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From: Hugh Dickins <hugh@veritas.com>
To: Prakash Bhurke <prakash_bhurke@yahoo.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: memory mapping of vmalloc
Date: Tue, 1 Mar 2005 17:17:36 +0000 (GMT)	[thread overview]
Message-ID: <Pine.LNX.4.61.0503011713470.31799@goblin.wat.veritas.com> (raw)
In-Reply-To: <20050301130803.34688.qmail@web54610.mail.yahoo.com>

On Tue, 1 Mar 2005, Prakash Bhurke wrote:
>   I am trying to map a vmalloc kernel buffer to user
> space using remap_page_range(). In my module, this
> function returns success if we call mmap() from user
> space, but i can not access content of vmalloc buffer
> from user space. Pointer returned by mmap() syscall
> seems pointing to other memory page which contains
> zeros. I am using linux 2.6.10 kernel on Pentium 4
> system.

Look for "rvmalloc" in various drivers in the kernel source tree:
you must SetPageReserved before remap_pfn_range (or remap_page_range)
agrees to map the page, and ClearPageReserved before freeing after.

Hugh

  reply	other threads:[~2005-03-01 17:19 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-03-01 13:08 Prakash Bhurke
2005-03-01 17:17 ` Hugh Dickins [this message]
2005-03-02 14:28   ` Prakash Bhurke

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