Type Alias SpinLock

pub type SpinLock<T> = Lock<T, SpinLockBackend>;

A spinlock.

Exposes the kernel’s spinlock_t. When multiple CPUs attempt to lock the same spinlock, only one at a time is allowed to progress, the others will block (spinning) until the spinlock is unlocked, at which point another CPU will be allowed to make progress.

Instances of SpinLock need a lock class and to be pinned. The recommended way to create such instances is with the pin_init and new_spinlock macros.

Examples

The following example shows how to declare, allocate and initialise a struct (Example) that contains an inner struct (Inner) that is protected by a spinlock.

use kernel::sync::{new_spinlock, SpinLock};

struct Inner {
    a: u32,
    b: u32,
}

#[pin_data]
struct Example {
    c: u32,
    #[pin]
    d: SpinLock<Inner>,
}

impl Example {
    fn new() -> impl PinInit<Self> {
        pin_init!(Self {
            c: 10,
            d <- new_spinlock!(Inner { a: 20, b: 30 }),
        })
    }
}

// Allocate a boxed `Example`.
let e = KBox::pin_init(Example::new(), GFP_KERNEL)?;
assert_eq!(e.c, 10);
assert_eq!(e.d.lock().a, 20);
assert_eq!(e.d.lock().b, 30);

The following example shows how to use interior mutability to modify the contents of a struct protected by a spinlock despite only having a shared reference:

use kernel::sync::SpinLock;

struct Example {
    a: u32,
    b: u32,
}

fn example(m: &SpinLock<Example>) {
    let mut guard = m.lock();
    guard.a += 10;
    guard.b += 20;
}

Aliased Type

struct SpinLock<T> { /* private fields */ }