On Tue, Mar 27 2018, Herbert Xu wrote: > On Tue, Mar 27, 2018 at 10:33:04AM +1100, NeilBrown wrote: >> >> -int rhashtable_walk_start_check(struct rhashtable_iter *iter) >> +int rhashtable_walk_start_continue(struct rhashtable_iter *iter, struct >> rhash_head *obj) >> __acquires(RCU) >> { >> struct rhashtable *ht = iter->ht; >> >> rcu_read_lock(); >> >> + if (!obj || iter->p != obj) >> + iter->p = NULL; > > Why bother with this check at all? Couldn't we make it so that > if you call continue then you continue with the cursor otherwise > you set it to NULL as we currently do.
Possibly. I particularly want the interface to require that you pass the previously returned object to _continue. That makes it easy to see that the object is still being used. If someone changes to code to delete the object before the _continue, there should be a strong hint that it won't work. Maybe it would be better to make it a WARN_ON() if (!obj || WARN_ON(iter->p != obj)) iter->p = NULL; ?? Thanks, NeilBrown
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