On Fri, Mar 6, 2026 at 6:05 AM Michal Luczaj <[email protected]> wrote: > > On 3/6/26 06:44, Kuniyuki Iwashima wrote: > > On Thu, Mar 5, 2026 at 3:32 PM Michal Luczaj <[email protected]> wrote: > >> > >> Instead of repeating the same (un)locking pattern, reuse > >> sock_map_sk_{acquire,release}(). This centralizes the code and makes it > >> easier to adapt sockmap to af_unix-specific locking. > >> > >> Signed-off-by: Michal Luczaj <[email protected]> > >> --- > >> net/core/sock_map.c | 21 +++++++-------------- > >> 1 file changed, 7 insertions(+), 14 deletions(-) > >> > >> diff --git a/net/core/sock_map.c b/net/core/sock_map.c > >> index 02a68be3002a..7ba6a7f24ccd 100644 > >> --- a/net/core/sock_map.c > >> +++ b/net/core/sock_map.c > >> @@ -353,11 +353,9 @@ static void sock_map_free(struct bpf_map *map) > >> sk = xchg(psk, NULL); > >> if (sk) { > >> sock_hold(sk); > >> - lock_sock(sk); > >> - rcu_read_lock(); > >> + sock_map_sk_acquire(sk); > >> sock_map_unref(sk, psk); > >> - rcu_read_unlock(); > >> - release_sock(sk); > >> + sock_map_sk_release(sk); > >> sock_put(sk); > >> } > >> } > >> @@ -1176,11 +1174,9 @@ static void sock_hash_free(struct bpf_map *map) > >> */ > >> hlist_for_each_entry_safe(elem, node, &unlink_list, node) { > >> hlist_del(&elem->node); > >> - lock_sock(elem->sk); > >> - rcu_read_lock(); > >> + sock_map_sk_acquire(elem->sk); > >> sock_map_unref(elem->sk, elem); > >> - rcu_read_unlock(); > >> - release_sock(elem->sk); > >> + sock_map_sk_release(elem->sk); > >> sock_put(elem->sk); > >> sock_hash_free_elem(htab, elem); > >> } > >> @@ -1676,8 +1672,7 @@ void sock_map_close(struct sock *sk, long timeout) > >> void (*saved_close)(struct sock *sk, long timeout); > >> struct sk_psock *psock; > >> > >> - lock_sock(sk); > >> - rcu_read_lock(); > >> + sock_map_sk_acquire(sk); > >> psock = sk_psock(sk); > >> if (likely(psock)) { > >> saved_close = psock->saved_close; > >> @@ -1685,16 +1680,14 @@ void sock_map_close(struct sock *sk, long timeout) > >> psock = sk_psock_get(sk); > >> if (unlikely(!psock)) > >> goto no_psock; > >> - rcu_read_unlock(); > >> sk_psock_stop(psock); > >> - release_sock(sk); > >> + sock_map_sk_release(sk); > > > > I think sk_psock_stop() was intentionally put outside > > of rcu_read_lock() to not extend the grace period > > unnecessarily. e.g. while + __sk_msg_free(). > > > > Maybe add __sock_map_sk_release() without > > rcu_read_unlock() ? > > How about dropping this patch completely? The more I stare at it, I see no > reason why af_unix state lock would matter in any of these places.
I agree. Actually, once it's held, it can be released right away. The lock is only to ensure that peer is set after checking TCP_ESTABLISHED, but it continues holding unix_state_lock() unnecessarily long. Honestly I prefer Martin's idea, using unix_peer_get() in unix_stream_bpf_update_proto().
