Re: [PATCH V6 08/30] block: introduce chunk_last_segment()

From: Ming Lei
Date: Mon Jun 11 2018 - 23:24:43 EST

On Mon, Jun 11, 2018 at 10:19:38AM -0700, Christoph Hellwig wrote:
> I think both callers would be just as easy to understand by using
> nth_page() instead of these magic helpers. E.g. for guard_bio_eod:
> unsigned offset = (bv.bv_offset + bv.bv_len);
> struct page *page = nth_page(bv.bv_page, offset);

The above lines should have been written as:

struct page *page = nth_page(bv.bv_page, offset / PAGE_SIZE)

but this way may cause 'page' points to the next page of bv's last
page if offset == N * PAGE_SIZE.