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Commit e23a6217 authored by Nicolin Chen's avatar Nicolin Chen Committed by Alex Williamson
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iommufd/device: Add iommufd_access_detach() API



Previously, the detach routine is only done by the destroy(). And it was
called by vfio_iommufd_emulated_unbind() when the device runs close(), so
all the mappings in iopt were cleaned in that setup, when the call trace
reaches this detach() routine.

Now, there's a need of a detach uAPI, meaning that it does not only need
a new iommufd_access_detach() API, but also requires access->ops->unmap()
call as a cleanup. So add one.

However, leaving that unprotected can introduce some potential of a race
condition during the pin_/unpin_pages() call, where access->ioas->iopt is
getting referenced. So, add an ioas_lock to protect the context of iopt
referencings.

Also, to allow the iommufd_access_unpin_pages() callback to happen via
this unmap() call, add an ioas_unpin pointer, so the unpin routine won't
be affected by the "access->ioas = NULL" trick.

Reviewed-by: default avatarKevin Tian <kevin.tian@intel.com>
Reviewed-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Tested-by: default avatarTerrence Xu <terrence.xu@intel.com>
Tested-by: default avatarNicolin Chen <nicolinc@nvidia.com>
Tested-by: default avatarMatthew Rosato <mjrosato@linux.ibm.com>
Tested-by: default avatarYanting Jiang <yanting.jiang@intel.com>
Tested-by: default avatarShameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Tested-by: default avatarZhenzhong Duan <zhenzhong.duan@intel.com>
Signed-off-by: default avatarNicolin Chen <nicolinc@nvidia.com>
Signed-off-by: default avatarYi Liu <yi.l.liu@intel.com>
Link: https://lore.kernel.org/r/20230718135551.6592-15-yi.l.liu@intel.com


Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent 9048c734
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