[PATCH net-next v3 04/13] net: move promiscuity handling into dev_rx_mode_work
From: Stanislav Fomichev <sdf@fomichev.me>
Date: 2026-03-20 01:25:09
Also in:
intel-wired-lan, linux-doc, linux-kselftest, linux-rdma, linux-wireless, lkml
Subsystem:
documentation, networking [general], the rest · Maintainers:
Jonathan Corbet, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Move unicast promiscuity tracking into dev_rx_mode_work so it runs under netdev_ops_lock instead of under the addr_lock spinlock. This is required because __dev_set_promiscuity calls dev_change_rx_flags and __dev_notify_flags, both of which may need to sleep. Change ASSERT_RTNL() to netdev_ops_assert_locked() in __dev_set_promiscuity, netif_set_allmulti and __dev_change_flags since these are now called from the work queue under the ops lock. Reviewed-by: Aleksandr Loktionov <redacted> Signed-off-by: Stanislav Fomichev <sdf@fomichev.me> --- Documentation/networking/netdevices.rst | 4 ++ net/core/dev.c | 79 +++++++++++++++++-------- 2 files changed, 57 insertions(+), 26 deletions(-)
diff --git a/Documentation/networking/netdevices.rst b/Documentation/networking/netdevices.rst
index dc83d78d3b27..5cdaa1a3dcc8 100644
--- a/Documentation/networking/netdevices.rst
+++ b/Documentation/networking/netdevices.rst@@ -298,6 +298,10 @@ struct net_device synchronization rules Notes: Sleepable version of ndo_set_rx_mode. Receives snapshots of the unicast and multicast address lists. +ndo_change_rx_flags: + Synchronization: rtnl_lock() semaphore. In addition, netdev instance + lock if the driver implements queue management or shaper API. + ndo_setup_tc: ``TC_SETUP_BLOCK`` and ``TC_SETUP_FT`` are running under NFT locks (i.e. no ``rtnl_lock`` and no device instance lock). The rest of
diff --git a/net/core/dev.c b/net/core/dev.c
index fedc423306fc..fc5c9b14faa0 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c@@ -9574,7 +9574,7 @@ static int __dev_set_promiscuity(struct net_device *dev, int inc, bool notify) kuid_t uid; kgid_t gid; - ASSERT_RTNL(); + netdev_ops_assert_locked(dev); promiscuity = dev->promiscuity + inc; if (promiscuity == 0) {
@@ -9610,16 +9610,8 @@ static int __dev_set_promiscuity(struct net_device *dev, int inc, bool notify) dev_change_rx_flags(dev, IFF_PROMISC); } - if (notify) { - /* The ops lock is only required to ensure consistent locking - * for `NETDEV_CHANGE` notifiers. This function is sometimes - * called without the lock, even for devices that are ops - * locked, such as in `dev_uc_sync_multiple` when using - * bonding or teaming. - */ - netdev_ops_assert_locked(dev); + if (notify) __dev_notify_flags(dev, old_flags, IFF_PROMISC, 0, NULL); - } return 0; }
@@ -9641,7 +9633,7 @@ int netif_set_allmulti(struct net_device *dev, int inc, bool notify) unsigned int old_flags = dev->flags, old_gflags = dev->gflags; unsigned int allmulti, flags; - ASSERT_RTNL(); + netdev_ops_assert_locked(dev); allmulti = dev->allmulti + inc; if (allmulti == 0) {
@@ -9671,12 +9663,36 @@ int netif_set_allmulti(struct net_device *dev, int inc, bool notify) return 0; } +/** + * dev_uc_promisc_update() - evaluate whether uc_promisc should be toggled. + * @dev: device + * + * Must be called under netif_addr_lock_bh. + * Return: +1 to enter promisc, -1 to leave, 0 for no change. + */ +static int dev_uc_promisc_update(struct net_device *dev) +{ + if (dev->priv_flags & IFF_UNICAST_FLT) + return 0; + + if (!netdev_uc_empty(dev) && !dev->uc_promisc) { + dev->uc_promisc = true; + return 1; + } + if (netdev_uc_empty(dev) && dev->uc_promisc) { + dev->uc_promisc = false; + return -1; + } + return 0; +} + static void dev_rx_mode_work(struct work_struct *work) { struct net_device *dev = container_of(work, struct net_device, rx_mode_work); struct netdev_hw_addr_list uc_snap, mc_snap, uc_ref, mc_ref; const struct net_device_ops *ops = dev->netdev_ops; + int promisc_inc; int err; __hw_addr_init(&uc_snap);
@@ -9704,16 +9720,29 @@ static void dev_rx_mode_work(struct work_struct *work) if (!err) err = __hw_addr_list_snapshot(&mc_ref, &dev->mc, dev->addr_len); - netif_addr_unlock_bh(dev); if (err) { netdev_WARN(dev, "failed to sync uc/mc addresses\n"); __hw_addr_flush(&uc_snap); __hw_addr_flush(&uc_ref); __hw_addr_flush(&mc_snap); + netif_addr_unlock_bh(dev); goto out; } + promisc_inc = dev_uc_promisc_update(dev); + + netif_addr_unlock_bh(dev); + } else { + netif_addr_lock_bh(dev); + promisc_inc = dev_uc_promisc_update(dev); + netif_addr_unlock_bh(dev); + } + + if (promisc_inc) + __dev_set_promiscuity(dev, promisc_inc, false); + + if (ops->ndo_set_rx_mode_async) { ops->ndo_set_rx_mode_async(dev, &uc_snap, &mc_snap); netif_addr_lock_bh(dev);
@@ -9722,6 +9751,10 @@ static void dev_rx_mode_work(struct work_struct *work) __hw_addr_list_reconcile(&dev->mc, &mc_snap, &mc_ref, dev->addr_len); netif_addr_unlock_bh(dev); + } else if (ops->ndo_set_rx_mode) { + netif_addr_lock_bh(dev); + ops->ndo_set_rx_mode(dev); + netif_addr_unlock_bh(dev); } out:
@@ -9740,28 +9773,22 @@ static void dev_rx_mode_work(struct work_struct *work) void __dev_set_rx_mode(struct net_device *dev) { const struct net_device_ops *ops = dev->netdev_ops; + int promisc_inc; /* dev_open will call this function so the list will stay sane. */ if (!netif_up_and_present(dev)) return; - if (ops->ndo_set_rx_mode_async) { + if (ops->ndo_set_rx_mode_async || ops->ndo_change_rx_flags) { queue_work(rx_mode_wq, &dev->rx_mode_work); return; } - if (!(dev->priv_flags & IFF_UNICAST_FLT)) { - /* Unicast addresses changes may only happen under the rtnl, - * therefore calling __dev_set_promiscuity here is safe. - */ - if (!netdev_uc_empty(dev) && !dev->uc_promisc) { - __dev_set_promiscuity(dev, 1, false); - dev->uc_promisc = true; - } else if (netdev_uc_empty(dev) && dev->uc_promisc) { - __dev_set_promiscuity(dev, -1, false); - dev->uc_promisc = false; - } - } + /* Legacy path for non-ops locked HW devices. */ + + promisc_inc = dev_uc_promisc_update(dev); + if (promisc_inc) + __dev_set_promiscuity(dev, promisc_inc, false); if (ops->ndo_set_rx_mode) ops->ndo_set_rx_mode(dev);
@@ -9811,7 +9838,7 @@ int __dev_change_flags(struct net_device *dev, unsigned int flags, unsigned int old_flags = dev->flags; int ret; - ASSERT_RTNL(); + netdev_ops_assert_locked(dev); /* * Set the flags on our device.
--
2.53.0