184     struct anon_vma_t *anon_vma = (struct anon_vma_t *)kmalloc(sizeof(struct anon_vma_t), 0);  in __anon_vma_create_alloc()  local
185     if (unlikely(anon_vma == NULL))  in __anon_vma_create_alloc()
187     memset(anon_vma, 0, sizeof(struct anon_vma_t));  in __anon_vma_create_alloc()
189     list_init(&anon_vma->vma_list);  in __anon_vma_create_alloc()
190     semaphore_init(&anon_vma->sem, 1);  in __anon_vma_create_alloc()
199             page->anon_vma = anon_vma;  in __anon_vma_create_alloc()
203             page->anon_vma = anon_vma;  in __anon_vma_create_alloc()
205         anon_vma->page = page;  in __anon_vma_create_alloc()
207     return anon_vma;  in __anon_vma_create_alloc()
217 int __anon_vma_add(struct anon_vma_t *anon_vma, struct vm_area_struct *vma)  in __anon_vma_add()  argument
219     semaphore_down(&anon_vma->sem);  in __anon_vma_add()
220     list_add(&anon_vma->vma_list, &vma->anon_vma_list);  in __anon_vma_add()
221     vma->anon_vma = anon_vma;  in __anon_vma_add()
222     atomic_inc(&anon_vma->ref_count);  in __anon_vma_add()
223     semaphore_up(&anon_vma->sem);  in __anon_vma_add()
233 int __anon_vma_free(struct anon_vma_t *anon_vma)  in __anon_vma_free()  argument
235     if (anon_vma->page != NULL)  in __anon_vma_free()
237         spin_lock(&anon_vma->page->op_lock);  in __anon_vma_free()
238         anon_vma->page->anon_vma = NULL;  in __anon_vma_free()
239         spin_unlock(&anon_vma->page->op_lock);  in __anon_vma_free()
241     kfree(anon_vma);  in __anon_vma_free()
255     if (vma->anon_vma == NULL)  in __anon_vma_del()
259     atomic_dec(&vma->anon_vma->ref_count);  in __anon_vma_del()
262     if (unlikely(atomic_read(&vma->anon_vma->ref_count) == 0)) // 应当释放该anon_vma  in __anon_vma_del()
265         if (vma->anon_vma->page->attr & PAGE_DEVICE)  in __anon_vma_del()
266             kfree(vma->anon_vma->page);  in __anon_vma_del()
268             free_pages(vma->anon_vma->page, 1);  in __anon_vma_del()
269         __anon_vma_free(vma->anon_vma);  in __anon_vma_del()
273     vma->anon_vma = NULL;  in __anon_vma_del()