On Thu, 2016-09-01 at 12:28 +0300, Hadar Hen Zion wrote: > > As you suggested above, I can do it by adding "int action" to struct > tcf_tunnel_key_paramse. > But, it means that act_tunnel_key would have a different behavior than > all the other actions and even though > "struct tc_action" has a designated parameters to store this action we > won't use it. > So it won't be completely clean... > > Do you think we have a cleaner way to protect it?
Fact that the act_ modules had a spinlock made them all share the same structure. Now we want RCU protection, here is the thing. Say you want to access 3 different fields, A, B and C. If you put A and B in the rcu protected pointer, but leave C in the 'control part, protected by spinlock' Then your fast path wont be able to have a consistent view of 3 variables A, B C. It might read an old value of A & B, and the recently updated C, Or it might read an old C, and the updated values of A & B As Cong very kindly pointed to us/me, if we want to be 'clean', we want to make sure we read a consistent 3-tuple. I will send updates when I have time to act_mirred.c
