Commit 65aaca11 authored by Jason Gunthorpe's avatar Jason Gunthorpe
Browse files

iommufd: Remove iommufd_ref_to_users() 

This no longer has any callers, remove the function

Kevin noticed that after commit 99f98a7c ("iommufd: IOMMUFD_DESTROY
should not increase the refcount") there was only one other user and it
turns out the rework in commit 9227da78 ("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: default avatarKevin Tian <kevin.tian@intel.com>
Reviewed-by: default avatarKevin Tian <kevin.tian@intel.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent a35762dd

drivers/iommu/iommufd/iommufd_private.h

+0 −23
Original line number Diff line number Diff line
@@ -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);