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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>
This commit is contained in:
Robin Murphy 2016-11-11 17:59:25 +00:00 committed by Joerg Roedel
parent 3a8d40b6ce
commit 5d1d43b0f6
1 changed files with 2 additions and 0 deletions
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2
drivers/iommu/mtk_iommu_v1.c
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@ -502,6 +502,8 @@ static struct iommu_group *mtk_iommu_device_group(struct device *dev)
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;
}