a question on packet_sock struct

Hi. I have a question on packet_sock struct
defined in net/packet/af_packet.c of Linux 2.6.30.4.

Is it necessary to hold a packet_sock's bind_lock
before accessing its ifindex field?

According to the definition of packet_sock struct,
it seems that an access to ifindex field should be
synchronized by the bind_lock.

However, according to the its usage in the code,
ifindex accesses are not consistently protected
by the bind_lock.

Thank you

Sincerely
Shin Hong