Re: [PATCH 5/8] vmalloc: simplify vread()/vwrite()

From: Wu Fengguang
Date: Thu Jan 21 2010 - 00:49:44 EST


On Wed, Jan 20, 2010 at 10:21:06PM -0700, KAMEZAWA Hiroyuki wrote:
> On Thu, 21 Jan 2010 13:05:21 +0800
> Wu Fengguang <fengguang.wu@xxxxxxxxx> wrote:
>
> > On Mon, Jan 18, 2010 at 07:23:43PM -0700, KAMEZAWA Hiroyuki wrote:

> > I did some audit and find that
> >
> > - set_memory_uc(), set_memory_array_uc(), set_pages_uc(),
> > set_pages_array_uc() are called EFI code and various video drivers,
> > all of them don't touch HIGHMEM RAM
> >
> > - Kame: ioremap() won't allow remap of physical RAM
> >
> > So kmap_atomic() is safe. Let's just settle on this patch?
> >
> I recommend you to keep check on VM_IOREMAP. That was checked far before
> I started to see Linux. Some _unknown_ driver can call get_vm_area() and
> map arbitrary pages there.

OK, I'll turn this patch into a less radical one.

Thanks,
Fengguang
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