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

[YueHaibing]

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 <yuehaib...@huawei.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
>>
>>
> 
> .
>