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Date: Sat, 25 Feb 2017 10:23:06 -0800
From: Christoph Hellwig <hch@infradead.org>
To: Ming Lei <tom.leiming@gmail.com>
Cc: Shaohua Li <shli@kernel.org>, Jens Axboe <axboe@fb.com>,
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Subject: Re: [PATCH v1 02/14] block: introduce bio_remove_last_page()
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On Fri, Feb 24, 2017 at 11:42:39PM +0800, Ming Lei wrote:
> MD need this helper to remove the last added page, so introduce
> it.

If MD really has a valid use case for this it should open code the
operation.  The semantics look deeply fishy to me.