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Commit cca61bb1 authored by Nikolay Aleksandrov's avatar Nikolay Aleksandrov Committed by Greg Kroah-Hartman
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net: ipv6: add fib6_nh_release_dsts stub 



[ Upstream commit 8837cbbf854246f5f4d565f21e6baa945d37aded ]

We need a way to release a fib6_nh's per-cpu dsts when replacing
nexthops otherwise we can end up with stale per-cpu dsts which hold net
device references, so add a new IPv6 stub called fib6_nh_release_dsts.
It must be used after an RCU grace period, so no new dsts can be created
through a group's nexthop entry.
Similar to fib6_nh_release it shouldn't be used if fib6_nh_init has failed
so it doesn't need a dummy stub when IPv6 is not enabled.

Fixes: 7bf4796d ("nexthops: add support for replace")
Signed-off-by: default avatarNikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent ddd0518c

include/net/ip6_fib.h

+1 −0
Original line number Diff line number Diff line
@@ -451,6 +451,7 @@ int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh, 
		 struct fib6_config *cfg, gfp_t gfp_flags,

		 struct netlink_ext_ack *extack);

void fib6_nh_release(struct fib6_nh *fib6_nh);

void fib6_nh_release_dsts(struct fib6_nh *fib6_nh);



int call_fib6_entry_notifiers(struct net *net,

			      enum fib_event_type event_type,

include/net/ipv6_stubs.h

+1 −0
Original line number Diff line number Diff line
@@ -47,6 +47,7 @@ struct ipv6_stub { 
			    struct fib6_config *cfg, gfp_t gfp_flags,

			    struct netlink_ext_ack *extack);

	void (*fib6_nh_release)(struct fib6_nh *fib6_nh);

	void (*fib6_nh_release_dsts)(struct fib6_nh *fib6_nh);

	void (*fib6_update_sernum)(struct net *net, struct fib6_info *rt);

	int (*ip6_del_rt)(struct net *net, struct fib6_info *rt);

	void (*fib6_rt_update)(struct net *net, struct fib6_info *rt,

net/ipv6/af_inet6.c

+1 −0
Original line number Diff line number Diff line
@@ -955,6 +955,7 @@ static const struct ipv6_stub ipv6_stub_impl = { 
	.ip6_mtu_from_fib6 = ip6_mtu_from_fib6,

	.fib6_nh_init	   = fib6_nh_init,

	.fib6_nh_release   = fib6_nh_release,

	.fib6_nh_release_dsts = fib6_nh_release_dsts,

	.fib6_update_sernum = fib6_update_sernum_stub,

	.fib6_rt_update	   = fib6_rt_update,

	.ip6_del_rt	   = ip6_del_rt,

net/ipv6/route.c

+19 −0
Original line number Diff line number Diff line
@@ -3585,6 +3585,25 @@ void fib6_nh_release(struct fib6_nh *fib6_nh) 
	fib_nh_common_release(&fib6_nh->nh_common);

}



void fib6_nh_release_dsts(struct fib6_nh *fib6_nh)

{

	int cpu;



	if (!fib6_nh->rt6i_pcpu)

		return;



	for_each_possible_cpu(cpu) {

		struct rt6_info *pcpu_rt, **ppcpu_rt;



		ppcpu_rt = per_cpu_ptr(fib6_nh->rt6i_pcpu, cpu);

		pcpu_rt = xchg(ppcpu_rt, NULL);

		if (pcpu_rt) {

			dst_dev_put(&pcpu_rt->dst);

			dst_release(&pcpu_rt->dst);

		}

	}

}



static struct fib6_info *ip6_route_info_create(struct fib6_config *cfg,

					      gfp_t gfp_flags,

					      struct netlink_ext_ack *extack)