mm: make vm_area_alloc() initialize core fields

Like vm_area_dup(), it initializes the anon_vma_chain head, and the
basic mm pointer.

The rest of the fields end up being different for different users,
although the plan is to also initialize the 'vm_ops' field to a dummy
entry.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 8 insertions, 2 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index 67253e41bfb0..a191c05e757d 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -308,9 +308,15 @@ static struct kmem_cache *vm_area_cachep;
 /* SLAB cache for mm_struct structures (tsk->mm) */
 static struct kmem_cache *mm_cachep;
 
-struct vm_area_struct *vm_area_alloc(void)
+struct vm_area_struct *vm_area_alloc(struct mm_struct *mm)
 {
-        return kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
+        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);
+        }
+        return vma;
 }
 
 struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig)