uring 0.1.0

Pure Rust library for io_uring
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158

use std::io::{self, Error};
use std::mem;
use std::os::unix::io::RawFd;
use std::ptr::NonNull;
use sys_call::sys_call;

mod offsets;
use offsets::{CompletionOffsets, SubmissionOffsets};

mod queue;
use queue::Queue;

mod completion;
pub use completion::{CompletionQueue, CompletionQueueEntry};

mod submission;
pub use submission::{SubmissionQueue, SubmissionQueueEntry};

#[repr(C)]
#[derive(Debug)]
struct Params {
    sq_entries: u32,
    cq_entries: u32,
    flags: u32,
    sq_thread_cpu: u32,
    sq_thread_idle: u32,
    resv: [u32; 5],
    sq_off: SubmissionOffsets,
    cq_off: CompletionOffsets,
}

pub struct IoUring {
    pub sq_entries: u32,
    pub cq_entries: u32,
    pub flags: u32,
    pub sq_thread_cpu: u32,
    pub sq_thread_idle: u32,
}

impl Default for IoUring {
    fn default() -> Self {
        Self {
            sq_entries: 0,
            cq_entries: 0,
            flags: 0,
            sq_thread_cpu: 0,
            sq_thread_idle: 0,
        }
    }
}

impl IoUring {
    pub fn with_entries(sq_entries: u32) -> Self {
        Self {
            sq_entries,
            ..Default::default()
        }
    }
    pub fn setup(&self) -> io::Result<(SubmissionQueue, CompletionQueue)> {
        let mut params = Params {
            sq_entries: self.sq_entries,
            cq_entries: self.cq_entries,
            flags: self.flags,
            sq_thread_cpu: self.sq_thread_cpu,
            sq_thread_idle: self.sq_thread_idle,
            resv: [0; 5],
            sq_off: Default::default(),
            cq_off: Default::default(),
        };

        to_result(unsafe {
            const IO_URING_SETUP: isize = 425;
            sys_call!(
                IO_URING_SETUP,
                self.sq_entries as isize,
                &mut params as *mut _ as isize
            )
        })
        .and_then(|fd| {
            to_result(unsafe {
                const OFFSET_SQ_RING: isize = 0;
                mmap(
                    params.sq_off.array as isize
                        + (self.sq_entries as isize * mem::size_of::<u32>() as isize),
                    fd,
                    OFFSET_SQ_RING,
                )
            })
            .and_then(|sq_ptr| {
                to_result(unsafe {
                    const OFFSET_CQ_RING: isize = 0x8000000;
                    mmap(
                        params.cq_off.cqes as isize
                            + (self.cq_entries as isize
                                * mem::size_of::<CompletionQueueEntry>() as isize),
                        fd,
                        OFFSET_CQ_RING,
                    )
                })
                .and_then(|cq_ptr| {
                    to_result(unsafe {
                        const OFFSET_SQES: isize = 0x10000000;
                        mmap(
                            self.sq_entries as isize
                                * mem::size_of::<SubmissionQueueEntry>() as isize,
                            fd,
                            OFFSET_SQES,
                        )
                    })
                    .map(|sqes| {
                        let sqes = sqes as *mut SubmissionQueueEntry;
                        let cqes = (cq_ptr + params.cq_off.cqes as isize) as *mut _;
                        unsafe {
                            (
                                SubmissionQueue {
                                    queue: Queue {
                                        head: field(sq_ptr, params.sq_off.head),
                                        tail: field(sq_ptr, params.sq_off.tail),
                                        mask: field(sq_ptr, params.sq_off.mask),
                                        len: self.sq_entries,
                                        entries: NonNull::new_unchecked(sqes),
                                    },
                                    array: field(sq_ptr, params.sq_off.array),
                                },
                                CompletionQueue {
                                    fd: fd as RawFd,
                                    queue: Queue {
                                        head: field(cq_ptr, params.cq_off.head),
                                        tail: field(cq_ptr, params.cq_off.tail),
                                        mask: field(cq_ptr, params.cq_off.mask),
                                        len: self.cq_entries,
                                        entries: NonNull::new_unchecked(cqes),
                                    },
                                },
                            )
                        }
                    })
                })
            })
        })
    }
}

fn to_result(ret: isize) -> io::Result<isize> {
    if ret > 0 {
        Ok(ret)
    } else {
        Err(Error::from_raw_os_error(ret as i32 * -1))
    }
}

unsafe fn mmap(size: isize, fd: isize, offset: isize) -> isize {
    sys_call!(9, 0, size, 1 | 2, 0x0001 | 0x08000, fd, offset)
}

unsafe fn field(ptr: isize, field: u32) -> NonNull<u32> {
    NonNull::new_unchecked((ptr + field as isize) as *mut u32)
}