netdev - Re: [PATCH net-next] mdio_bus: Fix PTR_ERR() usage after initialization to constant

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Message-ID: <eeb532d5-45a7-648f-f835-82448465762a@huawei.com>
Date:   Tue, 29 Jan 2019 11:30:27 +0800
From:   YueHaibing <yuehaibing@...wei.com>
To:     Andrew Lunn <andrew@...n.ch>
CC:     <davem@...emloft.net>, <f.fainelli@...il.com>,
        <hkallweit1@...il.com>, <linux-kernel@...r.kernel.org>,
        <netdev@...r.kernel.org>
Subject: Re: [PATCH net-next] mdio_bus: Fix PTR_ERR() usage after
 initialization to constant


On 2019/1/28 22:36, Andrew Lunn wrote:
> On Mon, Jan 28, 2019 at 09:24:09PM +0800, YueHaibing wrote:
>> Fix coccinelle warning:
>>
>> ./drivers/net/phy/mdio_bus.c:51:5-12: ERROR: PTR_ERR applied after initialization to constant on line 44
>> ./drivers/net/phy/mdio_bus.c:52:5-12: ERROR: PTR_ERR applied after initialization to constant on line 44
>>
>> fix this by using IS_ERR before PTR_ERR
>>
>> Fixes: bafbdd527d56 ("phylib: Add device reset GPIO support")
>> Signed-off-by: YueHaibing <yuehaibing@...wei.com>
>> ---
>>  drivers/net/phy/mdio_bus.c | 13 ++++++++-----
>>  1 file changed, 8 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
>> index 3d31358..802716a 100644
>> --- a/drivers/net/phy/mdio_bus.c
>> +++ b/drivers/net/phy/mdio_bus.c
>> @@ -42,17 +42,20 @@
>>  static int mdiobus_register_gpiod(struct mdio_device *mdiodev)
>>  {
>>  	struct gpio_desc *gpiod = NULL;
>> +	int ret;
>>  
> 
> Hi YueHaibing
> 
> I think i prefer the simpler fix:
> 
>  static int mdiobus_register_gpiod(struct mdio_device *mdiodev)
>  {
> -  	struct gpio_desc *gpiod = NULL;
> +       struct gpio_desc *gpiod = ERR_PTR(-ENOENT);
> 

But a56c69803f5a ("net: phy: Handle not having GPIO enabled in the kernel")
add a new check:

@@ -56,7 +56,8 @@ static int mdiobus_register_gpiod(struct mdio_device *mdiodev)
                gpiod = fwnode_get_named_gpiod(&mdiodev->dev.of_node->fwnode,
                                               "reset-gpios", 0, GPIOD_OUT_LOW,
                                               "PHY reset");
-       if (PTR_ERR(gpiod) == -ENOENT)
+       if (PTR_ERR(gpiod) == -ENOENT ||
+           PTR_ERR(gpiod) == -ENOSYS)
                gpiod = NULL;
        else if (IS_ERR(gpiod))
                return PTR_ERR(gpiod);


> Totally untested...
> 
> 	Andrew
> 
>>  	/* Deassert the optional reset signal */
>>  	if (mdiodev->dev.of_node)
>>  		gpiod = fwnode_get_named_gpiod(&mdiodev->dev.of_node->fwnode,
>>  					       "reset-gpios", 0, GPIOD_OUT_LOW,
>>  					       "PHY reset");
>> -	if (PTR_ERR(gpiod) == -ENOENT ||
>> -	    PTR_ERR(gpiod) == -ENOSYS)
>> -		gpiod = NULL;
>> -	else if (IS_ERR(gpiod))
>> -		return PTR_ERR(gpiod);
>> +	if (IS_ERR(gpiod)) {
>> +		ret = PTR_ERR(gpiod);
>> +		if (ret == -ENOENT || ret == -ENOSYS)
>> +			gpiod = NULL;
>> +		else
>> +			return ret;
>> +	}
>>  
>>  	mdiodev->reset = gpiod;
>>  
>> -- 
>> 2.7.4
>>
>>
> 
> .
>