iommu: Same critical region for device release and removal

iommu: Same critical region for device release and removal

In a non-driver context, it is crucial to ensure the consistency of a
device's iommu ops. Otherwise, it may result in a situation where a
device is released but it's iommu ops are still used.

Put the ops->release_device and __iommu_group_remove_device() in a same
group->mutext critical region, so that, as long as group->mutex is held
and the device is in its group's device list, its iommu ops are always
consistent. Add check of group ownership if the released device is the
last one.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20230322064956.263419-4-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>