Commit 9f1ab186 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

tcp_metrics: fix wrong lockdep annotations 



Changes in tcp_metric hash table are protected by tcp_metrics_lock
only, not by genl_mutex

While we are at it use deref_locked() instead of rcu_dereference()
in tcp_new() to avoid unnecessary barrier, as we hold tcp_metrics_lock
as well.

Reported-by: default avatarAndrew Vagin <avagin@parallels.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Fixes: 098a697b ("tcp_metrics: Use a single hash table for all network namespaces.")
Reviewed-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent bd76a116

net/ipv4/tcp_metrics.c

+8 −12
Original line number Diff line number Diff line
@@ -152,6 +152,9 @@ static void tcpm_check_stamp(struct tcp_metrics_block *tm, struct dst_entry *dst 
#define TCP_METRICS_RECLAIM_DEPTH	5

#define TCP_METRICS_RECLAIM_PTR		(struct tcp_metrics_block *) 0x1UL



#define deref_locked(p)	\

	rcu_dereference_protected(p, lockdep_is_held(&tcp_metrics_lock))



static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst,

					  struct inetpeer_addr *saddr,

					  struct inetpeer_addr *daddr,
@@ -180,9 +183,9 @@ static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst, 
	if (unlikely(reclaim)) {

		struct tcp_metrics_block *oldest;



		oldest = rcu_dereference(tcp_metrics_hash[hash].chain);

		for (tm = rcu_dereference(oldest->tcpm_next); tm;

		     tm = rcu_dereference(tm->tcpm_next)) {

		oldest = deref_locked(tcp_metrics_hash[hash].chain);

		for (tm = deref_locked(oldest->tcpm_next); tm;

		     tm = deref_locked(tm->tcpm_next)) {

			if (time_before(tm->tcpm_stamp, oldest->tcpm_stamp))

				oldest = tm;

		}
@@ -1040,12 +1043,6 @@ out_free: 
	return ret;

}



#define deref_locked_genl(p)	\

	rcu_dereference_protected(p, lockdep_genl_is_held() && \

				     lockdep_is_held(&tcp_metrics_lock))



#define deref_genl(p)	rcu_dereference_protected(p, lockdep_genl_is_held())



static void tcp_metrics_flush_all(struct net *net)

{

	unsigned int max_rows = 1U << tcp_metrics_hash_log;
@@ -1057,8 +1054,7 @@ static void tcp_metrics_flush_all(struct net *net) 
		struct tcp_metrics_block __rcu **pp;

		spin_lock_bh(&tcp_metrics_lock);

		pp = &hb->chain;

		for (tm = deref_locked_genl(*pp); tm;

		     tm = deref_locked_genl(*pp)) {

		for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) {

			if (net_eq(tm_net(tm), net)) {

				*pp = tm->tcpm_next;

				kfree_rcu(tm, rcu_head);
@@ -1097,7 +1093,7 @@ static int tcp_metrics_nl_cmd_del(struct sk_buff *skb, struct genl_info *info) 
	hb = tcp_metrics_hash + hash;

	pp = &hb->chain;

	spin_lock_bh(&tcp_metrics_lock);

	for (tm = deref_locked_genl(*pp); tm; tm = deref_locked_genl(*pp)) {

	for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) {

		if (addr_same(&tm->tcpm_daddr, &daddr) &&

		    (!src || addr_same(&tm->tcpm_saddr, &saddr)) &&

		    net_eq(tm_net(tm), net)) {

CRA Git | Maintained and supported by SUSTech CRA and CCSE