From: Jamie Wellnitz <Jamie.Wellnitz@emulex.com>
To: linux-kernel@vger.kernel.org
Subject: virt_to_page/pci_map_page vs. pci_map_single
Date: Sun, 2 Nov 2003 13:12:24 -0500 [thread overview]
Message-ID: <20031102181224.GD2149@ma.emulex.com> (raw)
I see code similar to the following in a few drivers (qlogicfc,
sym53c8xx, acenic does something similar):
page = virt_to_page(buffer);
offset = ((unsigned long)buffer & ~PAGE_MASK);
busaddr = pci_map_page(pci_dev, page, offset, len, direction);
How is this preferable to:
pci_map_single( pci_dev, buffer, len, direction);
?
pci_map_single can't handle highmem pages (because they don't have a
kernel virtual address) but doesn't virt_to_page suffer from the same
limitation? Is there some benefit on architectures that don't have
highmem?
Thanks,
Jamie Wellnitz
Jamie.Wellnitz@emulex.com
next reply other threads:[~2003-11-02 18:12 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-11-02 18:12 Jamie Wellnitz [this message]
2003-11-03 8:10 ` virt_to_page/pci_map_page vs. pci_map_single Jes Sorensen
2003-11-03 12:52 ` Jamie Wellnitz
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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