From 8033d2aef51722fe74068b52553625ed91ea256c Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Wed, 12 Mar 2025 12:05:12 -0700 Subject: [PATCH] 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 --- drivers/net/tap.c | 2 +- drivers/net/tun.c | 2 +- include/linux/netdevice.h | 6 ++++- net/core/dev.c | 52 +++++++++++++++++++-------------------- net/core/dev.h | 3 ++- net/core/dev_api.c | 17 +++++++++++-- net/core/dev_ioctl.c | 2 +- net/core/net-sysfs.c | 7 ++++-- net/core/rtnetlink.c | 6 +---- 9 files changed, 56 insertions(+), 41 deletions(-) diff --git a/drivers/net/tap.c b/drivers/net/tap.c index 4382f5e323b0..d4ece538f1b2 100644 --- a/drivers/net/tap.c +++ b/drivers/net/tap.c @@ -1017,7 +1017,7 @@ static long tap_ioctl(struct file *file, unsigned int cmd, rtnl_unlock(); return -ENOLINK; } - ret = dev_set_mac_address(tap->dev, &sa, NULL); + ret = dev_set_mac_address_user(tap->dev, &sa, NULL); tap_put_tap_dev(tap); rtnl_unlock(); return ret; diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 55b60cb68d00..f75f912a0225 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -3193,7 +3193,7 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, case SIOCSIFHWADDR: /* Set hw address */ - ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr, NULL); + ret = dev_set_mac_address_user(tun->dev, &ifr.ifr_hwaddr, NULL); break; case TUNGETSNDBUF: diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 67527243459b..0db9fc0afe36 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -2498,7 +2498,7 @@ struct net_device { * * Protects: * @gro_flush_timeout, @napi_defer_hard_irqs, @napi_list, - * @net_shaper_hierarchy, @reg_state, @threaded, @dev_addr + * @net_shaper_hierarchy, @reg_state, @threaded * * Partially protects (writers must hold both @lock and rtnl_lock): * @up @@ -4196,6 +4196,10 @@ int netif_set_mac_address(struct net_device *dev, struct sockaddr *sa, struct netlink_ext_ack *extack); int dev_set_mac_address(struct net_device *dev, struct sockaddr *sa, struct netlink_ext_ack *extack); +int netif_set_mac_address_user(struct net_device *dev, struct sockaddr *sa, + struct netlink_ext_ack *extack); +int dev_set_mac_address_user(struct net_device *dev, struct sockaddr *sa, + struct netlink_ext_ack *extack); int dev_get_mac_address(struct sockaddr *sa, struct net *net, char *dev_name); int dev_get_port_parent_id(struct net_device *dev, struct netdev_phys_item_id *ppid, bool recurse); 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); diff --git a/net/core/dev.h b/net/core/dev.h index 0ddd3631acb0..7ee203395d8e 100644 --- a/net/core/dev.h +++ b/net/core/dev.h @@ -29,7 +29,6 @@ netdev_napi_by_id_lock(struct net *net, unsigned int napi_id); struct net_device *dev_get_by_napi_id(unsigned int napi_id); struct net_device *netdev_get_by_index_lock(struct net *net, int ifindex); -struct net_device *netdev_get_by_name_lock(struct net *net, const char *name); struct net_device *__netdev_put_lock(struct net_device *dev); struct net_device * netdev_xa_find_lock(struct net *net, struct net_device *dev, @@ -71,6 +70,8 @@ extern int weight_p; extern int dev_weight_rx_bias; extern int dev_weight_tx_bias; +extern struct rw_semaphore dev_addr_sem; + /* rtnl helpers */ extern struct list_head net_todo_list; void netdev_run_todo(void); diff --git a/net/core/dev_api.c b/net/core/dev_api.c index 1f0e24849bc6..2e17548af685 100644 --- a/net/core/dev_api.c +++ b/net/core/dev_api.c @@ -84,6 +84,19 @@ void dev_set_group(struct net_device *dev, int new_group) netdev_unlock_ops(dev); } +int dev_set_mac_address_user(struct net_device *dev, struct sockaddr *sa, + struct netlink_ext_ack *extack) +{ + int ret; + + netdev_lock_ops(dev); + ret = netif_set_mac_address_user(dev, sa, extack); + netdev_unlock_ops(dev); + + return ret; +} +EXPORT_SYMBOL(dev_set_mac_address_user); + /** * dev_change_net_namespace() - move device to different nethost namespace * @dev: device @@ -299,9 +312,9 @@ int dev_set_mac_address(struct net_device *dev, struct sockaddr *sa, { int ret; - netdev_lock(dev); + netdev_lock_ops(dev); ret = netif_set_mac_address(dev, sa, extack); - netdev_unlock(dev); + netdev_unlock_ops(dev); return ret; } diff --git a/net/core/dev_ioctl.c b/net/core/dev_ioctl.c index 5471cf4fc984..eb8b41ec5523 100644 --- a/net/core/dev_ioctl.c +++ b/net/core/dev_ioctl.c @@ -575,7 +575,7 @@ static int dev_ifsioc(struct net *net, struct ifreq *ifr, void __user *data, case SIOCSIFHWADDR: if (dev->addr_len > sizeof(struct sockaddr)) return -EINVAL; - return dev_set_mac_address(dev, &ifr->ifr_hwaddr, NULL); + return dev_set_mac_address_user(dev, &ifr->ifr_hwaddr, NULL); case SIOCSIFHWBROADCAST: if (ifr->ifr_hwaddr.sa_family != dev->type) diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index 529a0f721268..abaa1c919b98 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -263,11 +263,14 @@ static ssize_t address_show(struct device *dev, struct device_attribute *attr, struct net_device *ndev = to_net_dev(dev); ssize_t ret = -EINVAL; - netdev_lock(ndev); + down_read(&dev_addr_sem); + + rcu_read_lock(); if (dev_isalive(ndev)) ret = sysfs_format_mac(buf, ndev->dev_addr, ndev->addr_len); - netdev_unlock(ndev); + rcu_read_unlock(); + up_read(&dev_addr_sem); return ret; } static DEVICE_ATTR_RO(address); diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 90597bf84e3d..9355058bf996 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -3090,11 +3090,7 @@ static int do_setlink(const struct sk_buff *skb, struct net_device *dev, sa->sa_family = dev->type; memcpy(sa->sa_data, nla_data(tb[IFLA_ADDRESS]), dev->addr_len); - if (!netdev_need_ops_lock(dev)) - netdev_lock(dev); - err = netif_set_mac_address(dev, sa, extack); - if (!netdev_need_ops_lock(dev)) - netdev_unlock(dev); + err = netif_set_mac_address_user(dev, sa, extack); kfree(sa); if (err) goto errout; -- 2.49.0