From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750879AbWJLTGf (ORCPT ); Thu, 12 Oct 2006 15:06:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750983AbWJLTGf (ORCPT ); Thu, 12 Oct 2006 15:06:35 -0400 Received: from ug-out-1314.google.com ([66.249.92.169]:19865 "EHLO ug-out-1314.google.com") by vger.kernel.org with ESMTP id S1750879AbWJLTGe (ORCPT ); Thu, 12 Oct 2006 15:06:34 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:mime-version:content-type:content-transfer-encoding:content-disposition; b=eExLpc/iMhvqCa2NvbSm7x1eaictea/Zd861u9jtnFKAF51nBQ+6TLWjrc9vxUtr9FsoH8cQ6FBXyto0bmNnjd2coQoIwv7aVtlpF9YYXpf18Di/RDxbk8f2jipoobTFt3si/abx2KXDFBpp7ku7o10Y4qOqeeIeQAk8yV4saJ4= Message-ID: Date: Thu, 12 Oct 2006 21:06:33 +0200 From: "Franck Bui-Huu" To: "Linus Torvalds" Subject: [PATCH] Fix up mmap_kmem Cc: lkml MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: Franck Bui-Huu vma->vm_pgoff is an pfn _offset_ relatif to the begining of the memory start. The previous code was doing at first: vma->vm_pgoff << PAGE_SHIFT which results into a wrong physical address since some platforms have a physical mem start that can be different from 0. After that the previous call __pa() on this wrong physical address, however __pa() is used to convert a _virtual_ address into a physical one. This patch rewrites this convertion. It calculates the pfn of PAGE_OFFSET which is the pfn of the mem start then it adds the vma->vm_pgoff to it. It also uses virt_to_phys() instead of __pa() since the latter shouldn't be used by drivers. Signed-off-by: Franck Bui-Huu --- drivers/char/mem.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/char/mem.c b/drivers/char/mem.c index 6511012..a89cb52 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -292,8 +292,8 @@ static int mmap_kmem(struct file * file, { unsigned long pfn; - /* Turn a kernel-virtual address into a physical page frame */ - pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT; + /* Turn a pfn offset into an absolute pfn */ + pfn = PFN_DOWN(virt_to_phys((void *)PAGE_OFFSET)) + vma->vm_pgoff; /* * RED-PEN: on some architectures there is more mapped memory -- 1.4.2.1.gcd6f1-dirty