[PATCH 5.15.y] iommu/qcom: fix device leak on of_xlate()

[Sasha Levin <sashal@kernel.org>]

From: Johan Hovold <johan@kernel.org>

[ 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>
---
 drivers/iommu/arm/arm-smmu/qcom_iommu.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu/qcom_iommu.c b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
index 9438203f08de..c4379109f11d 100644
--- 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);
-- 
2.51.0