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Date: Fri, 9 Mar 2001 13:35:03 -0500
From: Johannes Erdfelt <johannes@erdfelt.com>
To: linux-usb-devel@lists.sourceforge.net
Cc: Manfred Spraul <manfred@colorfullife.com>,
        David Brownell <david-b@pacbell.net>,
        Russell King <rmk@arm.linux.org.uk>, zaitcev@redhat.com,
        linux-kernel@vger.kernel.org
Subject: Re: [linux-usb-devel] Re: SLAB vs. pci_alloc_xxx in usb-uhci patch [RFC: API]
Message-ID: <20010309133502.R31345@sventech.com>
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In-Reply-To: <15017.7950.106874.276894@pizda.ninka.net>; from David S. Miller on Fri, Mar 09, 2001 at 10:21:02AM -0800
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On Fri, Mar 09, 2001, David S. Miller <davem@redhat.com> wrote:
> Manfred Spraul writes:
>  > Do lots of drivers need the reverse mapping? It wasn't on my todo list
>  > yet.
> 
> I am against any API which provides this.  It can be extremely
> expensive to do this on some architectures, and since the rest
> of the PCI dma API does not provide such an interface neither
> should the pool routines.

The API I hacked together for uhci.c didn't have this.

> Drivers can keep track of this kind of information themselves,
> and that is what I tell every driver author to do who complains
> of a lack of a "bus_to_virt()" type thing, it's just lazy
> programming.

Once I worked around not having a "bus_to_virt()" type thing I was happier
with the resulting code. I completely agree.

JE

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