[Click] which element should add ELEMENT_MT_SAFE?

[Jiangbo Li]

hi, clickers,
 
I found that a few elements don't have ELEMENT_MT_SAFE(...) at
the end of .cc file. Elements like CheckIPHeader don't have the 
ELEMENT_MT_SAFE(..) statement. Since CheckIPHeader use 
the hardware atomic increment instruction ( as described in the 
USENIX paper), it should be SMP safe. And IPFilter also don't 
have such statement.

Why? Is there something I missed.

Thanks.

Jiangbo Li