Method: IOU::Ring#setup_buffer_ring

Defined in:

ext/iou/iou.c

#setup_buffer_ring(opts) ⇒ Object

# File 'ext/iou/iou.c', line 168

VALUE IOU_setup_buffer_ring(VALUE self, VALUE opts) {
  IOU_t *iou = get_iou(self);

  if (iou->br_counter == BUFFER_RING_MAX_COUNT)
    rb_raise(rb_eRuntimeError, "Cannot setup more than BUFFER_RING_MAX_COUNT buffer rings");

  VALUE values[2];
  get_required_kwargs(opts, values, 2, SYM_count, SYM_size);
  VALUE count = values[0];
  VALUE size = values[1];

  struct buf_ring_descriptor *desc = iou->brs + iou->br_counter;
  desc->buf_count = NUM2UINT(count);
  desc->buf_size = NUM2UINT(size);

  desc->br_size = sizeof(struct io_uring_buf) * desc->buf_count;
  void *mapped = mmap(
    NULL, desc->br_size, PROT_READ | PROT_WRITE,
    MAP_ANONYMOUS | MAP_PRIVATE, 0, 0
  );
  if (mapped == MAP_FAILED)
    rb_raise(rb_eRuntimeError, "Failed to allocate buffer ring");

  desc->br = (struct io_uring_buf_ring *)mapped;
  io_uring_buf_ring_init(desc->br);

  unsigned bg_id = iou->br_counter;
  struct io_uring_buf_reg reg = {
    .ring_addr = (unsigned long)desc->br,
    .ring_entries = desc->buf_count,
    .bgid = bg_id
  };
  int ret = io_uring_register_buf_ring(&iou->ring, &reg, 0);
  if (ret) {
    munmap(desc->br, desc->br_size);
    rb_syserr_fail(-ret, strerror(-ret));
  }

  desc->buf_base = malloc(desc->buf_count * desc->buf_size);
  if (!desc->buf_base) {
    io_uring_free_buf_ring(&iou->ring, desc->br, desc->buf_count, bg_id);
    rb_raise(rb_eRuntimeError, "Failed to allocate buffers");
  }

  int mask = io_uring_buf_ring_mask(desc->buf_count);
  for (unsigned i = 0; i < desc->buf_count; i++) {
    io_uring_buf_ring_add(
      desc->br, desc->buf_base + i * desc->buf_size, desc->buf_size,
      i, mask, i);
  }
  io_uring_buf_ring_advance(desc->br, desc->buf_count);
  iou->br_counter++;
  return UINT2NUM(bg_id);
}