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ibmvnic: Return error code on TX scrq flush fail

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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: Nick Child <nnac123@linux.ibm.com>
Link: https://lore.kernel.org/r/20240416164128.387920-1-nnac123@linux.ibm.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Nick Child 2024-04-16 11:41:28 -05:00 • committed by Paolo Abeni
parent eabf425bc6
commit 5cb431dcf8
1 changed files with 7 additions and 3 deletions
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10
drivers/net/ethernet/ibm/ibmvnic.c
View file

@ -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;
}