iommu/qcom: fix device leak on of_xlate()

[ Upstream commit 6a3908ce56e6879920b44ef136252b2f0c954194 ]

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

Note that commit e2eae09939a8 ("iommu/qcom: add missing put_device()
call in qcom_iommu_of_xlate()") fixed the leak in a couple of error
paths, but the reference is still leaking on success and late failures.

Fixes: 0ae349a0f33f ("iommu/qcom: Add qcom_iommu")
Cc: stable@vger.kernel.org	# 4.14: e2eae09939a8
Cc: Rob Clark <robin.clark@oss.qualcomm.com>
Cc: Yu Kuai <yukuai3@huawei.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
[ adapted validation logic from max_asid to num_ctxs ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/iommu/arm/arm-smmu/qcom_iommu.c b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
index 9438203f08de7fa01be08034cfd502ba2fe9bac8..c4379109f11d092c1fbb3a023c055d7e63ba2c60 100644 (file)
--- a/drivers/iommu/arm/arm-smmu/qcom_iommu.c
+++ b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
@@ -568,15 +568,15 @@ static int qcom_iommu_of_xlate(struct device *dev, struct of_phandle_args *args)
 
        qcom_iommu = platform_get_drvdata(iommu_pdev);
 
+       put_device(&iommu_pdev->dev);
+
        /* make sure the asid specified in dt is valid, so we don't have
         * to sanity check this elsewhere, since 'asid - 1' is used to
         * index into qcom_iommu->ctxs:
         */
        if (WARN_ON(asid < 1) ||
-           WARN_ON(asid > qcom_iommu->num_ctxs)) {
-               put_device(&iommu_pdev->dev);
+           WARN_ON(asid > qcom_iommu->num_ctxs))
                return -EINVAL;
-       }
 
        if (!dev_iommu_priv_get(dev)) {
                dev_iommu_priv_set(dev, qcom_iommu);
@@ -585,10 +585,8 @@ static int qcom_iommu_of_xlate(struct device *dev, struct of_phandle_args *args)
                 * multiple different iommu devices.  Multiple context
                 * banks are ok, but multiple devices are not:
                 */
-               if (WARN_ON(qcom_iommu != dev_iommu_priv_get(dev))) {
-                       put_device(&iommu_pdev->dev);
+               if (WARN_ON(qcom_iommu != dev_iommu_priv_get(dev)))
                        return -EINVAL;
-               }
        }
 
        return iommu_fwspec_add_ids(dev, &asid, 1);