diff options
| author |   Eric Dumazet <edumazet@google.com> | 2023-09-22 22:03:56 +0000 |
|---|---|---|
| committer |   Paolo Abeni <pabeni@redhat.com> | 2023-10-03 10:05:22 +0200 |
| commit | 6532e257aa73645e28dee5b2232cc3c88be62083 (patch) | |
| tree | 45163de0778a35d7a377062daa245e50c54464f5 | |
| parent | tcp_metrics: do not create an entry from tcp_init_metrics() (diff) | |
| download | linux-6532e257aa73645e28dee5b2232cc3c88be62083.tar.xz linux-6532e257aa73645e28dee5b2232cc3c88be62083.zip | |
tcp_metrics: optimize tcp_metrics_flush_all()
This is inspired by several syzbot reports where
tcp_metrics_flush_all() was seen in the traces.
We can avoid acquiring tcp_metrics_lock for empty buckets,
and we should add one cond_resched() to break potential long loops.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
| -rw-r--r-- | net/ipv4/tcp_metrics.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c index 7aca12c59c18..c2a925538542 100644 --- a/net/ipv4/tcp_metrics.c +++ b/net/ipv4/tcp_metrics.c @@ -898,11 +898,13 @@ static void tcp_metrics_flush_all(struct net *net) unsigned int row; for (row = 0; row < max_rows; row++, hb++) { - struct tcp_metrics_block __rcu **pp; + struct tcp_metrics_block __rcu **pp = &hb->chain; bool match; + if (!rcu_access_pointer(*pp)) + continue; + spin_lock_bh(&tcp_metrics_lock); - pp = &hb->chain; for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) { match = net ? net_eq(tm_net(tm), net) : !refcount_read(&tm_net(tm)->ns.count); @@ -914,6 +916,7 @@ static void tcp_metrics_flush_all(struct net *net) } } spin_unlock_bh(&tcp_metrics_lock); + cond_resched(); } } |