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
|
package kernel
import (
"context"
"sync/atomic"
"unsafe"
)
// An AtomicPtr is a pointer to a value of type Value that can be atomically
// loaded and stored. The zero value of an AtomicPtr represents nil.
//
// Note that copying AtomicPtr by value performs a non-atomic read of the
// stored pointer, which is unsafe if Store() can be called concurrently; in
// this case, do `dst.Store(src.Load())` instead.
//
// +stateify savable
type descriptorBucketAtomicPtr struct {
ptr unsafe.Pointer `state:".(*descriptorBucket)"`
}
func (p *descriptorBucketAtomicPtr) savePtr() *descriptorBucket {
return p.Load()
}
func (p *descriptorBucketAtomicPtr) loadPtr(_ context.Context, v *descriptorBucket) {
p.Store(v)
}
// Load returns the value set by the most recent Store. It returns nil if there
// has been no previous call to Store.
//
//go:nosplit
func (p *descriptorBucketAtomicPtr) Load() *descriptorBucket {
return (*descriptorBucket)(atomic.LoadPointer(&p.ptr))
}
// Store sets the value returned by Load to x.
func (p *descriptorBucketAtomicPtr) Store(x *descriptorBucket) {
atomic.StorePointer(&p.ptr, (unsafe.Pointer)(x))
}
// Swap atomically stores `x` into *p and returns the previous *p value.
func (p *descriptorBucketAtomicPtr) Swap(x *descriptorBucket) *descriptorBucket {
return (*descriptorBucket)(atomic.SwapPointer(&p.ptr, (unsafe.Pointer)(x)))
}
|
