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>

diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c
index ec5d7545e6dcbe2d1724e48b5e595b01071a3adc..0442d98367aec50f3810a332c81be5eac0a29a95 100644 (file)
--- 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))