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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: Andrew Vagin <avagin@parallels.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Fixes: 098a697b49 ("tcp_metrics: Use a single hash table for all network namespaces.")
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
hifive-unleashed-5.1
Eric Dumazet 2015-03-16 07:14:34 -07:00 committed by David S. Miller
parent bd76a11670
commit 9f1ab18672
1 changed files with 8 additions and 12 deletions
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20
net/ipv4/tcp_metrics.c
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@ -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)) {