From: Matthew Wilcox <willy@debian.org>
To: jd <jpd_hp_linux_scsi@yahoo.com>
Cc: linux-scsi <linux-scsi@vger.kernel.org>
Subject: Re: Scatter Gather question : 2.6.test4 . page to vaddr
Date: Mon, 22 Sep 2003 21:41:09 +0100 [thread overview]
Message-ID: <20030922204109.GY13172@parcelfarce.linux.theplanet.co.uk> (raw)
In-Reply-To: <20030922201540.68358.qmail@web60210.mail.yahoo.com>
On Mon, Sep 22, 2003 at 01:15:40PM -0700, jd wrote:
> I see that 2.6 scatterlist.h has eliminated the "address" element
> and uses page struct only, and that pci_map_sg() is used to
> populate the dma_address field. I'm not really planning on
> using DMA .
>
> How can I convert the page * entry
> pointed to by SCpnt->request_buffer back to a vaddr ?
> I don't see a page-to-vaddr() . function ?
The trick is that there may not be a vaddr for that struct page. If it's
in highmem on x86, then it only ever gets temporary mappings into the
kernel's space. You're probably looking for kmap(), kmap_atomic() or,
if you really really know it's a lowmem page, page_address().
--
"It's not Hollywood. War is real, war is primarily not about defeat or
victory, it is about death. I've seen thousands and thousands of dead bodies.
Do you think I want to have an academic debate on this subject?" -- Robert Fisk
prev parent reply other threads:[~2003-09-22 20:41 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-09-22 20:15 Scatter Gather question : 2.6.test4 . page to vaddr jd
2003-09-22 20:32 ` jd
2003-09-22 20:34 ` James Bottomley
2003-09-22 20:41 ` Matthew Wilcox [this message]
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