From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751703AbcF3E4p (ORCPT ); Thu, 30 Jun 2016 00:56:45 -0400 Received: from mail-oi0-f67.google.com ([209.85.218.67]:35478 "EHLO mail-oi0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750937AbcF3E4m (ORCPT ); Thu, 30 Jun 2016 00:56:42 -0400 Subject: Re: [PATCH net-next V3 5/6] net: introduce NETDEV_CHANGE_TX_QUEUE_LEN To: Jason Wang , mst@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, davem@davemloft.net References: <1467258779-3539-1-git-send-email-jasowang@redhat.com> <1467258779-3539-6-git-send-email-jasowang@redhat.com> Cc: kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, eric.dumazet@gmail.com, brouer@redhat.com From: John Fastabend Message-ID: <5774A67B.1060802@gmail.com> Date: Wed, 29 Jun 2016 21:56:27 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <1467258779-3539-6-git-send-email-jasowang@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 16-06-29 08:52 PM, Jason Wang wrote: > This patch introduces a new event - NETDEV_CHANGE_TX_QUEUE_LEN, this > will be triggered when tx_queue_len. It could be used by net device > who want to do some processing at that time. An example is tun who may > want to resize tx array when tx_queue_len is changed. > > Signed-off-by: Jason Wang > --- > include/linux/netdevice.h | 1 + > net/core/net-sysfs.c | 15 ++++++++++++++- > 2 files changed, 15 insertions(+), 1 deletion(-) > > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h > index e84d9d2..7dc2ec7 100644 > --- a/include/linux/netdevice.h > +++ b/include/linux/netdevice.h > @@ -2237,6 +2237,7 @@ struct netdev_lag_lower_state_info { > #define NETDEV_PRECHANGEUPPER 0x001A > #define NETDEV_CHANGELOWERSTATE 0x001B > #define NETDEV_UDP_TUNNEL_PUSH_INFO 0x001C > +#define NETDEV_CHANGE_TX_QUEUE_LEN 0x001E > > int register_netdevice_notifier(struct notifier_block *nb); > int unregister_netdevice_notifier(struct notifier_block *nb); > diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c > index 7a0b616..6e4f347 100644 > --- a/net/core/net-sysfs.c > +++ b/net/core/net-sysfs.c > @@ -322,7 +322,20 @@ NETDEVICE_SHOW_RW(flags, fmt_hex); > > static int change_tx_queue_len(struct net_device *dev, unsigned long new_len) > { > - dev->tx_queue_len = new_len; > + int res, orig_len = dev->tx_queue_len; > + > + if (new_len != orig_len) { > + dev->tx_queue_len = new_len; > + res = call_netdevice_notifiers(NETDEV_CHANGE_TX_QUEUE_LEN, dev); > + res = notifier_to_errno(res); > + if (res) { > + netdev_err(dev, > + "refused to change device tx_queue_len\n"); > + dev->tx_queue_len = orig_len; > + return -EFAULT; > + } > + } > + > return 0; > } > > Acked-by: John Fastabend Great timing I was just looking into this because I need it for the qdisc side. It looks like this covers the sysfs change but the tx_queue_len can also be changed via rtnetlink as well. So we need another patch for that path right? if (tb[IFLA_TXQLEN]) { unsigned long value = nla_get_u32(tb[IFLA_TXQLEN]); if (dev->tx_queue_len ^ value) status |= DO_SETLINK_NOTIFY; dev->tx_queue_len = value; } Thanks, John