Re: [PATCH net v8 03/15] net: cache snapshot entries for ndo_set_rx_mode_async

[Paolo Abeni <pabeni@redhat.com>]

On 4/16/26 8:57 PM, Stanislav Fomichev wrote:
> Add a per-device netdev_hw_addr_list cache (rx_mode_addr_cache) that
> allows __hw_addr_list_snapshot() and __hw_addr_list_reconcile() to
> reuse previously allocated entries instead of hitting GFP_ATOMIC on
> every snapshot cycle.
> 
> snapshot pops entries from the cache when available, falling back to
> __hw_addr_create(). reconcile splices both snapshot lists back into
> the cache via __hw_addr_splice(). The cache is flushed in
> free_netdev().
> 
> Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
> (cherry picked from commit ba3ab1832a511f660fdc6231245b14bf610c05bd)

Are you backporting from 7.2 via time machine??? :-P

> @@ -611,8 +633,8 @@ void __hw_addr_list_reconcile(struct netdev_hw_addr_list *real_list,
>  		}
>  	}
>  
> -	__hw_addr_flush(work);
> -	__hw_addr_flush(ref);
> +	__hw_addr_splice(cache, work);
> +	__hw_addr_splice(cache, ref);

I think here sashiko has a point, with the cache size being unbounded. I
guess syzkaller or the like will find a way to make it grow too much.

What about hard-limit it to some reasonable value?!?

/P