[PATCH v4 0/6] iommu/mediatek: Improve safety from invalid dts input

[PATCH v4 0/6] iommu/mediatek: Improve safety from invalid dts input

[Yong Wu]

This patchset contains misc improve patches. Mainly to improve safety from 
invalid dts input.

Change notes:
v4: a) Just remove the first patch about dev_err_probe since it was merged.
    b) Rebase v6.0-rc1

v3: https://lore.kernel.org/linux-mediatek/20220701053942.3266-1-yong.wu@mediatek.com/
    a) Add platform_device_put from Robin.
    b) Use component_match_add instead component_match_add_release suggested from Robin.
    
v2: https://lore.kernel.org/linux-mediatek/20220616054203.11365-1-yong.wu@mediatek.com/
    a) Rebase on v5.19-rc1.
    b) Add a New patch [5/5] just remove a variable that only is for v1.

v1: https://lore.kernel.org/linux-mediatek/20220511064920.18455-1-yong.wu@mediatek.com/
    Base on linux-next-20220510.
    the improve safety from dts is base on:
    https://lore.kernel.org/linux-mediatek/20211210205704.1664928-1-linux@roeck-us.net/

Guenter Roeck (1):
  iommu/mediatek: Validate number of phandles associated with
    "mediatek,larbs"

Yong Wu (5):
  iommu/mediatek: Add platform_device_put for recovering the device
    refcnt
  iommu/mediatek: Use component_match_add
  iommu/mediatek: Add error path for loop of mm_dts_parse
  iommu/mediatek: Improve safety for mediatek,smi property in larb nodes
  iommu/mediatek: Remove unused "mapping" member from mtk_iommu_data

 drivers/iommu/mtk_iommu.c | 115 +++++++++++++++++++++++++++-----------
 1 file changed, 83 insertions(+), 32 deletions(-)

-- 
2.18.0



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[PATCH v4 1/6] iommu/mediatek: Add platform_device_put for recovering the device refcnt

[Yong Wu]

Add platform_device_put to match with of_find_device_by_node.

Meanwhile, I add a new variable "pcommdev" which is for smi common device.
Otherwise, "platform_device_put(plarbdev)" for smi-common dev may be not
readable. And add a checking for whether pcommdev is NULL.

Fixes: d2e9a1102cfc ("iommu/mediatek: Contain MM IOMMU flow with the MM TYPE")
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
---
 drivers/iommu/mtk_iommu.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 7e363b1f24df..f2560ce72b6c 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -1041,7 +1041,7 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m
 				  struct mtk_iommu_data *data)
 {
 	struct device_node *larbnode, *smicomm_node, *smi_subcomm_node;
-	struct platform_device *plarbdev;
+	struct platform_device *plarbdev, *pcommdev;
 	struct device_link *link;
 	int i, larb_nr, ret;
 
@@ -1072,12 +1072,14 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m
 		}
 		if (!plarbdev->dev.driver) {
 			of_node_put(larbnode);
+			platform_device_put(plarbdev);
 			return -EPROBE_DEFER;
 		}
 		data->larb_imu[id].dev = &plarbdev->dev;
 
 		component_match_add_release(dev, match, component_release_of,
 					    component_compare_of, larbnode);
+		platform_device_put(plarbdev);
 	}
 
 	/* Get smi-(sub)-common dev from the last larb. */
@@ -1095,12 +1097,15 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m
 	else
 		smicomm_node = smi_subcomm_node;
 
-	plarbdev = of_find_device_by_node(smicomm_node);
+	pcommdev = of_find_device_by_node(smicomm_node);
 	of_node_put(smicomm_node);
-	data->smicomm_dev = &plarbdev->dev;
+	if (!pcommdev)
+		return -EINVAL;
+	data->smicomm_dev = &pcommdev->dev;
 
 	link = device_link_add(data->smicomm_dev, dev,
 			       DL_FLAG_STATELESS | DL_FLAG_PM_RUNTIME);
+	platform_device_put(pcommdev);
 	if (!link) {
 		dev_err(dev, "Unable to link %s.\n", dev_name(data->smicomm_dev));
 		return -EINVAL;
-- 
2.18.0


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[PATCH v4 2/6] iommu/mediatek: Use component_match_add

[Yong Wu]

In order to simplify the error patch(avoid call of_node_put), Use
component_match_add instead component_match_add_release since we are only
interested in the "device" here. Then we could always call of_node_put in
normal path.

Strictly this is not a fixes patch, but it is a prepare for adding the
error path, thus I add a Fixes tag too.

Fixes: d2e9a1102cfc ("iommu/mediatek: Contain MM IOMMU flow with the MM TYPE")
Suggested-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
---
 drivers/iommu/mtk_iommu.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index f2560ce72b6c..9c5902207bef 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -1066,19 +1066,17 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m
 			id = i;
 
 		plarbdev = of_find_device_by_node(larbnode);
-		if (!plarbdev) {
-			of_node_put(larbnode);
+		of_node_put(larbnode);
+		if (!plarbdev)
 			return -ENODEV;
-		}
+
 		if (!plarbdev->dev.driver) {
-			of_node_put(larbnode);
 			platform_device_put(plarbdev);
 			return -EPROBE_DEFER;
 		}
 		data->larb_imu[id].dev = &plarbdev->dev;
 
-		component_match_add_release(dev, match, component_release_of,
-					    component_compare_of, larbnode);
+		component_match_add(dev, match, component_compare_dev, &plarbdev->dev);
 		platform_device_put(plarbdev);
 	}
 
-- 
2.18.0


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[PATCH v4 3/6] iommu/mediatek: Add error path for loop of mm_dts_parse

[Yong Wu]

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 0..i 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;"
   That means set data->larb_imu[id].dev before the error path.
   then we don't need "platform_device_put(plarbdev)" again while
   probe_defer case. All depend on "put_device" in 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>
---
 drivers/iommu/mtk_iommu.c | 42 ++++++++++++++++++++++++++++-----------
 1 file changed, 30 insertions(+), 12 deletions(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 9c5902207bef..f63d4210043d 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);
@@ -1082,8 +1086,10 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m
 
 	/* Get smi-(sub)-common dev from the last larb. */
 	smi_subcomm_node = of_parse_phandle(larbnode, "mediatek,smi", 0);
-	if (!smi_subcomm_node)
-		return -EINVAL;
+	if (!smi_subcomm_node) {
+		ret = -EINVAL;
+		goto err_larbdev_put;
+	}
 
 	/*
 	 * It may have two level smi-common. the node is smi-sub-common if it
@@ -1097,8 +1103,10 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m
 
 	pcommdev = of_find_device_by_node(smicomm_node);
 	of_node_put(smicomm_node);
-	if (!pcommdev)
-		return -EINVAL;
+	if (!pcommdev) {
+		ret = -EINVAL;
+		goto err_larbdev_put;
+	}
 	data->smicomm_dev = &pcommdev->dev;
 
 	link = device_link_add(data->smicomm_dev, dev,
@@ -1106,9 +1114,19 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m
 	platform_device_put(pcommdev);
 	if (!link) {
 		dev_err(dev, "Unable to link %s.\n", dev_name(data->smicomm_dev));
-		return -EINVAL;
+		ret = -EINVAL;
+		goto err_larbdev_put;
 	}
 	return 0;
+
+err_larbdev_put:
+	/* id may be not linear mapping, loop whole the array */
+	for (i = 0; i < MTK_LARB_NR_MAX; 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


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[PATCH v4 4/6] iommu/mediatek: Validate number of phandles associated with "mediatek,larbs"

[Yong Wu]

From: Guenter Roeck <groeck@chromium.org>

Fix the smatch warnings:
drivers/iommu/mtk_iommu.c:878 mtk_iommu_mm_dts_parse() error: uninitialized
symbol 'larbnode'.

If someone abuse the dtsi node(Don't follow the definition of dt-binding),
for example "mediatek,larbs" is provided as boolean property, "larb_nr"
will be zero and cause abnormal.

To fix this problem and improve the code safety, add some checking
for the invalid input from dtsi, e.g. checking the larb_nr/larbid valid
range, and avoid "mediatek,larb-id" property conflicts in the smi-larb
nodes.

Fixes: d2e9a1102cfc ("iommu/mediatek: Contain MM IOMMU flow with the MM TYPE")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
 drivers/iommu/mtk_iommu.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index f63d4210043d..21195ac060f1 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -1048,6 +1048,8 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m
 	larb_nr = of_count_phandle_with_args(dev->of_node, "mediatek,larbs", NULL);
 	if (larb_nr < 0)
 		return larb_nr;
+	if (larb_nr == 0 || larb_nr > MTK_LARB_NR_MAX)
+		return -EINVAL;
 
 	for (i = 0; i < larb_nr; i++) {
 		u32 id;
@@ -1066,6 +1068,11 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m
 		ret = of_property_read_u32(larbnode, "mediatek,larb-id", &id);
 		if (ret)/* The id is consecutive if there is no this property */
 			id = i;
+		if (id >= MTK_LARB_NR_MAX) {
+			of_node_put(larbnode);
+			ret = -EINVAL;
+			goto err_larbdev_put;
+		}
 
 		plarbdev = of_find_device_by_node(larbnode);
 		of_node_put(larbnode);
@@ -1073,6 +1080,11 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m
 			ret = -ENODEV;
 			goto err_larbdev_put;
 		}
+		if (data->larb_imu[id].dev) {
+			platform_device_put(plarbdev);
+			ret = -EEXIST;
+			goto err_larbdev_put;
+		}
 		data->larb_imu[id].dev = &plarbdev->dev;
 
 		if (!plarbdev->dev.driver) {
-- 
2.18.0


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[PATCH v4 5/6] iommu/mediatek: Improve safety for mediatek,smi property in larb nodes

[Yong Wu]

No functional change. Just improve safety from dts.

All the larbs that connect to one IOMMU must connect with the same
smi-common. This patch checks all the mediatek,smi property for each
larb, If their mediatek,smi are different, it will return fails.
Also avoid there is no available smi-larb nodes.

Suggested-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
---
 drivers/iommu/mtk_iommu.c | 53 +++++++++++++++++++++++++++------------
 1 file changed, 37 insertions(+), 16 deletions(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 21195ac060f1..ea387c762509 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -1040,7 +1040,7 @@ static const struct component_master_ops mtk_iommu_com_ops = {
 static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **match,
 				  struct mtk_iommu_data *data)
 {
-	struct device_node *larbnode, *smicomm_node, *smi_subcomm_node;
+	struct device_node *larbnode, *frst_avail_smicomm_node = NULL;
 	struct platform_device *plarbdev, *pcommdev;
 	struct device_link *link;
 	int i, larb_nr, ret;
@@ -1052,6 +1052,7 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m
 		return -EINVAL;
 
 	for (i = 0; i < larb_nr; i++) {
+		struct device_node *smicomm_node, *smi_subcomm_node;
 		u32 id;
 
 		larbnode = of_parse_phandle(dev->of_node, "mediatek,larbs", i);
@@ -1092,29 +1093,49 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m
 			goto err_larbdev_put;
 		}
 
+		/* Get smi-(sub)-common dev from the last larb. */
+		smi_subcomm_node = of_parse_phandle(larbnode, "mediatek,smi", 0);
+		if (!smi_subcomm_node) {
+			ret = -EINVAL;
+			goto err_larbdev_put;
+		}
+
+		/*
+		 * It may have two level smi-common. the node is smi-sub-common if it
+		 * has a new mediatek,smi property. otherwise it is smi-commmon.
+		 */
+		smicomm_node = of_parse_phandle(smi_subcomm_node, "mediatek,smi", 0);
+		if (smicomm_node)
+			of_node_put(smi_subcomm_node);
+		else
+			smicomm_node = smi_subcomm_node;
+
+		/*
+		 * All the larbs that connect to one IOMMU must connect with the same
+		 * smi-common.
+		 */
+		if (!frst_avail_smicomm_node) {
+			frst_avail_smicomm_node = smicomm_node;
+		} else if (frst_avail_smicomm_node != smicomm_node) {
+			dev_err(dev, "mediatek,smi property is not right @larb%d.", id);
+			of_node_put(smicomm_node);
+			ret = -EINVAL;
+			goto err_larbdev_put;
+		} else {
+			of_node_put(smicomm_node);
+		}
+
 		component_match_add(dev, match, component_compare_dev, &plarbdev->dev);
 		platform_device_put(plarbdev);
 	}
 
-	/* Get smi-(sub)-common dev from the last larb. */
-	smi_subcomm_node = of_parse_phandle(larbnode, "mediatek,smi", 0);
-	if (!smi_subcomm_node) {
+	if (!frst_avail_smicomm_node) {
 		ret = -EINVAL;
 		goto err_larbdev_put;
 	}
 
-	/*
-	 * It may have two level smi-common. the node is smi-sub-common if it
-	 * has a new mediatek,smi property. otherwise it is smi-commmon.
-	 */
-	smicomm_node = of_parse_phandle(smi_subcomm_node, "mediatek,smi", 0);
-	if (smicomm_node)
-		of_node_put(smi_subcomm_node);
-	else
-		smicomm_node = smi_subcomm_node;
-
-	pcommdev = of_find_device_by_node(smicomm_node);
-	of_node_put(smicomm_node);
+	pcommdev = of_find_device_by_node(frst_avail_smicomm_node);
+	of_node_put(frst_avail_smicomm_node);
 	if (!pcommdev) {
 		ret = -EINVAL;
 		goto err_larbdev_put;
-- 
2.18.0


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[PATCH v4 6/6] iommu/mediatek: Remove unused "mapping" member from mtk_iommu_data

[Yong Wu]

Just remove a unused variable that only is for mtk_iommu_v1.

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>
---
 drivers/iommu/mtk_iommu.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index ea387c762509..b06c91f5a9b2 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -221,10 +221,7 @@ struct mtk_iommu_data {
 	struct device			*smicomm_dev;
 
 	struct mtk_iommu_bank_data	*bank;
-
-	struct dma_iommu_mapping	*mapping; /* For mtk_iommu_v1.c */
 	struct regmap			*pericfg;
-
 	struct mutex			mutex; /* Protect m4u_group/m4u_dom above */
 
 	/*
-- 
2.18.0


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Re: [PATCH v4 3/6] iommu/mediatek: Add error path for loop of mm_dts_parse

[AngeloGioacchino Del Regno]

Il 24/08/22 08:43, Yong Wu ha scritto:
> 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 0..i 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;"
>     That means set data->larb_imu[id].dev before the error path.
>     then we don't need "platform_device_put(plarbdev)" again while
>     probe_defer case. All depend on "put_device" in 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>
> ---
>   drivers/iommu/mtk_iommu.c | 42 ++++++++++++++++++++++++++++-----------
>   1 file changed, 30 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index 9c5902207bef..f63d4210043d 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);
> @@ -1082,8 +1086,10 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m
>   
>   	/* Get smi-(sub)-common dev from the last larb. */
>   	smi_subcomm_node = of_parse_phandle(larbnode, "mediatek,smi", 0);
> -	if (!smi_subcomm_node)
> -		return -EINVAL;
> +	if (!smi_subcomm_node) {
> +		ret = -EINVAL;
> +		goto err_larbdev_put;
> +	}
>   
>   	/*
>   	 * It may have two level smi-common. the node is smi-sub-common if it
> @@ -1097,8 +1103,10 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m
>   
>   	pcommdev = of_find_device_by_node(smicomm_node);
>   	of_node_put(smicomm_node);
> -	if (!pcommdev)
> -		return -EINVAL;
> +	if (!pcommdev) {
> +		ret = -EINVAL;
> +		goto err_larbdev_put;
> +	}
>   	data->smicomm_dev = &pcommdev->dev;
>   
>   	link = device_link_add(data->smicomm_dev, dev,
> @@ -1106,9 +1114,19 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m
>   	platform_device_put(pcommdev);
>   	if (!link) {
>   		dev_err(dev, "Unable to link %s.\n", dev_name(data->smicomm_dev));
> -		return -EINVAL;
> +		ret = -EINVAL;
> +		goto err_larbdev_put;
>   	}
>   	return 0;
> +
> +err_larbdev_put:
> +	/* id may be not linear mapping, loop whole the array */
> +	for (i = 0; i < MTK_LARB_NR_MAX; i++) {

Since there may be a case in which the mapping is linear and we're doing teardown,
I think it would be sensible to loop the other way around instead, from
MTK_LARB_NR_MAX to 0.

Everything else looks good to me.

Cheers,
Angelo

> +		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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Re: [PATCH v4 5/6] iommu/mediatek: Improve safety for mediatek,smi property in larb nodes

[AngeloGioacchino Del Regno]

Il 24/08/22 08:43, Yong Wu ha scritto:
> No functional change. Just improve safety from dts.
> 
> All the larbs that connect to one IOMMU must connect with the same
> smi-common. This patch checks all the mediatek,smi property for each
> larb, If their mediatek,smi are different, it will return fails.
> Also avoid there is no available smi-larb nodes.
> 
> Suggested-by: Guenter Roeck <groeck@chromium.org>
> Signed-off-by: Yong Wu <yong.wu@mediatek.com>

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>


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Re: [PATCH v4 1/6] iommu/mediatek: Add platform_device_put for recovering the device refcnt

[AngeloGioacchino Del Regno]

Il 24/08/22 08:43, Yong Wu ha scritto:
> Add platform_device_put to match with of_find_device_by_node.
> 
> Meanwhile, I add a new variable "pcommdev" which is for smi common device.
> Otherwise, "platform_device_put(plarbdev)" for smi-common dev may be not
> readable. And add a checking for whether pcommdev is NULL.
> 
> 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>


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Re: [PATCH v4 3/6] iommu/mediatek: Add error path for loop of mm_dts_parse

[Dan Carpenter]

On Wed, Aug 24, 2022 at 02:43:03PM +0800, 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 0..i 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;"
>    That means set data->larb_imu[id].dev before the error path.
>    then we don't need "platform_device_put(plarbdev)" again while
>    probe_defer case. All depend on "put_device" in the error path in error
>    cases.

I don't understand what you're saying here.  There is still a
platform_device_put(plarbdev) on the success path after
component_match_add().

So if we fail when i == 2 then we do:

	put_device(data->larb_imu[2].dev);

But for the previous iterations has both platform_device_put()
and put_device() called for them.

regards,
dan carpenter


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Re: [PATCH v4 3/6] iommu/mediatek: Add error path for loop of mm_dts_parse

[Yong Wu]

On Tue, 2022-08-30 at 10:14 +0200, AngeloGioacchino Del Regno wrote:
> Il 24/08/22 08:43, Yong Wu ha scritto:
> > 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 0..i 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;"
> >     That means set data->larb_imu[id].dev before the error path.
> >     then we don't need "platform_device_put(plarbdev)" again while
> >     probe_defer case. All depend on "put_device" in 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>
> > ---
> >   drivers/iommu/mtk_iommu.c | 42 ++++++++++++++++++++++++++++----
> > -------
> >   1 file changed, 30 insertions(+), 12 deletions(-)

[...]

> > +
> > +err_larbdev_put:
> > +	/* id may be not linear mapping, loop whole the array */
> > +	for (i = 0; i < MTK_LARB_NR_MAX; i++) {
> 
> Since there may be a case in which the mapping is linear and we're
> doing teardown,
> I think it would be sensible to loop the other way around instead,
> from
> MTK_LARB_NR_MAX to 0.

Thanks very much. I will change from MTK_LARB_NR_MAX to 0.

> 
> Everything else looks good to me.
> 
> Cheers,
> Angelo
> 
> > +		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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Re: [PATCH v4 3/6] iommu/mediatek: Add error path for loop of mm_dts_parse

[Yong Wu]

Hi Dan,

Thanks very much for your review:)

On Tue, 2022-08-30 at 11:32 +0300, Dan Carpenter wrote:
> On Wed, Aug 24, 2022 at 02:43:03PM +0800, 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 0..i 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;"
> >    That means set data->larb_imu[id].dev before the error path.
> >    then we don't need "platform_device_put(plarbdev)" again while
> >    probe_defer case. All depend on "put_device" in the error path
> > in error
> >    cases.
> 
> I don't understand what you're saying here.  There is still a
> platform_device_put(plarbdev) on the success path after
> component_match_add().
> 
> So if we fail when i == 2 then we do:
> 
> 	put_device(data->larb_imu[2].dev);
> 
> But for the previous iterations has both platform_device_put()
> and put_device() called for them.

Sorry for this. Right! For the goto outside the loop, it did put twice.
I will fix this.

> 
> regards,
> dan carpenter
> 


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