From: William Lee Irwin III <wli@holomorphy.com>
To: Jeff Garzik <jgarzik@pobox.com>
Cc: Christoph Hellwig <hch@infradead.org>,
Linux Kernel <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org,
Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>,
"Randy.Dunlap" <rddunlap@osdl.org>, Jens Axboe <axboe@suse.de>,
James Bottomley <James.Bottomley@SteelEye.com>
Subject: Re: news about IDE PIO HIGHMEM bug
Date: Wed, 27 Oct 2004 11:48:36 -0700 [thread overview]
Message-ID: <20041027184836.GA12934@holomorphy.com> (raw)
In-Reply-To: <417FEA09.6080502@pobox.com>
Christoph Hellwig wrote:
>> I think this is the wrong level of interface exposed. Just add two hepler
>> kmap_atomic_sg/kunmap_atomic_sg that gurantee to map/unmap a sg list entry,
>> even if it's bigger than a page.
On Wed, Oct 27, 2004 at 02:33:45PM -0400, Jeff Garzik wrote:
> Why bother mapping anything larger than a page, when none of the users
> need it?
> P.S. In your scheme you would need four helpers; you forgot kmap_sg()
> and kunmap_sg().
This is all a non-issue. The page structure just represents little more
than a physical address to the block layer in the context of merging,
so the pfn_to_page(page_to_pfn(...) + ...) bits calculate this properly.
There is just nothing interesting going on here. Generate the page
structure for the piece of the segment, kmap_atomic() it, and it's done.
-- wli
WARNING: multiple messages have this Message-ID (diff)
From: William Lee Irwin III <wli@holomorphy.com>
To: Jeff Garzik <jgarzik@pobox.com>
Cc: Christoph Hellwig <hch@infradead.org>,
Linux Kernel <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org,
Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>,
"Randy.Dunlap" <rddunlap@osdl.org>, Jens Axboe <axboe@suse.de>,
James Bottomley <James.Bottomley@SteelEye.com>
Subject: Re: news about IDE PIO HIGHMEM bug
Date: Wed, 27 Oct 2004 11:48:36 -0700 [thread overview]
Message-ID: <20041027184836.GA12934@holomorphy.com> (raw)
In-Reply-To: <417FEA09.6080502@pobox.com>
Christoph Hellwig wrote:
>> I think this is the wrong level of interface exposed. Just add two hepler
>> kmap_atomic_sg/kunmap_atomic_sg that gurantee to map/unmap a sg list entry,
>> even if it's bigger than a page.
On Wed, Oct 27, 2004 at 02:33:45PM -0400, Jeff Garzik wrote:
> Why bother mapping anything larger than a page, when none of the users
> need it?
> P.S. In your scheme you would need four helpers; you forgot kmap_sg()
> and kunmap_sg().
This is all a non-issue. The page structure just represents little more
than a physical address to the block layer in the context of merging,
so the pfn_to_page(page_to_pfn(...) + ...) bits calculate this properly.
There is just nothing interesting going on here. Generate the page
structure for the piece of the segment, kmap_atomic() it, and it's done.
-- wli
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next prev parent reply other threads:[~2004-10-27 18:53 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
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 [this message]
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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