _IOWR('u', UBLK_CMD_ADD_DEV, struct ublksrv_ctrl_cmd)#define UBLK_U_CMD_DEL_DEV \ _IOWR('u', UBLK_CMD_DEL_DEV, struct ublksrv_ctrl_cmd)#define UBLK_U_CMD_START_DEV \ _IOWR('u', UBLK_CMD_START_DEV, struct ublksrv_ctrl_cmd)#define UBLK_U_CMD_STOP_DEV \ _IOWR('u', UBLK_CMD_STOP_DEV, struct ublksrv_ctrl_cmd)#define UBLK_U_CMD_SET_PARAMS \ _IOWR('u', UBLK_CMD_SET_PARAMS, struct ublksrv_ctrl_cmd)#define UBLK_U_CMD_GET_PARAMS \ _IOR('u', UBLK_CMD_GET_PARAMS, struct ublksrv_ctrl_cmd)#define UBLK_U_CMD_START_USER_RECOVERY \ _IOWR('u', UBLK_CMD_START_USER_RECOVERY, struct ublksrv_ctrl_cmd)#define UBLK_U_CMD_END_USER_RECOVERY \ _IOWR('u', UBLK_CMD_END_USER_RECOVERY, struct ublksrv_ctrl_cmd)#define UBLK_U_CMD_GET_DEV_INFO2 \ _IOR('u', UBLK_CMD_GET_DEV_INFO2, struct ublksrv_ctrl_cmd)#define UBLK_U_CMD_GET_FEATURES \ _IOR('u', 0x13, struct ublksrv_ctrl_cmd)#define UBLK_U_CMD_DEL_DEV_ASYNC \ _IOR('u', 0x14, struct ublksrv_ctrl_cmd)#define UBLK_U_CMD_UPDATE_SIZE \ _IOWR('u', 0x15, struct ublksrv_ctrl_cmd)#define UBLK_U_CMD_QUIESCE_DEV \ _IOWR('u', 0x16, struct ublksrv_ctrl_cmd)#define UBLK_U_CMD_TRY_STOP_DEV \ _IOWR('u', 0x17, struct ublksrv_ctrl_cmd)/* * Register a shared memory buffer for zero-copy I/O. * Input: ctrl_cmd.addr points to struct ublk_shmem_buf_reg (buffer VA + size) * ctrl_cmd.len = sizeof(struct ublk_shmem_buf_reg) * Result: >= 0 is the assigned buffer index, < 0 is error * * The kernel pins pages from the calling process's address space * and inserts PFN ranges into a per-device maple tree. When a block * request's pages match registered pages, the driver sets * UBLK_IO_F_SHMEM_ZC and encodes the buffer index + offset in addr, * allowing the server to access the data via its own mapping of the * same shared memory — true zero copy. * * The memory can be backed by memfd, hugetlbfs, or any GUP-compatible * shared mapping. Queue freeze is handled internally. * * The buffer VA and size are passed via a user buffer (not inline in * ctrl_cmd) so that unprivileged devices can prepend the device path * to ctrl_cmd.addr without corrupting the VA. */#define UBLK_U_CMD_REG_BUF \ _IOWR('u', 0x18, struct ublksrv_ctrl_cmd)/* * Unregister a shared memory buffer. * Input: ctrl_cmd.data[0] = buffer index */#define UBLK_U_CMD_UNREG_BUF \ _IOWR('u', 0x19, struct ublksrv_ctrl_cmd)
/* Parameter buffer for UBLK_U_CMD_REG_BUF, pointed to by ctrl_cmd.addr */struct ublk_shmem_buf_reg { __u64 addr; /* userspace virtual address of shared memory */ __u64 len; /* buffer size in bytes, page-aligned, default max 4GB */ __u32 flags; __u32 reserved;};
/* Pin pages without FOLL_WRITE; usable with write-sealed memfd */#define UBLK_SHMEM_BUF_READ_ONLY (1U << 0)/* * 64bits are enough now, and it should be easy to extend in case of * running out of feature flags */#define UBLK_FEATURES_LEN 8
/* * IO commands, issued by ublk server, and handled by ublk driver. * * FETCH_REQ: issued via sqe(URING_CMD) beforehand for fetching IO request * from ublk driver, should be issued only when starting device. After * the associated cqe is returned, request's tag can be retrieved via * cqe->userdata. * * COMMIT_AND_FETCH_REQ: issued via sqe(URING_CMD) after ublkserver handled * this IO request, request's handling result is committed to ublk * driver, meantime FETCH_REQ is piggyback, and FETCH_REQ has to be * handled before completing io request. * * NEED_GET_DATA: only used for write requests to set io addr and copy data * When NEED_GET_DATA is set, ublksrv has to issue UBLK_IO_NEED_GET_DATA * command after ublk driver returns UBLK_IO_RES_NEED_GET_DATA. * * It is only used if ublksrv set UBLK_F_NEED_GET_DATA flag * while starting a ublk device. */
/* * Legacy IO command definition, don't use in new application, and don't * add new such definition any more */#define UBLK_IO_FETCH_REQ 0x20#define UBLK_IO_COMMIT_AND_FETCH_REQ 0x21#define UBLK_IO_NEED_GET_DATA 0x22
/* Any new IO command should encode by __IOWR() */#define UBLK_U_IO_FETCH_REQ \ _IOWR('u', UBLK_IO_FETCH_REQ, struct ublksrv_io_cmd)#define UBLK_U_IO_COMMIT_AND_FETCH_REQ \ _IOWR('u', UBLK_IO_COMMIT_AND_FETCH_REQ, struct ublksrv_io_cmd)#define UBLK_U_IO_NEED_GET_DATA \ _IOWR('u', UBLK_IO_NEED_GET_DATA, struct ublksrv_io_cmd)#define UBLK_U_IO_REGISTER_IO_BUF \ _IOWR('u', 0x23, struct ublksrv_io_cmd)#define UBLK_U_IO_UNREGISTER_IO_BUF \ _IOWR('u', 0x24, struct ublksrv_io_cmd)
/* * return 0 if the command is run successfully, otherwise failure code * is returned */#define UBLK_U_IO_PREP_IO_CMDS \ _IOWR('u', 0x25, struct ublk_batch_io)/* * If failure code is returned, nothing in the command buffer is handled. * Otherwise, the returned value means how many bytes in command buffer * are handled actually, then number of handled IOs can be calculated with * `elem_bytes` for each IO. IOs in the remained bytes are not committed, * userspace has to check return value for dealing with partial committing * correctly. */#define UBLK_U_IO_COMMIT_IO_CMDS \ _IOWR('u', 0x26, struct ublk_batch_io)
/* * Fetch io commands to provided buffer in multishot style, * `IORING_URING_CMD_MULTISHOT` is required for this command. */#define UBLK_U_IO_FETCH_IO_CMDS \ _IOWR('u', 0x27, struct ublk_batch_io)
/* only ABORT means that no re-fetch */#define UBLK_IO_RES_OK 0#define UBLK_IO_RES_NEED_GET_DATA 1#define UBLK_IO_RES_ABORT (-ENODEV)
#define UBLKSRV_CMD_BUF_OFFSET 0#define UBLKSRV_IO_BUF_OFFSET 0x80000000
/* tag bit is 16bit, so far limit at most 4096 IOs for each queue */#define UBLK_MAX_QUEUE_DEPTH 4096
/* single IO buffer max size is 32MB */#define UBLK_IO_BUF_OFF 0#define UBLK_IO_BUF_BITS 25#define UBLK_IO_BUF_BITS_MASK ((1ULL << UBLK_IO_BUF_BITS) - 1)
/* so at most 64K IOs for each queue */#define UBLK_TAG_OFF UBLK_IO_BUF_BITS#define UBLK_TAG_BITS 16#define UBLK_TAG_BITS_MASK ((1ULL << UBLK_TAG_BITS) - 1)
/* max 4096 queues */#define UBLK_QID_OFF (UBLK_TAG_OFF + UBLK_TAG_BITS)#define UBLK_QID_BITS 12#define UBLK_QID_BITS_MASK ((1ULL << UBLK_QID_BITS) - 1)
#define UBLK_MAX_NR_QUEUES (1U << UBLK_QID_BITS)
#define UBLKSRV_IO_BUF_TOTAL_BITS (UBLK_QID_OFF + UBLK_QID_BITS)#define UBLKSRV_IO_BUF_TOTAL_SIZE (1ULL << UBLKSRV_IO_BUF_TOTAL_BITS)
/* Copy to/from request integrity buffer instead of data buffer */#define UBLK_INTEGRITY_FLAG_OFF 62#define UBLKSRV_IO_INTEGRITY_FLAG (1ULL << UBLK_INTEGRITY_FLAG_OFF)
/* * ublk server can register data buffers for incoming I/O requests with a sparse * io_uring buffer table. The request buffer can then be used as the data buffer * for io_uring operations via the fixed buffer index. * Note that the ublk server can never directly access the request data memory. * * To use this feature, the ublk server must first register a sparse buffer * table on an io_uring instance. * When an incoming ublk request is received, the ublk server submits a * UBLK_U_IO_REGISTER_IO_BUF command to that io_uring instance. The * ublksrv_io_cmd's q_id and tag specify the request whose buffer to register * and addr is the index in the io_uring's buffer table to install the buffer. * SQEs can now be submitted to the io_uring to read/write the request's buffer * by enabling fixed buffers (e.g. using IORING_OP_{READ,WRITE}_FIXED or * IORING_URING_CMD_FIXED) and passing the registered buffer index in buf_index. * Once the last io_uring operation using the request's buffer has completed, * the ublk server submits a UBLK_U_IO_UNREGISTER_IO_BUF command with q_id, tag, * and addr again specifying the request buffer to unregister. * The ublk request is completed when its buffer is unregistered from all * io_uring instances and the ublk server issues UBLK_U_IO_COMMIT_AND_FETCH_REQ. * * Not available for UBLK_F_UNPRIVILEGED_DEV, as a ublk server can leak * uninitialized kernel memory by not reading into the full request buffer. */#define UBLK_F_SUPPORT_ZERO_COPY (1ULL << 0)
/* * Force to complete io cmd via io_uring_cmd_complete_in_task so that * performance comparison is done easily with using task_work_add */#define UBLK_F_URING_CMD_COMP_IN_TASK (1ULL << 1)
/* * User should issue io cmd again for write requests to * set io buffer address and copy data from bio vectors * to the userspace io buffer. * * In this mode, task_work is not used. */#define UBLK_F_NEED_GET_DATA (1UL << 2)
/* * - Block devices are recoverable if ublk server exits and restarts * - Outstanding I/O when ublk server exits is met with errors * - I/O issued while there is no ublk server queues */#define UBLK_F_USER_RECOVERY (1UL << 3)
/* * - Block devices are recoverable if ublk server exits and restarts * - Outstanding I/O when ublk server exits is reissued * - I/O issued while there is no ublk server queues */#define UBLK_F_USER_RECOVERY_REISSUE (1UL << 4)
/* * Unprivileged user can create /dev/ublkcN and /dev/ublkbN. * * /dev/ublk-control needs to be available for unprivileged user, and it * can be done via udev rule to make all control commands available to * unprivileged user. Except for the command of UBLK_CMD_ADD_DEV, all * other commands are only allowed for the owner of the specified device. * * When userspace sends UBLK_CMD_ADD_DEV, the device pair's owner_uid and * owner_gid are stored to ublksrv_ctrl_dev_info by kernel, so far only * the current user's uid/gid is stored, that said owner of the created * device is always the current user. * * We still need udev rule to apply OWNER/GROUP with the stored owner_uid * and owner_gid. * * Then ublk server can be run as unprivileged user, and /dev/ublkbN can * be accessed and managed by its owner represented by owner_uid/owner_gid. */#define UBLK_F_UNPRIVILEGED_DEV (1UL << 5)
/* use ioctl encoding for uring command */#define UBLK_F_CMD_IOCTL_ENCODE (1UL << 6)
/* * Copy between request and user buffer by pread()/pwrite() * * Not available for UBLK_F_UNPRIVILEGED_DEV, otherwise userspace may * deceive us by not filling request buffer, then kernel uninitialized * data may be leaked. */#define UBLK_F_USER_COPY (1UL << 7)
/* * User space sets this flag when setting up the device to request zoned storage support. Kernel may * deny the request by returning an error. */#define UBLK_F_ZONED (1ULL << 8)
/* * - Block devices are recoverable if ublk server exits and restarts * - Outstanding I/O when ublk server exits is met with errors * - I/O issued while there is no ublk server is met with errors */#define UBLK_F_USER_RECOVERY_FAIL_IO (1ULL << 9)
/* * Resizing a block device is possible with UBLK_U_CMD_UPDATE_SIZE * New size is passed in cmd->data[0] and is in units of sectors */#define UBLK_F_UPDATE_SIZE (1ULL << 10)
/* * request buffer is registered automatically to uring_cmd's io_uring * context before delivering this io command to ublk server, meantime * it is un-registered automatically when completing this io command. * * For using this feature: * * - ublk server has to create sparse buffer table on the same `io_ring_ctx` * for issuing `UBLK_IO_FETCH_REQ` and `UBLK_IO_COMMIT_AND_FETCH_REQ`. * If uring_cmd isn't issued on same `io_ring_ctx`, it is ublk server's * responsibility to unregister the buffer by issuing `IO_UNREGISTER_IO_BUF` * manually, otherwise this ublk request won't complete. * * - ublk server passes auto buf register data via uring_cmd's sqe->addr, * `struct ublk_auto_buf_reg` is populated from sqe->addr, please see * the definition of ublk_sqe_addr_to_auto_buf_reg() * * - pass buffer index from `ublk_auto_buf_reg.index` * * - all reserved fields in `ublk_auto_buf_reg` need to be zeroed * * - pass flags from `ublk_auto_buf_reg.flags` if needed * * This way avoids extra cost from two uring_cmd, but also simplifies backend * implementation, such as, the dependency on IO_REGISTER_IO_BUF and * IO_UNREGISTER_IO_BUF becomes not necessary. * * If wrong data or flags are provided, both IO_FETCH_REQ and * IO_COMMIT_AND_FETCH_REQ are failed, for the latter, the ublk IO request * won't be completed until new IO_COMMIT_AND_FETCH_REQ command is issued * successfully */#define UBLK_F_AUTO_BUF_REG (1ULL << 11)
/* * Control command `UBLK_U_CMD_QUIESCE_DEV` is added for quiescing device, * which state can be transitioned to `UBLK_S_DEV_QUIESCED` or * `UBLK_S_DEV_FAIL_IO` finally, and it needs ublk server cooperation for * handling `UBLK_IO_RES_ABORT` correctly. * * Typical use case is for supporting to upgrade ublk server application, * meantime keep ublk block device persistent during the period. * * This feature is only available when UBLK_F_USER_RECOVERY is enabled. * * Note, this command returns -EBUSY in case that all IO commands are being * handled by ublk server and not completed in specified time period which * is passed from the control command parameter. */#define UBLK_F_QUIESCE (1ULL << 12)
/* * If this feature is set, ublk_drv supports each (qid,tag) pair having * its own independent daemon task that is responsible for handling it. * If it is not set, daemons are per-queue instead, so for two pairs * (qid1,tag1) and (qid2,tag2), if qid1 == qid2, then the same task must * be responsible for handling (qid1,tag1) and (qid2,tag2). */#define UBLK_F_PER_IO_DAEMON (1ULL << 13)
/* * If this feature is set, UBLK_U_IO_REGISTER_IO_BUF/UBLK_U_IO_UNREGISTER_IO_BUF * can be issued for an I/O on any task. q_id and tag are also ignored in * UBLK_U_IO_UNREGISTER_IO_BUF's ublksrv_io_cmd. * If it is unset, zero-copy buffers can only be registered and unregistered by * the I/O's daemon task. The q_id and tag of the registered buffer are required * in UBLK_U_IO_UNREGISTER_IO_BUF's ublksrv_io_cmd. */#define UBLK_F_BUF_REG_OFF_DAEMON (1ULL << 14)
/* * Support the following commands for delivering & committing io command * in batch. * * - UBLK_U_IO_PREP_IO_CMDS * - UBLK_U_IO_COMMIT_IO_CMDS * - UBLK_U_IO_FETCH_IO_CMDS * - UBLK_U_IO_REGISTER_IO_BUF * - UBLK_U_IO_UNREGISTER_IO_BUF * * The existing UBLK_U_IO_FETCH_REQ, UBLK_U_IO_COMMIT_AND_FETCH_REQ and * UBLK_U_IO_NEED_GET_DATA uring_cmd are not supported for this feature. */#define UBLK_F_BATCH_IO (1ULL << 15)
/* * ublk device supports requests with integrity/metadata buffer. * Requires UBLK_F_USER_COPY. */#define UBLK_F_INTEGRITY (1ULL << 16)
/* * The device supports the UBLK_CMD_TRY_STOP_DEV command, which * allows stopping the device only if there are no openers. */#define UBLK_F_SAFE_STOP_DEV (1ULL << 17)
/* Disable automatic partition scanning when device is started */#define UBLK_F_NO_AUTO_PART_SCAN (1ULL << 18)
/* * Enable shared memory zero copy. When enabled, the server can register * shared memory buffers via UBLK_U_CMD_REG_BUF. If a block request's * pages match a registered buffer, UBLK_IO_F_SHMEM_ZC is set and addr * encodes the buffer index + offset instead of a userspace buffer address. */#define UBLK_F_SHMEM_ZC (1ULL << 19)
/* ublksrv_io_desc size is specified by ublksrv_ctrl_dev_info's io_desc_size */#define UBLK_F_IO_DESC_SIZE (1ULL << 20)
/* device state */#define UBLK_S_DEV_DEAD 0#define UBLK_S_DEV_LIVE 1#define UBLK_S_DEV_QUIESCED 2#define UBLK_S_DEV_FAIL_IO 3
/* shipped via sqe->cmd of io_uring command */struct ublksrv_ctrl_cmd { /* sent to which device, must be valid */ __u32 dev_id;
/* sent to which queue, must be -1 if the cmd isn't for queue */ __u16 queue_id; /* * cmd specific buffer, can be IN or OUT. */ __u16 len; __u64 addr;
/* inline data */ __u64 data[1];
/* * Used for UBLK_F_UNPRIVILEGED_DEV and UBLK_CMD_GET_DEV_INFO2 * only, include null char */ __u16 dev_path_len; __u16 pad; __u32 reserved;};
struct ublksrv_ctrl_dev_info { __u16 nr_hw_queues; __u16 queue_depth; __u16 state; __u16 io_desc_size;
__u32 max_io_buf_bytes; __u32 dev_id;
__s32 ublksrv_pid; __u32 pad1;
__u64 flags;
/* For ublksrv internal use, invisible to ublk driver */ __u64 ublksrv_flags;
__u32 owner_uid; /* store by kernel */ __u32 owner_gid; /* store by kernel */ __u64 reserved1; __u64 reserved2;};
#define UBLK_IO_OP_READ 0#define UBLK_IO_OP_WRITE 1#define UBLK_IO_OP_FLUSH 2#define UBLK_IO_OP_DISCARD 3#define UBLK_IO_OP_WRITE_SAME 4#define UBLK_IO_OP_WRITE_ZEROES 5#define UBLK_IO_OP_ZONE_OPEN 10#define UBLK_IO_OP_ZONE_CLOSE 11#define UBLK_IO_OP_ZONE_FINISH 12#define UBLK_IO_OP_ZONE_APPEND 13#define UBLK_IO_OP_ZONE_RESET_ALL 14#define UBLK_IO_OP_ZONE_RESET 15/* * Construct a zone report. The report request is carried in `struct * ublksrv_io_desc`. The `start_sector` field must be the first sector of a zone * and shall indicate the first zone of the report. The `nr_zones` shall * indicate how many zones should be reported at most. The report shall be * delivered as a `struct blk_zone` array. To report fewer zones than requested, * zero the last entry of the returned array. * * Related definitions(blk_zone, blk_zone_cond, blk_zone_type, ...) in * include/uapi/linux/blkzoned.h are part of ublk UAPI. */#define UBLK_IO_OP_REPORT_ZONES 18
#define UBLK_IO_F_FAILFAST_DEV (1U << 8)#define UBLK_IO_F_FAILFAST_TRANSPORT (1U << 9)#define UBLK_IO_F_FAILFAST_DRIVER (1U << 10)#define UBLK_IO_F_META (1U << 11)#define UBLK_IO_F_FUA (1U << 13)#define UBLK_IO_F_NOUNMAP (1U << 15)#define UBLK_IO_F_SWAP (1U << 16)/* * For UBLK_F_AUTO_BUF_REG & UBLK_AUTO_BUF_REG_FALLBACK only. * * This flag is set if auto buffer register is failed & ublk server passes * UBLK_AUTO_BUF_REG_FALLBACK, and ublk server need to register buffer * manually for handling the delivered IO command if this flag is observed * * ublk server has to check this flag if UBLK_AUTO_BUF_REG_FALLBACK is * passed in. */#define UBLK_IO_F_NEED_REG_BUF (1U << 17)/* Request has an integrity data buffer */#define UBLK_IO_F_INTEGRITY (1UL << 18)/* * I/O buffer is in a registered shared memory buffer. When set, the addr * field in ublksrv_io_desc encodes buffer index and byte offset instead * of a userspace virtual address. */#define UBLK_IO_F_SHMEM_ZC (1U << 19)
/* * io cmd is described by this structure, and stored in share memory, indexed * by request tag. * * The data is stored by ublk driver, and read by ublksrv after one fetch command * returns. */struct ublksrv_io_desc { /* op: bit 0-7, flags: bit 8-31 */ __u32 op_flags;
union { __u32 nr_sectors; __u32 nr_zones; /* for UBLK_IO_OP_REPORT_ZONES */ };
/* start sector for this io */ __u64 start_sector;
/* buffer address in ublksrv daemon vm space, from ublk driver */ __u64 addr;};
static inline __u8 ublksrv_get_op(const struct ublksrv_io_desc *iod){ return iod->op_flags & 0xff;}
static inline __u32 ublksrv_get_flags(const struct ublksrv_io_desc *iod){ return iod->op_flags >> 8;}
/* * If this flag is set, fallback by completing the uring_cmd and setting * `UBLK_IO_F_NEED_REG_BUF` in case of auto-buf-register failure; * otherwise the client ublk request is failed silently * * If ublk server passes this flag, it has to check if UBLK_IO_F_NEED_REG_BUF * is set in `ublksrv_io_desc.op_flags`. If UBLK_IO_F_NEED_REG_BUF is set, * ublk server needs to register io buffer manually for handling IO command. */#define UBLK_AUTO_BUF_REG_FALLBACK (1 << 0)#define UBLK_AUTO_BUF_REG_F_MASK UBLK_AUTO_BUF_REG_FALLBACK
struct ublk_auto_buf_reg { /* index for registering the delivered request buffer */ __u16 index; __u8 flags; __u8 reserved0;
/* * io_ring FD can be passed via the reserve field in future for * supporting to register io buffer to external io_uring */ __u32 reserved1;};
/* * For UBLK_F_AUTO_BUF_REG, auto buffer register data is carried via * uring_cmd's sqe->addr: * * - bit0 ~ bit15: buffer index * - bit16 ~ bit23: flags * - bit24 ~ bit31: reserved0 * - bit32 ~ bit63: reserved1 */static inline struct ublk_auto_buf_reg ublk_sqe_addr_to_auto_buf_reg( __u64 sqe_addr){ struct ublk_auto_buf_reg reg = { .index = (__u16)sqe_addr, .flags = (__u8)(sqe_addr >> 16), .reserved0 = (__u8)(sqe_addr >> 24), .reserved1 = (__u32)(sqe_addr >> 32), };
return reg;}
static inline __u64ublk_auto_buf_reg_to_sqe_addr(const struct ublk_auto_buf_reg *buf){ __u64 addr = buf->index | (__u64)buf->flags << 16 | (__u64)buf->reserved0 << 24 | (__u64)buf->reserved1 << 32;
return addr;}
/* issued to ublk driver via /dev/ublkcN */struct ublksrv_io_cmd { __u16 q_id;
/* for fetch/commit which result */ __u16 tag;
/* io result, it is valid for COMMIT* command only */ __s32 result;
union { /* * userspace buffer address in ublksrv daemon process, valid for * FETCH* command only * * `addr` should not be used when UBLK_F_USER_COPY is enabled, * because userspace handles data copy by pread()/pwrite() over * /dev/ublkcN. But in case of UBLK_F_ZONED, this union is * re-used to pass back the allocated LBA for * UBLK_IO_OP_ZONE_APPEND which actually depends on * UBLK_F_USER_COPY */ __u64 addr; __u64 zone_append_lba; };};
struct ublk_elem_header { __u16 tag; /* IO tag */
/* * Buffer index for incoming io command, only valid iff * UBLK_F_AUTO_BUF_REG is set */ __u16 buf_index; __s32 result; /* I/O completion result (commit only) */};
/* * uring_cmd buffer structure for batch commands * * buffer includes multiple elements, which number is specified by * `nr_elem`. Each element buffer is organized in the following order: * * struct ublk_elem_buffer { * // Mandatory fields (8 bytes) * struct ublk_elem_header header; * * // Optional fields (8 bytes each, included based on flags) * * // Buffer address (if UBLK_BATCH_F_HAS_BUF_ADDR) for copying data * // between ublk request and ublk server buffer * __u64 buf_addr; * * // returned Zone append LBA (if UBLK_BATCH_F_HAS_ZONE_LBA) * __u64 zone_lba; * } * * Used for `UBLK_U_IO_PREP_IO_CMDS` and `UBLK_U_IO_COMMIT_IO_CMDS` */struct ublk_batch_io { __u16 q_id;#define UBLK_BATCH_F_HAS_ZONE_LBA (1 << 0)#define UBLK_BATCH_F_HAS_BUF_ADDR (1 << 1)#define UBLK_BATCH_F_AUTO_BUF_REG_FALLBACK (1 << 2) __u16 flags; __u16 nr_elem; __u8 elem_bytes; __u8 reserved; __u64 reserved2;};
struct ublk_param_basic {#define UBLK_ATTR_READ_ONLY (1 << 0)#define UBLK_ATTR_ROTATIONAL (1 << 1)#define UBLK_ATTR_VOLATILE_CACHE (1 << 2)#define UBLK_ATTR_FUA (1 << 3) __u32 attrs; __u8 logical_bs_shift; __u8 physical_bs_shift; __u8 io_opt_shift; __u8 io_min_shift;
__u32 max_sectors; __u32 chunk_sectors;
__u64 dev_sectors; __u64 virt_boundary_mask;};
struct ublk_param_discard { __u32 discard_alignment;
__u32 discard_granularity; __u32 max_discard_sectors;
__u32 max_write_zeroes_sectors; __u16 max_discard_segments; __u16 reserved0;};
/* * read-only, can't set via UBLK_CMD_SET_PARAMS, disk_devt is available * after device is started */struct ublk_param_devt { __u32 char_major; __u32 char_minor; __u32 disk_major; __u32 disk_minor;};
struct ublk_param_zoned { __u32 max_open_zones; __u32 max_active_zones; __u32 max_zone_append_sectors; __u8 reserved[20];};
struct ublk_param_dma_align { __u32 alignment; __u8 pad[4];};
#define UBLK_MIN_SEGMENT_SIZE 4096/* * If any one of the three segment parameter is set as 0, the behavior is * undefined. */struct ublk_param_segment { /* * seg_boundary_mask + 1 needs to be power_of_2(), and the sum has * to be >= UBLK_MIN_SEGMENT_SIZE(4096) */ __u64 seg_boundary_mask;
/* * max_segment_size could be override by virt_boundary_mask, so be * careful when setting both. * * max_segment_size has to be >= UBLK_MIN_SEGMENT_SIZE(4096) */ __u32 max_segment_size; __u16 max_segments; __u8 pad[2];};
struct ublk_param_integrity { __u32 flags; /* LBMD_PI_CAP_* from linux/fs.h */ __u16 max_integrity_segments; /* 0 means no limit */ __u8 interval_exp; __u8 metadata_size; /* UBLK_PARAM_TYPE_INTEGRITY requires nonzero */ __u8 pi_offset; __u8 csum_type; /* LBMD_PI_CSUM_* from linux/fs.h */ __u8 tag_size; __u8 pad[5];};
struct ublk_params { /* * Total length of parameters, userspace has to set 'len' for both * SET_PARAMS and GET_PARAMS command, and driver may update len * if two sides use different version of 'ublk_params', same with * 'types' fields. */ __u32 len;#define UBLK_PARAM_TYPE_BASIC (1 << 0)#define UBLK_PARAM_TYPE_DISCARD (1 << 1)#define UBLK_PARAM_TYPE_DEVT (1 << 2)#define UBLK_PARAM_TYPE_ZONED (1 << 3)#define UBLK_PARAM_TYPE_DMA_ALIGN (1 << 4)#define UBLK_PARAM_TYPE_SEGMENT (1 << 5)#define UBLK_PARAM_TYPE_INTEGRITY (1 << 6) /* requires UBLK_F_INTEGRITY */ __u32 types; /* types of parameter included */
struct ublk_param_basic basic; struct ublk_param_discard discard; struct ublk_param_devt devt; struct ublk_param_zoned zoned; struct ublk_param_dma_align dma; struct ublk_param_segment seg; struct ublk_param_integrity integrity;};
/* * Shared memory zero-copy addr encoding for UBLK_IO_F_SHMEM_ZC. * * When UBLK_IO_F_SHMEM_ZC is set, ublksrv_io_desc.addr is encoded as: * bits [0:31] = byte offset within the buffer (up to 4GB) * bits [32:47] = buffer index (up to 65536) * bits [48:63] = reserved (must be zero) */#define UBLK_SHMEM_ZC_OFF_MASK 0xffffffffULL#define UBLK_SHMEM_ZC_IDX_OFF 32#define UBLK_SHMEM_ZC_IDX_MASK 0xffffULL
static inline __u64 ublk_shmem_zc_addr(__u16 index, __u32 offset){ return ((__u64)index << UBLK_SHMEM_ZC_IDX_OFF) | offset;}
static inline __u16 ublk_shmem_zc_index(__u64 addr){ return (addr >> UBLK_SHMEM_ZC_IDX_OFF) & UBLK_SHMEM_ZC_IDX_MASK;}
static inline __u32 ublk_shmem_zc_offset(__u64 addr){ return (__u32)(addr & UBLK_SHMEM_ZC_OFF_MASK);}
#endif