[PATCH net 1/3] net: ipv6: add fib6_nh_release_dsts stub
From: Nikolay Aleksandrov <razor@blackwall.org>
Date: 2021-11-21 15:25:14
Subsystem:
networking [general], networking [ipv4/ipv6], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
From: Nikolay Aleksandrov <redacted>
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: 7bf4796dd099 ("nexthops: add support for replace")
Signed-off-by: Nikolay Aleksandrov <redacted>
---
include/net/ip6_fib.h | 1 +
include/net/ipv6_stubs.h | 1 +
net/ipv6/af_inet6.c | 1 +
net/ipv6/route.c | 19 +++++++++++++++++++
4 files changed, 22 insertions(+)
diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index c412dde4d67d..83b8070d1cc9 100644
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h@@ -485,6 +485,7 @@ 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,
diff --git a/include/net/ipv6_stubs.h b/include/net/ipv6_stubs.h
index afbce90c4480..45e0339be6fa 100644
--- a/include/net/ipv6_stubs.h
+++ b/include/net/ipv6_stubs.h@@ -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, bool skip_notify); void (*fib6_rt_update)(struct net *net, struct fib6_info *rt,
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 0c4da163535a..dab4a047590b 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c@@ -1026,6 +1026,7 @@ 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,
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 3ae25b8ffbd6..42d60c76d30a 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c@@ -3680,6 +3680,25 @@ 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)
--
2.31.1