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Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/tcp_ipv4.c26
1 files changed, 19 insertions, 7 deletions
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 44c1e934824b..37ca3843c40b 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1946,6 +1946,12 @@ static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
return rc;
}
+static inline int empty_bucket(struct tcp_iter_state *st)
+{
+ return hlist_empty(&tcp_hashinfo.ehash[st->bucket].chain) &&
+ hlist_empty(&tcp_hashinfo.ehash[st->bucket].twchain);
+}
+
static void *established_get_first(struct seq_file *seq)
{
struct tcp_iter_state* st = seq->private;
@@ -1958,6 +1964,10 @@ static void *established_get_first(struct seq_file *seq)
struct inet_timewait_sock *tw;
rwlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
+ /* Lockless fast path for the common case of empty buckets */
+ if (empty_bucket(st))
+ continue;
+
read_lock_bh(lock);
sk_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
if (sk->sk_family != st->family ||
@@ -2008,13 +2018,15 @@ get_tw:
read_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
st->state = TCP_SEQ_STATE_ESTABLISHED;
- if (++st->bucket < tcp_hashinfo.ehash_size) {
- read_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
- sk = sk_head(&tcp_hashinfo.ehash[st->bucket].chain);
- } else {
- cur = NULL;
- goto out;
- }
+ /* Look for next non empty bucket */
+ while (++st->bucket < tcp_hashinfo.ehash_size &&
+ empty_bucket(st))
+ ;
+ if (st->bucket >= tcp_hashinfo.ehash_size)
+ return NULL;
+
+ read_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
+ sk = sk_head(&tcp_hashinfo.ehash[st->bucket].chain);
} else
sk = sk_next(sk);