Re: [PATCH v2] examples/kni: clear warning about discarding const qualifier

[Ferruh Yigit <ferruh.yigit@xilinx.com>]

On 6/1/2022 6:45 AM, Ke Zhang wrote:
> The warning info:
> warning: passing argument 1 of ‘memcpy’ discards ‘const’
> qualifier from pointer target type
> 
> Variable is done const intentionally to prevent using it
> directly, using the new helper functions :
> 'eth_hw_addr_set()' and 'eth_hw_addr_random()'
> 
> Fixes: ea6b39b5b847 ("kni: remove ethtool support")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Ke Zhang <ke1x.zhang@intel.com>
> ---
>   kernel/linux/kni/kni_misc.c | 4 ++--
>   kernel/linux/kni/kni_net.c  | 2 +-
>   2 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/kernel/linux/kni/kni_misc.c b/kernel/linux/kni/kni_misc.c
> index 780187d8bf..1da8e812b7 100644
> --- a/kernel/linux/kni/kni_misc.c
> +++ b/kernel/linux/kni/kni_misc.c
> @@ -403,10 +403,10 @@ kni_ioctl_create(struct net *net, uint32_t ioctl_num,
>   
>   	/* if user has provided a valid mac address */
>   	if (is_valid_ether_addr(dev_info.mac_addr))
> -		memcpy(net_dev->dev_addr, dev_info.mac_addr, ETH_ALEN);
> +		eth_hw_addr_set(net_dev, dev_info.mac_addr);
>   	else
>   		/* Generate random MAC address. */
> -		eth_random_addr(net_dev->dev_addr);
> +		eth_hw_addr_random(net_dev);
>   
>   	if (dev_info.mtu)
>   		net_dev->mtu = dev_info.mtu;
> diff --git a/kernel/linux/kni/kni_net.c b/kernel/linux/kni/kni_net.c
> index 29e5b9e21f..1da4f836aa 100644
> --- a/kernel/linux/kni/kni_net.c
> +++ b/kernel/linux/kni/kni_net.c
> @@ -779,7 +779,7 @@ kni_net_set_mac(struct net_device *netdev, void *p)
>   		return -EADDRNOTAVAIL;
>   
>   	memcpy(req.mac_addr, addr->sa_data, netdev->addr_len);
> -	memcpy(netdev->dev_addr, addr->sa_data, netdev->addr_len);
> +	eth_hw_addr_set(netdev, addr->sa_data);
>   
>   	ret = kni_net_process_request(netdev, &req);
>   

Hi Ke,

We can't just use new APIs, otherwise this will fail with old kernels.
A version check is needed, please check 'compat.h' for various samples.