From 723de3ebef03bc14bd72531f00f9094337654009 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Fri, 26 Jan 2024 12:14:49 -0800 Subject: [PATCH] net: free altname using an RCU callback We had to add another synchronize_rcu() in recent fix. Bite the bullet and add an rcu_head to netdev_name_node, free from RCU. Note that name_node does not hold any reference on dev to which it points, but there must be a synchronize_rcu() on device removal path, so we should be fine. Signed-off-by: Jakub Kicinski Reviewed-by: Jiri Pirko Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller --- net/core/dev.c | 27 ++++++++++++++++----------- net/core/dev.h | 1 + 2 files changed, 17 insertions(+), 11 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index cb2dab0feee0..b53b9c94de40 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -341,13 +341,22 @@ int netdev_name_node_alt_create(struct net_device *dev, const char *name) return 0; } -static void __netdev_name_node_alt_destroy(struct netdev_name_node *name_node) +static void netdev_name_node_alt_free(struct rcu_head *head) { - list_del(&name_node->list); + struct netdev_name_node *name_node = + container_of(head, struct netdev_name_node, rcu); + kfree(name_node->name); netdev_name_node_free(name_node); } +static void __netdev_name_node_alt_destroy(struct netdev_name_node *name_node) +{ + netdev_name_node_del(name_node); + list_del(&name_node->list); + call_rcu(&name_node->rcu, netdev_name_node_alt_free); +} + int netdev_name_node_alt_destroy(struct net_device *dev, const char *name) { struct netdev_name_node *name_node; @@ -362,10 +371,7 @@ int netdev_name_node_alt_destroy(struct net_device *dev, const char *name) if (name_node == dev->name_node || name_node->dev != dev) return -EINVAL; - netdev_name_node_del(name_node); - synchronize_rcu(); __netdev_name_node_alt_destroy(name_node); - return 0; } @@ -373,8 +379,10 @@ static void netdev_name_node_alt_flush(struct net_device *dev) { struct netdev_name_node *name_node, *tmp; - list_for_each_entry_safe(name_node, tmp, &dev->name_node->list, list) - __netdev_name_node_alt_destroy(name_node); + list_for_each_entry_safe(name_node, tmp, &dev->name_node->list, list) { + list_del(&name_node->list); + netdev_name_node_alt_free(&name_node->rcu); + } } /* Device list insertion */ @@ -11576,11 +11584,8 @@ static void __net_exit default_device_exit_net(struct net *net) snprintf(fb_name, IFNAMSIZ, "dev%%d"); netdev_for_each_altname_safe(dev, name_node, tmp) - if (netdev_name_in_use(&init_net, name_node->name)) { - netdev_name_node_del(name_node); - synchronize_rcu(); + if (netdev_name_in_use(&init_net, name_node->name)) __netdev_name_node_alt_destroy(name_node); - } err = dev_change_net_namespace(dev, &init_net, fb_name); if (err) { diff --git a/net/core/dev.h b/net/core/dev.h index 7480b4c84298..a43dfe3de50e 100644 --- a/net/core/dev.h +++ b/net/core/dev.h @@ -56,6 +56,7 @@ struct netdev_name_node { struct list_head list; struct net_device *dev; const char *name; + struct rcu_head rcu; }; int netdev_get_name(struct net *net, char *name, int ifindex);