Thread (15 messages) 15 messages, 3 authors, 2022-12-05

Re: [PATCH v7 3/6] iommu/mediatek: Add error path for loop of mm_dts_parse

From: Matthias Brugger <matthias.bgg@gmail.com>
Date: 2022-11-22 16:33:22
Also in: linux-iommu, linux-mediatek, lkml


On 18/10/2022 04:42, Yong Wu wrote:
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@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>

quoted hunk ↗ jump to hunk
---
  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 38112ad87d70..912322494bc0 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -1055,8 +1055,10 @@ 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);
@@ -1069,14 +1071,16 @@ 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);
@@ -1111,6 +1115,15 @@ 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)
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