From 8033d2aef51722fe74068b52553625ed91ea256c Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Wed, 12 Mar 2025 12:05:12 -0700 Subject: Revert "net: replace dev_addr_sem with netdev instance lock" This reverts commit df43d8bf10316a7c3b1e47e3cc0057a54df4a5b8. Cc: Kohei Enju Reviewed-by: Kuniyuki Iwashima Fixes: df43d8bf1031 ("net: replace dev_addr_sem with netdev instance lock") Signed-off-by: Stanislav Fomichev Link: https://patch.msgid.link/20250312190513.1252045-2-sdf@fomichev.me Tested-by: Lei Yang Signed-off-by: Paolo Abeni --- net/core/dev.c | 52 +++++++++++++++++++++++++--------------------------- 1 file changed, 25 insertions(+), 27 deletions(-) (limited to 'net/core/dev.c') diff --git a/net/core/dev.c b/net/core/dev.c index 6fa6ed5b5798..977a9946d39c 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1059,28 +1059,6 @@ struct net_device *netdev_get_by_index_lock(struct net *net, int ifindex) return __netdev_put_lock(dev); } -/** - * netdev_get_by_name_lock() - find a device by its name - * @net: the applicable net namespace - * @name: name of device - * - * Search for an interface by name. If a valid device - * with @name is found it will be returned with netdev->lock held. - * netdev_unlock() must be called to release it. - * - * Return: pointer to a device with lock held, NULL if not found. - */ -struct net_device *netdev_get_by_name_lock(struct net *net, const char *name) -{ - struct net_device *dev; - - dev = dev_get_by_name(net, name); - if (!dev) - return NULL; - - return __netdev_put_lock(dev); -} - struct net_device * netdev_xa_find_lock(struct net *net, struct net_device *dev, unsigned long *index) @@ -9597,24 +9575,44 @@ int netif_set_mac_address(struct net_device *dev, struct sockaddr *sa, return 0; } +DECLARE_RWSEM(dev_addr_sem); + +int netif_set_mac_address_user(struct net_device *dev, struct sockaddr *sa, + struct netlink_ext_ack *extack) +{ + int ret; + + down_write(&dev_addr_sem); + ret = netif_set_mac_address(dev, sa, extack); + up_write(&dev_addr_sem); + return ret; +} + int dev_get_mac_address(struct sockaddr *sa, struct net *net, char *dev_name) { size_t size = sizeof(sa->sa_data_min); struct net_device *dev; + int ret = 0; - dev = netdev_get_by_name_lock(net, dev_name); - if (!dev) - return -ENODEV; + down_read(&dev_addr_sem); + rcu_read_lock(); + dev = dev_get_by_name_rcu(net, dev_name); + if (!dev) { + ret = -ENODEV; + goto unlock; + } if (!dev->addr_len) memset(sa->sa_data, 0, size); else memcpy(sa->sa_data, dev->dev_addr, min_t(size_t, size, dev->addr_len)); sa->sa_family = dev->type; - netdev_unlock(dev); - return 0; +unlock: + rcu_read_unlock(); + up_read(&dev_addr_sem); + return ret; } EXPORT_SYMBOL(dev_get_mac_address); -- cgit v1.2.3 From 6dd132516f8e467f144f7871ff2708ce827417a1 Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Wed, 12 Mar 2025 12:05:13 -0700 Subject: net: reorder dev_addr_sem lock Lockdep complains about circular lock in 1 -> 2 -> 3 (see below). Change the lock ordering to be: - rtnl_lock - dev_addr_sem - netdev_ops (only for lower devices!) - team_lock (or other per-upper device lock) 1. rtnl_lock -> netdev_ops -> dev_addr_sem rtnl_setlink rtnl_lock do_setlink IFLA_ADDRESS on lower netdev_ops dev_addr_sem 2. rtnl_lock -> team_lock -> netdev_ops rtnl_newlink rtnl_lock do_setlink IFLA_MASTER on lower do_set_master team_add_slave team_lock team_port_add dev_set_mtu netdev_ops 3. rtnl_lock -> dev_addr_sem -> team_lock rtnl_newlink rtnl_lock do_setlink IFLA_ADDRESS on upper dev_addr_sem netif_set_mac_address team_set_mac_address team_lock 4. rtnl_lock -> netdev_ops -> dev_addr_sem rtnl_lock dev_ifsioc dev_set_mac_address_user __tun_chr_ioctl rtnl_lock dev_set_mac_address_user tap_ioctl rtnl_lock dev_set_mac_address_user dev_set_mac_address_user netdev_lock_ops netif_set_mac_address_user dev_addr_sem v2: - move lock reorder to happen after kmalloc (Kuniyuki) Cc: Kohei Enju Fixes: df43d8bf1031 ("net: replace dev_addr_sem with netdev instance lock") Signed-off-by: Stanislav Fomichev Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250312190513.1252045-3-sdf@fomichev.me Tested-by: Lei Yang Signed-off-by: Paolo Abeni --- net/core/dev.c | 11 ----------- 1 file changed, 11 deletions(-) (limited to 'net/core/dev.c') diff --git a/net/core/dev.c b/net/core/dev.c index 977a9946d39c..235560341765 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -9577,17 +9577,6 @@ int netif_set_mac_address(struct net_device *dev, struct sockaddr *sa, DECLARE_RWSEM(dev_addr_sem); -int netif_set_mac_address_user(struct net_device *dev, struct sockaddr *sa, - struct netlink_ext_ack *extack) -{ - int ret; - - down_write(&dev_addr_sem); - ret = netif_set_mac_address(dev, sa, extack); - up_write(&dev_addr_sem); - return ret; -} - int dev_get_mac_address(struct sockaddr *sa, struct net *net, char *dev_name) { size_t size = sizeof(sa->sa_data_min); -- cgit v1.2.3