From 1b18f09d31cfa7148df15a7d5c5e0e86f105f7d1 Mon Sep 17 00:00:00 2001
From: Rick Lindsley <ricklind@us.ibm.com>
Date: Sat, 2 Jul 2022 03:37:12 -0700
Subject: [PATCH] ibmvnic: Properly dispose of all skbs during a failover.
References: bsc#1200925
Patch-mainline: v5.19-rc6
Git-commit: 1b18f09d31cfa7148df15a7d5c5e0e86f105f7d1
During a reset, there may have been transmits in flight that are no
longer valid and cannot be fulfilled. Resetting and clearing the
queues is insufficient; each skb also needs to be explicitly freed
so that upper levels are not left waiting for confirmation of a
transmit that will never happen. If this happens frequently enough,
the apparent backlog will cause TCP to begin "congestion control"
unnecessarily, culminating in permanently decreased throughput.
Fixes: d7c0ef36bde03 ("ibmvnic: Free and re-allocate scrqs when tx/rx scrqs change")
Tested-by: Nick Child <nnac123@linux.ibm.com>
Reviewed-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Rick Lindsley <ricklind@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Ali Abdallah <ali.abdallah@suse.com>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
drivers/net/ethernet/ibm/ibmvnic.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 7e7fe5bdf1f8..5ab7c0f81e9a 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -5981,6 +5981,15 @@ static int ibmvnic_reset_init(struct ibmvnic_adapter *adapter, bool reset)
release_sub_crqs(adapter, 0);
rc = init_sub_crqs(adapter);
} else {
+ /* no need to reinitialize completely, but we do
+ * need to clean up transmits that were in flight
+ * when we processed the reset. Failure to do so
+ * will confound the upper layer, usually TCP, by
+ * creating the illusion of transmits that are
+ * awaiting completion.
+ */
+ clean_tx_pools(adapter);
+
rc = reset_sub_crq_queues(adapter);
}
} else {
--
2.35.3