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Date:   Sat, 5 Aug 2023 18:07:05 +0100
From:   Matthew Wilcox <willy@infradead.org>
To:     Yongqin Liu <yongqin.liu@linaro.org>
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Subject: Re: [PATCH v2 04/32] mm/pgtable: allow pte_offset_map[_lock]() to
 fail
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On Sun, Aug 06, 2023 at 12:06:28AM +0800, Yongqin Liu wrote:
> On Sat, 29 Jul 2023 at 00:58, Hugh Dickins <hughd@google.com> wrote:
> >
> > On Fri, 28 Jul 2023, Matthew Wilcox wrote:
> > > On Fri, Jul 28, 2023 at 09:53:29PM +0800, Yongqin Liu wrote:
> > > > Hi, Hugh
> > > >
> > > > It seems this change makes pte_offset_map_lock not possible to be
> > > > called in out of tree modules,
> > > > otherwise it will report error like this:
> > > >         ERROR: modpost: "__pte_offset_map_lock"
> > > > [../omap-modules/android-mainline/pvr/pvrsrvkm.ko] undefined!
> > > >
> > > > Not sure if you have any idea about it, and any suggestions on how to
> > > > resolve it?
> > >
> > > Please explain why this module needs to map page tables
> >
> > +1
> Sorry, I am not able to give any explanation here,
> I am not familiar with the pvrsrvkm source, I just use it to have one
> working AOSP build.
> 
> here is the source file where pte_offset_map_lock is called,
>     https://android-git.linaro.org/kernel/omap-modules.git/tree/pvr/services4/srvkm/env/linux/osfunc.c?h=android-mainline#n3508
> in case you could know something with a quick look.

Isn't this just get_user_pages()?