Replace the CpuLocal's borrow* APIs with get_with

This commit is contained in:
Zhang Junyang
2024-08-24 14:03:03 +08:00
committed by Tate, Hongliang Tian
parent f7a9510be0
commit 54cbacb2ff
5 changed files with 36 additions and 41 deletions

View File

@ -5,10 +5,7 @@
use core::{marker::Sync, ops::Deref};
use super::{__cpu_local_end, __cpu_local_start};
use crate::{
arch,
trap::{self, DisabledLocalIrqGuard},
};
use crate::{arch, trap::DisabledLocalIrqGuard};
/// Defines a CPU-local variable.
///
@ -16,14 +13,13 @@ use crate::{
///
/// You can get the reference to the inner object on one CPU by calling
/// [`CpuLocal::get_on_cpu`]. Also if you intend to access the inner object
/// on the current CPU, you can use [`CpuLocal::borrow_irq_disabled`] or
/// [`CpuLocal::borrow_with`]. The latter two accessors can be used even if
/// the inner object is not `Sync`.
/// on the current CPU, you can use [`CpuLocal::get_with`]. The latter
/// accessors can be used even if the inner object is not `Sync`.
///
/// # Example
///
/// ```rust
/// use ostd::{cpu_local, cpu::PinCurrentCpu, task::disable_preempt};
/// use ostd::{cpu_local, cpu::PinCurrentCpu, task::disable_preempt, trap};
/// use core::{sync::atomic::{AtomicU32, Ordering}, cell::Cell};
///
/// cpu_local! {
@ -37,7 +33,8 @@ use crate::{
/// let val_of_foo = ref_of_foo.load(Ordering::Relaxed);
/// println!("FOO VAL: {}", val_of_foo);
///
/// let bar_guard = BAR.borrow_irq_disabled();
/// let irq_guard = trap::disable_local();
/// let bar_guard = BAR.get_with(&irq_guard);
/// let val_of_bar = bar_guard.get();
/// println!("BAR VAL: {}", val_of_bar);
/// }
@ -87,29 +84,19 @@ impl<T: 'static> CpuLocal<T> {
Self(val)
}
/// Get access to the underlying value with IRQs disabled.
/// Get access to the underlying value on the current CPU with a
/// provided IRQ guard.
///
/// By this method, you can borrow a reference to the underlying value
/// even if `T` is not `Sync`. Because that it is per-CPU and IRQs are
/// disabled, no other running tasks can access it.
pub fn borrow_irq_disabled(&'static self) -> CpuLocalDerefGuard<'_, T> {
CpuLocalDerefGuard {
cpu_local: self,
_guard: InnerGuard::Created(trap::disable_local()),
}
}
/// Get access to the underlying value with a provided guard.
///
/// Similar to [`CpuLocal::borrow_irq_disabled`], but you can provide
/// a guard to disable IRQs if you already have one.
pub fn borrow_with<'a>(
pub fn get_with<'a>(
&'static self,
guard: &'a DisabledLocalIrqGuard,
) -> CpuLocalDerefGuard<'a, T> {
CpuLocalDerefGuard {
cpu_local: self,
_guard: InnerGuard::Provided(guard),
guard,
}
}
@ -199,19 +186,12 @@ impl<T: 'static> !Send for CpuLocal<T> {}
/// A guard for accessing the CPU-local object.
///
/// It ensures that the CPU-local object is accessed with IRQs disabled.
/// It is created by [`CpuLocal::borrow_irq_disabled`] or
/// [`CpuLocal::borrow_with`]. Do not hold this guard for a longtime.
/// It is created by [`CpuLocal::borrow_with`].
#[must_use]
pub struct CpuLocalDerefGuard<'a, T: 'static> {
cpu_local: &'static CpuLocal<T>,
_guard: InnerGuard<'a>,
}
enum InnerGuard<'a> {
#[allow(dead_code)]
Created(DisabledLocalIrqGuard),
#[allow(dead_code)]
Provided(&'a DisabledLocalIrqGuard),
guard: &'a DisabledLocalIrqGuard,
}
impl<T: 'static> Deref for CpuLocalDerefGuard<'_, T> {

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@ -189,7 +189,8 @@ mod test {
crate::cpu_local! {
static FOO: RefCell<usize> = RefCell::new(1);
}
let foo_guard = FOO.borrow_irq_disabled();
let irq_guard = crate::trap::disable_local();
let foo_guard = FOO.get_with(&irq_guard);
assert_eq!(*foo_guard.borrow(), 1);
*foo_guard.borrow_mut() = 2;
assert_eq!(*foo_guard.borrow(), 2);