linux-kernel - Re: [PATCH] iommu: Remove stub functions for !CONFIG_IOMMU

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Date:	Mon, 29 Aug 2011 15:05:52 +0200
From:	"Roedel, Joerg" <Joerg.Roedel@....com>
To:	Ohad Ben-Cohen <ohad@...ery.com>
CC:	"iommu@...ts.linux-foundation.org" <iommu@...ts.linux-foundation.org>,
	Stepan Moskovchenko <stepanm@...eaurora.org>,
	David Woodhouse <dwmw2@...radead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	David Brown <davidb@...eaurora.org>
Subject: Re: [PATCH] iommu: Remove stub functions for !CONFIG_IOMMU_API

On Mon, Aug 29, 2011 at 08:55:40AM -0400, Ohad Ben-Cohen wrote:
> On Mon, Aug 29, 2011 at 3:25 PM, Roedel, Joerg <Joerg.Roedel@....com> wrote:
> > Right, when the system has an iommu then the iommu-api is the right
> > choice to do that. But how to you handle this on systems without an
> > iommu?
> 
> On iommu-less systems this is completely moot, as the remote processor
> can access the bus directly, and thus doesn't need any iommu
> configuration to take place before it boots.
> 
> So in case there is an iommu - we configure it appropriately, and if
> there isn't, we just skip that part.

So in this case you can skip this whole part when CONFIG_IOMMU_API is
disabled (just don't compile the code in that requires the iommu-api).
This saves you even more .text size, no?

	Joerg

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