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Date:   Fri, 21 Jul 2023 08:25:58 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Hannes Reinecke <hare@suse.de>
Cc:     Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
        "Darrick J. Wong" <djwong@kernel.org>,
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Subject: Re: [PATCH 6/6] fs: add CONFIG_BUFFER_HEAD
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References: <20230720140452.63817-1-hch@lst.de> <20230720140452.63817-7-hch@lst.de> <80507f03-86b4-6406-5ab1-5687b6d12d93@suse.de>
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On Thu, Jul 20, 2023 at 05:53:52PM +0200, Hannes Reinecke wrote:
> Can we modify this to not have a compile-time option but rather a setting 
> somewhere? EG kernel option or flag in struct address_space?

Modify what?  The current code diables buffer_head suport on the
block devices when the kernel does not support buffer_heads.  There
is no good way to make that a run time decision :)