From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
Sent: Tuesday, June 14, 2022 10:52 AM
The iommu->lock is used to protect the per-IOMMU domain ID resource.
Moving the lock into the ID alloc/free helpers makes the code more
compact. At the same time, the device_domain_lock is irrelevant to
the domain ID resource, remove its assertion as well.
On the other hand, the iommu->lock is never used in interrupt context,
there's no need to use the irqsave variant of the spinlock calls.
I still prefer to separating reduction of lock ranges from changing irqsave.
Locking is tricky. From bisect p.o.v. it will be a lot easier if we just change
one logic in one patch.