From e60ea45447768c48309b944596a8a34f6bae50e2 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 9 Oct 2024 18:44:03 +0000 Subject: [PATCH] ipv6: use READ_ONCE()/WRITE_ONCE() on fib6_table->fib_seq Using RTNL to protect ops->fib_rules_seq reads seems a big hammer. Writes are protected by RTNL. We can use READ_ONCE() when reading it. Constify 'struct net' argument of fib6_tables_seq_read() and fib6_rules_seq_read(). Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Reviewed-by: David Ahern Link: https://patch.msgid.link/20241009184405.3752829-4-edumazet@google.com Signed-off-by: Jakub Kicinski --- include/net/ip6_fib.h | 8 ++++---- net/ipv6/fib6_rules.c | 2 +- net/ipv6/ip6_fib.c | 14 +++++++------- 3 files changed, 12 insertions(+), 12 deletions(-) diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h index 6cb867ce4878..7c87873ae211 100644 --- a/include/net/ip6_fib.h +++ b/include/net/ip6_fib.h @@ -394,7 +394,7 @@ struct fib6_table { struct fib6_node tb6_root; struct inet_peer_base tb6_peers; unsigned int flags; - unsigned int fib_seq; + unsigned int fib_seq; /* writes protected by rtnl_mutex */ struct hlist_head tb6_gc_hlist; /* GC candidates */ #define RT6_TABLE_HAS_DFLT_ROUTER BIT(0) }; @@ -563,7 +563,7 @@ int call_fib6_notifiers(struct net *net, enum fib_event_type event_type, int __net_init fib6_notifier_init(struct net *net); void __net_exit fib6_notifier_exit(struct net *net); -unsigned int fib6_tables_seq_read(struct net *net); +unsigned int fib6_tables_seq_read(const struct net *net); int fib6_tables_dump(struct net *net, struct notifier_block *nb, struct netlink_ext_ack *extack); @@ -632,7 +632,7 @@ void fib6_rules_cleanup(void); bool fib6_rule_default(const struct fib_rule *rule); int fib6_rules_dump(struct net *net, struct notifier_block *nb, struct netlink_ext_ack *extack); -unsigned int fib6_rules_seq_read(struct net *net); +unsigned int fib6_rules_seq_read(const struct net *net); static inline bool fib6_rules_early_flow_dissect(struct net *net, struct sk_buff *skb, @@ -676,7 +676,7 @@ static inline int fib6_rules_dump(struct net *net, struct notifier_block *nb, { return 0; } -static inline unsigned int fib6_rules_seq_read(struct net *net) +static inline unsigned int fib6_rules_seq_read(const struct net *net) { return 0; } diff --git a/net/ipv6/fib6_rules.c b/net/ipv6/fib6_rules.c index 04a9ed5e8310..c85c1627cb16 100644 --- a/net/ipv6/fib6_rules.c +++ b/net/ipv6/fib6_rules.c @@ -56,7 +56,7 @@ int fib6_rules_dump(struct net *net, struct notifier_block *nb, return fib_rules_dump(net, nb, AF_INET6, extack); } -unsigned int fib6_rules_seq_read(struct net *net) +unsigned int fib6_rules_seq_read(const struct net *net) { return fib_rules_seq_read(net, AF_INET6); } diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index eb111d20615c..cea160b249d2 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -345,17 +345,17 @@ static void __net_init fib6_tables_init(struct net *net) #endif -unsigned int fib6_tables_seq_read(struct net *net) +unsigned int fib6_tables_seq_read(const struct net *net) { unsigned int h, fib_seq = 0; rcu_read_lock(); for (h = 0; h < FIB6_TABLE_HASHSZ; h++) { - struct hlist_head *head = &net->ipv6.fib_table_hash[h]; - struct fib6_table *tb; + const struct hlist_head *head = &net->ipv6.fib_table_hash[h]; + const struct fib6_table *tb; hlist_for_each_entry_rcu(tb, head, tb6_hlist) - fib_seq += tb->fib_seq; + fib_seq += READ_ONCE(tb->fib_seq); } rcu_read_unlock(); @@ -400,7 +400,7 @@ int call_fib6_entry_notifiers(struct net *net, .rt = rt, }; - rt->fib6_table->fib_seq++; + WRITE_ONCE(rt->fib6_table->fib_seq, rt->fib6_table->fib_seq + 1); return call_fib6_notifiers(net, event_type, &info.info); } @@ -416,7 +416,7 @@ int call_fib6_multipath_entry_notifiers(struct net *net, .nsiblings = nsiblings, }; - rt->fib6_table->fib_seq++; + WRITE_ONCE(rt->fib6_table->fib_seq, rt->fib6_table->fib_seq + 1); return call_fib6_notifiers(net, event_type, &info.info); } @@ -427,7 +427,7 @@ int call_fib6_entry_notifiers_replace(struct net *net, struct fib6_info *rt) .nsiblings = rt->fib6_nsiblings, }; - rt->fib6_table->fib_seq++; + WRITE_ONCE(rt->fib6_table->fib_seq, rt->fib6_table->fib_seq + 1); return call_fib6_notifiers(net, FIB_EVENT_ENTRY_REPLACE, &info.info); }