On Wed, Oct 09, 2024 at 09:38:03AM -0700, Nicolin Chen wrote: > + struct iommufd_viommu *(*viommu_alloc)(struct iommu_device *iommu_dev, > + struct iommu_domain *domain, Let's call this parent_domain ie nesting parent > +/* > + * Helpers for IOMMU driver to allocate driver structures that will be freed by > + * the iommufd core. Yet, a driver is responsible for its own > struct cleanup. 'own struct cleanup via the free callback' > diff --git a/drivers/iommu/iommufd/viommu_api.c b/drivers/iommu/iommufd/viommu_api.c > new file mode 100644 > index 000000000000..c1731f080d6b > --- /dev/null > +++ b/drivers/iommu/iommufd/viommu_api.c Let's call this file driver.c to match CONFIG_IOMMUFD_DRIVER > +struct iommufd_viommu * > +__iommufd_viommu_alloc(struct iommufd_ctx *ictx, size_t size, > + const struct iommufd_viommu_ops *ops) > +{ > + struct iommufd_viommu *viommu; > + struct iommufd_object *obj; > + > + if (WARN_ON(size < sizeof(*viommu))) > + return ERR_PTR(-EINVAL); The macro does this already > + obj = iommufd_object_alloc_elm(ictx, size, IOMMUFD_OBJ_VIOMMU); > + if (IS_ERR(obj)) > + return ERR_CAST(obj); > + viommu = container_of(obj, struct iommufd_viommu, obj); And this too.. > + if (ops) > + viommu->ops = ops; No need for an if... It could just be in the macro which is a bit appealing given we want this linked into the drivers.. /* * Helpers for IOMMU driver to allocate driver structures that will be freed by * the iommufd core. The free op will be called prior to freeing the memory. */ #define iommufd_viommu_alloc(ictx, drv_struct, member, viommu_ops) \ ({ \ struct drv_struct *ret; \ \ static_assert( \ __same_type(struct iommufd_viommu, \ ((struct drv_struct *)NULL)->member)); \ static_assert(offsetof(struct drv_struct, member.obj) == 0); \ ret = (struct drv_struct *)iommufd_object_alloc_elm( \ ictx, sizeof(struct drv_struct), IOMMUFD_OBJ_VIOMMU); \ ret->member.ops = viommu_ops; \ ret; \ }) Jason