[PATCH] x86: kernel: fix unused variable warning in vm86_32.c

[Seunghun Han]

If CONFIG_TRANSPARENT_HUGEPAGE is not set in kernel config, a warning is shown
in vm86_32.c.

The warning is as follows:
>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, 0xA);

The vma variable is used to call split_huge_pmd() macro function, but
split_huge_pmd() is defined as a null macro when CONFIG_TRANSPARENT_HUGEPAGE is
not set in kernel config. Therefore, the compiler shows an unused variable
warning.

To remove this warning, I change the split_huge_pmd() macro function to static
inline function and static inline null function.
Inline function works like a macro function, therefore there is no impact on
Linux kernel working.

Signed-off-by: Seunghun Han 
---
 include/linux/huge_mm.h | 20 
 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index a3762d4..912a763 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -123,15 +123,12 @@ void deferred_split_huge_page(struct page *page);
 void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
unsigned long address, bool freeze, struct page *page);
 
-#define split_huge_pmd(__vma, __pmd, __address)
\
-   do {\
-   pmd_t *pmd = (__pmd);   \
-   if (pmd_trans_huge(*pmd)\
-   || pmd_devmap(*pmd))\
-   __split_huge_pmd(__vma, __pmd, __address,   \
-   false, NULL);   \
-   }  while (0)
-
+static inline void split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
+   unsigned long address)
+{
+   if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd))
+   __split_huge_pmd(vma, pmd, address, false, NULL);
+}
 
 void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address,
bool freeze, struct page *page);
@@ -241,9 +238,8 @@ static inline int split_huge_page(struct page *page)
return 0;
 }
 static inline void deferred_split_huge_page(struct page *page) {}
-#define split_huge_pmd(__vma, __pmd, __address)\
-   do { } while (0)
-
+static inline void split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
+   unsigned long address) {}
 static inline void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
unsigned long address, bool freeze, struct page *page) {}
 static inline void split_huge_pmd_address(struct vm_area_struct *vma,
-- 
2.1.4

[PATCH] x86: kernel: fix unused variable warning in vm86_32.c

[Seunghun Han]

If CONFIG_TRANSPARENT_HUGEPAGE is not set in kernel config, a warning is shown
in vm86_32.c.

The warning is as follows:
>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, 0xA);

The vma variable is used to call split_huge_pmd() macro function, but
split_huge_pmd() is defined as a null macro when CONFIG_TRANSPARENT_HUGEPAGE is
not set in kernel config. Therefore, the compiler shows an unused variable
warning.

To remove this warning, I change the split_huge_pmd() macro function to static
inline function and static inline null function.
Inline function works like a macro function, therefore there is no impact on
Linux kernel working.

Signed-off-by: Seunghun Han 
---
 include/linux/huge_mm.h | 20 
 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index a3762d4..912a763 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -123,15 +123,12 @@ void deferred_split_huge_page(struct page *page);
 void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
unsigned long address, bool freeze, struct page *page);
 
-#define split_huge_pmd(__vma, __pmd, __address)
\
-   do {\
-   pmd_t *pmd = (__pmd);   \
-   if (pmd_trans_huge(*pmd)\
-   || pmd_devmap(*pmd))\
-   __split_huge_pmd(__vma, __pmd, __address,   \
-   false, NULL);   \
-   }  while (0)
-
+static inline void split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
+   unsigned long address)
+{
+   if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd))
+   __split_huge_pmd(vma, pmd, address, false, NULL);
+}
 
 void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address,
bool freeze, struct page *page);
@@ -241,9 +238,8 @@ static inline int split_huge_page(struct page *page)
return 0;
 }
 static inline void deferred_split_huge_page(struct page *page) {}
-#define split_huge_pmd(__vma, __pmd, __address)\
-   do { } while (0)
-
+static inline void split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
+   unsigned long address) {}
 static inline void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
unsigned long address, bool freeze, struct page *page) {}
 static inline void split_huge_pmd_address(struct vm_area_struct *vma,
-- 
2.1.4