Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1579975

[tip:x86/urgent] x86/vm86: Fix unused variable warning if THP is disabled

Show all headers | View raw

Commit-ID:  3ba5b5ea7dc3a10ef50819b43a9f8de2705f4eec
Gitweb:     http://git.kernel.org/tip/3ba5b5ea7dc3a10ef50819b43a9f8de2705f4eec
Author:     Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
AuthorDate: Mon, 13 Feb 2017 15:52:28 +0300
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Mon, 13 Feb 2017 19:04:38 +0100

x86/vm86: Fix unused variable warning if THP is disabled

GCC complains about unused variable 'vma' in mark_screen_rdonly() if THP is
disabled:

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);

That's silly. pmd_trans_huge() resolves to 0 when THP is disabled, so the
whole block should be eliminated.

Moving the variable declaration outside the if() block shuts GCC up.

Reported-by: Jérémy Lefaure <jeremy.lefaure@lse.epita.fr>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Borislav Petkov <bp@suse.de>
Cc: Carlos O'Donell <carlos@redhat.com>
Link: http://lkml.kernel.org/r/20170213125228.63645-1-kirill.shutemov@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

---
 arch/x86/kernel/vm86_32.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c
index ec5d754..0442d98 100644
--- a/arch/x86/kernel/vm86_32.c
+++ b/arch/x86/kernel/vm86_32.c
@@ -160,11 +160,12 @@ void save_v86_state(struct kernel_vm86_regs *regs, int retval)
 
 static void mark_screen_rdonly(struct mm_struct *mm)
 {
+	struct vm_area_struct *vma;
+	spinlock_t *ptl;
 	pgd_t *pgd;
 	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *pte;
-	spinlock_t *ptl;
 	int i;
 
 	down_write(&mm->mmap_sem);
@@ -177,7 +178,7 @@ static void mark_screen_rdonly(struct mm_struct *mm)
 	pmd = pmd_offset(pud, 0xA0000);
 
 	if (pmd_trans_huge(*pmd)) {
-		struct vm_area_struct *vma = find_vma(mm, 0xA0000);
+		vma = find_vma(mm, 0xA0000);
 		split_huge_pmd(vma, pmd, 0xA0000);
 	}
 	if (pmd_none_or_clear_bad(pmd))

Back to linux.kernel | Previous | Next — Previous in thread | Find similar | Unroll thread

Thread

Re: [PATCH] x86/vm86: fix compilation warning on a unused variable Borislav Petkov <bp@suse.de> - 2017-02-12 15:10 +0100
  Re: [PATCH] x86/vm86: fix compilation warning on a unused variable Jérémy Lefaure <jeremy.lefaure@lse.epita.fr> - 2017-02-13 05:40 +0100
    Re: [PATCH] x86/vm86: fix compilation warning on a unused variable Borislav Petkov <bp@suse.de> - 2017-02-13 11:10 +0100
      [PATCH] x86/vm86: fix unused variable warning if THP is disabled. "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-02-13 14:00 +0100
        Re: [PATCH] x86/vm86: fix unused variable warning if THP is  disabled. Thomas Gleixner <tglx@linutronix.de> - 2017-02-13 17:00 +0100
        Re: [PATCH] x86/vm86: fix unused variable warning if THP is disabled. Borislav Petkov <bp@suse.de> - 2017-02-13 18:50 +0100
        [tip:x86/urgent] x86/vm86: Fix unused variable warning if THP is  disabled "tip-bot for Kirill A. Shutemov" <tipbot@zytor.com> - 2017-02-13 19:10 +0100

csiph-web