iommu/mediatek: fix device leak on of_xlate()

commit b3f1ee18280363ef17f82b564fc379ceba9ec86f upstream.

Make sure to drop the reference taken to the iommu platform device when
looking up its driver data during of_xlate().

Fixes: 0df4fabe208d ("iommu/mediatek: Add mt8173 IOMMU driver")
Cc: stable@vger.kernel.org	# 4.6
Acked-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Yong Wu <yong.wu@mediatek.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 04ac40d11fdff2012f07d68a388cdca68e95d8e1..de6978fbfe2284eb6746a188e06ebcee32de728d 100644 (file)
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -669,6 +669,8 @@ static int mtk_iommu_of_xlate(struct device *dev, struct of_phandle_args *args)
                        return -EINVAL;
 
                dev_iommu_priv_set(dev, platform_get_drvdata(m4updev));
+
+               put_device(&m4updev->dev);
        }
 
        return iommu_fwspec_add_ids(dev, args->args, 1);