On Tue, 2015-05-26 at 14:44 +0200, Bart Van Assche wrote: > On 05/26/15 08:57, Nicholas A. Bellinger wrote: > > - Add various rcu_dereference and lockless_dereference RCU notation > > Hello Nic, > > Feedback from an RCU expert (which I'm not) would be appreciated here. > But my understanding is that lockless_dereference(p) should be used for > a pointer p that has *not* been annotated as an RCU pointer. I think in > the for-next branch of the target repository that this macro is used to > access RCU-annotated pointers. Is that why sparse complains about how > lockless_dereference() is used in the target tree ? >
Was curious about this myself.. Thanks for raising the question! The intention of lockless_dereference() in both this and preceding series is for __rcu protected pointers that are accessed outside of rcu_read_lock() protection, and who's lifetime is controlled by a: - struct kref - struct percpu_ref - struct config_group symlink - RCU updater path with some manner of mutex or spinlock held This is supposed to be following Paul's comment in rcupdate.h: * Similar to rcu_dereference(), but for situations where the pointed-to * object's lifetime is managed by something other than RCU. That * "something other" might be reference counting or simple immortality. Paul, would you be to kind to clarify the intention for us..? Thank you, --nab -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
