Re: [RFC PATCH]: Dynamically sized routing cache hash table.

[Eric Dumazet <dada1@cosmosbay.com>]

On Tuesday 06 March 2007 10:11, Nick Piggin wrote:

> Cool! I have some fixes for the rcu barrier issues, with some C-style
> comments and questions :)
>
> I was going to send you a fix first for the rcu barriers, then a
> second to convert the read-side to a barrier-less one that I described,
> however considering that your patch is a WIP in progress anyway, I
> won't worry too much about the normal protocol.
>
> I _think_ my reasoning regarding the rcu barriers and grace periods
> is correct. I'll keep thinking about it though. (Paul cc'ed).
>
> I'm not so familiar with this code, so I have sprinkled around a lot
> of comments that could be pure crap ;) They are mainly just to help
> you ensure that you cover all bases... compile tested only at this
> stage.

I think we missed :

+static void rt_hash_resize_work(struct work_struct *work)

+
+			*head = rth->u.dst.rt_next;
+
+			hash = rt_hashfn(rt_hash,
+					 rth->fl.fl4_dst,
+					 rth->fl.fl4_src,
+					 iface);
+			rth->u.dst.rt_next = rt_hash->table[hash].chain;
+			rt_hash->table[hash].chain = rth;

This really needs some ..._del_rcu()/..._add_rcu()_ ... primitives, no ?
Or else a reader might be very confused...