On Wed, Jul 1, 2026 at 5:12 AM Nikolay Aleksandrov [off-list ref] wrote:

On 01/07/2026 11:22, Eric Dumazet wrote:

quoted

Add READ_ONCE()/WRITE_ONCE() annotations on vlan->mode, vlan->flags,
vlan->bc_queue_len_req and port->bc_cutoff.

Fill IFLA_MACVLAN_MACADDR_DATA nested attribute and compute
on the fly the precise number of elements we put in it,
to fill an accurate IFLA_MACVLAN_MACADDR_COUNT attribute
as some user space applications could depend on its value
and the attributes order.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
  drivers/net/macvlan.c | 71 +++++++++++++++++++++++++++++--------------
  1 file changed, 48 insertions(+), 23 deletions(-)

The snippet that sets macaddr_count gave me pause. :)
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>

same here :p

Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>

[snip]

quoted

+
+     if (READ_ONCE(vlan->macaddr_count) > 0) {
              nest = nla_nest_start_noflag(skb, IFLA_MACVLAN_MACADDR_DATA);
              if (nest == NULL)
                      goto nla_put_failure;

              for (i = 0; i < MACVLAN_HASH_SIZE; i++) {
-                     if (macvlan_fill_info_macaddr(skb, vlan, i))
+                     cnt = macvlan_fill_info_macaddr(skb, vlan, i);
+                     if (cnt < 0)
                              goto nla_put_failure;
+                     macaddr_count += cnt;
              }
-             nla_nest_end(skb, nest);
+             if (!macaddr_count)
+                     nla_nest_cancel(skb, nest);
+             else if (nla_nest_end_safe(skb, nest) < 0)
+                     goto nla_put_failure;
      }
-     if (nla_put_u32(skb, IFLA_MACVLAN_BC_QUEUE_LEN, vlan->bc_queue_len_req))
+     *(u32 *)nla_data(attr) = macaddr_count;
+