Messages in this thread | | | From | Eric Dumazet <> | Date | Fri, 13 Jan 2023 13:16:20 +0100 | Subject | Re: [PATCH v2] inet: fix fast path in __inet_hash_connect() |
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On Fri, Jan 13, 2023 at 12:40 PM Pietro Borrello <borrello@diag.uniroma1.it> wrote: > > __inet_hash_connect() has a fast path taken if sk_head(&tb->owners) is > equal to the sk parameter. > sk_head() returns the hlist_entry() with respect to the sk_node field. > 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") > Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> > Signed-off-by: Pietro Borrello <borrello@diag.uniroma1.it> > --- > Changes in v2: > - nit: s/list_entry/hlist_entry/ > - Link to v1: https://lore.kernel.org/r/20230112-inet_hash_connect_bind_head-v1-1-7e3c770157c8@diag.uniroma1.it > --- > 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);
1) Given this path was never really used, we have no coverage.
2) Given that we do not check inet_ehash_nolisten() return code here.
I would recommend _not_ adding the Fixes: tag, and target net-next tree
In fact, I would remove this dead code, and reduce complexity.
I doubt the difference is going to be noticed. (We have to access the ehash bucket anyway)
> spin_unlock_bh(&head->lock); > return 0; > > --- > base-commit: 1b929c02afd37871d5afb9d498426f83432e71c2 > change-id: 20230112-inet_hash_connect_bind_head-8f2dc98f08b1 > > Best regards, > -- > Pietro Borrello <borrello@diag.uniroma1.it>
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