tcp: free request sock directly upon TFO or syncookies error

Since the request socket is created locally, it'd make more sense to
use reqsk_free() instead of reqsk_put() in TFO and syncookies' error
path.

However, tcp_get_cookie_sock() may set ->rsk_refcnt before freeing the
socket; tcp_conn_request() may also have non-null ->rsk_refcnt because
of tcp_try_fastopen(). In both cases 'req' hasn't been exposed
to the outside world and is safe to free immediately, but that'd
trigger the WARN_ON_ONCE in reqsk_free().

Define __reqsk_free() for these situations where we know nobody's
referencing the socket, even though ->rsk_refcnt might be non-null.
Now we can consolidate the error path of tcp_get_cookie_sock() and
tcp_conn_request().

Signed-off-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Guillaume Nault
2019-03-19 16:05:44 +01:00
committed by David S. Miller
parent 56dc6d6355
commit 9403cf2302
3 changed files with 17 additions and 15 deletions

View File

@@ -216,16 +216,15 @@ struct sock *tcp_get_cookie_sock(struct sock *sk, struct sk_buff *skb,
refcount_set(&req->rsk_refcnt, 1);
tcp_sk(child)->tsoffset = tsoff;
sock_rps_save_rxhash(child, skb);
if (!inet_csk_reqsk_queue_add(sk, req, child)) {
bh_unlock_sock(child);
sock_put(child);
child = NULL;
reqsk_put(req);
}
} else {
reqsk_free(req);
if (inet_csk_reqsk_queue_add(sk, req, child))
return child;
bh_unlock_sock(child);
sock_put(child);
}
return child;
__reqsk_free(req);
return NULL;
}
EXPORT_SYMBOL(tcp_get_cookie_sock);