From: Jeff Garzik <jgarzik@pobox.com>
To: Andrew Morton <akpm@osdl.org>
Cc: mbligh@aracnet.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, bzolnier@gmail.com, rddunlap@osdl.org,
wli@holomorphy.com, axboe@suse.de
Subject: Re: [PATCH] Re: news about IDE PIO HIGHMEM bug (was: Re: 2.6.9-mm1)
Date: Wed, 27 Oct 2004 17:31:11 -0400 [thread overview]
Message-ID: <20041027213111.GA13627@havoc.gtf.org> (raw)
In-Reply-To: <20041027142914.197c72ed.akpm@osdl.org>
On Wed, Oct 27, 2004 at 02:29:14PM -0700, Andrew Morton wrote:
> spose so. The scatterlist API is being a bit silly there.
Well, it depends on your perspective :)
Each scatterlist entry is supposed to map to a physical segment to be
passed to h/w. Hardware S/G tables just want to see a addr/len pair,
and don't care about machine page size. scatterlist follows a similar
model.
dma_map_sg() and other helpers create a favorable situation, where >90%
of the drivers don't have to care about the VM-size details.
Unfortunately those drivers that need need to do their own data transfer
(like ATA's PIO, instead of DMA) need direct access to each member of an
s/g list.
Jeff
WARNING: multiple messages have this Message-ID (diff)
From: Jeff Garzik <jgarzik@pobox.com>
To: Andrew Morton <akpm@osdl.org>
Cc: mbligh@aracnet.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, bzolnier@gmail.com, rddunlap@osdl.org,
wli@holomorphy.com, axboe@suse.de
Subject: Re: [PATCH] Re: news about IDE PIO HIGHMEM bug (was: Re: 2.6.9-mm1)
Date: Wed, 27 Oct 2004 17:31:11 -0400 [thread overview]
Message-ID: <20041027213111.GA13627@havoc.gtf.org> (raw)
In-Reply-To: <20041027142914.197c72ed.akpm@osdl.org>
On Wed, Oct 27, 2004 at 02:29:14PM -0700, Andrew Morton wrote:
> spose so. The scatterlist API is being a bit silly there.
Well, it depends on your perspective :)
Each scatterlist entry is supposed to map to a physical segment to be
passed to h/w. Hardware S/G tables just want to see a addr/len pair,
and don't care about machine page size. scatterlist follows a similar
model.
dma_map_sg() and other helpers create a favorable situation, where >90%
of the drivers don't have to care about the VM-size details.
Unfortunately those drivers that need need to do their own data transfer
(like ATA's PIO, instead of DMA) need direct access to each member of an
s/g list.
Jeff
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next prev parent reply other threads:[~2004-10-27 21:36 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <58cb370e041027074676750027@mail.gmail.com>
2004-10-27 15:14 ` news about IDE PIO HIGHMEM bug (was: Re: 2.6.9-mm1) Jeff Garzik
2004-10-27 15:14 ` Jeff Garzik
2004-10-27 15:52 ` Martin J. Bligh
2004-10-27 15:52 ` Martin J. Bligh
2004-10-27 15:59 ` Jeff Garzik
2004-10-27 15:59 ` Jeff Garzik
2004-10-27 17:36 ` Martin J. Bligh
2004-10-27 17:36 ` Martin J. Bligh
2004-10-27 16:01 ` Martin J. Bligh
2004-10-27 16:01 ` Martin J. Bligh
2004-10-27 16:35 ` [PATCH] " Jeff Garzik
2004-10-27 21:29 ` Andrew Morton
2004-10-27 21:29 ` Andrew Morton
2004-10-27 21:31 ` Jeff Garzik [this message]
2004-10-27 21:31 ` Jeff Garzik
2004-10-27 21:34 ` William Lee Irwin III
2004-10-27 21:34 ` William Lee Irwin III
2004-10-27 18:08 ` Christoph Hellwig
2004-10-27 18:08 ` Christoph Hellwig
2004-10-27 18:33 ` news about IDE PIO HIGHMEM bug Jeff Garzik
2004-10-27 18:33 ` Jeff Garzik
2004-10-27 18:48 ` William Lee Irwin III
2004-10-27 18:48 ` William Lee Irwin III
2004-10-28 0:18 ` William Lee Irwin III
2004-10-28 0:18 ` William Lee Irwin III
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