/* SPDX-License-Identifier: (GPL-2.0 WITH Linux-syscall-note) OR MIT */
/*
 * Header file for the io_uring interface.
 *
 * Copyright (C) 2019 Jens Axboe
 * Copyright (C) 2019 Christoph Hellwig
 */
#ifndef LINUX_IO_URING_H
#define LINUX_IO_URING_H

#include <linux/fs.h>
#include <linux/types.h>

/*
 * IO submission data structure (Submission Queue Entry)
 */
struct io_uring_sqe {
        __u8    opcode;         /* type of operation for this sqe */
        __u8    flags;          /* IOSQE_ flags */
        __u16   ioprio;         /* ioprio for the request */
        __s32   fd;             /* file descriptor to do IO on */
        union {
                __u64   off;    /* offset into file */
                __u64   addr2;
        };
        union {
                __u64   addr;   /* pointer to buffer or iovecs */
                __u64   splice_off_in;
        };
        __u32   len;            /* buffer size or number of iovecs */
        union {
                __kernel_rwf_t  rw_flags;
                __u32           fsync_flags;
                __u16           poll_events;    /* compatibility */
                __u32           poll32_events;  /* word-reversed for BE */
                __u32           sync_range_flags;
                __u32           msg_flags;
                __u32           timeout_flags;
                __u32           accept_flags;
                __u32           cancel_flags;
                __u32           open_flags;
                __u32           statx_flags;
                __u32           fadvise_advice;
                __u32           splice_flags;
        };
        __u64   user_data;      /* data to be passed back at completion time */
        union {
                struct {
                        /* pack this to avoid bogus arm OABI complaints */
                        union {
                                /* index into fixed buffers, if used */
                                __u16   buf_index;
                                /* for grouped buffer selection */
                                __u16   buf_group;
                        } __attribute__((packed));
                        /* personality to use, if used */
                        __u16   personality;
                        __s32   splice_fd_in;
                };
                __u64   __pad2[3];
        };
};

enum {
        IOSQE_FIXED_FILE_BIT,
        IOSQE_IO_DRAIN_BIT,
        IOSQE_IO_LINK_BIT,
        IOSQE_IO_HARDLINK_BIT,
        IOSQE_ASYNC_BIT,
        IOSQE_BUFFER_SELECT_BIT,
};

/*
 * sqe->flags
 */
/* use fixed fileset */
#define IOSQE_FIXED_FILE        (1U << IOSQE_FIXED_FILE_BIT)
/* issue after inflight IO */
#define IOSQE_IO_DRAIN          (1U << IOSQE_IO_DRAIN_BIT)
/* links next sqe */
#define IOSQE_IO_LINK           (1U << IOSQE_IO_LINK_BIT)
/* like LINK, but stronger */
#define IOSQE_IO_HARDLINK       (1U << IOSQE_IO_HARDLINK_BIT)
/* always go async */
#define IOSQE_ASYNC             (1U << IOSQE_ASYNC_BIT)
/* select buffer from sqe->buf_group */
#define IOSQE_BUFFER_SELECT     (1U << IOSQE_BUFFER_SELECT_BIT)

/*
 * io_uring_setup() flags
 */
#define IORING_SETUP_IOPOLL     (1U << 0)       /* io_context is polled */
#define IORING_SETUP_SQPOLL     (1U << 1)       /* SQ poll thread */
#define IORING_SETUP_SQ_AFF     (1U << 2)       /* sq_thread_cpu is valid */
#define IORING_SETUP_CQSIZE     (1U << 3)       /* app defines CQ size */
#define IORING_SETUP_CLAMP      (1U << 4)       /* clamp SQ/CQ ring sizes */
#define IORING_SETUP_ATTACH_WQ  (1U << 5)       /* attach to existing wq */
#define IORING_SETUP_R_DISABLED (1U << 6)       /* start with ring disabled */

enum {
        IORING_OP_NOP,
        IORING_OP_READV,
        IORING_OP_WRITEV,
        IORING_OP_FSYNC,
        IORING_OP_READ_FIXED,
        IORING_OP_WRITE_FIXED,
        IORING_OP_POLL_ADD,
        IORING_OP_POLL_REMOVE,
        IORING_OP_SYNC_FILE_RANGE,
        IORING_OP_SENDMSG,
        IORING_OP_RECVMSG,
        IORING_OP_TIMEOUT,
        IORING_OP_TIMEOUT_REMOVE,
        IORING_OP_ACCEPT,
        IORING_OP_ASYNC_CANCEL,
        IORING_OP_LINK_TIMEOUT,
        IORING_OP_CONNECT,
        IORING_OP_FALLOCATE,
        IORING_OP_OPENAT,
        IORING_OP_CLOSE,
        IORING_OP_FILES_UPDATE,
        IORING_OP_STATX,
        IORING_OP_READ,
        IORING_OP_WRITE,
        IORING_OP_FADVISE,
        IORING_OP_MADVISE,
        IORING_OP_SEND,
        IORING_OP_RECV,
        IORING_OP_OPENAT2,
        IORING_OP_EPOLL_CTL,
        IORING_OP_SPLICE,
        IORING_OP_PROVIDE_BUFFERS,
        IORING_OP_REMOVE_BUFFERS,
        IORING_OP_TEE,

        /* this goes last, obviously */
        IORING_OP_LAST,
};

/*
 * sqe->fsync_flags
 */
#define IORING_FSYNC_DATASYNC   (1U << 0)

/*
 * sqe->timeout_flags
 */
#define IORING_TIMEOUT_ABS      (1U << 0)

/*
 * sqe->splice_flags
 * extends splice(2) flags
 */
#define SPLICE_F_FD_IN_FIXED    (1U << 31) /* the last bit of __u32 */

/*
 * IO completion data structure (Completion Queue Entry)
 */
struct io_uring_cqe {
        __u64   user_data;      /* sqe->data submission passed back */
        __s32   res;            /* result code for this event */
        __u32   flags;
};

/*
 * cqe->flags
 *
 * IORING_CQE_F_BUFFER  If set, the upper 16 bits are the buffer ID
 */
#define IORING_CQE_F_BUFFER             (1U << 0)

enum {
        IORING_CQE_BUFFER_SHIFT         = 16,
};

/*
 * Magic offsets for the application to mmap the data it needs
 */
#define IORING_OFF_SQ_RING              0ULL
#define IORING_OFF_CQ_RING              0x8000000ULL
#define IORING_OFF_SQES                 0x10000000ULL

/*
 * Filled with the offset for mmap(2)
 */
struct io_sqring_offsets {
        __u32 head;
        __u32 tail;
        __u32 ring_mask;
        __u32 ring_entries;
        __u32 flags;
        __u32 dropped;
        __u32 array;
        __u32 resv1;
        __u64 resv2;
};

/*
 * sq_ring->flags
 */
#define IORING_SQ_NEED_WAKEUP   (1U << 0) /* needs io_uring_enter wakeup */
#define IORING_SQ_CQ_OVERFLOW   (1U << 1) /* CQ ring is overflown */

struct io_cqring_offsets {
        __u32 head;
        __u32 tail;
        __u32 ring_mask;
        __u32 ring_entries;
        __u32 overflow;
        __u32 cqes;
        __u32 flags;
        __u32 resv1;
        __u64 resv2;
};

/*
 * cq_ring->flags
 */

/* disable eventfd notifications */
#define IORING_CQ_EVENTFD_DISABLED      (1U << 0)

/*
 * io_uring_enter(2) flags
 */
#define IORING_ENTER_GETEVENTS  (1U << 0)
#define IORING_ENTER_SQ_WAKEUP  (1U << 1)
#define IORING_ENTER_SQ_WAIT    (1U << 2)

/*
 * Passed in for io_uring_setup(2). Copied back with updated info on success
 */
struct io_uring_params {
        __u32 sq_entries;
        __u32 cq_entries;
        __u32 flags;
        __u32 sq_thread_cpu;
        __u32 sq_thread_idle;
        __u32 features;
        __u32 wq_fd;
        __u32 resv[3];
        struct io_sqring_offsets sq_off;
        struct io_cqring_offsets cq_off;
};

/*
 * io_uring_params->features flags
 */
#define IORING_FEAT_SINGLE_MMAP         (1U << 0)
#define IORING_FEAT_NODROP              (1U << 1)
#define IORING_FEAT_SUBMIT_STABLE       (1U << 2)
#define IORING_FEAT_RW_CUR_POS          (1U << 3)
#define IORING_FEAT_CUR_PERSONALITY     (1U << 4)
#define IORING_FEAT_FAST_POLL           (1U << 5)
#define IORING_FEAT_POLL_32BITS         (1U << 6)

/*
 * io_uring_register(2) opcodes and arguments
 */
enum {
        IORING_REGISTER_BUFFERS                 = 0,
        IORING_UNREGISTER_BUFFERS               = 1,
        IORING_REGISTER_FILES                   = 2,
        IORING_UNREGISTER_FILES                 = 3,
        IORING_REGISTER_EVENTFD                 = 4,
        IORING_UNREGISTER_EVENTFD               = 5,
        IORING_REGISTER_FILES_UPDATE            = 6,
        IORING_REGISTER_EVENTFD_ASYNC           = 7,
        IORING_REGISTER_PROBE                   = 8,
        IORING_REGISTER_PERSONALITY             = 9,
        IORING_UNREGISTER_PERSONALITY           = 10,
        IORING_REGISTER_RESTRICTIONS            = 11,
        IORING_REGISTER_ENABLE_RINGS            = 12,

        /* this goes last */
        IORING_REGISTER_LAST
};

struct io_uring_files_update {
        __u32 offset;
        __u32 resv;
        __aligned_u64 /* __s32 * */ fds;
};

#define IO_URING_OP_SUPPORTED   (1U << 0)

struct io_uring_probe_op {
        __u8 op;
        __u8 resv;
        __u16 flags;    /* IO_URING_OP_* flags */
        __u32 resv2;
};

struct io_uring_probe {
        __u8 last_op;   /* last opcode supported */
        __u8 ops_len;   /* length of ops[] array below */
        __u16 resv;
        __u32 resv2[3];
        struct io_uring_probe_op ops[0];
};

struct io_uring_restriction {
        __u16 opcode;
        union {
                __u8 register_op; /* IORING_RESTRICTION_REGISTER_OP */
                __u8 sqe_op;      /* IORING_RESTRICTION_SQE_OP */
                __u8 sqe_flags;   /* IORING_RESTRICTION_SQE_FLAGS_* */
        };
        __u8 resv;
        __u32 resv2[3];
};

/*
 * io_uring_restriction->opcode values
 */
enum {
        /* Allow an io_uring_register(2) opcode */
        IORING_RESTRICTION_REGISTER_OP          = 0,

        /* Allow an sqe opcode */
        IORING_RESTRICTION_SQE_OP               = 1,

        /* Allow sqe flags */
        IORING_RESTRICTION_SQE_FLAGS_ALLOWED    = 2,

        /* Require sqe flags (these flags must be set on each submission) */
        IORING_RESTRICTION_SQE_FLAGS_REQUIRED   = 3,

        IORING_RESTRICTION_LAST
};

#endif