tipc: eliminate the dummy packet in link synching (d0d605c5) · Commits · 戴 / test

When preparing tunnel packets for the link failover or synchronization, as for the safe algorithm, we added a dummy packet on the pair link but never sent it out. In the case of failover, the pair link will be reset anyway. But for link synching, it will always result in retransmission of the dummy packet after that. We have also observed that such the retransmission at the early stage when a new node comes in a large cluster will take some time and hard to be done, leading to the repeated retransmit failures and the link is reset. Since in commit ("tipc: optimize link synching mechanism") we have already built a dummy 'TUNNEL_PROTOCOL' message on the new link for the synchronization, there's no need for the dummy on the pair one, this commit will skip it when the new mechanism takes in place. In case nothing exists in the pair link's transmq, the link synching will just start and stop shortly on the peer side. The patch is backward compatible. Acked-by:

Jon Maloy <jon.maloy@ericsson.com> Tested-by:

Hoang Le <hoang.h.le@dektech.com.au> Signed-off-by:

Tuong Lien <tuong.t.lien@dektech.com.au> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/tipc/link.c

+14 −15

Original line number	Diff line number	Diff line
		@@ -1731,21 +1731,6 @@ void tipc_link_tnl_prepare(struct tipc_link l, struct tipc_link tnl,
		return;

		__skb_queue_head_init(&tnlq);
		__skb_queue_head_init(&tmpxq);
		__skb_queue_head_init(&frags);

		/* At least one packet required for safe algorithm => add dummy */
		skb = tipc_msg_create(TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
		BASIC_H_SIZE, 0, l->addr, tipc_own_addr(l->net),
		0, 0, TIPC_ERR_NO_PORT);
		if (!skb) {
		pr_warn("%sunable to create tunnel packet\n", link_co_err);
		return;
		}
		__skb_queue_tail(&tnlq, skb);
		tipc_link_xmit(l, &tnlq, &tmpxq);
		__skb_queue_purge(&tmpxq);

		/* Link Synching:
		* From now on, send only one single ("dummy") SYNCH message
		* to peer. The SYNCH message does not contain any data, just
		@@ -1771,6 +1756,20 @@ void tipc_link_tnl_prepare(struct tipc_link l, struct tipc_link tnl,
		return;
		}

		__skb_queue_head_init(&tmpxq);
		__skb_queue_head_init(&frags);
		/* At least one packet required for safe algorithm => add dummy */
		skb = tipc_msg_create(TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
		BASIC_H_SIZE, 0, l->addr, tipc_own_addr(l->net),
		0, 0, TIPC_ERR_NO_PORT);
		if (!skb) {
		pr_warn("%sunable to create tunnel packet\n", link_co_err);
		return;
		}
		__skb_queue_tail(&tnlq, skb);
		tipc_link_xmit(l, &tnlq, &tmpxq);
		__skb_queue_purge(&tmpxq);

		/* Initialize reusable tunnel packet header */
		tipc_msg_init(tipc_own_addr(l->net), &tnlhdr, TUNNEL_PROTOCOL,
		mtyp, INT_H_SIZE, l->addr);

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