Messages in this thread | | | From | Toke Høiland-Jørgensen <> | Subject | Re: [PATCH] bpf: devmap: Pass lockdep expression to RCU lists | Date | Thu, 23 Jan 2020 14:42:03 +0100 |
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Jesper Dangaard Brouer <brouer@redhat.com> writes:
> On Thu, 23 Jan 2020 17:34:38 +0530 > Amol Grover <frextrite@gmail.com> wrote: > >> head is traversed using hlist_for_each_entry_rcu outside an >> RCU read-side critical section but under the protection >> of dtab->index_lock. > > We do hold the lock in update and delete cases, but not in the lookup > cases. Is it then still okay to add the lockdep_is_held() annotation?
I concluded 'yes' from the comment on hlist_for_each_entry_rcu():
The lockdep condition gets passed to this:
#define __list_check_rcu(dummy, cond, extra...) \ ({ \ check_arg_count_one(extra); \ RCU_LOCKDEP_WARN(!cond && !rcu_read_lock_any_held(), \ "RCU-list traversed in non-reader section!"); \ })
so that seems fine :)
-Toke
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