[PATCH v2 27/60][SRU][OEM-5.6] iommu: Keep a list of allocated groups in __iommu_probe_device()

[You-Sheng Yang]

From: Joerg Roedel <jroedel at suse.de>

BugLink: https://bugs.launchpad.net/bugs/1876707

This is needed to defer default_domain allocation for new IOMMU groups
until all devices have been added to the group.

Signed-off-by: Joerg Roedel <jroedel at suse.de>
Tested-by: Marek Szyprowski <m.szyprowski at samsung.com>
Acked-by: Marek Szyprowski <m.szyprowski at samsung.com>
Link: https://lore.kernel.org/r/20200429133712.31431-10-joro@8bytes.org
Signed-off-by: Joerg Roedel <jroedel at suse.de>
(cherry picked from commit 41df6dcc0a3ff4fb654c3d969ab96ba9c4f0e796
linux-next)
Signed-off-by: You-Sheng Yang <vicamo.yang at canonical.com>
---
 drivers/iommu/iommu.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index ffbe529e4107..3cd6395c3111 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -44,6 +44,7 @@ struct iommu_group {
 	int id;
 	struct iommu_domain *default_domain;
 	struct iommu_domain *domain;
+	struct list_head entry;
 };
 
 struct group_device {
@@ -185,7 +186,7 @@ static void dev_iommu_free(struct device *dev)
 	dev->iommu = NULL;
 }
 
-static int __iommu_probe_device(struct device *dev)
+static int __iommu_probe_device(struct device *dev, struct list_head *group_list)
 {
 	const struct iommu_ops *ops = dev->bus->iommu_ops;
 	struct iommu_device *iommu_dev;
@@ -205,6 +206,9 @@ static int __iommu_probe_device(struct device *dev)
 	}
 	iommu_group_put(group);
 
+	if (group_list && !group->default_domain && list_empty(&group->entry))
+		list_add_tail(&group->entry, group_list);
+
 	iommu_device_link(iommu_dev, dev);
 
 	return 0;
@@ -235,7 +239,7 @@ int iommu_probe_device(struct device *dev)
 	if (ops->probe_device) {
 		struct iommu_group *group;
 
-		ret = __iommu_probe_device(dev);
+		ret = __iommu_probe_device(dev, NULL);
 
 		/*
 		 * Try to allocate a default domain - needs support from the
@@ -568,6 +572,7 @@ struct iommu_group *iommu_group_alloc(void)
 	group->kobj.kset = iommu_group_kset;
 	mutex_init(&group->mutex);
 	INIT_LIST_HEAD(&group->devices);
+	INIT_LIST_HEAD(&group->entry);
 	BLOCKING_INIT_NOTIFIER_HEAD(&group->notifier);
 
 	ret = ida_simple_get(&iommu_group_ida, 0, 0, GFP_KERNEL);
-- 
2.25.1