5.15-stable review patch. If anyone has any objections, please let me know.
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From: Antoine Tenart atenart@kernel.org
[ Upstream commit 75ea27d0d62281c31ee259c872dfdeb072cf5e39 ]
__dev_get_by_name is currently used to either retrieve a net device reference using its name or to check if a name is already used by a registered net device (per ns). In the later case there is no need to return a reference to a net device.
Introduce a new helper, netdev_name_in_use, to check if a name is currently used by a registered net device without leaking a reference the corresponding net device. This helper uses netdev_name_node_lookup instead of __dev_get_by_name as we don't need the extra logic retrieving a reference to the corresponding net device.
Signed-off-by: Antoine Tenart atenart@kernel.org Signed-off-by: David S. Miller davem@davemloft.net Stable-dep-of: 311cca40661f ("net: fix ifname in netlink ntf during netns move") Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/netdevice.h | 1 + net/core/dev.c | 14 ++++++++++---- 2 files changed, 11 insertions(+), 4 deletions(-)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index b5df2e59a51d3..132f4344fee9f 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -2978,6 +2978,7 @@ struct net_device *__dev_get_by_flags(struct net *net, unsigned short flags, struct net_device *dev_get_by_name(struct net *net, const char *name); struct net_device *dev_get_by_name_rcu(struct net *net, const char *name); struct net_device *__dev_get_by_name(struct net *net, const char *name); +bool netdev_name_in_use(struct net *net, const char *name); int dev_alloc_name(struct net_device *dev, const char *name); int dev_open(struct net_device *dev, struct netlink_ext_ack *extack); void dev_close(struct net_device *dev); diff --git a/net/core/dev.c b/net/core/dev.c index 4d698ccf41726..d269c1760fa45 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -303,6 +303,12 @@ static struct netdev_name_node *netdev_name_node_lookup_rcu(struct net *net, return NULL; }
+bool netdev_name_in_use(struct net *net, const char *name) +{ + return netdev_name_node_lookup(net, name); +} +EXPORT_SYMBOL(netdev_name_in_use); + int netdev_name_node_alt_create(struct net_device *dev, const char *name) { struct netdev_name_node *name_node; @@ -1135,7 +1141,7 @@ static int __dev_alloc_name(struct net *net, const char *name, char *buf) }
snprintf(buf, IFNAMSIZ, name, i); - if (!__dev_get_by_name(net, buf)) + if (!netdev_name_in_use(net, buf)) return i;
/* It is possible to run out of possible slots @@ -1189,7 +1195,7 @@ static int dev_get_valid_name(struct net *net, struct net_device *dev,
if (strchr(name, '%')) return dev_alloc_name_ns(net, dev, name); - else if (__dev_get_by_name(net, name)) + else if (netdev_name_in_use(net, name)) return -EEXIST; else if (dev->name != name) strlcpy(dev->name, name, IFNAMSIZ); @@ -11170,7 +11176,7 @@ int __dev_change_net_namespace(struct net_device *dev, struct net *net, * we can use it in the destination network namespace. */ err = -EEXIST; - if (__dev_get_by_name(net, dev->name)) { + if (netdev_name_in_use(net, dev->name)) { /* We get here if we can't use the current device name */ if (!pat) goto out; @@ -11522,7 +11528,7 @@ static void __net_exit default_device_exit(struct net *net)
/* Push remaining network devices to init_net */ snprintf(fb_name, IFNAMSIZ, "dev%d", dev->ifindex); - if (__dev_get_by_name(&init_net, fb_name)) + if (netdev_name_in_use(&init_net, fb_name)) snprintf(fb_name, IFNAMSIZ, "dev%%d"); err = dev_change_net_namespace(dev, &init_net, fb_name); if (err) {