Message-ID: <43DA7CD1.4040301@drzeus.cx>
Date: Fri, 27 Jan 2006 21:04:33 +0100
From: Pierre Ossman <drzeus-list@drzeus.cx>
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To: Pierre Ossman <drzeus-list@drzeus.cx>, Jens Axboe <axboe@suse.de>,
       LKML <linux-kernel@vger.kernel.org>
Subject: Re: How to map high memory for block io
References: <43D9C19F.7090707@drzeus.cx> <20060127102611.GC4311@suse.de> <43D9F705.5000403@drzeus.cx> <20060127104321.GE4311@suse.de> <43DA0E97.5030504@drzeus.cx> <20060127194318.GA1433@flint.arm.linux.org.uk>
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Russell King wrote:
>
> I don't see what the problem is.  A sg entry is a list of struct page
> pointers, an offset, and a size.  As such, it can't describe a transfer
> which crosses a page because such a structure does not imply that one
> struct page follows another struct page.
>
>   

If the pages do not strictly follow each other then there is a lot of
broken code in the kernel. drivers/mmc/mmci.c and drivers/block/ub.c
being two occurences since both assume they can access the entire entry
through a single mapping.

Rgds
Pierre

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