iommu/mediatek: Fix M4Uv1 group refcounting
For each subsequent device assigned to the m4u_group after its initial
allocation, we need to take an additional reference. Otherwise, the
caller of iommu_group_get_for_dev() will inadvertently remove the
reference taken by iommu_group_add_device(), and the group will be
freed prematurely if any device is removed.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c
index b8aeb07..c7063e9 100644
--- a/drivers/iommu/mtk_iommu_v1.c
+++ b/drivers/iommu/mtk_iommu_v1.c
@@ -502,6 +502,8 @@
data->m4u_group = iommu_group_alloc();
if (IS_ERR(data->m4u_group))
dev_err(dev, "Failed to allocate M4U IOMMU group\n");
+ } else {
+ iommu_group_ref_get(data->m4u_group);
}
return data->m4u_group;
}