Hi, Sorry if this is a silly question. Looking at the list_entry_rcu primitive, I see it does direct READ_ONCE on ptr. That's Ok, but rcu_dereference also does additional lockdep and sparse checking. Why not call rcu_dereference instead of READ_ONCE? The pointer may be dereference by the caller so IMO makes sense to check. Here is the definition of list_entry_rcu: /** * list_entry_rcu - get the struct for this entry [snip] * This primitive may safely run concurrently with the _rcu list-mutation * primitives such as list_add_rcu() as long as it's guarded by rcu_read_lock(). */ #define list_entry_rcu(ptr, type, member) \ container_of(READ_ONCE(ptr), type, member) Also, I was curious why hlist_for_each_entry_rcu() uses rcu_dereference_raw() while __hlist_for_each_rcu)_ uses rcu_dereference(). I feel both should use rcu_dereference to have the lockdep checking. Is this not done due to performance reasons? thanks! - Joel https://cdn-images-1.medium.com/max/1600/0*XTYvSNj_rT2UZwfm.png
