netdev - Re: [PATCH -next] net: broadcom: Use helper function IS_ERR_OR

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Message-ID: <dd7e3f9a-1348-1d13-3b0b-5165070dd342@huawei.com>
Date: Thu, 17 Aug 2023 17:01:51 +0800
From: Ruan Jinjie <ruanjinjie@...wei.com>
To: Leon Romanovsky <leon@...nel.org>
CC: <netdev@...r.kernel.org>, Rafał Miłecki
	<rafal@...ecki.pl>, Broadcom internal kernel review list
	<bcm-kernel-feedback-list@...adcom.com>, "David S. Miller"
	<davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski
	<kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, Doug Berger
	<opendmb@...il.com>, Florian Fainelli <florian.fainelli@...adcom.com>
Subject: Re: [PATCH -next] net: broadcom: Use helper function IS_ERR_OR_NULL()



On 2023/8/17 15:19, Leon Romanovsky wrote:
> On Wed, Aug 16, 2023 at 05:53:56PM +0800, Ruan Jinjie wrote:
>> Use IS_ERR_OR_NULL() instead of open-coding it
>> to simplify the code.
>>
>> Signed-off-by: Ruan Jinjie <ruanjinjie@...wei.com>
>> ---
>>  drivers/net/ethernet/broadcom/bgmac.c        | 2 +-
>>  drivers/net/ethernet/broadcom/genet/bcmmii.c | 2 +-
>>  2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/broadcom/bgmac.c b/drivers/net/ethernet/broadcom/bgmac.c
>> index 10c7c232cc4e..4cd7c6abb548 100644
>> --- a/drivers/net/ethernet/broadcom/bgmac.c
>> +++ b/drivers/net/ethernet/broadcom/bgmac.c
>> @@ -1448,7 +1448,7 @@ int bgmac_phy_connect_direct(struct bgmac *bgmac)
>>  	int err;
>>  
>>  	phy_dev = fixed_phy_register(PHY_POLL, &fphy_status, NULL);
> 
> When can fixed_phy_register() return NULL?
> It looks like it returns or valid phy_dev or ERR_PTR().

It seems the following code has a problem:

226 static struct phy_device *__fixed_phy_register(unsigned int irq,
227                            struct fixed_phy_status *status,
228                            struct device_node *np,
229                            struct gpio_desc *gpiod)
230 {
231     struct fixed_mdio_bus *fmb = &platform_fmb;
232     struct phy_device *phy;
233     int phy_addr;
234     int ret;
235
236     if (!fmb->mii_bus || fmb->mii_bus->state != MDIOBUS_REGISTERED)
237         return ERR_PTR(-EPROBE_DEFER);
238
239     /* Check if we have a GPIO associated with this fixed phy */
240     if (!gpiod) {
241         gpiod = fixed_phy_get_gpiod(np);
242         if (IS_ERR(gpiod))
243             return ERR_CAST(gpiod);
244     }

fixed_phy_get_gpiod() return valid gpio_desc or NULL.If
fixed_phy_get_gpiod(np) failed, the error can not be returned with
IS_ERR(gpiod) is true, so the 243 line code is a dead code.

> 
> Thanks
> 
> 
>> -	if (!phy_dev || IS_ERR(phy_dev)) {
>> +	if (IS_ERR_OR_NULL(phy_dev)) {
>>  		dev_err(bgmac->dev, "Failed to register fixed PHY device\n");
>>  		return -ENODEV;
>>  	}
>> diff --git a/drivers/net/ethernet/broadcom/genet/bcmmii.c b/drivers/net/ethernet/broadcom/genet/bcmmii.c
>> index 0092e46c46f8..aa9a436fb3ce 100644
>> --- a/drivers/net/ethernet/broadcom/genet/bcmmii.c
>> +++ b/drivers/net/ethernet/broadcom/genet/bcmmii.c
>> @@ -617,7 +617,7 @@ static int bcmgenet_mii_pd_init(struct bcmgenet_priv *priv)
>>  		};
>>  
>>  		phydev = fixed_phy_register(PHY_POLL, &fphy_status, NULL);
>> -		if (!phydev || IS_ERR(phydev)) {
>> +		if (IS_ERR_OR_NULL(phydev)) {
>>  			dev_err(kdev, "failed to register fixed PHY device\n");
>>  			return -ENODEV;
>>  		}
>> -- 
>> 2.34.1
>>
>>