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ringbuf: Use uintptr for positions for 32-bit compatibility #1843

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Merged
florianl merged 1 commit into from
Aug 7, 2025
Merged

ringbuf: Use uintptr for positions for 32-bit compatibility #1843

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28 changes: 14 additions & 14 deletions ringbuf/ring.go
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Original file line number Diff line number Diff line change
Expand Up @@ -33,8 +33,8 @@ func newRingBufEventRing(mapFD, size int) (*ringbufEventRing, error) {
return nil, fmt.Errorf("can't mmap data pages: %w", err)
}

cons_pos := (*uint64)(unsafe.Pointer(&cons[0]))
prod_pos := (*uint64)(unsafe.Pointer(&prod[0]))
cons_pos := (*uintptr)(unsafe.Pointer(&cons[0]))
prod_pos := (*uintptr)(unsafe.Pointer(&prod[0]))

ring := &ringbufEventRing{
prod: prod,
Expand All @@ -58,17 +58,17 @@ func (ring *ringbufEventRing) Close() {

type ringReader struct {
// These point into mmap'ed memory and must be accessed atomically.
prod_pos, cons_pos *uint64
mask uint64
prod_pos, cons_pos *uintptr
mask uintptr
ring []byte
}

func newRingReader(cons_ptr, prod_ptr *uint64, ring []byte) *ringReader {
func newRingReader(cons_ptr, prod_ptr *uintptr, ring []byte) *ringReader {
return &ringReader{
prod_pos: prod_ptr,
cons_pos: cons_ptr,
// cap is always a power of two
mask: uint64(cap(ring)/2 - 1),
mask: uintptr(cap(ring)/2 - 1),
ring: ring,
}
}
Expand All @@ -82,15 +82,15 @@ func (rr *ringReader) size() int {

// The amount of data available to read in the ring buffer.
func (rr *ringReader) AvailableBytes() uint64 {
prod := atomic.LoadUint64(rr.prod_pos)
cons := atomic.LoadUint64(rr.cons_pos)
return prod - cons
prod := atomic.LoadUintptr(rr.prod_pos)
cons := atomic.LoadUintptr(rr.cons_pos)
return uint64(prod - cons)
}

// Read a record from an event ring.
func (rr *ringReader) readRecord(rec *Record) error {
prod := atomic.LoadUint64(rr.prod_pos)
cons := atomic.LoadUint64(rr.cons_pos)
prod := atomic.LoadUintptr(rr.prod_pos)
cons := atomic.LoadUintptr(rr.cons_pos)

for {
if remaining := prod - cons; remaining == 0 {
Expand All @@ -117,7 +117,7 @@ func (rr *ringReader) readRecord(rec *Record) error {
cons += sys.BPF_RINGBUF_HDR_SZ

// Data is always padded to 8 byte alignment.
dataLenAligned := uint64(internal.Align(header.dataLen(), 8))
dataLenAligned := uintptr(internal.Align(header.dataLen(), 8))
if remaining := prod - cons; remaining < dataLenAligned {
return fmt.Errorf("read sample data: %w", io.ErrUnexpectedEOF)
}
Expand All @@ -129,7 +129,7 @@ func (rr *ringReader) readRecord(rec *Record) error {
// when the record header indicates that the data should be
// discarded, we skip it by just updating the consumer position
// to the next record.
atomic.StoreUint64(rr.cons_pos, cons)
atomic.StoreUintptr(rr.cons_pos, cons)
continue
}

Expand All @@ -141,7 +141,7 @@ func (rr *ringReader) readRecord(rec *Record) error {

copy(rec.RawSample, rr.ring[start:])
rec.Remaining = int(prod - cons)
atomic.StoreUint64(rr.cons_pos, cons)
atomic.StoreUintptr(rr.cons_pos, cons)
return nil
}
}
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