mm: introduce vma_init()

kiryl · torvalds · commit 027232da7c7c · 2018-07-26T19:38:03.000-07:00
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
@@ -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
@@ -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;
 }
 

Original file line number	Diff line number	Diff line change
`@@ -312,10 +312,8 @@ struct vm_area_struct vm_area_alloc(struct mm_struct mm)`
`312`	`312`	`{`
`313`	`313`	`struct vm_area_struct *vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);`
`314`	`314`
`315`		`- if (vma) {`
`316`		`- vma->vm_mm = mm;`
`317`		`- INIT_LIST_HEAD(&vma->anon_vma_chain);`
`318`		`- }`
	`315`	`+ if (vma)`
	`316`	`+ vma_init(vma, mm);`
`319`	`317`	`return vma;`
`320`	`318`	`}`
`321`	`319`