Date: Mon, 30 Mar 2009 14:11:56 -0700 (PDT)
Message-Id: <20090330.141156.62568451.davem@davemloft.net>
To: arnd@arndb.de
Cc: geert.uytterhoeven@gmail.com, michal.simek@petalogix.com,
       linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
       linux-api@vger.kernel.org
Subject: Re: Removing __kernel_old_uid_t, git_t, dev_t
From: David Miller <davem@davemloft.net>
In-Reply-To: <200903301717.57184.arnd@arndb.de>
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	<200903301717.57184.arnd@arndb.de>
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From: Arnd Bergmann <arnd@arndb.de>
Date: Mon, 30 Mar 2009 17:17:56 +0200

> dma_addr_t is a big mess that was traditionally defined per
> architecture, in lots of wrong ways, including the misconception
> of dma64_addr_t. Sparc64 still uses a 32 bit dma_addr_t, possibly
> because it always uses an IOMMU (?). It can save some space in
> scatterlists, but might come back to bite us if someone tries
> to build a sparc64 system with actual 64-bit DMA.

There is no reason to use anything larger than a 32-bit DMA address
type on sparc64, and using 32-bit saves lots of space in many
data structures so I am unlikely to ever change this. :-)
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