iommu/mediatek: Fix leaked of_node references

The call to of_parse_phandle returns a node pointer with refcount
incremented thus it must be explicitly decremented after the last
usage.

581 static int mtk_iommu_probe(struct platform_device *pdev)
582 {
    ...
626         for (i = 0; i < larb_nr; i++) {
627                 struct device_node *larbnode;
    ...
631                 larbnode = of_parse_phandle(...);
632                 if (!larbnode)
633                         return -EINVAL;
634
635                 if (!of_device_is_available(larbnode))
636                         continue;             ---> leaked here
637
    ...
643                 if (!plarbdev)
644                         return -EPROBE_DEFER; ---> leaked here
    ...
647                 component_match_add_release(dev, &match, release_of,
648                                             compare_of, larbnode);
                                   ---> release_of will call of_node_put
649         }
    ...
650

Detected by coccinelle with the following warnings:
./drivers/iommu/mtk_iommu.c:644:3-9: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 631, but without a corresponding object release within this function.

Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: iommu@lists.linux-foundation.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mediatek@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Matthias Brugger <mbrugger@suse.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index de3e02277b706390bd70abe8f22fd6f96971ce04..b66d11b0286efb7c73262731558c76a7c09d2bb5 100644 (file)
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -632,16 +632,20 @@ static int mtk_iommu_probe(struct platform_device *pdev)
                if (!larbnode)
                        return -EINVAL;
 
-               if (!of_device_is_available(larbnode))
+               if (!of_device_is_available(larbnode)) {
+                       of_node_put(larbnode);
                        continue;
+               }
 
                ret = of_property_read_u32(larbnode, "mediatek,larb-id", &id);
                if (ret)/* The id is consecutive if there is no this property */
                        id = i;
 
                plarbdev = of_find_device_by_node(larbnode);
-               if (!plarbdev)
+               if (!plarbdev) {
+                       of_node_put(larbnode);
                        return -EPROBE_DEFER;
+               }
                data->smi_imu.larb_imu[id].dev = &plarbdev->dev;
 
                component_match_add_release(dev, &match, release_of,