From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:44090 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726857AbgCRMzY (ORCPT ); Wed, 18 Mar 2020 08:55:24 -0400 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 02ICaDEO065265 for ; Wed, 18 Mar 2020 08:55:24 -0400 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0a-001b2d01.pphosted.com with ESMTP id 2yua2avcf4-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 18 Mar 2020 08:55:24 -0400 Received: from localhost by e06smtp07.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 18 Mar 2020 12:55:22 -0000 From: Julian Wiedmann Subject: [PATCH net-next 05/11] s390/qeth: allow configuration of TX queues for IQD devices Date: Wed, 18 Mar 2020 13:54:49 +0100 In-Reply-To: <20200318125455.5838-1-jwi@linux.ibm.com> References: <20200318125455.5838-1-jwi@linux.ibm.com> Message-Id: <20200318125455.5838-6-jwi@linux.ibm.com> Sender: linux-s390-owner@vger.kernel.org List-ID: To: David Miller Cc: netdev , linux-s390 , Heiko Carstens , Ursula Braun , Julian Wiedmann 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 --- drivers/s390/net/qeth_core_main.c | 6 +++++- drivers/s390/net/qeth_ethtool.c | 19 ++++++++++++++++--- 2 files changed, 21 insertions(+), 4 deletions(-) diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c index f13495d9209b..aa493edc0082 100644 --- a/drivers/s390/net/qeth_core_main.c +++ b/drivers/s390/net/qeth_core_main.c @@ -6644,9 +6644,13 @@ EXPORT_SYMBOL_GPL(qeth_get_stats64); u16 qeth_iqd_select_queue(struct net_device *dev, struct sk_buff *skb, u8 cast_type, struct net_device *sb_dev) { + u16 txq; + if (cast_type != RTN_UNICAST) return QETH_IQD_MCAST_TXQ; - return QETH_IQD_MIN_UCAST_TXQ; + + txq = netdev_pick_tx(dev, skb, sb_dev); + return (txq == QETH_IQD_MCAST_TXQ) ? QETH_IQD_MIN_UCAST_TXQ : txq; } EXPORT_SYMBOL_GPL(qeth_iqd_select_queue); 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); } -- 2.17.1