mm/vma: introduce VM_ACCESS_FLAGS

There are many places where all basic VMA access flags (read, write,
exec) are initialized or checked against as a group.  One such example
is during page fault.  Existing vma_is_accessible() wrapper already
creates the notion of VMA accessibility as a group access permissions.

Hence lets just create VM_ACCESS_FLAGS (VM_READ|VM_WRITE|VM_EXEC) which
will not only reduce code duplication but also extend the VMA
accessibility concept in general.

Signed-off-by: Anshuman Khandual <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Vlastimil Babka <[email protected]>
Cc: Russell King <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Mark Salter <[email protected]>
Cc: Nick Hu <[email protected]>
Cc: Ley Foon Tan <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Yoshinori Sato <[email protected]>
Cc: Guan Xuetao <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Rob Springer <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 5 insertions, 1 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 33076fa149c8..4db1522d7c48 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -369,6 +369,10 @@ extern unsigned int kobjsize(const void *objp);
 
 #define VM_STACK_FLAGS	(VM_STACK | VM_STACK_DEFAULT_FLAGS | VM_ACCOUNT)
 
+/* VMA basic access permission flags */
+#define VM_ACCESS_FLAGS (VM_READ | VM_WRITE | VM_EXEC)
+
+
 /*
  * Special vmas that are non-mergable, non-mlock()able.
  */
@@ -646,7 +650,7 @@ static inline bool vma_is_foreign(struct vm_area_struct *vma)
 
 static inline bool vma_is_accessible(struct vm_area_struct *vma)
 {
-	return vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC);
+	return vma->vm_flags & VM_ACCESS_FLAGS;
 }
 
 #ifdef CONFIG_SHMEM