[PATCH net-next v6 3/3] net: add sysfs attribute to control napi threaded mode
From: Wei Wang <hidden>
Date: 2021-01-15 00:32:24
Subsystem:
networking drivers, networking [general], the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
This patch adds a new sysfs attribute to the network device class. Said attribute provides a per-device control to enable/disable the threaded mode for all the napi instances of the given network device. Co-developed-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Co-developed-by: Hannes Frederic Sowa <redacted> Signed-off-by: Hannes Frederic Sowa <redacted> Co-developed-by: Felix Fietkau <nbd@nbd.name> Signed-off-by: Felix Fietkau <nbd@nbd.name> Signed-off-by: Wei Wang <redacted> --- include/linux/netdevice.h | 2 ++ net/core/dev.c | 28 +++++++++++++++++ net/core/net-sysfs.c | 63 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 93 insertions(+)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index c24ed232c746..11ae0c9b9350 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h@@ -497,6 +497,8 @@ static inline bool napi_complete(struct napi_struct *n) return napi_complete_done(n, 0); } +int dev_set_threaded(struct net_device *dev, bool threaded); + /** * napi_disable - prevent NAPI from scheduling * @n: NAPI context
diff --git a/net/core/dev.c b/net/core/dev.c
index edcfec1361e9..d5fb95316ea8 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c@@ -6754,6 +6754,34 @@ static int napi_set_threaded(struct napi_struct *n, bool threaded) return err; } +static void dev_disable_threaded_all(struct net_device *dev) +{ + struct napi_struct *napi; + + list_for_each_entry(napi, &dev->napi_list, dev_list) + napi_set_threaded(napi, false); +} + +int dev_set_threaded(struct net_device *dev, bool threaded) +{ + struct napi_struct *napi; + int ret; + + dev->threaded = threaded; + list_for_each_entry(napi, &dev->napi_list, dev_list) { + ret = napi_set_threaded(napi, threaded); + if (ret) { + /* Error occurred on one of the napi, + * reset threaded mode on all napi. + */ + dev_disable_threaded_all(dev); + break; + } + } + + return ret; +} + void netif_napi_add(struct net_device *dev, struct napi_struct *napi, int (*poll)(struct napi_struct *, int), int weight) {
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index daf502c13d6d..2017f8f07b8d 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c@@ -538,6 +538,68 @@ static ssize_t phys_switch_id_show(struct device *dev, } static DEVICE_ATTR_RO(phys_switch_id); +static ssize_t threaded_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct net_device *netdev = to_net_dev(dev); + struct napi_struct *n; + bool enabled; + int ret; + + if (!rtnl_trylock()) + return restart_syscall(); + + if (!dev_isalive(netdev)) { + ret = -EINVAL; + goto unlock; + } + + if (list_empty(&netdev->napi_list)) { + ret = -EOPNOTSUPP; + goto unlock; + } + + /* Only return true if all napi have threaded mode. + * The inconsistency could happen when the device driver calls + * napi_disable()/napi_enable() with dev->threaded set to true, + * but napi_kthread_create() fails. + * We return false in this case to remind the user that one or + * more napi did not have threaded mode enabled properly. + */ + list_for_each_entry(n, &netdev->napi_list, dev_list) { + enabled = !!test_bit(NAPI_STATE_THREADED, &n->state); + if (!enabled) + break; + } + + ret = sprintf(buf, fmt_dec, enabled); + +unlock: + rtnl_unlock(); + return ret; +} + +static int modify_napi_threaded(struct net_device *dev, unsigned long val) +{ + struct napi_struct *napi; + int ret; + + if (list_empty(&dev->napi_list)) + return -EOPNOTSUPP; + + ret = dev_set_threaded(dev, !!val); + + return ret; +} + +static ssize_t threaded_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t len) +{ + return netdev_store(dev, attr, buf, len, modify_napi_threaded); +} +static DEVICE_ATTR_RW(threaded); + static struct attribute *net_class_attrs[] __ro_after_init = { &dev_attr_netdev_group.attr, &dev_attr_type.attr,
@@ -570,6 +632,7 @@ static struct attribute *net_class_attrs[] __ro_after_init = { &dev_attr_proto_down.attr, &dev_attr_carrier_up_count.attr, &dev_attr_carrier_down_count.attr, + &dev_attr_threaded.attr, NULL, }; ATTRIBUTE_GROUPS(net_class);
--
2.30.0.284.gd98b1dd5eaa7-goog