s390/qeth: add TX multiqueue support for IQD devices
qeth has been supporting multiple HW Output Queues for a long time. But
rather than exposing those queues to the stack, it uses its own queue
selection logic in .ndo_start_xmit... with all the drawbacks that
entails.
Start off by switching IQD devices over to a proper mqs net_device,
and converting all the netdev_queue management code.
One oddity with IQD devices is the requirement to place all mcast
traffic on the _highest_ established HW queue. Doing so via
.ndo_select_queue seems straight-forward - but that won't work if only
some of the HW queues are active
(ie. when dev->real_num_tx_queues < dev->num_tx_queues), since
netdev_cap_txqueue() will not allow us to put skbs on the higher queues.
To make this work, we
1. let .ndo_select_queue() map all mcast traffic to netdev_queue 0, and
2. later re-map the netdev_queue and HW queue indices in
.ndo_start_xmit and the TX completion handler.
With this patch we default to a fixed set of 1 ucast and 1 mcast queue.
Support for dynamic reconfiguration is added at a later time.
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/s390/net/qeth_ethtool.c b/drivers/s390/net/qeth_ethtool.c
index 93a53fe..a443e5f 100644
--- a/drivers/s390/net/qeth_ethtool.c
+++ b/drivers/s390/net/qeth_ethtool.c
@@ -154,6 +154,21 @@ static void qeth_get_drvinfo(struct net_device *dev,
CARD_RDEV_ID(card), CARD_WDEV_ID(card), CARD_DDEV_ID(card));
}
+static void qeth_get_channels(struct net_device *dev,
+ struct ethtool_channels *channels)
+{
+ struct qeth_card *card = dev->ml_priv;
+
+ channels->max_rx = dev->num_rx_queues;
+ channels->max_tx = card->qdio.no_out_queues;
+ channels->max_other = 0;
+ channels->max_combined = 0;
+ channels->rx_count = dev->real_num_rx_queues;
+ channels->tx_count = dev->real_num_tx_queues;
+ channels->other_count = 0;
+ channels->combined_count = 0;
+}
+
/* Helper function to fill 'advertising' and 'supported' which are the same. */
/* Autoneg and full-duplex are supported and advertised unconditionally. */
/* Always advertise and support all speeds up to specified, and only one */
@@ -359,6 +374,7 @@ const struct ethtool_ops qeth_ethtool_ops = {
.get_ethtool_stats = qeth_get_ethtool_stats,
.get_sset_count = qeth_get_sset_count,
.get_drvinfo = qeth_get_drvinfo,
+ .get_channels = qeth_get_channels,
.get_link_ksettings = qeth_get_link_ksettings,
};