This is a note to let you know that I've just added the patch titled
net: introduce a function to check if a netdev name is in use
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-introduce-a-function-to-check-if-a-netdev-name-i.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit b0994db2200c5f54ab2b494a45201e2cb3925b12
Author: Antoine Tenart <atenart@xxxxxxxxxx>
Date: Thu Oct 7 18:16:50 2021 +0200
net: introduce a function to check if a netdev name is in use
[ 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@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Stable-dep-of: 311cca40661f ("net: fix ifname in netlink ntf during netns move")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
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) {
