RE: [PATCH v2 6/7] vfio: Remove dead code

Tian, Kevin
2022-04-22T01:52:35Z

> From: Jason Gunthorpe <jgg@nvidia.com>
> Sent: Friday, April 22, 2022 12:29 AM
>
> Now that callers have been updated to use the vfio_device APIs the driver
> facing group interface is no longer used, delete it:
>
> - vfio_group_get_external_user_from_dev()
> - vfio_group_pin_pages()
> - vfio_group_unpin_pages()
> - vfio_group_iommu_domain()
>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

Reviewed-by: Kevin Tian <kevin.tian@intel.com>

> ---
> drivers/vfio/vfio.c | 151 -------------------------------------------
> include/linux/vfio.h | 11 ----
> 2 files changed, 162 deletions(-)
>
> vfio_group_put_external_user() is removable too when combined with the
> KVM series
>
> diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
> index d10d20d393b706..ba6fae95555ec7 100644
> --- a/drivers/vfio/vfio.c
> +++ b/drivers/vfio/vfio.c
> @@ -1947,44 +1947,6 @@ struct vfio_group
> *vfio_group_get_external_user(struct file *filep)
> }
> EXPORT_SYMBOL_GPL(vfio_group_get_external_user);
>
> -/*
> - * External user API, exported by symbols to be linked dynamically.
> - * The external user passes in a device pointer
> - * to verify that:
> - * - A VFIO group is assiciated with the device;
> - * - IOMMU is set for the group.
> - * If both checks passed, vfio_group_get_external_user_from_dev()
> - * increments the container user counter to prevent the VFIO group
> - * from disposal before external user exits and returns the pointer
> - * to the VFIO group.
> - *
> - * When the external user finishes using the VFIO group, it calls
> - * vfio_group_put_external_user() to release the VFIO group and
> - * decrement the container user counter.
> - *
> - * @dev [in] : device
> - * Return error PTR or pointer to VFIO group.
> - */
> -
> -struct vfio_group *vfio_group_get_external_user_from_dev(struct device
> *dev)
> -{
> - struct vfio_group *group;
> - int ret;
> -
> - group = vfio_group_get_from_dev(dev);
> - if (!group)
> - return ERR_PTR(-ENODEV);
> -
> - ret = vfio_group_add_container_user(group);
> - if (ret) {
> - vfio_group_put(group);
> - return ERR_PTR(ret);
> - }
> -
> - return group;
> -}
> -EXPORT_SYMBOL_GPL(vfio_group_get_external_user_from_dev);
> -
> void vfio_group_put_external_user(struct vfio_group *group)
> {
> vfio_group_try_dissolve_container(group);
> @@ -2218,101 +2180,6 @@ int vfio_unpin_pages(struct vfio_device *vdev,
> unsigned long *user_pfn,
> }
> EXPORT_SYMBOL(vfio_unpin_pages);
>
> -/*
> - * Pin a set of guest IOVA PFNs and return their associated host PFNs for a
> - * VFIO group.
> - *
> - * The caller needs to call vfio_group_get_external_user() or
> - * vfio_group_get_external_user_from_dev() prior to calling this interface,
> - * so as to prevent the VFIO group from disposal in the middle of the call.
> - * But it can keep the reference to the VFIO group for several calls into
> - * this interface.
> - * After finishing using of the VFIO group, the caller needs to release the
> - * VFIO group by calling vfio_group_put_external_user().
> - *
> - * @group [in] : VFIO group
> - * @user_iova_pfn [in] : array of user/guest IOVA PFNs to be pinned.
> - * @npage [in] : count of elements in user_iova_pfn array.
> - * This count should not be greater
> - * VFIO_PIN_PAGES_MAX_ENTRIES.
> - * @prot [in] : protection flags
> - * @phys_pfn [out] : array of host PFNs
> - * Return error or number of pages pinned.
> - */
> -int vfio_group_pin_pages(struct vfio_group *group,
> - unsigned long *user_iova_pfn, int npage,
> - int prot, unsigned long *phys_pfn)
> -{
> - struct vfio_container *container;
> - struct vfio_iommu_driver *driver;
> - int ret;
> -
> - if (!group || !user_iova_pfn || !phys_pfn || !npage)
> - return -EINVAL;
> -
> - if (group->dev_counter > 1)
> - return -EINVAL;
> -
> - if (npage > VFIO_PIN_PAGES_MAX_ENTRIES)
> - return -E2BIG;
> -
> - container = group->container;
> - driver = container->iommu_driver;
> - if (likely(driver && driver->ops->pin_pages))
> - ret = driver->ops->pin_pages(container->iommu_data,
> - group->iommu_group,
> user_iova_pfn,
> - npage, prot, phys_pfn);
> - else
> - ret = -ENOTTY;
> -
> - return ret;
> -}
> -EXPORT_SYMBOL(vfio_group_pin_pages);
> -
> -/*
> - * Unpin a set of guest IOVA PFNs for a VFIO group.
> - *
> - * The caller needs to call vfio_group_get_external_user() or
> - * vfio_group_get_external_user_from_dev() prior to calling this interface,
> - * so as to prevent the VFIO group from disposal in the middle of the call.
> - * But it can keep the reference to the VFIO group for several calls into
> - * this interface.
> - * After finishing using of the VFIO group, the caller needs to release the
> - * VFIO group by calling vfio_group_put_external_user().
> - *
> - * @group [in] : vfio group
> - * @user_iova_pfn [in] : array of user/guest IOVA PFNs to be
> unpinned.
> - * @npage [in] : count of elements in user_iova_pfn array.
> - * This count should not be greater than
> - * VFIO_PIN_PAGES_MAX_ENTRIES.
> - * Return error or number of pages unpinned.
> - */
> -int vfio_group_unpin_pages(struct vfio_group *group,
> - unsigned long *user_iova_pfn, int npage)
> -{
> - struct vfio_container *container;
> - struct vfio_iommu_driver *driver;
> - int ret;
> -
> - if (!group || !user_iova_pfn || !npage)
> - return -EINVAL;
> -
> - if (npage > VFIO_PIN_PAGES_MAX_ENTRIES)
> - return -E2BIG;
> -
> - container = group->container;
> - driver = container->iommu_driver;
> - if (likely(driver && driver->ops->unpin_pages))
> - ret = driver->ops->unpin_pages(container->iommu_data,
> - user_iova_pfn, npage);
> - else
> - ret = -ENOTTY;
> -
> - return ret;
> -}
> -EXPORT_SYMBOL(vfio_group_unpin_pages);
> -
> -
> /*
> * This interface allows the CPUs to perform some sort of virtual DMA on
> * behalf of the device.
> @@ -2515,24 +2382,6 @@ int vfio_unregister_notifier(struct vfio_device
> *dev,
> }
> EXPORT_SYMBOL(vfio_unregister_notifier);
>
> -struct iommu_domain *vfio_group_iommu_domain(struct vfio_group
> *group)
> -{
> - struct vfio_container *container;
> - struct vfio_iommu_driver *driver;
> -
> - if (!group)
> - return ERR_PTR(-EINVAL);
> -
> - container = group->container;
> - driver = container->iommu_driver;
> - if (likely(driver && driver->ops->group_iommu_domain))
> - return driver->ops->group_iommu_domain(container-
> >iommu_data,
> - group->iommu_group);
> -
> - return ERR_PTR(-ENOTTY);
> -}
> -EXPORT_SYMBOL_GPL(vfio_group_iommu_domain);
> -
> /*
> * Module/class support
> */
> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> index 91d46e532ca104..9a9981c2622896 100644
> --- a/include/linux/vfio.h
> +++ b/include/linux/vfio.h
> @@ -140,8 +140,6 @@ int vfio_mig_get_next_state(struct vfio_device
> *device,
> */
> extern struct vfio_group *vfio_group_get_external_user(struct file *filep);
> extern void vfio_group_put_external_user(struct vfio_group *group);
> -extern struct vfio_group *vfio_group_get_external_user_from_dev(struct
> device
> - *dev);
> extern bool vfio_external_group_match_file(struct vfio_group *group,
> struct file *filep);
> extern int vfio_external_user_iommu_id(struct vfio_group *group);
> @@ -154,18 +152,9 @@ extern int vfio_pin_pages(struct vfio_device *vdev,
> unsigned long *user_pfn,
> int npage, int prot, unsigned long *phys_pfn);
> extern int vfio_unpin_pages(struct vfio_device *vdev, unsigned long
> *user_pfn,
> int npage);
> -
> -extern int vfio_group_pin_pages(struct vfio_group *group,
> - unsigned long *user_iova_pfn, int npage,
> - int prot, unsigned long *phys_pfn);
> -extern int vfio_group_unpin_pages(struct vfio_group *group,
> - unsigned long *user_iova_pfn, int npage);
> -
> extern int vfio_dma_rw(struct vfio_device *vdev, dma_addr_t user_iova,
> void *data, size_t len, bool write);
>
> -extern struct iommu_domain *vfio_group_iommu_domain(struct
> vfio_group *group);
> -
> /* each type has independent events */
> enum vfio_notify_type {
> VFIO_IOMMU_NOTIFY = 0,
> --
> 2.36.0