[PATCH net v2] net: emaclite: Add error handling for of_address_ and _mdio_setup functions

[PATCH net v2] net: emaclite: Add error handling for of_address_ and _mdio_setup functions

[Radhey Shyam Pandey]

From: Shravya Kumbham <shravya.kumbham@xilinx.com>

Add ret variable, condition to check the return value and error
path for the of_address_to_resource() function. It also adds error
handling for mdio setup and decrement refcount of phy node.

Addresses-Coverity: Event check_return value.
Signed-off-by: Shravya Kumbham <shravya.kumbham@xilinx.com>
Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
---
Changes for v2:

- Change subject_prefix to target net tree.
- Add error handling for mdio_setup and remove phy_read changes.
  Error checking of phy_read will be added along with phy_write
  in a followup patch. Document the changes in commit description.
---
 drivers/net/ethernet/xilinx/xilinx_emaclite.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/xilinx/xilinx_emaclite.c b/drivers/net/ethernet/xilinx/xilinx_emaclite.c
index 0c26f5bcc523..4e0005164785 100644
--- a/drivers/net/ethernet/xilinx/xilinx_emaclite.c
+++ b/drivers/net/ethernet/xilinx/xilinx_emaclite.c
@@ -820,7 +820,7 @@ static int xemaclite_mdio_write(struct mii_bus *bus, int phy_id, int reg,
 static int xemaclite_mdio_setup(struct net_local *lp, struct device *dev)
 {
 	struct mii_bus *bus;
-	int rc;
+	int rc, ret;
 	struct resource res;
 	struct device_node *np = of_get_parent(lp->phy_node);
 	struct device_node *npp;
@@ -834,7 +834,12 @@ static int xemaclite_mdio_setup(struct net_local *lp, struct device *dev)
 	}
 	npp = of_get_parent(np);
 
-	of_address_to_resource(npp, 0, &res);
+	ret = of_address_to_resource(npp, 0, &res);
+	if (ret) {
+		dev_err(dev, "%s resource error!\n",
+			dev->of_node->full_name);
+		return ret;
+	}
 	if (lp->ndev->mem_start != res.start) {
 		struct phy_device *phydev;
 		phydev = of_phy_find_device(lp->phy_node);
@@ -1173,7 +1178,11 @@ static int xemaclite_of_probe(struct platform_device *ofdev)
 	xemaclite_update_address(lp, ndev->dev_addr);
 
 	lp->phy_node = of_parse_phandle(ofdev->dev.of_node, "phy-handle", 0);
-	xemaclite_mdio_setup(lp, &ofdev->dev);
+	rc = xemaclite_mdio_setup(lp, &ofdev->dev);
+	if (rc) {
+		dev_warn(dev, "error registering MDIO bus: %d\n", rc);
+		goto error;
+	}
 
 	dev_info(dev, "MAC address is now %pM\n", ndev->dev_addr);
 
@@ -1197,6 +1206,7 @@ static int xemaclite_of_probe(struct platform_device *ofdev)
 	return 0;
 
 error:
+	of_node_put(lp->phy_node);
 	free_netdev(ndev);
 	return rc;
 }
-- 
2.7.4

Re: [PATCH net v2] net: emaclite: Add error handling for of_address_ and _mdio_setup functions

[Denis Kirjanov]

On 11/17/20, Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com> wrote:
> From: Shravya Kumbham <shravya.kumbham@xilinx.com>
>
> Add ret variable, condition to check the return value and error
> path for the of_address_to_resource() function. It also adds error
> handling for mdio setup and decrement refcount of phy node.
>
> Addresses-Coverity: Event check_return value.
> Signed-off-by: Shravya Kumbham <shravya.kumbham@xilinx.com>
> Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
> ---
> Changes for v2:
>
> - Change subject_prefix to target net tree.
> - Add error handling for mdio_setup and remove phy_read changes.
>   Error checking of phy_read will be added along with phy_write
>   in a followup patch. Document the changes in commit description.
> ---
>  drivers/net/ethernet/xilinx/xilinx_emaclite.c | 16 +++++++++++++---
>  1 file changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/ethernet/xilinx/xilinx_emaclite.c
> b/drivers/net/ethernet/xilinx/xilinx_emaclite.c
> index 0c26f5bcc523..4e0005164785 100644
> --- a/drivers/net/ethernet/xilinx/xilinx_emaclite.c
> +++ b/drivers/net/ethernet/xilinx/xilinx_emaclite.c
> @@ -820,7 +820,7 @@ static int xemaclite_mdio_write(struct mii_bus *bus, int
> phy_id, int reg,
>  static int xemaclite_mdio_setup(struct net_local *lp, struct device *dev)
>  {
>  	struct mii_bus *bus;
> -	int rc;
> +	int rc, ret;
>  	struct resource res;
>  	struct device_node *np = of_get_parent(lp->phy_node);
>  	struct device_node *npp;
> @@ -834,7 +834,12 @@ static int xemaclite_mdio_setup(struct net_local *lp,
> struct device *dev)
>  	}
>  	npp = of_get_parent(np);
>
> -	of_address_to_resource(npp, 0, &res);
> +	ret = of_address_to_resource(npp, 0, &res);
> +	if (ret) {
> +		dev_err(dev, "%s resource error!\n",
> +			dev->of_node->full_name);
> +		return ret;
> +	}

npp is not returned to of_node_put() in the error case below

>  	if (lp->ndev->mem_start != res.start) {
>  		struct phy_device *phydev;
>  		phydev = of_phy_find_device(lp->phy_node);
> @@ -1173,7 +1178,11 @@ static int xemaclite_of_probe(struct platform_device
> *ofdev)
>  	xemaclite_update_address(lp, ndev->dev_addr);
>
>  	lp->phy_node = of_parse_phandle(ofdev->dev.of_node, "phy-handle", 0);
> -	xemaclite_mdio_setup(lp, &ofdev->dev);
> +	rc = xemaclite_mdio_setup(lp, &ofdev->dev);
> +	if (rc) {
> +		dev_warn(dev, "error registering MDIO bus: %d\n", rc);
> +		goto error;
> +	}
>
>  	dev_info(dev, "MAC address is now %pM\n", ndev->dev_addr);
>
> @@ -1197,6 +1206,7 @@ static int xemaclite_of_probe(struct platform_device
> *ofdev)
>  	return 0;
>
>  error:
> +	of_node_put(lp->phy_node);
>  	free_netdev(ndev);
>  	return rc;
>  }
> --
> 2.7.4
>
>

RE: [PATCH net v2] net: emaclite: Add error handling for of_address_ and _mdio_setup functions

[Radhey Shyam Pandey]

> -----Original Message-----
> From: Denis Kirjanov <kda@linux-powerpc.org>
> Sent: Tuesday, November 17, 2020 6:43 PM
> To: Radhey Shyam Pandey <radheys@xilinx.com>
> Cc: davem@davemloft.net; netdev@vger.kernel.org; kuba@kernel.org;
> Michal Simek <michals@xilinx.com>; mchehab+samsung@kernel.org;
> gregkh@linuxfoundation.org; nicolas.ferre@microchip.com; linux-arm-
> kernel@lists.infradead.org; linux-kernel@vger.kernel.org; git
> <git@xilinx.com>; Shravya Kumbham <shravyak@xilinx.com>
> Subject: Re: [PATCH net v2] net: emaclite: Add error handling for
> of_address_ and _mdio_setup functions
> 
> On 11/17/20, Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
> wrote:
> > From: Shravya Kumbham <shravya.kumbham@xilinx.com>
> >
> > Add ret variable, condition to check the return value and error path
> > for the of_address_to_resource() function. It also adds error handling
> > for mdio setup and decrement refcount of phy node.
> >
> > Addresses-Coverity: Event check_return value.
> > Signed-off-by: Shravya Kumbham <shravya.kumbham@xilinx.com>
> > Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
> > ---
> > Changes for v2:
> >
> > - Change subject_prefix to target net tree.
> > - Add error handling for mdio_setup and remove phy_read changes.
> >   Error checking of phy_read will be added along with phy_write
> >   in a followup patch. Document the changes in commit description.
> > ---
> >  drivers/net/ethernet/xilinx/xilinx_emaclite.c | 16 +++++++++++++---
> >  1 file changed, 13 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/xilinx/xilinx_emaclite.c
> > b/drivers/net/ethernet/xilinx/xilinx_emaclite.c
> > index 0c26f5bcc523..4e0005164785 100644
> > --- a/drivers/net/ethernet/xilinx/xilinx_emaclite.c
> > +++ b/drivers/net/ethernet/xilinx/xilinx_emaclite.c
> > @@ -820,7 +820,7 @@ static int xemaclite_mdio_write(struct mii_bus
> > *bus, int phy_id, int reg,  static int xemaclite_mdio_setup(struct
> > net_local *lp, struct device *dev)  {
> >  	struct mii_bus *bus;
> > -	int rc;
> > +	int rc, ret;
> >  	struct resource res;
> >  	struct device_node *np = of_get_parent(lp->phy_node);
> >  	struct device_node *npp;
> > @@ -834,7 +834,12 @@ static int xemaclite_mdio_setup(struct net_local
> > *lp, struct device *dev)
> >  	}
> >  	npp = of_get_parent(np);
> >
> > -	of_address_to_resource(npp, 0, &res);
> > +	ret = of_address_to_resource(npp, 0, &res);
> > +	if (ret) {
> > +		dev_err(dev, "%s resource error!\n",
> > +			dev->of_node->full_name);
> > +		return ret;
> > +	}
> 
> npp is not returned to of_node_put() in the error case below

Yes, agree. The ref counting of npp device node is broken. 
I am planning to send v3 with a separate patch to simplify
this.

[1/2] net: emaclite: Simplify device node ref counting
[2/2] net: emaclite: Add error handling for of_address_
to_resource and xemaclite_mdio_setup functions

> 
> >  	if (lp->ndev->mem_start != res.start) {
> >  		struct phy_device *phydev;
> >  		phydev = of_phy_find_device(lp->phy_node); @@ -1173,7
> +1178,11 @@
> > static int xemaclite_of_probe(struct platform_device
> > *ofdev)
> >  	xemaclite_update_address(lp, ndev->dev_addr);
> >
> >  	lp->phy_node = of_parse_phandle(ofdev->dev.of_node, "phy-
> handle", 0);
> > -	xemaclite_mdio_setup(lp, &ofdev->dev);
> > +	rc = xemaclite_mdio_setup(lp, &ofdev->dev);
> > +	if (rc) {
> > +		dev_warn(dev, "error registering MDIO bus: %d\n", rc);
> > +		goto error;
> > +	}
> >
> >  	dev_info(dev, "MAC address is now %pM\n", ndev->dev_addr);
> >
> > @@ -1197,6 +1206,7 @@ static int xemaclite_of_probe(struct
> > platform_device
> > *ofdev)
> >  	return 0;
> >
> >  error:
> > +	of_node_put(lp->phy_node);
> >  	free_netdev(ndev);
> >  	return rc;
> >  }
> > --
> > 2.7.4
> >
> >