[PATCH v2 5/6] iommu: Do not revert set_domain for the last gdev

[Nicolin Chen]

The last gdev is the device that failed the __iommu_device_set_domain().
So, it doesn't need to be reverted, given it's attached to group->domain
already.

This is not a problem currently, since it's a simply re-attach. However,
the core will need to pass in the old domain to __iommu_device_set_domain
so the old domain pointers would be inconsistent between a failed device
and all its prior succeeded devices, as all the prior devices need to be
reverted.

Avoid the re-attach for the last gdev, by breaking before the revert.

Reviewed-by: Jason Gunthorpe <jgg at nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc at nvidia.com>
---
 drivers/iommu/iommu.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index adef1a37f9311..ce141f095f969 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2403,6 +2403,9 @@ static int __iommu_group_set_domain_internal(struct iommu_group *group,
 	 */
 	last_gdev = gdev;
 	for_each_group_device(group, gdev) {
+		/* No need to revert the last gdev that failed to set domain */
+		if (gdev == last_gdev)
+			break;
 		/*
 		 * A NULL domain can happen only for first probe, in which case
 		 * we leave group->domain as NULL and let release clean
@@ -2412,8 +2415,6 @@ static int __iommu_group_set_domain_internal(struct iommu_group *group,
 			WARN_ON(__iommu_device_set_domain(
 				group, gdev->dev, group->domain,
 				IOMMU_SET_DOMAIN_MUST_SUCCEED));
-		if (gdev == last_gdev)
-			break;
 	}
 	return ret;
 }
-- 
2.43.0