> From: Jason Gunthorpe <jgg@xxxxxxxxxx>
> Sent: Wednesday, March 24, 2021 1:55 AM
>
> The mdev API should accept and pass a 'struct mdev_device *' in all
> places, not pass a 'struct device *' and cast it internally with
> to_mdev_device(). Particularly in its struct mdev_driver functions, the
> whole point of a bus's struct device_driver wrapper is to provide type
> safety compared to the default struct device_driver.
>
> Further, the driver core standard is for bus drivers to expose their
> device structure in their public headers that can be used with
> container_of() inlines and '&foo->dev' to go between the class levels, and
> '&foo->dev' to be used with dev_err/etc driver core helper functions. Move
> 'struct mdev_device' to mdev.h
>
> Once done this allows moving some one instruction exported functions to
> static inlines, which in turns allows removing one of the two grotesque
> symbol_get()'s related to mdev in the core code.
>
> Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
> ---
> .../driver-api/vfio-mediated-device.rst | 4 +-
> drivers/vfio/mdev/mdev_core.c | 64 ++-----------------
> drivers/vfio/mdev/mdev_driver.c | 4 +-
> drivers/vfio/mdev/mdev_private.h | 23 +------
> drivers/vfio/mdev/mdev_sysfs.c | 26 ++++----
> drivers/vfio/mdev/vfio_mdev.c | 7 +-
> drivers/vfio/vfio_iommu_type1.c | 25 ++------
> include/linux/mdev.h | 58 +++++++++++++----
> 8 files changed, 83 insertions(+), 128 deletions(-)
>
> diff --git a/Documentation/driver-api/vfio-mediated-device.rst
> b/Documentation/driver-api/vfio-mediated-device.rst
> index 25eb7d5b834ba3..c43c1dc3333373 100644
> --- a/Documentation/driver-api/vfio-mediated-device.rst
> +++ b/Documentation/driver-api/vfio-mediated-device.rst
> @@ -105,8 +105,8 @@ structure to represent a mediated device's driver::
> */
> struct mdev_driver {
> const char *name;
> - int (*probe) (struct device *dev);
> - void (*remove) (struct device *dev);
> + int (*probe) (struct mdev_device *dev);
> + void (*remove) (struct mdev_device *dev);
> struct device_driver driver;
> };
>
> diff --git a/drivers/vfio/mdev/mdev_core.c
> b/drivers/vfio/mdev/mdev_core.c
> index 6de97d25a3f87d..057922a1707e04 100644
> --- a/drivers/vfio/mdev/mdev_core.c
> +++ b/drivers/vfio/mdev/mdev_core.c
> @@ -33,36 +33,6 @@ struct device *mdev_parent_dev(struct mdev_device
> *mdev)
> }
> EXPORT_SYMBOL(mdev_parent_dev);
>
> -void *mdev_get_drvdata(struct mdev_device *mdev)
> -{
> - return mdev->driver_data;
> -}
> -EXPORT_SYMBOL(mdev_get_drvdata);
> -
> -void mdev_set_drvdata(struct mdev_device *mdev, void *data)
> -{
> - mdev->driver_data = data;
> -}
> -EXPORT_SYMBOL(mdev_set_drvdata);
> -
> -struct device *mdev_dev(struct mdev_device *mdev)
> -{
> - return &mdev->dev;
> -}
> -EXPORT_SYMBOL(mdev_dev);
> -
> -struct mdev_device *mdev_from_dev(struct device *dev)
> -{
> - return dev_is_mdev(dev) ? to_mdev_device(dev) : NULL;
> -}
> -EXPORT_SYMBOL(mdev_from_dev);
> -
> -const guid_t *mdev_uuid(struct mdev_device *mdev)
> -{
> - return &mdev->uuid;
> -}
> -EXPORT_SYMBOL(mdev_uuid);
> -
> /* Should be called holding parent_list_lock */
> static struct mdev_parent *__find_parent_device(struct device *dev)
> {
> @@ -107,7 +77,7 @@ static void mdev_device_remove_common(struct
> mdev_device *mdev)
> int ret;
>
> type = to_mdev_type(mdev->type_kobj);
> - mdev_remove_sysfs_files(&mdev->dev, type);
> + mdev_remove_sysfs_files(mdev, type);
> device_del(&mdev->dev);
> parent = mdev->parent;
> lockdep_assert_held(&parent->unreg_sem);
> @@ -122,12 +92,10 @@ static void mdev_device_remove_common(struct
> mdev_device *mdev)
>
> static int mdev_device_remove_cb(struct device *dev, void *data)
> {
> - if (dev_is_mdev(dev)) {
> - struct mdev_device *mdev;
> + struct mdev_device *mdev = mdev_from_dev(dev);
>
> - mdev = to_mdev_device(dev);
> + if (mdev)
> mdev_device_remove_common(mdev);
> - }
> return 0;
> }
>
> @@ -332,7 +300,7 @@ int mdev_device_create(struct kobject *kobj,
> if (ret)
> goto add_fail;
>
> - ret = mdev_create_sysfs_files(&mdev->dev, type);
> + ret = mdev_create_sysfs_files(mdev, type);
> if (ret)
> goto sysfs_fail;
>
> @@ -354,13 +322,11 @@ int mdev_device_create(struct kobject *kobj,
> return ret;
> }
>
> -int mdev_device_remove(struct device *dev)
> +int mdev_device_remove(struct mdev_device *mdev)
> {
> - struct mdev_device *mdev, *tmp;
> + struct mdev_device *tmp;
> struct mdev_parent *parent;
>
> - mdev = to_mdev_device(dev);
> -
> mutex_lock(&mdev_list_lock);
> list_for_each_entry(tmp, &mdev_list, next) {
> if (tmp == mdev)
> @@ -390,24 +356,6 @@ int mdev_device_remove(struct device *dev)
> return 0;
> }
>
> -int mdev_set_iommu_device(struct device *dev, struct device
> *iommu_device)
> -{
> - struct mdev_device *mdev = to_mdev_device(dev);
> -
> - mdev->iommu_device = iommu_device;
> -
> - return 0;
> -}
> -EXPORT_SYMBOL(mdev_set_iommu_device);
> -
> -struct device *mdev_get_iommu_device(struct device *dev)
> -{
> - struct mdev_device *mdev = to_mdev_device(dev);
> -
> - return mdev->iommu_device;
> -}
> -EXPORT_SYMBOL(mdev_get_iommu_device);
> -
> static int __init mdev_init(void)
> {
> return mdev_bus_register();
> diff --git a/drivers/vfio/mdev/mdev_driver.c
> b/drivers/vfio/mdev/mdev_driver.c
> index 0d3223aee20b83..44c3ba7e56d923 100644
> --- a/drivers/vfio/mdev/mdev_driver.c
> +++ b/drivers/vfio/mdev/mdev_driver.c
> @@ -48,7 +48,7 @@ static int mdev_probe(struct device *dev)
> return ret;
>
> if (drv && drv->probe) {
> - ret = drv->probe(dev);
> + ret = drv->probe(mdev);
> if (ret)
> mdev_detach_iommu(mdev);
> }
> @@ -62,7 +62,7 @@ static int mdev_remove(struct device *dev)
> struct mdev_device *mdev = to_mdev_device(dev);
>
> if (drv && drv->remove)
> - drv->remove(dev);
> + drv->remove(mdev);
>
> mdev_detach_iommu(mdev);
>
> diff --git a/drivers/vfio/mdev/mdev_private.h
> b/drivers/vfio/mdev/mdev_private.h
> index 74c2e541146999..bb60ec4a8d9d21 100644
> --- a/drivers/vfio/mdev/mdev_private.h
> +++ b/drivers/vfio/mdev/mdev_private.h
> @@ -24,23 +24,6 @@ struct mdev_parent {
> struct rw_semaphore unreg_sem;
> };
>
> -struct mdev_device {
> - struct device dev;
> - struct mdev_parent *parent;
> - guid_t uuid;
> - void *driver_data;
> - struct list_head next;
> - struct kobject *type_kobj;
> - struct device *iommu_device;
> - bool active;
> -};
> -
> -static inline struct mdev_device *to_mdev_device(struct device *dev)
> -{
> - return container_of(dev, struct mdev_device, dev);
> -}
> -#define dev_is_mdev(d) ((d)->bus == &mdev_bus_type)
> -
> struct mdev_type {
> struct kobject kobj;
> struct kobject *devices_kobj;
> @@ -57,11 +40,11 @@ struct mdev_type {
> int parent_create_sysfs_files(struct mdev_parent *parent);
> void parent_remove_sysfs_files(struct mdev_parent *parent);
>
> -int mdev_create_sysfs_files(struct device *dev, struct mdev_type *type);
> -void mdev_remove_sysfs_files(struct device *dev, struct mdev_type *type);
> +int mdev_create_sysfs_files(struct mdev_device *mdev, struct mdev_type
> *type);
> +void mdev_remove_sysfs_files(struct mdev_device *mdev, struct
> mdev_type *type);
>
> int mdev_device_create(struct kobject *kobj,
> struct device *dev, const guid_t *uuid);
> -int mdev_device_remove(struct device *dev);
> +int mdev_device_remove(struct mdev_device *dev);
>
> #endif /* MDEV_PRIVATE_H */
> diff --git a/drivers/vfio/mdev/mdev_sysfs.c
> b/drivers/vfio/mdev/mdev_sysfs.c
> index 917fd84c1c6f24..6a5450587b79e9 100644
> --- a/drivers/vfio/mdev/mdev_sysfs.c
> +++ b/drivers/vfio/mdev/mdev_sysfs.c
> @@ -225,6 +225,7 @@ int parent_create_sysfs_files(struct mdev_parent
> *parent)
> static ssize_t remove_store(struct device *dev, struct device_attribute *attr,
> const char *buf, size_t count)
> {
> + struct mdev_device *mdev = to_mdev_device(dev);
> unsigned long val;
>
> if (kstrtoul(buf, 0, &val) < 0)
> @@ -233,7 +234,7 @@ static ssize_t remove_store(struct device *dev, struct
> device_attribute *attr,
> if (val && device_remove_file_self(dev, attr)) {
> int ret;
>
> - ret = mdev_device_remove(dev);
> + ret = mdev_device_remove(mdev);
> if (ret)
> return ret;
> }
> @@ -248,34 +249,37 @@ static const struct attribute *mdev_device_attrs[] =
> {
> NULL,
> };
>
> -int mdev_create_sysfs_files(struct device *dev, struct mdev_type *type)
> +int mdev_create_sysfs_files(struct mdev_device *mdev, struct mdev_type
> *type)
> {
> + struct kobject *kobj = &mdev->dev.kobj;
> int ret;
>
> - ret = sysfs_create_link(type->devices_kobj, &dev->kobj,
> dev_name(dev));
> + ret = sysfs_create_link(type->devices_kobj, kobj, dev_name(&mdev-
> >dev));
> if (ret)
> return ret;
>
> - ret = sysfs_create_link(&dev->kobj, &type->kobj, "mdev_type");
> + ret = sysfs_create_link(kobj, &type->kobj, "mdev_type");
> if (ret)
> goto type_link_failed;
>
> - ret = sysfs_create_files(&dev->kobj, mdev_device_attrs);
> + ret = sysfs_create_files(kobj, mdev_device_attrs);
> if (ret)
> goto create_files_failed;
>
> return ret;
>
> create_files_failed:
> - sysfs_remove_link(&dev->kobj, "mdev_type");
> + sysfs_remove_link(kobj, "mdev_type");
> type_link_failed:
> - sysfs_remove_link(type->devices_kobj, dev_name(dev));
> + sysfs_remove_link(type->devices_kobj, dev_name(&mdev->dev));
> return ret;
> }
>
> -void mdev_remove_sysfs_files(struct device *dev, struct mdev_type *type)
> +void mdev_remove_sysfs_files(struct mdev_device *mdev, struct
> mdev_type *type)
> {
> - sysfs_remove_files(&dev->kobj, mdev_device_attrs);
> - sysfs_remove_link(&dev->kobj, "mdev_type");
> - sysfs_remove_link(type->devices_kobj, dev_name(dev));
> + struct kobject *kobj = &mdev->dev.kobj;
> +
> + sysfs_remove_files(kobj, mdev_device_attrs);
> + sysfs_remove_link(kobj, "mdev_type");
> + sysfs_remove_link(type->devices_kobj, dev_name(&mdev->dev));
> }
> diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
> index ae7e322fbe3c26..91b7b8b9eb9cb8 100644
> --- a/drivers/vfio/mdev/vfio_mdev.c
> +++ b/drivers/vfio/mdev/vfio_mdev.c
> @@ -124,9 +124,8 @@ static const struct vfio_device_ops
> vfio_mdev_dev_ops = {
> .request = vfio_mdev_request,
> };
>
> -static int vfio_mdev_probe(struct device *dev)
> +static int vfio_mdev_probe(struct mdev_device *mdev)
> {
> - struct mdev_device *mdev = to_mdev_device(dev);
> struct vfio_device *vdev;
> int ret;
>
> @@ -144,9 +143,9 @@ static int vfio_mdev_probe(struct device *dev)
> return 0;
> }
>
> -static void vfio_mdev_remove(struct device *dev)
> +static void vfio_mdev_remove(struct mdev_device *mdev)
> {
> - struct vfio_device *vdev = dev_get_drvdata(dev);
> + struct vfio_device *vdev = dev_get_drvdata(&mdev->dev);
>
> vfio_unregister_group_dev(vdev);
> kfree(vdev);
> diff --git a/drivers/vfio/vfio_iommu_type1.c
> b/drivers/vfio/vfio_iommu_type1.c
> index 4bb162c1d649b3..90b45ff1d87a7b 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -1923,28 +1923,13 @@ static bool vfio_iommu_has_sw_msi(struct
> list_head *group_resv_regions,
> return ret;
> }
>
> -static struct device *vfio_mdev_get_iommu_device(struct device *dev)
> -{
> - struct device *(*fn)(struct device *dev);
> - struct device *iommu_device;
> -
> - fn = symbol_get(mdev_get_iommu_device);
> - if (fn) {
> - iommu_device = fn(dev);
> - symbol_put(mdev_get_iommu_device);
> -
> - return iommu_device;
> - }
> -
> - return NULL;
> -}
> -
> static int vfio_mdev_attach_domain(struct device *dev, void *data)
> {
> + struct mdev_device *mdev = to_mdev_device(dev);
> struct iommu_domain *domain = data;
> struct device *iommu_device;
>
> - iommu_device = vfio_mdev_get_iommu_device(dev);
> + iommu_device = mdev_get_iommu_device(mdev);
> if (iommu_device) {
> if (iommu_dev_feature_enabled(iommu_device,
> IOMMU_DEV_FEAT_AUX))
> return iommu_aux_attach_device(domain,
> iommu_device);
> @@ -1957,10 +1942,11 @@ static int vfio_mdev_attach_domain(struct
> device *dev, void *data)
>
> static int vfio_mdev_detach_domain(struct device *dev, void *data)
> {
> + struct mdev_device *mdev = to_mdev_device(dev);
> struct iommu_domain *domain = data;
> struct device *iommu_device;
>
> - iommu_device = vfio_mdev_get_iommu_device(dev);
> + iommu_device = mdev_get_iommu_device(mdev);
> if (iommu_device) {
> if (iommu_dev_feature_enabled(iommu_device,
> IOMMU_DEV_FEAT_AUX))
> iommu_aux_detach_device(domain, iommu_device);
> @@ -2008,9 +1994,10 @@ static bool vfio_bus_is_mdev(struct bus_type
> *bus)
>
> static int vfio_mdev_iommu_device(struct device *dev, void *data)
> {
> + struct mdev_device *mdev = to_mdev_device(dev);
> struct device **old = data, *new;
>
> - new = vfio_mdev_get_iommu_device(dev);
> + new = mdev_get_iommu_device(mdev);
> if (!new || (*old && *old != new))
> return -EINVAL;
>
> diff --git a/include/linux/mdev.h b/include/linux/mdev.h
> index 27eb383cb95de0..52f7ea19dd0f56 100644
> --- a/include/linux/mdev.h
> +++ b/include/linux/mdev.h
> @@ -10,7 +10,21 @@
> #ifndef MDEV_H
> #define MDEV_H
>
> -struct mdev_device;
> +struct mdev_device {
> + struct device dev;
> + struct mdev_parent *parent;
> + guid_t uuid;
> + void *driver_data;
> + struct list_head next;
> + struct kobject *type_kobj;
> + struct device *iommu_device;
> + bool active;
> +};
> +
> +static inline struct mdev_device *to_mdev_device(struct device *dev)
> +{
> + return container_of(dev, struct mdev_device, dev);
> +}
>
> /*
> * Called by the parent device driver to set the device which represents
> @@ -19,12 +33,17 @@ struct mdev_device;
> *
> * @dev: the mediated device that iommu will isolate.
> * @iommu_device: a pci device which represents the iommu for @dev.
> - *
> - * Return 0 for success, otherwise negative error value.
> */
> -int mdev_set_iommu_device(struct device *dev, struct device
> *iommu_device);
> +static inline void mdev_set_iommu_device(struct mdev_device *mdev,
> + struct device *iommu_device)
> +{
> + mdev->iommu_device = iommu_device;
> +}
>
> -struct device *mdev_get_iommu_device(struct device *dev);
> +static inline struct device *mdev_get_iommu_device(struct mdev_device
> *mdev)
> +{
> + return mdev->iommu_device;
> +}
>
> /**
> * struct mdev_parent_ops - Structure to be registered for each parent
> device to
> @@ -126,16 +145,25 @@ struct mdev_type_attribute
> mdev_type_attr_##_name = \
> **/
> struct mdev_driver {
> const char *name;
> - int (*probe)(struct device *dev);
> - void (*remove)(struct device *dev);
> + int (*probe)(struct mdev_device *dev);
> + void (*remove)(struct mdev_device *dev);
> struct device_driver driver;
> };
>
> #define to_mdev_driver(drv) container_of(drv, struct mdev_driver, driver)
>
> -void *mdev_get_drvdata(struct mdev_device *mdev);
> -void mdev_set_drvdata(struct mdev_device *mdev, void *data);
> -const guid_t *mdev_uuid(struct mdev_device *mdev);
> +static inline void *mdev_get_drvdata(struct mdev_device *mdev)
> +{
> + return mdev->driver_data;
> +}
> +static inline void mdev_set_drvdata(struct mdev_device *mdev, void *data)
> +{
> + mdev->driver_data = data;
> +}
> +static inline const guid_t *mdev_uuid(struct mdev_device *mdev)
> +{
> + return &mdev->uuid;
> +}
>
> extern struct bus_type mdev_bus_type;
>
> @@ -146,7 +174,13 @@ int mdev_register_driver(struct mdev_driver *drv,
> struct module *owner);
> void mdev_unregister_driver(struct mdev_driver *drv);
>
> struct device *mdev_parent_dev(struct mdev_device *mdev);
> -struct device *mdev_dev(struct mdev_device *mdev);
> -struct mdev_device *mdev_from_dev(struct device *dev);
> +static inline struct device *mdev_dev(struct mdev_device *mdev)
> +{
> + return &mdev->dev;
> +}
> +static inline struct mdev_device *mdev_from_dev(struct device *dev)
> +{
> + return dev->bus == &mdev_bus_type ? to_mdev_device(dev) : NULL;
> +}
>
> #endif /* MDEV_H */
> --
> 2.31.0
