func ReadAt(fd int, off int64, size int) ([]byte, error) {
idx := <-idle_event
retch := aio_result_map[idx]
defer func() { idle_event <- idx }()
var cb *C.struct_iocb = &cbs[idx]
var read_buf unsafe.Pointer
C.posix_memalign(&read_buf, pagesize, C.size_t(size))
defer C.free(read_buf)
C.io_prep_pread(cb, C.int(fd), read_buf, C.size_t(size), C.longlong(off))
cbs[idx].data = unsafe.Pointer(&idx)
aio_lock.Lock()
rt := C.io_submit(ctx, 1, &cb)
if int(rt) < 0 {
aio_lock.Unlock()
return nil, errors.New("io submit failed")
}
aiocount++
aio_lock.Unlock()
select {
case have_aio_event <- 0:
default:
}
ret := <-retch
return ret.buf, ret.err
}
func (sch *aioScheduler) submit(iocb *C.iocb_t) (*event, error) {
C.io_set_eventfd(iocb, C.int(sch.eventfd.Sysfd()))
ev := NewEvent()
sch.mu.Lock()
sch.reqs[iocb] = ev
sch.mu.Unlock()
errno := C.io_submit(sch.ctx, 1, &iocb)
if errno == 0 {
return nil, errors.New("Failed to submit io")
} else if errno < 0 {
return nil, syscall.Errno(-errno)
}
return ev, nil
}
func WriteAt(fd int, off int64, buf []byte) (int, error) {
size := len(buf)
if size == 0 {
return 0, nil
}
idx := <-idle_event
retch := aio_result_map[idx]
defer func() { idle_event <- idx }()
var cb *C.struct_iocb = &cbs[idx]
var write_buf unsafe.Pointer
C.posix_memalign(&write_buf, pagesize, C.size_t(size))
defer C.free(write_buf)
for i := 0; i < size; i++ {
*(*byte)(unsafe.Pointer(uintptr(write_buf) + uintptr(i))) = buf[i]
}
C.io_prep_pwrite(cb, C.int(fd), write_buf, C.size_t(size), C.longlong(off))
cbs[idx].data = unsafe.Pointer(&idx)
aio_lock.Lock()
rt := C.io_submit(ctx, 1, &cb)
if int(rt) < 0 {
aio_lock.Unlock()
return 0, errors.New("io submit failed")
}
aiocount++
aio_lock.Unlock()
select {
case have_aio_event <- 0:
default:
}
ret := <-retch
return ret.size, ret.err
}
