Re: [PATCH 1/4] net: add ethaddr sequence handling

[Sascha Hauer <s.hauer@pengutronix.de>]

On Tue, Nov 26, 2024 at 04:17:41PM +0100, Ahmad Fatoum wrote:
> Instead of storing every MAC address in full, boards may elect
> to store a base address and increment it N times. Add a helper
> to iterate over such an Ethernet address sequence. Example usage:
> 
>   const u8 *eth_addr;
>   u8 eth_base[ETH_ALEN] = "\x00\x01\x02\x03\x04\x05";
>   int i = 0, eth_count = 4;
> 
>   for_each_seq_ethaddr(eth_addr, eth_base, &eth_count)
>           eth_register_ethaddr(i++, eth_addr);

	for (i = 0; i < 4; i++, eth_addr_inc(eth_addr))
		eth_register_ethaddr(i, eth_addr);

I think the open coded variant is easier to read and write, I don't
think we should introduce a helper for this.

Sascha

> 
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
>  include/net.h | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/include/net.h b/include/net.h
> index a04ed5b0ab92..1b6995b50043 100644
> --- a/include/net.h
> +++ b/include/net.h
> @@ -516,6 +516,18 @@ static inline void eth_addr_add(u8 *addr, long offset)
>  	u64_to_ether_addr(u, addr);
>  }
>  
> +#define for_each_seq_ethaddr(eth_addr, eth_base, eth_count) \
> +	for (eth_addr = *eth_count ? eth_base : NULL; eth_addr; eth_addr = eth_addr_seq_next(eth_base, eth_count))
> +
> +static inline const u8 *eth_addr_seq_next(u8 eth_base[6], unsigned *eth_count)
> +{
> +	if (--(*eth_count) <= 0)
> +		return NULL;
> +
> +	eth_addr_inc(eth_base);
> +	return eth_base;
> +}
> +
>  typedef void rx_handler_f(void *ctx, char *packet, unsigned int len);
>  
>  struct eth_device *eth_get_byname(const char *name);
> -- 
> 2.39.5
> 
> 
> 

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