On Wed, Jun 23, 2021 at 02:58:32PM -0700, Omar Sandoval wrote:
> But what you described would look more like:
>
> // Needs to be large enough for maximum returned header + data.
> char buffer[...];
> struct iovec iov[] = {
> { buffer, sizeof(buffer) },
> };
> preadv2(fd, iov, 2, -1, RWF_ENCODED);
> // We should probably align the buffer.
> struct encoded_iov *encoded_iov = (void *)buffer;
> char *data = buffer + encoded_iov->size;
>
> That's a little uglier, but it should work, and allows for arbitrary
> extensions. So, among these three alternatives (fixed size structure
> with reserved space, variable size structure like above, or ioctl),
> which would you prefer?
Does that work for O_DIRECT and the required 512-byte alignment?
