io-uring 0.3.3

The `io_uring` library for Rust.
Documentation 
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
159

use io_uring::{ opcode, IoUring };


#[test]
fn test_basic() -> anyhow::Result<()> {
    let mut ring = IoUring::new(4)?;

    // nop
    let entry = opcode::Nop::new()
        .build()
        .user_data(0x42);

    unsafe {
        ring.submission()
            .available()
            .push(entry)
            .ok()
            .expect("squeue is full");
    }

    ring.submit_and_wait(1)?;

    let cqe = ring.completion()
        .available()
        .next()
        .expect("cqueue is empty");

    assert_eq!(cqe.user_data(), 0x42);

    Ok(())
}

#[test]
fn test_sq_full() -> anyhow::Result<()> {
    let mut ring = IoUring::new(4)?;

    for _ in 0..4 {
        unsafe {
            ring.submission()
                .available()
                .push(opcode::Nop::new().build())
                .ok()
                .expect("squeue is full");
        }
    }

    unsafe {
        let ret = ring.submission()
            .available()
            .push(opcode::Nop::new().build());

        assert!(ret.is_err());
    }

    assert!(ring.submission().is_full());
    assert_eq!(ring.submission().len(), 4);

    assert!(ring.submission().available().is_full());
    assert_eq!(ring.submission().available().len(), 4);

    Ok(())
}

#[test]
fn test_cq_overflow() -> anyhow::Result<()> {
    let mut ring = IoUring::new(4)?;

    // fill cq
    for _ in 0..2 {
        for _ in 0..4 {
            unsafe {
                ring.submission()
                    .available()
                    .push(opcode::Nop::new().build())
                    .ok()
                    .expect("squeue is full");
            }
        }

        ring.submit()?;
    }

    assert_eq!(ring.completion().len(), 8);
    assert!(ring.completion().is_full());

    if ring.params().is_feature_nodrop() {
        // 5.5+ kernel

        // overflow cq
        for _ in 0..4 {
            unsafe {
                ring.submission()
                    .available()
                    .push(opcode::Nop::new().build())
                    .ok()
                    .expect("squeue is full");
            }
        }

        ring.submit()?;

        assert_eq!(ring.completion().len(), 8);
        assert!(ring.completion().is_full());
        assert_eq!(ring.completion().overflow(), 0);

        // cq busy
        unsafe {
            ring.submission()
                .available()
                .push(opcode::Nop::new().build())
                .ok()
                .expect("squeue is full");
        }

        let err = ring.submit().unwrap_err();
        assert_eq!(err.raw_os_error(), Some(libc::EBUSY));
        assert_eq!(ring.completion().len(), 8);
        assert!(ring.completion().is_full());
        assert_eq!(ring.completion().overflow(), 0);

        // release cq
        ring.completion().available().take(4).for_each(drop);
        assert_eq!(ring.completion().len(), 4);

        unsafe {
            ring.submission()
                .available()
                .push(opcode::Nop::new().build())
                .ok()
                .expect("squeue is full");
        }

        ring.submit()?;

        // fill again
        assert_eq!(ring.completion().len(), 8);
    } else {
        // 5.4 kernel

        // overflow cq
        for _ in 0..4 {
            unsafe {
                ring.submission()
                    .available()
                    .push(opcode::Nop::new().build())
                    .ok()
                    .expect("squeue is full");
            }
        }

        ring.submit()?;

        assert_eq!(ring.completion().len(), 8);
        assert!(ring.completion().is_full());
        assert_eq!(ring.completion().overflow(), 4);
    }

    Ok(())
}