From: Jamie Wellnitz <Jamie.Wellnitz@emulex.com>
To: Jes Sorensen <jes@trained-monkey.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: virt_to_page/pci_map_page vs. pci_map_single
Date: Mon, 3 Nov 2003 07:52:59 -0500 [thread overview]
Message-ID: <20031103125259.GC16690@ma.emulex.com> (raw)
In-Reply-To: <yq0wuahan3t.fsf@trained-monkey.org>
On Mon, Nov 03, 2003 at 03:10:46AM -0500, Jes Sorensen wrote:
> >>>>> "Jamie" == Jamie Wellnitz <Jamie.Wellnitz@emulex.com> writes:
>
> Jamie> page = virt_to_page(buffer); offset = ((unsigned long)buffer &
> Jamie> ~PAGE_MASK); busaddr = pci_map_page(pci_dev, page, offset, len,
> Jamie> direction);
>
> Jamie> How is this preferable to:
>
> Jamie> pci_map_single( pci_dev, buffer, len, direction);
>
> Jamie> pci_map_single can't handle highmem pages (because they don't
> Jamie> have a kernel virtual address) but doesn't virt_to_page suffer
> Jamie> from the same limitation? Is there some benefit on
> Jamie> architectures that don't have highmem?
>
> virt_to_page() can handle any page in the standard kernel region
What is the "standard kernel region"? ZONE_NORMAL?
> including pages that are physically in 64-bit space if the
> architecture requires it. It doesn't handle vmalloc pages etc. but
> one shouldn't try and dynamically map vmalloc pages at
> random. pci_map_page() can handle all memory in the system though as
> every page that can be mapped has a struct page * entry.
>
> pci_map_page() is the correct API to use, pci_map_single() is
> deprecated.
Are you talking about 2.4 or 2.6 or both?
The Document/DMA-mapping.txt in 2.6.0-test9 says "To map a single
region, you do:" and then shows pci_map_single. Is DMA-mapping.txt in
need of patching?
>
> Cheers,
> Jes
Thanks,
Jamie
Jamie.Wellnitz@emulex.com
next prev parent reply other threads:[~2003-11-03 12:53 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-11-02 18:12 virt_to_page/pci_map_page vs. pci_map_single Jamie Wellnitz
2003-11-03 8:10 ` Jes Sorensen
2003-11-03 12:52 ` Jamie Wellnitz [this message]
2003-11-03 14:17 ` Jes Sorensen
2003-11-03 22:02 ` David Mosberger
2003-11-04 0:41 ` David S. Miller
2003-11-04 9:44 ` Jes Sorensen
2003-11-03 18:48 James Bottomley
2003-11-03 22:03 ` Jamie Wellnitz
2003-11-04 9:48 ` Jes Sorensen
2003-11-04 16:35 ` Matt Porter
2003-11-04 16:47 ` James Bottomley
2003-11-04 17:11 ` Matt Porter
2003-11-04 16:43 ` James Bottomley
2003-11-05 16:23 ` Anton Blanchard
2003-11-06 8:28 ` Jes Sorensen
[not found] <NuZH.1a5.7@gated-at.bofh.it>
[not found] ` <NI6s.1MM.3@gated-at.bofh.it>
[not found] ` <NMtC.7Vs.21@gated-at.bofh.it>
[not found] ` <NNSy.1Cd.1@gated-at.bofh.it>
[not found] ` <NV3O.5w7.19@gated-at.bofh.it>
[not found] ` <NWCA.7Qv.19@gated-at.bofh.it>
2003-11-04 8:41 ` Ihar 'Philips' Filipau
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