From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jeremy Fitzhardinge <jeremy@goop.org>
Subject: Re: [PATCH 0/9][RFC] stackable dma_ops for x86
Date: Mon, 22 Sep 2008 19:41:28 -0700
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References: <1222107681-8185-1-git-send-email-joerg.roedel@amd.com> <20080922113619.5075e7e4@infradead.org> <20080922183944.GJ24392@amd.com>
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Cc: Arjan van de Ven <arjan@infradead.org>,
	linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	iommu@lists.linux-foundation.org,
	David Woodhouse <dwmw2@infradead.org>,
	Muli Ben-Yehuda <muli@il.ibm.com>,
	Amit Shah <amit.shah@qumranet.com>,
	Ingo Molnar <mingo@redhat.com>,
	FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
To: Joerg Roedel <joerg.roedel@amd.com>
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Joerg Roedel wrote:
> Its implemented using the per-device dma-ops already there. With this
> patches there is a list of available dma_ops implementations which are
> asked in a particular order if they can handle the device. The first
> implementation which returns true is assigned to the device as the
> per-device dma_ops structure.
>
> (Hmm, maybe the name stackable is misleading, is "dma_ops multiplexing"
>  better?)

Is per-device the right level?  Wouldn't per-bus make more sense?  How
does a dma_ops implementation "know" whether it can handle a particular
device?

(I haven't had a chance to read the patches yet.)

    J