bc74b4f5e6
For events that are rare, such as referral DNS lookups, it makes limited sense to have a daemon constantly listening for upcalls on a channel. An alternative in those cases might simply be to run the app that fills the cache using call_usermodehelper_exec() and friends. The following patch allows the cache_detail to specify alternative upcall mechanisms for these particular cases. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>