Re: [PATCH net-next] tcp/dccp: remove twchain

[Ben Hutchings <bhutchings@solarflare.com>]

On Thu, 2013-10-03 at 00:22 -0700, Eric Dumazet wrote:
[...]
> @@ -146,26 +150,21 @@ void __inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
>  	spin_lock(lock);
>  
>  	/*
> -	 * Step 2: Hash TW into TIMEWAIT chain.
> -	 * Should be done before removing sk from established chain
> -	 * because readers are lockless and search established first.
> +	 * Step 2: Hash TW into tcp ehash chain.
> +	 * Notes :
> +	 * - tw_refcnt is set to 3 because :
> +	 * - We have one reference from bhash chain.
> +	 * - We have one reference from ehash chain.
> +	 * We can use atomic_set() because prior spin_lock()/spin_unlock()
> +	 * committed into memory all tw fields.
>  	*/
> -	inet_twsk_add_node_rcu(tw, &ehead->twchain);
> +	atomic_set(&tw->tw_refcnt, 1 + 1 + 1);
> +	inet_twsk_add_node_rcu(tw, &ehead->chain);
[...]

'will commit' rather than 'committed'?

But isn't this also a separate optimisation?

Ben.

-- 
Ben Hutchings, Staff Engineer, Solarflare
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They asked us to note that Solarflare product names are trademarked.