Re: [PATCH] inet: fix fast path in __inet_hash_connect()
From: Kuniyuki Iwashima <hidden>
Date: 2023-01-13 00:49:41
Also in:
lkml
From: Pietro Borrello <redacted> Date: Thu, 12 Jan 2023 15:39:23 +0000
__inet_hash_connect() has a fast path taken if sk_head(&tb->owners) is equal to the sk parameter. sk_head() returns the list_entry() with respect to the sk_node field.
nit: s/list_entry/hlist_entry/
However entries in the tb->owners list are inserted with respect to the
sk_bind_node field with sk_add_bind_node().
Thus the check would never pass and the fast path never execute.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Pietro Borrello <redacted>Good catch! Other than the nit above, looks good to me. Reviewed-by: Kuniyuki Iwashima <redacted> Thank you.
quoted hunk ↗ jump to hunk
--- include/net/sock.h | 10 ++++++++++ net/ipv4/inet_hashtables.c | 2 +- 2 files changed, 11 insertions(+), 1 deletion(-)diff --git a/include/net/sock.h b/include/net/sock.h index dcd72e6285b2..23fc403284db 100644 --- a/include/net/sock.h +++ b/include/net/sock.h@@ -860,6 +860,16 @@ static inline void sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_hea __sk_nulls_add_node_rcu(sk, list); } +static inline struct sock *__sk_bind_head(const struct hlist_head *head) +{ + return hlist_entry(head->first, struct sock, sk_bind_node); +} + +static inline struct sock *sk_bind_head(const struct hlist_head *head) +{ + return hlist_empty(head) ? NULL : __sk_bind_head(head); +} + static inline void __sk_del_bind_node(struct sock *sk) { __hlist_del(&sk->sk_bind_node);diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index d039b4e732a3..a805e086fb48 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c@@ -998,7 +998,7 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row, hinfo->bhash_size)]; tb = inet_csk(sk)->icsk_bind_hash; spin_lock_bh(&head->lock); - if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) { + if (sk_bind_head(&tb->owners) == sk && !sk->sk_bind_node.next) { inet_ehash_nolisten(sk, NULL, NULL); spin_unlock_bh(&head->lock); return 0;--- base-commit: 1b929c02afd37871d5afb9d498426f83432e71c2 change-id: 20230112-inet_hash_connect_bind_head-8f2dc98f08b1 Best regards, -- Pietro Borrello [off-list ref]