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s390/qeth: add TX multiqueue support for IQD devices

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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>
This commit is contained in:
Julian Wiedmann
2019-04-17 18:17:32 +02:00
committed by David S. Miller
parent 333ef9d1d5
commit 3a18d75400
6 changed files with 97 additions and 26 deletions
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30
drivers/s390/net/qeth_l3_main.c
View File

@@ -2062,28 +2062,36 @@ static int qeth_l3_xmit(struct qeth_card *card, struct sk_buff *skb,
static netdev_tx_t qeth_l3_hard_start_xmit(struct sk_buff *skb,
struct net_device *dev)
{
int cast_type = qeth_l3_get_cast_type(skb);
struct qeth_card *card = dev->ml_priv;
u16 txq = skb_get_queue_mapping(skb);
int ipv = qeth_get_ip_version(skb);
struct qeth_qdio_out_q *queue;
int tx_bytes = skb->len;
int rc;
queue = qeth_get_tx_queue(card, skb, ipv, cast_type);
int cast_type, rc;
if (IS_IQD(card)) {
queue = card->qdio.out_qs[qeth_iqd_translate_txq(dev, txq)];
if (card->options.sniffer)
goto tx_drop;
if ((card->options.cq != QETH_CQ_ENABLED && !ipv) ||
(card->options.cq == QETH_CQ_ENABLED &&
skb->protocol != htons(ETH_P_AF_IUCV)))
goto tx_drop;
if (txq == QETH_IQD_MCAST_TXQ)
cast_type = qeth_l3_get_cast_type(skb);
else
cast_type = RTN_UNICAST;
} else {
queue = qeth_get_tx_queue(card, skb, ipv);
cast_type = qeth_l3_get_cast_type(skb);
}
if (cast_type == RTN_BROADCAST && !card->info.broadcast_capable)
goto tx_drop;
netif_stop_queue(dev);
netif_stop_subqueue(dev, txq);
if (ipv == 4 || IS_IQD(card))
rc = qeth_l3_xmit(card, skb, queue, ipv, cast_type);
@@ -2094,7 +2102,7 @@ static netdev_tx_t qeth_l3_hard_start_xmit(struct sk_buff *skb,
if (!rc) {
QETH_TXQ_STAT_INC(queue, tx_packets);
QETH_TXQ_STAT_ADD(queue, tx_bytes, tx_bytes);
netif_wake_queue(dev);
netif_wake_subqueue(dev, txq);
return NETDEV_TX_OK;
} else if (rc == -EBUSY) {
return NETDEV_TX_BUSY;
@@ -2103,7 +2111,7 @@ static netdev_tx_t qeth_l3_hard_start_xmit(struct sk_buff *skb,
tx_drop:
QETH_TXQ_STAT_INC(queue, tx_dropped);
kfree_skb(skb);
netif_wake_queue(dev);
netif_wake_subqueue(dev, txq);
return NETDEV_TX_OK;
}
@@ -2147,11 +2155,19 @@ static netdev_features_t qeth_l3_osa_features_check(struct sk_buff *skb,
return qeth_features_check(skb, dev, features);
}
static u16 qeth_l3_iqd_select_queue(struct net_device *dev, struct sk_buff *skb,
struct net_device *sb_dev)
{
return qeth_iqd_select_queue(dev, skb, qeth_l3_get_cast_type(skb),
sb_dev);
}
static const struct net_device_ops qeth_l3_netdev_ops = {
.ndo_open = qeth_open,
.ndo_stop = qeth_stop,
.ndo_get_stats64 = qeth_get_stats64,
.ndo_start_xmit = qeth_l3_hard_start_xmit,
.ndo_select_queue = qeth_l3_iqd_select_queue,
.ndo_validate_addr = eth_validate_addr,
.ndo_set_rx_mode = qeth_l3_set_rx_mode,
.ndo_do_ioctl = qeth_do_ioctl,