diff options
| author | Julian Wiedmann <jwi@linux.ibm.com> | 2020-03-18 13:54:49 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-03-18 16:33:35 -0700 |
| commit | 66cddf101901a6cfcd21c840f0535e8f1c8c5186 (patch) | |
| tree | 4da44babbd507b5797611e5e0957906d74c42d8d /drivers/s390/net/qeth_ethtool.c | |
| parent | fcc2df8b8777c960c8125bc157423c76415a5419 (diff) | |
| download | linux-66cddf101901a6cfcd21c840f0535e8f1c8c5186.tar.gz | |
s390/qeth: allow configuration of TX queues for IQD devices
Similar to the support for z/VM NICs, but we need to take extra care about the dedicated mcast queue: 1. netdev_pick_tx() is unaware of this limitation and might select the mcast txq. Catch this. 2. require at least _two_ TX queues - one for ucast, one for mcast. 3. when reducing the number of TX queues, there's a potential race where netdev_cap_txqueue() over-rules the selected txq index and falls back to index 0. This would place ucast traffic on the mcast queue, and result in TX errors. So for IQD, reject a reduction while the interface is running. Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/s390/net/qeth_ethtool.c')
| -rw-r--r-- | drivers/s390/net/qeth_ethtool.c | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/drivers/s390/net/qeth_ethtool.c b/drivers/s390/net/qeth_ethtool.c index 19b9c8302d36..715ee0015847 100644 --- a/drivers/s390/net/qeth_ethtool.c +++ b/drivers/s390/net/qeth_ethtool.c @@ -180,14 +180,27 @@ static int qeth_set_channels(struct net_device *dev, { struct qeth_card *card = dev->ml_priv; - if (IS_IQD(card) || !IS_VM_NIC(card)) - return -EOPNOTSUPP; - if (channels->rx_count == 0 || channels->tx_count == 0) return -EINVAL; if (channels->tx_count > card->qdio.no_out_queues) return -EINVAL; + if (IS_IQD(card)) { + if (channels->tx_count < QETH_IQD_MIN_TXQ) + return -EINVAL; + + /* Reject downgrade while running. It could push displaced + * ucast flows onto txq0, which is reserved for mcast. + */ + if (netif_running(dev) && + channels->tx_count < dev->real_num_tx_queues) + return -EPERM; + } else { + /* OSA still uses the legacy prio-queue mechanism: */ + if (!IS_VM_NIC(card)) + return -EOPNOTSUPP; + } + return netif_set_real_num_tx_queues(dev, channels->tx_count); } |