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Subject: Re: [PATCH v3 2/2] mm: remove odd HAVE_PTE_SPECIAL
To:     Michal Hocko <mhocko@kernel.org>
Cc:     linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        linuxppc-dev@lists.ozlabs.org, x86@kernel.org,
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        Jonathan Corbet <corbet@lwn.net>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Yoshinori Sato <ysato@users.sourceforge.jp>,
        Rich Felker <dalias@libc.org>,
        "David S . Miller" <davem@davemloft.net>,
        Thomas Gleixner <tglx@linutronix.de>,
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        Vineet Gupta <vgupta@synopsys.com>,
        Palmer Dabbelt <palmer@sifive.com>,
        Albert Ou <albert@sifive.com>,
        Martin Schwidefsky <schwidefsky@de.ibm.com>,
        Heiko Carstens <heiko.carstens@de.ibm.com>,
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        Robin Murphy <robin.murphy@arm.com>
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 <20180411083315.GA23400@dhcp22.suse.cz>
From:   Laurent Dufour <ldufour@linux.vnet.ibm.com>
Date:   Wed, 11 Apr 2018 10:41:23 +0200
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On 11/04/2018 10:33, Michal Hocko wrote:
> On Wed 11-04-18 10:03:36, Laurent Dufour wrote:
>> @@ -881,7 +876,8 @@ struct page *_vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
>>  
>>  	if (is_zero_pfn(pfn))
>>  		return NULL;
>> -check_pfn:
>> +
>> +check_pfn: __maybe_unused
>>  	if (unlikely(pfn > highest_memmap_pfn)) {
>>  		print_bad_pte(vma, addr, pte, NULL);
>>  		return NULL;
>> @@ -891,7 +887,7 @@ struct page *_vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
>>  	 * NOTE! We still have PageReserved() pages in the page tables.
>>  	 * eg. VDSO mappings can cause them to exist.
>>  	 */
>> -out:
>> +out: __maybe_unused
>>  	return pfn_to_page(pfn);
> 
> Why do we need this ugliness all of the sudden?
Indeed the compiler doesn't complaint but in theory it should since these
labels are not used depending on CONFIG_ARCH_HAS_PTE_SPECIAL.