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Date:   Fri, 20 May 2022 08:07:58 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Keith Busch <kbusch@kernel.org>
Cc:     Christoph Hellwig <hch@lst.de>, Eric Biggers <ebiggers@kernel.org>,
        Keith Busch <kbusch@fb.com>, linux-fsdevel@vger.kernel.org,
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        Kernel Team <Kernel-team@fb.com>, bvanassche@acm.org,
        damien.lemoal@opensource.wdc.com
Subject: Re: [PATCHv2 3/3] block: relax direct io memory alignment
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On Thu, May 19, 2022 at 10:35:23AM -0600, Keith Busch wrote:
> > At least stacking drivers had all kinds of interesting limitations in
> > this area.  How much testing did this series get with all kinds of
> > interesting dm targets and md pesonalities?
> 
> The dma limit doesn't stack (should it?). It gets the default, sector size - 1,
> so their constraints are effectively unchanged.

In general it should stack, as modulo implementation issues stacking
drivers sould not care about the alignment.  However since it doesn't
there might be some of those.