vma_is_anon_shmem
bool vma_is_anon_shmem(const struct vm_area_struct *vma);
if (vma->vm_file && !vma_is_anon_shmem(vma))
if (!vma || !vma_is_anon_shmem(vma))
return vma_is_anon_shmem(vma) || vma->vm_ops == &shmem_vm_ops;