Re: [PATCH 24/27] block: implement bio helper to add iter kvec pages to bio

[Al Viro]

On Fri, Nov 30, 2018 at 09:56:43AM -0700, Jens Axboe wrote:
> For an ITER_KVEC, we can just iterate the iov and add the pages
> to the bio directly.

> +             page = virt_to_page(kv->iov_base);
> +             size = bio_add_page(bio, page, kv->iov_len,
> +                                     offset_in_page(kv->iov_base));

Who said that you *can* do virt_to_page() on those?  E.g. vmalloc()'ed
addresses are fine for ITER_KVEC, etc.