From 65aaca1134025d437882535c9eb54903b9cd09c9 Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Mon, 14 Aug 2023 20:24:34 -0300 Subject: iommufd: Remove iommufd_ref_to_users() This no longer has any callers, remove the function Kevin noticed that after commit 99f98a7c0d69 ("iommufd: IOMMUFD_DESTROY should not increase the refcount") there was only one other user and it turns out the rework in commit 9227da7816dd ("iommufd: Add iommufd_access_change_ioas(_id) helpers") got rid of the last one. Link: https://lore.kernel.org/r/0-v1-abb31bedd888+c1-iommufd_ref_to_users_jgg@nvidia.com Suggested-by: Kevin Tian Reviewed-by: Kevin Tian Signed-off-by: Jason Gunthorpe --- drivers/iommu/iommufd/iommufd_private.h | 23 ----------------------- 1 file changed, 23 deletions(-) (limited to 'drivers/iommu') diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h index 15596a08a057..5a45b8ba2e26 100644 --- a/drivers/iommu/iommufd/iommufd_private.h +++ b/drivers/iommu/iommufd/iommufd_private.h @@ -149,29 +149,6 @@ static inline void iommufd_put_object(struct iommufd_object *obj) up_read(&obj->destroy_rwsem); } -/** - * iommufd_ref_to_users() - Switch from destroy_rwsem to users refcount - * protection - * @obj - Object to release - * - * Objects have two refcount protections (destroy_rwsem and the refcount_t - * users). Holding either of these will prevent the object from being destroyed. - * - * Depending on the use case, one protection or the other is appropriate. In - * most cases references are being protected by the destroy_rwsem. This allows - * orderly destruction of the object because iommufd_object_destroy_user() will - * wait for it to become unlocked. However, as a rwsem, it cannot be held across - * a system call return. So cases that have longer term needs must switch - * to the weaker users refcount_t. - * - * With users protection iommufd_object_destroy_user() will return false, - * refusing to destroy the object, causing -EBUSY to userspace. - */ -static inline void iommufd_ref_to_users(struct iommufd_object *obj) -{ - up_read(&obj->destroy_rwsem); - /* iommufd_lock_obj() obtains users as well */ -} void iommufd_object_abort(struct iommufd_ctx *ictx, struct iommufd_object *obj); void iommufd_object_abort_and_destroy(struct iommufd_ctx *ictx, struct iommufd_object *obj); -- cgit