Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 13 Mar 2006 14:11:07 +1100 | From | Nick Piggin <> | Subject | Re: [patch 1/3] radix tree: RCU lockless read-side |
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Balbir Singh wrote: > On 3/11/06, Nick Piggin <nickpiggin@yahoo.com.au> wrote: > >>Balbir Singh wrote: >> >>><snip> >>> >>>> if (slot->slots[i]) { >>>>- results[nr_found++] = slot->slots[i]; >>>>+ results[nr_found++] = &slot->slots[i]; >>>> if (nr_found == max_items) >>>> goto out; >>>> } >>> >>> >>>A quick clarification - Shouldn't accesses to slot->slots[i] above be >>>protected using rcu_derefence()? >>> >> >>I think we're safe here -- this is the _address_ of the pointer. >>However, when dereferencing this address in _gang_lookup, >>I think we do need rcu_dereference indeed. >> > > > Yes, I saw the address operator, but we still derefence "slots" to get > the address. >
But we should have already rcu_dereference()ed "slot", right (in the loop above this one)? That means we are now able to dereference it, and the data at the other end will be valid.
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