On Fri, Dec 18, 2015 at 04:54:14AM -0800, Eric Dumazet wrote: > > You can avoid the comment by using the self documented and lockdep > enabled primitive > > iter->walker->tbl = rcu_dereference_protected(ht->tbl, > lockdep_is_held(&ht->lock));
That is just gross. I think a comment is much better in this case. If we were to have more place where ht->lock is taken and we had to do the RCU dereference on ht->tbl then we could add a helper for it. For now it's just a single place and I think a comment is the best way to deal with it. > But, storing the ht->tbl and then releasing the lock immediately after > escapes RCU protection. > > So why do we store ht->tbl in the first place ? > > What exactly prevents it from disappearing after lock is released ? We add ourselves to the walker list before we release the lock. The only entity that can destroy ht->tbl will take care of all walkers before doing so. Cheers, -- Email: Herbert Xu <herb...@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
