> From: Jason Gunthorpe <jgg@xxxxxxxxxx>
> Sent: Wednesday, March 24, 2021 1:55 AM
>
> This returns the index in the supported_type_groups array that is
> associated with the mdev_type attached to the struct mdev_device or its
> containing struct kobject.
>
> Each mdev_device can be spawned from exactly one mdev_type, which in
> turn
> originates from exactly one supported_type_group.
>
> Drivers are using weird string calculations to try and get back to this
> index, providing a direct access to the index removes a bunch of wonky
> driver code.
>
> mdev_type->group can be deleted as the group is obtained using the
> type_group_id.
>
> Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
> ---
> drivers/vfio/mdev/mdev_core.c | 20 ++++++++++++++++++++
> drivers/vfio/mdev/mdev_private.h | 2 +-
> drivers/vfio/mdev/mdev_sysfs.c | 15 +++++++++------
> include/linux/mdev.h | 3 +++
> 4 files changed, 33 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/vfio/mdev/mdev_core.c
> b/drivers/vfio/mdev/mdev_core.c
> index 493df3da451339..3ba5e9464b4d20 100644
> --- a/drivers/vfio/mdev/mdev_core.c
> +++ b/drivers/vfio/mdev/mdev_core.c
> @@ -33,6 +33,26 @@ struct device *mdev_parent_dev(struct mdev_device
> *mdev)
> }
> EXPORT_SYMBOL(mdev_parent_dev);
>
> +/*
> + * Return the index in supported_type_groups that this mdev_device was
> created
> + * from.
> + */
> +unsigned int mdev_get_type_group_id(struct mdev_device *mdev)
> +{
> + return mdev->type->type_group_id;
> +}
> +EXPORT_SYMBOL(mdev_get_type_group_id);
> +
> +/*
> + * Used in mdev_type_attribute sysfs functions to return the index in the
> + * supported_type_groups that the sysfs is called from.
> + */
> +unsigned int mtype_get_type_group_id(struct kobject *mtype_kobj)
> +{
> + return container_of(mtype_kobj, struct mdev_type, kobj)-
> >type_group_id;
> +}
> +EXPORT_SYMBOL(mtype_get_type_group_id);
> +
> /* Should be called holding parent_list_lock */
> static struct mdev_parent *__find_parent_device(struct device *dev)
> {
> diff --git a/drivers/vfio/mdev/mdev_private.h
> b/drivers/vfio/mdev/mdev_private.h
> index 10eccc35782c4d..a656cfe0346c33 100644
> --- a/drivers/vfio/mdev/mdev_private.h
> +++ b/drivers/vfio/mdev/mdev_private.h
> @@ -29,7 +29,7 @@ struct mdev_type {
> struct kobject *devices_kobj;
> struct mdev_parent *parent;
> struct list_head next;
> - struct attribute_group *group;
> + unsigned int type_group_id;
> };
>
> #define to_mdev_type_attr(_attr) \
> diff --git a/drivers/vfio/mdev/mdev_sysfs.c
> b/drivers/vfio/mdev/mdev_sysfs.c
> index d43775bd0ba340..91ecccdc2f2ec6 100644
> --- a/drivers/vfio/mdev/mdev_sysfs.c
> +++ b/drivers/vfio/mdev/mdev_sysfs.c
> @@ -92,9 +92,11 @@ static struct kobj_type mdev_type_ktype = {
> };
>
> static struct mdev_type *add_mdev_supported_type(struct mdev_parent
> *parent,
> - struct attribute_group
> *group)
> + unsigned int type_group_id)
> {
> struct mdev_type *type;
> + struct attribute_group *group =
> + parent->ops->supported_type_groups[type_group_id];
> int ret;
>
> if (!group->name) {
> @@ -110,6 +112,7 @@ static struct mdev_type
> *add_mdev_supported_type(struct mdev_parent *parent,
> type->parent = parent;
> /* Pairs with the put in mdev_type_release() */
> mdev_get_parent(parent);
> + type->type_group_id = type_group_id;
>
> ret = kobject_init_and_add(&type->kobj, &mdev_type_ktype, NULL,
> "%s-%s", dev_driver_string(parent->dev),
> @@ -135,8 +138,6 @@ static struct mdev_type
> *add_mdev_supported_type(struct mdev_parent *parent,
> ret = -ENOMEM;
> goto attrs_failed;
> }
> -
> - type->group = group;
> return type;
>
> attrs_failed:
> @@ -151,8 +152,11 @@ static struct mdev_type
> *add_mdev_supported_type(struct mdev_parent *parent,
>
> static void remove_mdev_supported_type(struct mdev_type *type)
> {
> + struct attribute_group *group =
> + type->parent->ops->supported_type_groups[type-
> >type_group_id];
> +
> sysfs_remove_files(&type->kobj,
> - (const struct attribute **)type->group->attrs);
> + (const struct attribute **)group->attrs);
> kobject_put(type->devices_kobj);
> sysfs_remove_file(&type->kobj, &mdev_type_attr_create.attr);
> kobject_del(&type->kobj);
> @@ -166,8 +170,7 @@ static int add_mdev_supported_type_groups(struct
> mdev_parent *parent)
> for (i = 0; parent->ops->supported_type_groups[i]; i++) {
> struct mdev_type *type;
>
> - type = add_mdev_supported_type(parent,
> - parent->ops-
> >supported_type_groups[i]);
> + type = add_mdev_supported_type(parent, i);
> if (IS_ERR(type)) {
> struct mdev_type *ltype, *tmp;
>
> diff --git a/include/linux/mdev.h b/include/linux/mdev.h
> index fb582adda28a9b..41e91936522394 100644
> --- a/include/linux/mdev.h
> +++ b/include/linux/mdev.h
> @@ -46,6 +46,9 @@ static inline struct device
> *mdev_get_iommu_device(struct mdev_device *mdev)
> return mdev->iommu_device;
> }
>
> +unsigned int mdev_get_type_group_id(struct mdev_device *mdev);
> +unsigned int mtype_get_type_group_id(struct kobject *mtype_kobj);
> +
> /**
> * struct mdev_parent_ops - Structure to be registered for each parent
> device to
> * register the device to mdev module.
> --
> 2.31.0
