netdev - Re: [PATCH v2] net: moxa: MAC address reading, generating, validity checking

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Date:   Thu, 18 Aug 2022 17:10:05 +0300
From:   Vladimir Oltean <olteanv@...il.com>
To:     Sergei Antonov <saproj@...il.com>
Cc:     netdev@...r.kernel.org, Andrew Lunn <andrew@...n.ch>,
        Jakub Kicinski <kuba@...nel.org>,
        Yang Yingliang <yangyingliang@...wei.com>,
        Pavel Skripkin <paskripkin@...il.com>,
        Guobin Huang <huangguobin4@...wei.com>,
        Yang Wei <yang.wei9@....com.cn>,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>
Subject: Re: [PATCH v2] net: moxa: MAC address reading, generating, validity
 checking

On Thu, Aug 18, 2022 at 12:23:17PM +0300, Sergei Antonov wrote:
> This device does not remember its MAC address, so add a possibility
> to get it from the platform. If it fails, generate a random address.
> This will provide a MAC address early during boot without user space
> being involved.
> 
> Also remove extra calls to is_valid_ether_addr().
> 
> Made after suggestions by Andrew Lunn:
> 1) Use eth_hw_addr_random() to assign a random MAC address during probe.
> 2) Remove is_valid_ether_addr() from moxart_mac_open()
> 3) Add a call to platform_get_ethdev_address() during probe
> 4) Remove is_valid_ether_addr() from moxart_set_mac_address(). The core does this
> 
> v1 -> v2:
> Handle EPROBE_DEFER returned from platform_get_ethdev_address().
> Move MAC reading code to the beginning of the probe function.
> 
> Signed-off-by: Sergei Antonov <saproj@...il.com>
> Suggested-by: Andrew Lunn <andrew@...n.ch>
> CC: Jakub Kicinski <kuba@...nel.org>
> CC: Vladimir Oltean <olteanv@...il.com>
> CC: Yang Yingliang <yangyingliang@...wei.com>
> CC: Pavel Skripkin <paskripkin@...il.com>
> CC: Guobin Huang <huangguobin4@...wei.com>
> CC: Yang Wei <yang.wei9@....com.cn>
> CC: Christophe JAILLET <christophe.jaillet@...adoo.fr>
> ---
>  drivers/net/ethernet/moxa/moxart_ether.c | 14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/net/ethernet/moxa/moxart_ether.c b/drivers/net/ethernet/moxa/moxart_ether.c
> index f11f1cb92025..402fea7505e6 100644
> --- a/drivers/net/ethernet/moxa/moxart_ether.c
> +++ b/drivers/net/ethernet/moxa/moxart_ether.c
> @@ -62,9 +62,6 @@ static int moxart_set_mac_address(struct net_device *ndev, void *addr)
>  {
>  	struct sockaddr *address = addr;
>  
> -	if (!is_valid_ether_addr(address->sa_data))
> -		return -EADDRNOTAVAIL;
> -
>  	eth_hw_addr_set(ndev, address->sa_data);
>  	moxart_update_mac_address(ndev);
>  
> @@ -172,9 +169,6 @@ static int moxart_mac_open(struct net_device *ndev)
>  {
>  	struct moxart_mac_priv_t *priv = netdev_priv(ndev);
>  
> -	if (!is_valid_ether_addr(ndev->dev_addr))
> -		return -EADDRNOTAVAIL;
> -
>  	napi_enable(&priv->napi);
>  
>  	moxart_mac_reset(ndev);
> @@ -488,6 +482,14 @@ static int moxart_mac_probe(struct platform_device *pdev)
>  	}
>  	ndev->base_addr = res->start;
>  
> +	// MAC address
> +	ret = platform_get_ethdev_address(p_dev, ndev);
> +	if (ret == -EPROBE_DEFER) // EEPROM has not probed yet?
> +		goto init_fail;

The comments are not very useful, and the kernel coding style is to use
the C-style comments /* */ rather than the C++ style //.
Anyway this is a minor remark, I don't think you have to resend for this.

Reviewed-by: Vladimir Oltean <olteanv@...il.com>

> +	if (ret)
> +		eth_hw_addr_random(ndev);
> +	moxart_update_mac_address(ndev);
> +
>  	spin_lock_init(&priv->txlock);
>  
>  	priv->tx_buf_size = TX_BUF_SIZE;
> -- 
> 2.32.0
>