From 6a643ddb5624be7e0694d49f5765a8d41c1ab6d0 Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Thu, 25 Jan 2018 18:26:22 -0800 Subject: [PATCH 1/3] net: introduce helper dev_change_tx_queue_len() This patch promotes the local change_tx_queue_len() to a core helper function, dev_change_tx_queue_len(), so that rtnetlink and net-sysfs could share the code. This also prepares for the following patch. Note, the -EFAULT in the original code doesn't make sense, we should propagate the errno from notifiers. Cc: John Fastabend Signed-off-by: Cong Wang Signed-off-by: David S. Miller --- include/linux/netdevice.h | 1 + net/core/dev.c | 28 ++++++++++++++++++++++++++++ net/core/net-sysfs.c | 25 +------------------------ net/core/rtnetlink.c | 16 ++++------------ 4 files changed, 34 insertions(+), 36 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index cd46d3d63aa0..4c77f39ebd65 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -3331,6 +3331,7 @@ int dev_get_alias(const struct net_device *, char *, size_t); int dev_change_net_namespace(struct net_device *, struct net *, const char *); int __dev_set_mtu(struct net_device *, int); int dev_set_mtu(struct net_device *, int); +int dev_change_tx_queue_len(struct net_device *, unsigned long); void dev_set_group(struct net_device *, int); int dev_set_mac_address(struct net_device *, struct sockaddr *); int dev_change_carrier(struct net_device *, bool new_carrier); diff --git a/net/core/dev.c b/net/core/dev.c index 858501b12869..520c24671bc5 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -7047,6 +7047,34 @@ int dev_set_mtu(struct net_device *dev, int new_mtu) } EXPORT_SYMBOL(dev_set_mtu); +/** + * dev_change_tx_queue_len - Change TX queue length of a netdevice + * @dev: device + * @new_len: new tx queue length + */ +int dev_change_tx_queue_len(struct net_device *dev, unsigned long new_len) +{ + unsigned int orig_len = dev->tx_queue_len; + int res; + + if (new_len != (unsigned int)new_len) + return -ERANGE; + + 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 res; + } + } + + return 0; +} + /** * dev_set_group - Change group this device belongs to * @dev: device diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index c4a28f4667b6..60a5ad2c33ee 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -346,29 +346,6 @@ static ssize_t flags_store(struct device *dev, struct device_attribute *attr, } NETDEVICE_SHOW_RW(flags, fmt_hex); -static int change_tx_queue_len(struct net_device *dev, unsigned long new_len) -{ - unsigned int orig_len = dev->tx_queue_len; - int res; - - if (new_len != (unsigned int)new_len) - return -ERANGE; - - 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; -} - static ssize_t tx_queue_len_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t len) @@ -376,7 +353,7 @@ static ssize_t tx_queue_len_store(struct device *dev, if (!capable(CAP_NET_ADMIN)) return -EPERM; - return netdev_store(dev, attr, buf, len, change_tx_queue_len); + return netdev_store(dev, attr, buf, len, dev_change_tx_queue_len); } NETDEVICE_SHOW_RW(tx_queue_len, fmt_dec); diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index e04af7b7f448..061e27cb6c12 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -2337,19 +2337,11 @@ static int do_setlink(const struct sk_buff *skb, if (tb[IFLA_TXQLEN]) { unsigned int value = nla_get_u32(tb[IFLA_TXQLEN]); - unsigned int orig_len = dev->tx_queue_len; - if (dev->tx_queue_len ^ value) { - dev->tx_queue_len = value; - err = call_netdevice_notifiers( - NETDEV_CHANGE_TX_QUEUE_LEN, dev); - err = notifier_to_errno(err); - if (err) { - dev->tx_queue_len = orig_len; - goto errout; - } - status |= DO_SETLINK_MODIFIED; - } + err = dev_change_tx_queue_len(dev, value); + if (err) + goto errout; + status |= DO_SETLINK_MODIFIED; } if (tb[IFLA_GSO_MAX_SIZE]) { From 48bfd55e7e4149a304e89c1999436cf52d094a27 Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Thu, 25 Jan 2018 18:26:23 -0800 Subject: [PATCH 2/3] net_sched: plug in qdisc ops change_tx_queue_len Introduce a new qdisc ops ->change_tx_queue_len() so that each qdisc could decide how to implement this if it wants. Previously we simply read dev->tx_queue_len, after pfifo_fast switches to skb array, we need this API to resize the skb array when we change dev->tx_queue_len. To avoid handling race conditions with TX BH, we need to deactivate all TX queues before change the value and bring them back after we are done, this also makes implementation easier. Cc: John Fastabend Signed-off-by: Cong Wang Signed-off-by: David S. Miller --- include/net/sch_generic.h | 2 ++ net/core/dev.c | 1 + net/sched/sch_generic.c | 33 +++++++++++++++++++++++++++++++++ 3 files changed, 36 insertions(+) diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h index eac43e8ca96d..e2ab13687fb9 100644 --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -200,6 +200,7 @@ struct Qdisc_ops { struct nlattr *arg, struct netlink_ext_ack *extack); void (*attach)(struct Qdisc *sch); + int (*change_tx_queue_len)(struct Qdisc *, unsigned int); int (*dump)(struct Qdisc *, struct sk_buff *); int (*dump_stats)(struct Qdisc *, struct gnet_dump *); @@ -489,6 +490,7 @@ void qdisc_class_hash_remove(struct Qdisc_class_hash *, void qdisc_class_hash_grow(struct Qdisc *, struct Qdisc_class_hash *); void qdisc_class_hash_destroy(struct Qdisc_class_hash *); +int dev_qdisc_change_tx_queue_len(struct net_device *dev); void dev_init_scheduler(struct net_device *dev); void dev_shutdown(struct net_device *dev); void dev_activate(struct net_device *dev); diff --git a/net/core/dev.c b/net/core/dev.c index 520c24671bc5..dda9d7b9a840 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -7070,6 +7070,7 @@ int dev_change_tx_queue_len(struct net_device *dev, unsigned long new_len) dev->tx_queue_len = orig_len; return res; } + return dev_qdisc_change_tx_queue_len(dev); } return 0; diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 1816bde47256..08f9fa27e06e 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -1178,6 +1178,39 @@ void dev_deactivate(struct net_device *dev) } EXPORT_SYMBOL(dev_deactivate); +static int qdisc_change_tx_queue_len(struct net_device *dev, + struct netdev_queue *dev_queue) +{ + struct Qdisc *qdisc = dev_queue->qdisc_sleeping; + const struct Qdisc_ops *ops = qdisc->ops; + + if (ops->change_tx_queue_len) + return ops->change_tx_queue_len(qdisc, dev->tx_queue_len); + return 0; +} + +int dev_qdisc_change_tx_queue_len(struct net_device *dev) +{ + bool up = dev->flags & IFF_UP; + unsigned int i; + int ret = 0; + + if (up) + dev_deactivate(dev); + + for (i = 0; i < dev->num_tx_queues; i++) { + ret = qdisc_change_tx_queue_len(dev, &dev->_tx[i]); + + /* TODO: revert changes on a partial failure */ + if (ret) + break; + } + + if (up) + dev_activate(dev); + return ret; +} + static void dev_init_scheduler_queue(struct net_device *dev, struct netdev_queue *dev_queue, void *_qdisc) From 7007ba630e4a6f809eab9abfc0e3a6e864e9d880 Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Thu, 25 Jan 2018 18:26:24 -0800 Subject: [PATCH 3/3] net_sched: implement ->change_tx_queue_len() for pfifo_fast pfifo_fast used to drop based on qdisc_dev(qdisc)->tx_queue_len, so we have to resize skb array when we change tx_queue_len. Other qdiscs which read tx_queue_len are fine because they all save it to sch->limit or somewhere else in qdisc during init. They don't have to implement this, it is nicer if they do so that users don't have to re-configure qdisc after changing tx_queue_len. Cc: John Fastabend Signed-off-by: Cong Wang Signed-off-by: David S. Miller --- net/sched/sch_generic.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 08f9fa27e06e..190570f21b20 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -763,6 +763,23 @@ static void pfifo_fast_destroy(struct Qdisc *sch) } } +static int pfifo_fast_change_tx_queue_len(struct Qdisc *sch, + unsigned int new_len) +{ + struct pfifo_fast_priv *priv = qdisc_priv(sch); + struct skb_array *bands[PFIFO_FAST_BANDS]; + int prio; + + for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) { + struct skb_array *q = band2list(priv, prio); + + bands[prio] = q; + } + + return skb_array_resize_multiple(bands, PFIFO_FAST_BANDS, new_len, + GFP_KERNEL); +} + struct Qdisc_ops pfifo_fast_ops __read_mostly = { .id = "pfifo_fast", .priv_size = sizeof(struct pfifo_fast_priv), @@ -773,6 +790,7 @@ struct Qdisc_ops pfifo_fast_ops __read_mostly = { .destroy = pfifo_fast_destroy, .reset = pfifo_fast_reset, .dump = pfifo_fast_dump, + .change_tx_queue_len = pfifo_fast_change_tx_queue_len, .owner = THIS_MODULE, .static_flags = TCQ_F_NOLOCK | TCQ_F_CPUSTATS, };