From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: "Jérémy Lefaure" <jeremy.lefaure@lse.epita.fr>
Cc: x86@kernel.org, Borislav Petkov <bp@suse.de>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86/vm86: fix compilation warning on a unused variable
Date: Thu, 8 Dec 2016 13:50:11 +0300 [thread overview]
Message-ID: <20161208105011.2jmuvlgdnirnv33b@black.fi.intel.com> (raw)
In-Reply-To: <20161208043833.15088-1-jeremy.lefaure@lse.epita.fr>
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
next prev parent reply other threads:[~2016-12-08 10:50 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-08 4:38 [PATCH] x86/vm86: fix compilation warning on a unused variable Jérémy Lefaure
2016-12-08 8:33 ` Borislav Petkov
2016-12-08 17:51 ` Jérémy Lefaure
2016-12-08 10:50 ` Kirill A. Shutemov [this message]
2016-12-08 11:44 ` Kirill A. Shutemov
2016-12-08 18:25 ` Jérémy Lefaure
2016-12-12 14:52 ` Kirill A. Shutemov
2016-12-17 4:19 ` Jérémy Lefaure
2017-02-12 14:01 ` Borislav Petkov
2017-02-13 4:20 ` Jérémy Lefaure
2017-02-13 10:03 ` Borislav Petkov
2017-02-13 12:52 ` [PATCH] x86/vm86: fix unused variable warning if THP is disabled Kirill A. Shutemov
2017-02-13 15:49 ` Thomas Gleixner
2017-02-13 17:47 ` Borislav Petkov
2017-02-13 18:07 ` [tip:x86/urgent] x86/vm86: Fix " tip-bot for Kirill A. Shutemov
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