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Date: Tue, 12 Jun 2018 11:24:20 +0800
From: Ming Lei <ming.lei@redhat.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: Jens Axboe <axboe@fb.com>, Alexander Viro <viro@zeniv.linux.org.uk>,
	Kent Overstreet <kent.overstreet@gmail.com>,
	David Sterba <dsterba@suse.cz>, Huang Ying <ying.huang@intel.com>,
	linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
	Theodore Ts'o <tytso@mit.edu>,
	"Darrick J . Wong" <darrick.wong@oracle.com>,
	Coly Li <colyli@suse.de>, Filipe Manana <fdmanana@gmail.com>,
	Randy Dunlap <rdunlap@infradead.org>
Subject: Re: [PATCH V6 08/30] block: introduce chunk_last_segment()
Message-ID: <20180612032419.GB26412@ming.t460p>
References: <20180609123014.8861-1-ming.lei@redhat.com>
 <20180609123014.8861-9-ming.lei@redhat.com>
 <20180611171938.GA5101@infradead.org>
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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.


Thanks,
Ming