Re: [PATCH v3 05/49] fs/buffer: comment on direct access to bvec table

[Christoph Hellwig]

> +	/*
> +	 * It is safe to truncate the last bvec in the following way
> +	 * even though multipage bvec is supported, but we need to
> +	 * fix the parameters passed to zero_user().
> +	 */
> +	struct bio_vec *bvec = &bio->bi_io_vec[bio->bi_vcnt - 1];

A 'we need to fix XXX' comment isn't very useful.  Just fix it in the
series (which I suspect you're going to do anyway).

Also a bio_last_vec helper might be nice for something like this and
documents properly converted places much better than these comments.