iommu: Replace __iommu_group_dma_first_attach() with set_domain

Reorganize the attach_deferred logic to set dev->iommu->attach_deferred
immediately during probe and then have __iommu_device_set_domain() check
it and not attach the default_domain.

This is to prepare for removing the group->domain set from
iommu_group_alloc_default_domain() by calling __iommu_group_set_domain()
to set the group->domain.

Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/6-v5-1b99ae392328+44574-iommu_err_unwind_jgg@nvidia.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Author: jgunthorpe

drivers/iommu/iommu.c

@@ -365,6 +365,8 @@ static int __iommu_probe_device(struct device *dev, struct list_head *group_list
 
 	dev->iommu->iommu_dev = iommu_dev;
 	dev->iommu->max_pasids = dev_iommu_get_max_pasids(dev);
+	if (ops->is_attach_deferred)
+		dev->iommu->attach_deferred = ops->is_attach_deferred(dev);
 
 	group = iommu_group_get_for_dev(dev);
 	if (IS_ERR(group)) {
@@ -399,27 +401,14 @@ static int __iommu_probe_device(struct device *dev, struct list_head *group_list
 	return ret;
 }
 
-static bool iommu_is_attach_deferred(struct device *dev)
-{
-	const struct iommu_ops *ops = dev_iommu_ops(dev);
-
-	if (ops->is_attach_deferred)
-		return ops->is_attach_deferred(dev);
-
-	return false;
-}
-
 static int iommu_group_do_dma_first_attach(struct device *dev, void *data)
 {
 	struct iommu_domain *domain = data;
 
 	lockdep_assert_held(&dev->iommu_group->mutex);
 
-	if (iommu_is_attach_deferred(dev)) {
-		dev->iommu->attach_deferred = 1;
+	if (dev->iommu->attach_deferred)
 		return 0;
-	}
-
 	return __iommu_attach_device(domain, dev);
 }
 
@@ -1831,12 +1820,6 @@ static void probe_alloc_default_domain(const struct bus_type *bus,
 
 }
 
-static int __iommu_group_dma_first_attach(struct iommu_group *group)
-{
-	return __iommu_group_for_each_dev(group, group->default_domain,
-					  iommu_group_do_dma_first_attach);
-}
-
 static int iommu_group_do_probe_finalize(struct device *dev, void *data)
 {
 	const struct iommu_ops *ops = dev_iommu_ops(dev);
@@ -1899,7 +1882,8 @@ int bus_iommu_probe(const struct bus_type *bus)
 
 		iommu_group_create_direct_mappings(group);
 
-		ret = __iommu_group_dma_first_attach(group);
+		group->domain = NULL;
+		ret = __iommu_group_set_domain(group, group->default_domain);
 
 		mutex_unlock(&group->mutex);
 
@@ -2200,6 +2184,12 @@ static int __iommu_device_set_domain(struct iommu_group *group,
 {
 	int ret;
 
+	if (dev->iommu->attach_deferred) {
+		if (new_domain == group->default_domain)
+			return 0;
+		dev->iommu->attach_deferred = 0;
+	}
+
 	ret = __iommu_attach_device(new_domain, dev);
 	if (ret) {
 		/*