[PATCH 1/2] intel-iommu: Unlink domain from iommu

[Alex Williamson <alex.williamson@redhat.com>]

When we remove a device, we unlink the iommu from the domain, but
we never do the reverse unlinking of the domain from the iommu.
This means that we never clear iommu->domain_ids, eventually leading
to resource exhaustion if we repeatedly bind and unbind a device
to a driver.  Also free empty domains to avoid a resource leak.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---

 drivers/pci/intel-iommu.c |   10 +++++++++-
 1 files changed, 9 insertions(+), 1 deletions(-)

diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index 4789f8e..8bc56c1 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -3260,8 +3260,11 @@ static int device_notifier(struct notifier_block *nb,
 	if (!domain)
 		return 0;
 
-	if (action == BUS_NOTIFY_UNBOUND_DRIVER && !iommu_pass_through)
+	if (action == BUS_NOTIFY_UNBOUND_DRIVER && !iommu_pass_through) {
 		domain_remove_one_dev_info(domain, pdev);
+		if (list_empty(&domain->devices))
+			domain_exit(domain);
+	}
 
 	return 0;
 }
@@ -3411,6 +3414,11 @@ static void domain_remove_one_dev_info(struct dmar_domain *domain,
 		domain->iommu_count--;
 		domain_update_iommu_cap(domain);
 		spin_unlock_irqrestore(&domain->iommu_lock, tmp_flags);
+
+		spin_lock_irqsave(&iommu->lock, tmp_flags);
+		clear_bit(domain->id, iommu->domain_ids);
+		iommu->domains[domain->id] = NULL;
+		spin_unlock_irqrestore(&iommu->lock, tmp_flags);
 	}
 
 	spin_unlock_irqrestore(&device_domain_lock, flags);