Re: [PATCH v2 net-next 2/2] ipv6: frags: cleanup __IP6_INC_STATS() confusion

[Ido Schimmel <idosch@nvidia.com>]

On Tue, May 26, 2026 at 02:55:29PM +0000, Eric Dumazet wrote:
> After commits e1ae5c2ea478 ("vrf: Increment Icmp6InMsgs on the original
> netdev") and bdb7cc643fc9 ("ipv6: Count interface receive statistics
> on the ingress netdev") net/ipv6/reassembly.c uses three different
> ways to reach idev in various __IP6_INC_STATS() calls.
> 
> - ip6_dst_idev(skb_dst(skb))
> - __in6_dev_get_safely(skb->dev)
> - __in6_dev_stats_get(skb->dev)
> 
> Lets centralize this from ipv6_frag_rcv() and use __in6_dev_stats_get().
> 
> Note that ipv6_frag_rcv() tests if skb->dev could be NULL already, so
> I chose to also guard against NULL, but we probably can remove the
> tests in a followup patch, because I do not think skb->dev could be NULL.
> 
> iif = skb->dev ? skb->dev->ifindex : 0;
> 
> idev can be NULL, __IP6_INC_STATS() deals with this possibility.
> 
> Small code size reduction as a bonus.
> 
> $ scripts/bloat-o-meter -t vmlinux.old vmlinux.new
> add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-145 (-145)
> Function                                     old     new   delta
> ipv6_frag_rcv                               2399    2362     -37
> ip6_frag_reasm                               705     597    -108
> Total: Before=31455552, After=31455407, chg -0.00%
> 
> Signed-off-by: Eric Dumazet <edumazet@google.com>

Reviewed-by: Ido Schimmel <idosch@nvidia.com>