Hi, Alexey, Increasing the reference count here is to prevent this route being deleted by fib6_age() within 30secs. There is no dereference in this function. This route will be deleted after expire time 10 mins no matter whether it has any reference or not. Thanks Shirley Ma IBM Linux Technology Center Tel: (503)578-7638 Fax:(503)578-3228 kuznet@ms2.inr.ac.ru@vger.kernel.org on 08/28/2002 10:50:38 AM Sent by: linux-net-owner@vger.kernel.org To: Shirley Ma/Beaverton/IBM@IBMUS cc: linux-net@vger.kernel.org Subject: Re: [PATCH] IPv6 PMTU/MTU for 2.5.31 Hello! I do not understand this: > @@ -1014,9 +1018,14 @@ > nrt = rt6_cow(rt, daddr, saddr); > if (!nrt->u.dst.error) { > nrt->u.dst.pmtu = pmtu; > - dst_set_expires(&rt->u.dst, ip6_rt_mtu_expires); > + /* According to RFC 1981, detecting PMTU increase shouldn't be > + happened within 5 mins, the recommended timer is 10 mins. > + Here this route expiration time is set to ip6_rt_mtu_expires > + which is 10 mins. After 10 mins the decreased pmtu is expired > + and detecting PMTU increase will be automatically happened. > + */ > + dst_set_expires(&nrt->u.dst, ip6_rt_mtu_expires); > nrt->rt6i_flags |= RTF_DYNAMIC|RTF_EXPIRES; > - dst_release(&nrt->u.dst); ^^^^^^^^^^^^^^^^^^^^^^^ and similar dst_hold() below. Where is this reference released? I do not see. Alexey - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html