clean up physical merging helpers

To: Jens Axboe <axboe@xxxxxxxxx>
Subject: clean up physical merging helpers
From: Christoph Hellwig <hch@xxxxxx>
Date: Tue, 25 Sep 2018 13:30:04 -0700
Cc: Ming Lei <ming.lei@xxxxxxxxxx>, Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>, Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>, linux-block@xxxxxxxxxxxxxxx, xen-devel@xxxxxxxxxxxxx, linux-arm-kernel@xxxxxxxxxxxxxxxxxxx

Hi Jens,

this series moves Xen special handling of block merges from arch hooks
into common code.  A previous version has been reviewed by Boris.

Follow-Ups:
- Re: clean up physical merging helpers
  - From: Jens Axboe
- [PATCH 5/5] xen: don't include <xen/xen.h> from <asm/io.h> and <asm/dma-mapping.h>
  - From: Christoph Hellwig
- [PATCH 4/5] block: remove ARCH_BIOVEC_PHYS_MERGEABLE
  - From: Christoph Hellwig
- [PATCH 3/5] xen: provide a prototype for xen_biovec_phys_mergeable in xen.h
  - From: Christoph Hellwig
- [PATCH 2/5] xen: remove the xen_biovec_phys_mergeable export
  - From: Christoph Hellwig
- [PATCH 1/5] arm: remove the unused BIOVEC_MERGEABLE define
  - From: Christoph Hellwig