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From: Brice Goglin <>
To: Nikolaus Rath <>
Cc: LKML <>
Subject: Re: virt_to_page for userspace pointers
Date: Sun, 13 Feb 2011 21:37:10 +0100	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

Le 13/02/2011 21:24, Nikolaus Rath a écrit :
> On 02/05/2011 04:36 PM, Brice Goglin wrote:
>>> Is there an equivalent function to virt_to_page (and virt_to_phys) that
>>> works with userspace pointers? Or do I have to manually walk through the
>>> page tables? In the later case, are there any examples of this kind of
>>> search that I could use as a basis?
>> You probably want get_user_pages() (or get_user_pages_fast()).
> Thanks for the pointer, that already helped a lot!
> I would, however, prefer a more primitive function that just gives me
> the struct page without locking it. And if the page is swapped out, I'd
> rather get a NULL pointer than having a page frame allocated.  Is there
> anything like that?

If you don't lock the page, you have no guarantee that it won't get
swapped out or migrated while you look at the physical page.


  reply	other threads:[~2011-02-13 20:37 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-02-03 20:50 Reversing a memory mapping? Nikolaus Rath
2011-02-05 21:04 ` virt_to_page for userspace pointers (was: Reversing a memory mapping?) Nikolaus Rath
2011-02-05 21:36   ` virt_to_page for userspace pointers Brice Goglin
2011-02-13 20:24     ` Nikolaus Rath
2011-02-13 20:37       ` Brice Goglin [this message]
2011-02-13 21:56         ` Nikolaus Rath
2011-02-13 22:06           ` Alan Cox
2011-02-13 22:11             ` Nikolaus Rath
2011-02-14 22:46       ` Nikolaus Rath
2011-07-26 12:03         ` Alexey Skidanov

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