Commit 5cb431dc authored by Nick Child's avatar Nick Child Committed by Paolo Abeni
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ibmvnic: Return error code on TX scrq flush fail 



In ibmvnic_xmit() if ibmvnic_tx_scrq_flush() returns H_CLOSED then
it will inform upper level networking functions to disable tx
queues. H_CLOSED signals that the connection with the vnic server is
down and a transport event is expected to recover the device.

Previously, ibmvnic_tx_scrq_flush() was hard-coded to return success.
Therefore, the queues would remain active until ibmvnic_cleanup() is
called within do_reset().

The problem is that do_reset() depends on the RTNL lock. If several
ibmvnic devices are resetting then there can be a long wait time until
the last device can grab the lock. During this time the tx/rx queues
still appear active to upper level functions.

FYI, we do make a call to netif_carrier_off() outside the RTNL lock but
its calls to dev_deactivate() are also dependent on the RTNL lock.

As a result, large amounts of retransmissions were observed in a short
period of time, eventually leading to ETIMEOUT. This was specifically
seen with HNV devices, likely because of even more RTNL dependencies.

Therefore, ensure the return code of ibmvnic_tx_scrq_flush() is
propagated to the xmit function to allow for an earlier (and lock-less)
response to a transport event.

Signed-off-by: default avatarNick Child <nnac123@linux.ibm.com>
Link: https://lore.kernel.org/r/20240416164128.387920-1-nnac123@linux.ibm.com


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent eabf425b

drivers/net/ethernet/ibm/ibmvnic.c

+7 −3
Original line number Diff line number Diff line
@@ -2371,7 +2371,7 @@ static int ibmvnic_tx_scrq_flush(struct ibmvnic_adapter *adapter, 
		ibmvnic_tx_scrq_clean_buffer(adapter, tx_scrq);

	else

		ind_bufp->index = 0;

	return 0;

	return rc;

}



static netdev_tx_t ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev)
@@ -2424,7 +2424,9 @@ static netdev_tx_t ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev) 
		tx_dropped++;

		tx_send_failed++;

		ret = NETDEV_TX_OK;

		ibmvnic_tx_scrq_flush(adapter, tx_scrq);

		lpar_rc = ibmvnic_tx_scrq_flush(adapter, tx_scrq);

		if (lpar_rc != H_SUCCESS)

			goto tx_err;

		goto out;

	}
@@ -2439,8 +2441,10 @@ static netdev_tx_t ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev) 
		dev_kfree_skb_any(skb);

		tx_send_failed++;

		tx_dropped++;

		ibmvnic_tx_scrq_flush(adapter, tx_scrq);

		ret = NETDEV_TX_OK;

		lpar_rc = ibmvnic_tx_scrq_flush(adapter, tx_scrq);

		if (lpar_rc != H_SUCCESS)

			goto tx_err;

		goto out;

	}