[IPV6]: ROUTE: Eliminate lock for default route pointer. (554cfb7e) · Commits · EulixOS / Software / Kernel

include/net/ip6_route.h

+0 −2

Original line number	Original line	Diff line number	Diff line
	@@ -91,8 +91,6 @@ extern struct rt6_info * rt6_add_dflt_router(struct in6_addr *gwaddr,

	extern void rt6_purge_dflt_routers(void);		extern void rt6_purge_dflt_routers(void);

	extern void rt6_reset_dflt_pointer(struct rt6_info *rt);

	extern void rt6_redirect(struct in6_addr *dest,		extern void rt6_redirect(struct in6_addr *dest,
	struct in6_addr *saddr,		struct in6_addr *saddr,
	struct neighbour *neigh,		struct neighbour *neigh,

net/ipv6/ip6_fib.c

+0 −1

Original line number	Original line	Diff line number	Diff line
	@@ -1105,7 +1105,6 @@ static int fib6_age(struct rt6_info rt, void arg)
	if (rt->rt6i_flags&RTF_EXPIRES && rt->rt6i_expires) {		if (rt->rt6i_flags&RTF_EXPIRES && rt->rt6i_expires) {
	if (time_after(now, rt->rt6i_expires)) {		if (time_after(now, rt->rt6i_expires)) {
	RT6_TRACE("expiring %p\n", rt);		RT6_TRACE("expiring %p\n", rt);
	rt6_reset_dflt_pointer(rt);
	return -1;		return -1;
	}		}
	gc_args.more++;		gc_args.more++;

net/ipv6/route.c

+69 −128

Original line number	Original line	Diff line number	Diff line
	@@ -74,6 +74,9 @@

	#define CLONE_OFFLINK_ROUTE 0		#define CLONE_OFFLINK_ROUTE 0

			#define RT6_SELECT_F_IFACE 0x1
			#define RT6_SELECT_F_REACHABLE 0x2

	static int ip6_rt_max_size = 4096;		static int ip6_rt_max_size = 4096;
	static int ip6_rt_gc_min_interval = HZ / 2;		static int ip6_rt_gc_min_interval = HZ / 2;
	static int ip6_rt_gc_timeout = 60*HZ;		static int ip6_rt_gc_timeout = 60*HZ;
	@@ -216,148 +219,89 @@ static __inline__ struct rt6_info rt6_device_match(struct rt6_info rt,
	}		}

	/*		/*
	* pointer to the last default router chosen. BH is disabled locally.		* Default Router Selection (RFC 2461 6.3.6)
	*/		*/
	static struct rt6_info *rt6_dflt_pointer;		static int inline rt6_check_dev(struct rt6_info *rt, int oif)
	static DEFINE_SPINLOCK(rt6_dflt_lock);

	void rt6_reset_dflt_pointer(struct rt6_info *rt)
	{		{
	spin_lock_bh(&rt6_dflt_lock);		struct net_device *dev = rt->rt6i_dev;
	if (rt == NULL \|\| rt == rt6_dflt_pointer) {		if (!oif \|\| dev->ifindex == oif)
	RT6_TRACE("reset default router: %p->NULL\n", rt6_dflt_pointer);		return 2;
	rt6_dflt_pointer = NULL;		if ((dev->flags & IFF_LOOPBACK) &&
	}		rt->rt6i_idev && rt->rt6i_idev->dev->ifindex == oif)
	spin_unlock_bh(&rt6_dflt_lock);		return 1;
			return 0;
	}		}

	/* Default Router Selection (RFC 2461 6.3.6) */		static int inline rt6_check_neigh(struct rt6_info *rt)
	static struct rt6_info rt6_best_dflt(struct rt6_info rt, int oif)
	{		{
	struct rt6_info *match = NULL;		struct neighbour *neigh = rt->rt6i_nexthop;
	struct rt6_info *sprt;
	int mpri = 0;

	for (sprt = rt; sprt; sprt = sprt->u.next) {
	struct neighbour *neigh;
	int m = 0;		int m = 0;
			if (neigh) {
			read_lock_bh(&neigh->lock);
			if (neigh->nud_state & NUD_VALID)
			m = 1;
			read_unlock_bh(&neigh->lock);
			}
			return m;
			}

	if (!oif \|\|		static int rt6_score_route(struct rt6_info *rt, int oif,
	(sprt->rt6i_dev &&		int strict)
	sprt->rt6i_dev->ifindex == oif))		{
	m += 8;		int m = rt6_check_dev(rt, oif);
			if (!m && (strict & RT6_SELECT_F_IFACE))
			return -1;
			if (rt6_check_neigh(rt))
			m \|= 4;
			else if (strict & RT6_SELECT_F_REACHABLE)
			return -1;
			return m;
			}

	if (rt6_check_expired(sprt))		static struct rt6_info rt6_select(struct rt6_info *head, int oif,
	continue;		int strict)
			{
			struct rt6_info match = NULL, last = NULL;
			struct rt6_info rt, rt0 = *head;
			u32 metric;
			int mpri = -1;

	if (sprt == rt6_dflt_pointer)		RT6_TRACE("%s(head=%p(*head=%p), oif=%d)\n",
	m += 4;		__FUNCTION__, head, head ? *head : NULL, oif);

	if ((neigh = sprt->rt6i_nexthop) != NULL) {		for (rt = rt0, metric = rt0->rt6i_metric;
	read_lock_bh(&neigh->lock);		rt && rt->rt6i_metric == metric;
	switch (neigh->nud_state) {		rt = rt->u.next) {
	case NUD_REACHABLE:		int m;
	m += 3;
	break;

	case NUD_STALE:		if (rt6_check_expired(rt))
	case NUD_DELAY:		continue;
	case NUD_PROBE:
	m += 2;
	break;

	case NUD_NOARP:		last = rt;
	case NUD_PERMANENT:
	m += 1;
	break;

	case NUD_INCOMPLETE:		m = rt6_score_route(rt, oif, strict);
	default:		if (m < 0)
	read_unlock_bh(&neigh->lock);
	continue;
	}
	read_unlock_bh(&neigh->lock);
	} else {
	continue;		continue;
	}

	if (m > mpri \|\| m >= 12) {		if (m > mpri) {
	match = sprt;		match = rt;
	mpri = m;		mpri = m;
	if (m >= 12) {
	/* we choose the last default router if it
	* is in (probably) reachable state.
	* If route changed, we should do pmtu
	* discovery. --yoshfuji
	*/
	break;
	}
	}
	}

	spin_lock(&rt6_dflt_lock);
	if (!match) {
	/*
	* No default routers are known to be reachable.
	* SHOULD round robin
	*/
	if (rt6_dflt_pointer) {
	for (sprt = rt6_dflt_pointer->u.next;
	sprt; sprt = sprt->u.next) {
	if (sprt->u.dst.obsolete <= 0 &&
	sprt->u.dst.error == 0 &&
	!rt6_check_expired(sprt)) {
	match = sprt;
	break;
	}
	}
	for (sprt = rt;
	!match && sprt;
	sprt = sprt->u.next) {
	if (sprt->u.dst.obsolete <= 0 &&
	sprt->u.dst.error == 0 &&
	!rt6_check_expired(sprt)) {
	match = sprt;
	break;
	}
	if (sprt == rt6_dflt_pointer)
	break;
	}
	}		}
	}		}

	if (match) {		if (!match &&
	if (rt6_dflt_pointer != match)		(strict & RT6_SELECT_F_REACHABLE) &&
	RT6_TRACE("changed default router: %p->%p\n",		last && last != rt0) {
	rt6_dflt_pointer, match);		/* no entries matched; do round-robin */
	rt6_dflt_pointer = match;		*head = rt0->u.next;
			rt0->u.next = last->u.next;
			last->u.next = rt0;
	}		}
	spin_unlock(&rt6_dflt_lock);

	if (!match) {		RT6_TRACE("%s() => %p, score=%d\n",
	/*		__FUNCTION__, match, mpri);
	* Last Resort: if no default routers found,
	* use addrconf default route.
	* We don't record this route.
	*/
	for (sprt = ip6_routing_table.leaf;
	sprt; sprt = sprt->u.next) {
	if (!rt6_check_expired(sprt) &&
	(sprt->rt6i_flags & RTF_DEFAULT) &&
	(!oif \|\|
	(sprt->rt6i_dev &&
	sprt->rt6i_dev->ifindex == oif))) {
	match = sprt;
	break;
	}
	}
	if (!match) {
	/* no default route. give up. */
	match = &ip6_null_entry;
	}
	}

	return match;		return (match ? match : &ip6_null_entry);
	}		}

	struct rt6_info rt6_lookup(struct in6_addr daddr, struct in6_addr *saddr,		struct rt6_info rt6_lookup(struct in6_addr daddr, struct in6_addr *saddr,
	@@ -542,7 +486,7 @@ struct dst_entry * ip6_route_output(struct sock sk, struct flowi fl)
	int attempts = 3;		int attempts = 3;
	int err;		int err;

	strict = ipv6_addr_type(&fl->fl6_dst) & (IPV6_ADDR_MULTICAST\|IPV6_ADDR_LINKLOCAL);		strict = ipv6_addr_type(&fl->fl6_dst) & (IPV6_ADDR_MULTICAST\|IPV6_ADDR_LINKLOCAL) ? RT6_SELECT_F_IFACE : 0;

	relookup:		relookup:
	read_lock_bh(&rt6_lock);		read_lock_bh(&rt6_lock);
	@@ -558,8 +502,9 @@ struct dst_entry * ip6_route_output(struct sock sk, struct flowi fl)
	goto out;		goto out;
	}		}
	if (rt->rt6i_flags & RTF_DEFAULT) {		if (rt->rt6i_flags & RTF_DEFAULT) {
	if (rt->rt6i_metric >= IP6_RT_PRIO_ADDRCONF)		rt = rt6_select(&fn->leaf, fl->oif, strict \| RT6_SELECT_F_REACHABLE);
	rt = rt6_best_dflt(rt, fl->oif);		if (rt == &ip6_null_entry)
			rt = rt6_select(&fn->leaf, fl->oif, strict);
	} else {		} else {
	rt = rt6_device_match(rt, fl->oif, strict);		rt = rt6_device_match(rt, fl->oif, strict);
	BACKTRACK();		BACKTRACK();
	@@ -1025,8 +970,6 @@ int ip6_del_rt(struct rt6_info rt, struct nlmsghdr nlh, void *_rtattr, struct

	write_lock_bh(&rt6_lock);		write_lock_bh(&rt6_lock);

	rt6_reset_dflt_pointer(NULL);

	err = fib6_del(rt, nlh, _rtattr, req);		err = fib6_del(rt, nlh, _rtattr, req);
	dst_release(&rt->u.dst);		dst_release(&rt->u.dst);

	@@ -1341,8 +1284,6 @@ void rt6_purge_dflt_routers(void)
	if (rt->rt6i_flags & (RTF_DEFAULT \| RTF_ADDRCONF)) {		if (rt->rt6i_flags & (RTF_DEFAULT \| RTF_ADDRCONF)) {
	dst_hold(&rt->u.dst);		dst_hold(&rt->u.dst);

	rt6_reset_dflt_pointer(NULL);

	read_unlock_bh(&rt6_lock);		read_unlock_bh(&rt6_lock);

	ip6_del_rt(rt, NULL, NULL, NULL);		ip6_del_rt(rt, NULL, NULL, NULL);