Commit 0711d15c authored Jul 02, 2022 by Rick Lindsley Committed by Greg Kroah-Hartman Jul 12, 2022

ibmvnic: Properly dispose of all skbs during a failover.



[ Upstream 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During a reset, there may have been transmits in flight that are no
longer valid and cannot be fulfilled.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: d7c0ef36 ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent aa698aff

drivers/net/ethernet/ibm/ibmvnic.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -5022,6 +5022,15 @@ static int ibmvnic_reset_init(struct ibmvnic_adapter *adapter)
		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 {