6.1-stable review patch. If anyone has any objections, please let me know.
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From: Breno Leitao leitao@debian.org
[ Upstream commit 4b5a28b38c4a0106c64416a1b2042405166b26ce ]
Add dedicated helper for finding devices by hardware address when holding rtnl_lock, similar to existing dev_getbyhwaddr_rcu(). This prevents PROVE_LOCKING warnings when rtnl_lock is held but RCU read lock is not.
Extract common address comparison logic into dev_addr_cmp().
The context about this change could be found in the following discussion:
Link: https://lore.kernel.org/all/20250206-scarlet-ermine-of-improvement-1fcac5@le...
Cc: kuniyu@amazon.com Cc: ushankar@purestorage.com Suggested-by: Eric Dumazet edumazet@google.com Signed-off-by: Breno Leitao leitao@debian.org Reviewed-by: Kuniyuki Iwashima kuniyu@amazon.com Link: https://patch.msgid.link/20250218-arm_fix_selftest-v5-1-d3d6892db9e1@debian.... Signed-off-by: Jakub Kicinski kuba@kernel.org Stable-dep-of: 4eae0ee0f1e6 ("arp: switch to dev_getbyhwaddr() in arp_req_set_public()") Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/netdevice.h | 2 ++ net/core/dev.c | 37 ++++++++++++++++++++++++++++++++++--- 2 files changed, 36 insertions(+), 3 deletions(-)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index d0b4920dee730..f44701b82ea80 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -3011,6 +3011,8 @@ static inline struct net_device *first_net_device_rcu(struct net *net) }
int netdev_boot_setup_check(struct net_device *dev); +struct net_device *dev_getbyhwaddr(struct net *net, unsigned short type, + const char *hwaddr); struct net_device *dev_getbyhwaddr_rcu(struct net *net, unsigned short type, const char *hwaddr); struct net_device *dev_getfirstbyhwtype(struct net *net, unsigned short type); diff --git a/net/core/dev.c b/net/core/dev.c index 90559cb668039..212a909b48405 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -921,6 +921,12 @@ int netdev_get_name(struct net *net, char *name, int ifindex) return ret; }
+static bool dev_addr_cmp(struct net_device *dev, unsigned short type, + const char *ha) +{ + return dev->type == type && !memcmp(dev->dev_addr, ha, dev->addr_len); +} + /** * dev_getbyhwaddr_rcu - find a device by its hardware address * @net: the applicable net namespace @@ -929,7 +935,7 @@ int netdev_get_name(struct net *net, char *name, int ifindex) * * Search for an interface by MAC address. Returns NULL if the device * is not found or a pointer to the device. - * The caller must hold RCU or RTNL. + * The caller must hold RCU. * The returned device has not had its ref count increased * and the caller must therefore be careful about locking * @@ -941,14 +947,39 @@ struct net_device *dev_getbyhwaddr_rcu(struct net *net, unsigned short type, struct net_device *dev;
for_each_netdev_rcu(net, dev) - if (dev->type == type && - !memcmp(dev->dev_addr, ha, dev->addr_len)) + if (dev_addr_cmp(dev, type, ha)) return dev;
return NULL; } EXPORT_SYMBOL(dev_getbyhwaddr_rcu);
+/** + * dev_getbyhwaddr() - find a device by its hardware address + * @net: the applicable net namespace + * @type: media type of device + * @ha: hardware address + * + * Similar to dev_getbyhwaddr_rcu(), but the owner needs to hold + * rtnl_lock. + * + * Context: rtnl_lock() must be held. + * Return: pointer to the net_device, or NULL if not found + */ +struct net_device *dev_getbyhwaddr(struct net *net, unsigned short type, + const char *ha) +{ + struct net_device *dev; + + ASSERT_RTNL(); + for_each_netdev(net, dev) + if (dev_addr_cmp(dev, type, ha)) + return dev; + + return NULL; +} +EXPORT_SYMBOL(dev_getbyhwaddr); + struct net_device *dev_getfirstbyhwtype(struct net *net, unsigned short type) { struct net_device *dev, *ret = NULL;