Re: [PATCH net-next v18 17/25] ovpn: implement keepalive mechanism

2025-01-13, 10:31:36 +0100, Antonio Quartulli wrote:

+void ovpn_xmit_special(struct ovpn_peer *peer, const void *data,
+		       const unsigned int len)
+{
+	struct ovpn_priv *ovpn;
+	struct sk_buff *skb;
+
+	ovpn = peer->ovpn;
+	if (unlikely(!ovpn))
+		return;
+
+	skb = alloc_skb(256 + len, GFP_ATOMIC);
+	if (unlikely(!skb))
+		return;
+
+	skb_reserve(skb, 128);
+	skb->priority = TC_PRIO_BESTEFFORT;
+	__skb_put_data(skb, data, len);
+
+	/* increase reference counter when passing peer to sending queue */
+	if (!ovpn_peer_hold(peer)) {
+		netdev_dbg(ovpn->dev,
+			   "cannot hold peer reference for sending special packet\n");
+		kfree_skb(skb);
+		return;
+	}
+
+	ovpn_send(ovpn, skb, peer);
+}

[...]

+static void ovpn_peer_keepalive_send(struct work_struct *work)
+{
+	struct ovpn_peer *peer = container_of(work, struct ovpn_peer,
+					      keepalive_work);
+
+	local_bh_disable();
+	ovpn_xmit_special(peer, ovpn_keepalive_message,
+			  sizeof(ovpn_keepalive_message));
+	local_bh_enable();
+	ovpn_peer_put(peer);

nit: could we simply drop this put and the hold in ovpn_xmit_special?
ovpn_peer_keepalive_send has a reference on the peer from the WQ, just
transfer it to ovpn_xmit_special and then ovpn_send. No need to
pretend to acquire one for ovpn_send's sake and drop the one we got
from the WQ? (ovpn_xmit_special would need to _put(peer) in case of
early return)

+}

-- 
Sabrina