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Date:   Wed, 11 Apr 2018 10:49:36 +0200
From:   Michal Hocko <mhocko@kernel.org>
To:     Laurent Dufour <ldufour@linux.vnet.ibm.com>
Cc:     linux-kernel@vger.kernel.org, linux-mm@kvack.org,
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Subject: Re: [PATCH v3 2/2] mm: remove odd HAVE_PTE_SPECIAL
Message-ID: <20180411084936.GC23400@dhcp22.suse.cz>
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On Wed 11-04-18 10:41:23, Laurent Dufour wrote:
> 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.

Well, such a warning would be quite pointless so I would rather not make
the code ugly. The value of unused label is quite questionable to start
with...

-- 
Michal Hocko
SUSE Labs