mm: introduce vma_init()

Not all VMAs allocated with vm_area_alloc().  Some of them allocated on
stack or in data segment.

The new helper can be use to initialize VMA properly regardless where it
was allocated.

Link: http://lkml.kernel.org/r/20180724121139.62570-2-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/mm.h b/include/linux/mm.h
index d3a3842..31540f1 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -452,6 +452,12 @@ struct vm_operations_struct {
                                          unsigned long addr);
 };
 
+static inline void vma_init(struct vm_area_struct *vma, struct mm_struct *mm)
+{
+       vma->vm_mm = mm;
+       INIT_LIST_HEAD(&vma->anon_vma_chain);
+}
+
 struct mmu_gather;
 struct inode;
 

diff --git a/kernel/fork.c b/kernel/fork.c
index a191c05..1b27bab 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -312,10 +312,8 @@ struct vm_area_struct *vm_area_alloc(struct mm_struct *mm)
 {
        struct vm_area_struct *vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
 
-       if (vma) {
-               vma->vm_mm = mm;
-               INIT_LIST_HEAD(&vma->anon_vma_chain);
-       }
+       if (vma)
+               vma_init(vma, mm);
        return vma;
 }