linux-kernel - [PATCH v6 3/6] iommu/mediatek: Add error path for loop of mm_dts

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Message-ID: <20220920063733.21770-4-yong.wu@mediatek.com>
Date:   Tue, 20 Sep 2022 14:37:30 +0800
From:   Yong Wu <yong.wu@...iatek.com>
To:     Joerg Roedel <joro@...tes.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Will Deacon <will@...nel.org>
CC:     Robin Murphy <robin.murphy@....com>, <iommu@...ts.linux.dev>,
        <linux-mediatek@...ts.infradead.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, Yong Wu <yong.wu@...iatek.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        <mingyuan.ma@...iatek.com>, <yf.wang@...iatek.com>,
        <libo.kang@...iatek.com>, <chengci.xu@...iatek.com>,
        <youlin.pei@...iatek.com>, <anan.sun@...iatek.com>,
        <xueqi.zhang@...iatek.com>, Guenter Roeck <groeck@...omium.org>,
        Dan Carpenter <dan.carpenter@...cle.com>
Subject: [PATCH v6 3/6] iommu/mediatek: Add error path for loop of mm_dts_parse

The mtk_iommu_mm_dts_parse will parse the smi larbs nodes. if the i+1
larb is parsed fail, we should put_device for the i..0 larbs.

There are two places need to comment:
1) The larbid may be not linear mapping, we should loop whole
   the array in the error path.
2) I move this line position: "data->larb_imu[id].dev = &plarbdev->dev;"
   before "if (!plarbdev->dev.driver)", That means set
   data->larb_imu[id].dev before the error path. then we don't need
   "platform_device_put(plarbdev)" again in probe_defer case. All depend
   on "put_device" of the error path in error cases.

Fixes: d2e9a1102cfc ("iommu/mediatek: Contain MM IOMMU flow with the MM TYPE")
Signed-off-by: Yong Wu <yong.wu@...iatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
---
 drivers/iommu/mtk_iommu.c | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 83b279432406..97b721006a47 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -1053,8 +1053,10 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m
 		u32 id;
 
 		larbnode = of_parse_phandle(dev->of_node, "mediatek,larbs", i);
-		if (!larbnode)
-			return -EINVAL;
+		if (!larbnode) {
+			ret = -EINVAL;
+			goto err_larbdev_put;
+		}
 
 		if (!of_device_is_available(larbnode)) {
 			of_node_put(larbnode);
@@ -1067,14 +1069,16 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m
 
 		plarbdev = of_find_device_by_node(larbnode);
 		of_node_put(larbnode);
-		if (!plarbdev)
-			return -ENODEV;
+		if (!plarbdev) {
+			ret = -ENODEV;
+			goto err_larbdev_put;
+		}
+		data->larb_imu[id].dev = &plarbdev->dev;
 
 		if (!plarbdev->dev.driver) {
-			platform_device_put(plarbdev);
-			return -EPROBE_DEFER;
+			ret = -EPROBE_DEFER;
+			goto err_larbdev_put;
 		}
-		data->larb_imu[id].dev = &plarbdev->dev;
 
 		component_match_add(dev, match, component_compare_dev, &plarbdev->dev);
 		platform_device_put(plarbdev);
@@ -1109,6 +1113,15 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m
 		return -EINVAL;
 	}
 	return 0;
+
+err_larbdev_put:
+	/* id may be not linear mapping, loop whole the array */
+	for (i = MTK_LARB_NR_MAX - 1; i >= 0; i++) {
+		if (!data->larb_imu[i].dev)
+			continue;
+		put_device(data->larb_imu[i].dev);
+	}
+	return ret;
 }
 
 static int mtk_iommu_probe(struct platform_device *pdev)
-- 
2.18.0