OVS_GREP_IFELSE([$KSRC26/include/linux/rcupdate.h], [rcu_read_lock_held], [],
[OVS_GREP_IFELSE([$KSRC26/include/linux/rtnetlink.h],
OVS_GREP_IFELSE([$KSRC26/include/linux/rcupdate.h], [rcu_read_lock_held], [],
[OVS_GREP_IFELSE([$KSRC26/include/linux/rtnetlink.h],