mm/mmap.c:insert_vm_struct(): check for failure before setting values

There's no point in initializing vma->vm_pgoff if the insertion attempt will be failing anyway. Run the checks before performing the initialization. Signed-off-by: Chen Gang <[email protected]> Cc: Michal Hocko <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
bjacke · Sep 8, 2015 · c9d13f5 · c9d13f5
1 parent bde43c6
commit c9d13f5
Showing 1 changed file with 7 additions and 6 deletions.
diff --git a/mm/mmap.c b/mm/mmap.c
@@ -2871,6 +2871,13 @@ int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
 	struct vm_area_struct *prev;
 	struct rb_node **rb_link, *rb_parent;
 
+	if (find_vma_links(mm, vma->vm_start, vma->vm_end,
+			   &prev, &rb_link, &rb_parent))
+		return -ENOMEM;
+	if ((vma->vm_flags & VM_ACCOUNT) &&
+	     security_vm_enough_memory_mm(mm, vma_pages(vma)))
+		return -ENOMEM;
+
 	/*
 	 * The vm_pgoff of a purely anonymous vma should be irrelevant
 	 * until its first write fault, when page's anon_vma and index
@@ -2887,12 +2894,6 @@ int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
 		BUG_ON(vma->anon_vma);
 		vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
 	}
-	if (find_vma_links(mm, vma->vm_start, vma->vm_end,
-			   &prev, &rb_link, &rb_parent))
-		return -ENOMEM;
-	if ((vma->vm_flags & VM_ACCOUNT) &&
-	     security_vm_enough_memory_mm(mm, vma_pages(vma)))
-		return -ENOMEM;
 
 	vma_link(mm, vma, prev, rb_link, rb_parent);
 	return 0;