[PATCH 4/5] iommu: Use blocking domain for empty domain attaching

Lu Baolu
2022-05-16T02:01:57Z

If a NULL domain is about to set to a device, let's set the blocking
domain instead.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
drivers/iommu/iommu.c | 35 +++--------------------------------
1 file changed, 3 insertions(+), 32 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index dcbc55c9d8d7..ba0f427c2823 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2058,16 +2058,6 @@ int iommu_deferred_attach(struct device *dev, struct iommu_domain *domain)
return 0;
}

-static void __iommu_detach_device(struct iommu_domain *domain,
- struct device *dev)
-{
- if (iommu_is_attach_deferred(dev))
- return;
-
- domain->ops->detach_dev(domain, dev);
- trace_detach_device_from_domain(dev);
-}
-
void iommu_detach_device(struct iommu_domain *domain, struct device *dev)
{
struct iommu_group *group;
@@ -2160,15 +2150,6 @@ int iommu_attach_group(struct iommu_domain *domain, struct iommu_group *group)
}
EXPORT_SYMBOL_GPL(iommu_attach_group);

-static int iommu_group_do_detach_device(struct device *dev, void *data)
-{
- struct iommu_domain *domain = data;
-
- __iommu_detach_device(domain, dev);
-
- return 0;
-}
-
static int __iommu_group_set_domain(struct iommu_group *group,
struct iommu_domain *new_domain)
{
@@ -2177,19 +2158,9 @@ static int __iommu_group_set_domain(struct iommu_group *group,
if (group->domain == new_domain)
return 0;

- /*
- * New drivers should support default domains and so the detach_dev() op
- * will never be called. Otherwise the NULL domain represents some
- * platform specific behavior.
- */
- if (!new_domain) {
- if (WARN_ON(!group->domain->ops->detach_dev))
- return -EINVAL;
- __iommu_group_for_each_dev(group, group->domain,
- iommu_group_do_detach_device);
- group->domain = NULL;
- return 0;
- }
+ /* The NULL domain represents some platform specific behavior. */
+ if (!new_domain)
+ new_domain = group->blocking_domain;

/*
* Changing the domain is done by calling set_dev() on the new
--
2.25.1