From: Nicolin Chen <nicolinc@nvidia.com>
Date: Thu, 23 Oct 2025 02:21:08 +0000 (-0700)
Subject: iommu: Do not revert set_domain for the last gdev
X-Git-Tag: v6.19-rc1~133^2^8~57
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2b33598e666d0c7b761148ffee86140238968861;p=thirdparty%2Fkernel%2Flinux.git

iommu: Do not revert set_domain for the last gdev

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@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---

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 @@ err_revert:
 	 */
 	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 @@ err_revert:
 			WARN_ON(__iommu_device_set_domain(
 				group, gdev->dev, group->domain,
 				IOMMU_SET_DOMAIN_MUST_SUCCEED));
-		if (gdev == last_gdev)
-			break;
 	}
 	return ret;
 }