[PATCH V4] hsr: fix don't prune the master node from the node_db

[PATCH V4] hsr: fix don't prune the master node from the node_db

[Andreas Oetken]

Don't prune the master node in the hsr_prune_nodes function.
Neither time_in[HSR_PT_SLAVE_A] nor time_in[HSR_PT_SLAVE_B]
will ever be updated by hsr_register_frame_in for the master port.
Thus, the master node will be repeatedly pruned leading to
repeated packet loss.
This bug never appeared because the hsr_prune_nodes function
was only called once. Since commit 5150b45fd355
("net: hsr: Fix node prune function for forget time expiry") this issue
is fixed unveiling the issue described above.

Fixes: 5150b45fd355 ("net: hsr: Fix node prune function for forget time expiry")
Signed-off-by: Andreas Oetken <andreas.oetken@siemens.com>
Tested-by: Murali Karicheri <m-karicheri2@ti.com>
---
 net/hsr/hsr_framereg.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/net/hsr/hsr_framereg.c b/net/hsr/hsr_framereg.c
index 9fa9abd83018..2d7a19750436 100644
--- a/net/hsr/hsr_framereg.c
+++ b/net/hsr/hsr_framereg.c
@@ -365,6 +365,14 @@ void hsr_prune_nodes(struct timer_list *t)
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(node, &hsr->node_db, mac_list) {
+		/* Don't prune own node. Neither time_in[HSR_PT_SLAVE_A]
+		 * nor time_in[HSR_PT_SLAVE_B], will ever be updated for
+		 * the master port. Thus the master node will be repeatedly
+		 * pruned leading to packet loss.
+		 */
+		if (hsr_addr_is_self(hsr, node->macaddress_A))
+			continue;
+
 		/* Shorthand */
 		time_a = node->time_in[HSR_PT_SLAVE_A];
 		time_b = node->time_in[HSR_PT_SLAVE_B];
-- 
2.20.1

Re: [PATCH V4] hsr: fix don't prune the master node from the node_db

[David Miller]

From: Andreas Oetken <andreas.oetken@siemens.com>
Date: Thu, 23 May 2019 13:57:14 +0200

> Don't prune the master node in the hsr_prune_nodes function.
> Neither time_in[HSR_PT_SLAVE_A] nor time_in[HSR_PT_SLAVE_B]
> will ever be updated by hsr_register_frame_in for the master port.
> Thus, the master node will be repeatedly pruned leading to
> repeated packet loss.
> This bug never appeared because the hsr_prune_nodes function
> was only called once. Since commit 5150b45fd355
> ("net: hsr: Fix node prune function for forget time expiry") this issue
> is fixed unveiling the issue described above.
> 
> Fixes: 5150b45fd355 ("net: hsr: Fix node prune function for forget time expiry")
> Signed-off-by: Andreas Oetken <andreas.oetken@siemens.com>
> Tested-by: Murali Karicheri <m-karicheri2@ti.com>

Applied.