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Date: Sun, 29 Mar 2015 10:13:39 +0200
From: Hans Petter Selasky <hps@selasky.org>
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To: Gleb Smirnoff <glebius@FreeBSD.org>, Fabien Thomas <fabient@FreeBSD.org>
Subject: Re: svn commit: r280759 - head/sys/netinet
References: <201503271326.t2RDQxd3056112@svn.freebsd.org>
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On 03/28/15 20:16, Gleb Smirnoff wrote:
> +uint16_t
> +ip_newid(void)
> +{
> +
> +	counter_u64_add(V_ip_id, 1);
> +	return (htons((*(uint64_t *)zpcpu_get(V_ip_id)) & 0xffff));
> +}

Technically you would need to enter a critical section here, so that the 
current process doesn't get swapped to a different CPU between the 
counter add and the zpcpu_get.

--HPS