[PATCH 4/9] relay: allow the use of const callback structs

[Christoph Hellwig]

> +/* subbuf_start callback wrapper */
> +static int cb_subbuf_start(struct rchan_buf *buf, void *subbuf,
> +			   void *prev_subbuf, size_t prev_padding)

I don't think the comment adds any information over just looking at the
function and the two callers.  I'd also name it relay_subbuf_start
instead of the cb_ prefix not used anywhere else in the file.


>  {
> +	if (buf->chan->cb->subbuf_start)
> +		return buf->chan->cb->subbuf_start(buf, subbuf,
> +						   prev_subbuf, prev_padding);
> +
>  	if (relay_buf_full(buf))
>  		return 0;

This could also be simplified a bit more to:

	if (!buf->chan->cb->subbuf_start)
		return !relay_buf_full(buf);
	return buf->chan->cb->subbuf_start(buf, subbuf, prev_subbuf,
					   prev_padding);

Otherwise this looks good to me:

Reviewed-by: Christoph Hellwig <hch at lst.de>