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Subject: Re: [PATCH] powerpc/highmem: change BUG_ON() to WARN_ON()
To:     Michael Ellerman <mpe@ellerman.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>
Cc:     linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
References: <0365f99ce2b9273e269a241394957cba924f995e.1551951985.git.christophe.leroy@c-s.fr>
 <87va0c23s8.fsf@concordia.ellerman.id.au>
 <9048ba12-a014-3ebe-c414-26f87401c758@c-s.fr>
 <87sgvg1qxk.fsf@concordia.ellerman.id.au>
From:   Christophe Leroy <christophe.leroy@c-s.fr>
Message-ID: <7c65e445-5a15-082e-3d45-1ba17a1c780e@c-s.fr>
Date:   Thu, 21 Mar 2019 11:14:51 +0100
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Le 21/03/2019 à 11:07, Michael Ellerman a écrit :
> Christophe Leroy <christophe.leroy@c-s.fr> writes:
> 
>> Le 21/03/2019 à 06:29, Michael Ellerman a écrit :
>>> Christophe Leroy <christophe.leroy@c-s.fr> writes:
>>>> In arch/powerpc/mm/highmem.c, BUG_ON() is called only when
>>>> CONFIG_DEBUG_HIGHMEM is selected, this means the BUG_ON() is
>>>> not vital and can be replaced by a a WARN_ON
>>>>
>>>> At the sametime, use IS_ENABLED() instead of #ifdef to clean a bit.
>>>>
>>>> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
>>>> ---
>>>>    arch/powerpc/mm/highmem.c | 12 ++++--------
>>>>    1 file changed, 4 insertions(+), 8 deletions(-)
>>>>
>>>> diff --git a/arch/powerpc/mm/highmem.c b/arch/powerpc/mm/highmem.c
>>>> index 82a0e37557a5..b68c9f20fbdf 100644
>>>> --- a/arch/powerpc/mm/highmem.c
>>>> +++ b/arch/powerpc/mm/highmem.c
>>>> @@ -56,7 +54,7 @@ EXPORT_SYMBOL(kmap_atomic_prot);
>>>>    void __kunmap_atomic(void *kvaddr)
>>>>    {
>>>>    	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
>>>> -	int type __maybe_unused;
>>>> +	int type;
>>>
>>> Why don't we move type into the block below.
>>
>> Yes you're right, when Mathieu introduced the __maybe_unused, I was
>> wrongly thinging that kmap_atomic_idx() was doing something important
>> that had to be done also when DEBUG was not selected, but indeed it does
>> nothing else than returning the type.
>>
>> I'll send a new patch.
> 
> I can just fix it up when applying.
> 

Ok, thanks

Christophe