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Re: [PATCH] x86/vm86: fix compilation warning on a unused variable

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On Wed, Dec 07, 2016 at 11:38:33PM -0500, Jérémy Lefaure wrote:
> When CONFIG_TRANSPARENT_HUGEPAGE is disabled, split_huge_pmd is a no-op
> stub. In such case, vma is unused and a compiler raises a warning:
> 
> arch/x86/kernel/vm86_32.c: In function ‘mark_screen_rdonly’:
> arch/x86/kernel/vm86_32.c:180:26: warning: unused variable ‘vma’
> [-Wunused-variable]
>    struct vm_area_struct *vma = find_vma(mm, 0xA0000);
>                              ^~~
> Adding __maybe_unused in the vma declaration fixes this warning.

Hm. pmd_trans_huge() is zero if CONFIG_TRANSPARENT_HUGEPAGE is not set.
Compiler should get rid of whole block of code under the 'if'.

Could you share your kernel config which triggers the warning?
And what compiler do you use?

-- 
 Kirill A. Shutemov

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[PATCH] x86/vm86: fix compilation warning on a unused variable Jérémy Lefaure          <jeremy.lefaure@lse.epita.fr> - 2016-12-08 05:50 +0100
  Re: [PATCH] x86/vm86: fix compilation warning on a unused variable Borislav Petkov <bp@suse.de> - 2016-12-08 09:40 +0100
    Re: [PATCH] x86/vm86: fix compilation warning on a unused variable Jérémy Lefaure <jeremy.lefaure@lse.epita.fr> - 2016-12-08 19:00 +0100
  Re: [PATCH] x86/vm86: fix compilation warning on a unused variable "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-12-08 12:00 +0100
    Re: [PATCH] x86/vm86: fix compilation warning on a unused variable "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-12-08 12:50 +0100
    Re: [PATCH] x86/vm86: fix compilation warning on a unused variable Jérémy Lefaure <jeremy.lefaure@lse.epita.fr> - 2016-12-08 19:30 +0100

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