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

[Stanislav Fomichev <sdf.kernel@gmail.com>]

On 04/21, Paolo Abeni wrote:
> On 4/21/26 11:52 AM, Paolo Abeni wrote:
> > 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?!?
> 
> There are a few more remarks from sashiko at the driver level, but
> AFAICS are all pre-existing issues.
> 
> I think even the above one it's better handled as a follow-up, so I'm
> applying the series as-is (I'll just drop the cherry-pick statement above).

I have a follow-up series to add retries here, but not sure it's the
right direction. I can send it once net-next opens just to opinions.