Commit e60ea454 authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

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: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20241009184405.3752829-4-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 16207384

include/net/ip6_fib.h

+4 −4
Original line number Diff line number Diff line
@@ -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;

}

net/ipv6/fib6_rules.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

}

net/ipv6/ip6_fib.c

+7 −7
Original line number Diff line number Diff line
@@ -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);

}