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From:   Anshuman Khandual <anshuman.khandual@arm.com>
Subject: Re: [PATCH] mm/pgtable/debug: Fix test validating architecture page
 table helpers
To:     Christophe Leroy <christophe.leroy@c-s.fr>, linux-mm@kvack.org
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Date:   Fri, 13 Sep 2019 12:28:08 +0530
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On 09/13/2019 11:53 AM, Christophe Leroy wrote:
> Fix build failure on powerpc.
> 
> Fix preemption imbalance.
> 
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
> ---
>  mm/arch_pgtable_test.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/mm/arch_pgtable_test.c b/mm/arch_pgtable_test.c
> index 8b4a92756ad8..f2b3c9ec35fa 100644
> --- a/mm/arch_pgtable_test.c
> +++ b/mm/arch_pgtable_test.c
> @@ -24,6 +24,7 @@
>  #include <linux/swap.h>
>  #include <linux/swapops.h>
>  #include <linux/sched/mm.h>
> +#include <linux/highmem.h>

This is okay.

>  #include <asm/pgalloc.h>
>  #include <asm/pgtable.h>
>  
> @@ -400,6 +401,8 @@ static int __init arch_pgtable_tests_init(void)
>  	p4d_clear_tests(p4dp);
>  	pgd_clear_tests(mm, pgdp);
>  
> +	pte_unmap(ptep);
> +

Now the preemption imbalance via pte_alloc_map() path i.e

pte_alloc_map() -> pte_offset_map() -> kmap_atomic()

Is not this very much powerpc 32 specific or this will be applicable
for all platform which uses kmap_XXX() to map high memory ?