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Merge branch 'net-core-improvements-to-device-lookup-by-hardware-address'

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Breno Leitao says:

====================
net: core: improvements to device lookup by hardware address.

The first patch adds a new dev_getbyhwaddr() helper function for
finding devices by hardware address when the rtnl lock is held. This
prevents PROVE_LOCKING warnings that occurred when rtnl lock was held
but the RCU read lock wasn't. The common address comparison logic is
extracted into dev_comp_addr() to avoid code duplication.

The second coverts arp_req_set_public() to the new helper.
====================

Link: https://patch.msgid.link/20250218-arm_fix_selftest-v5-0-d3d6892db9e1@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Jakub Kicinski 2025-02-19 19:01:00 -08:00
commit 62520094e9
3 changed files with 37 additions and 4 deletions
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2
include/linux/netdevice.h
View File

@ -3275,6 +3275,8 @@ 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);

37
net/core/dev.c
View File

@ -1121,6 +1121,12 @@ 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
@ -1129,7 +1135,7 @@ 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
*
@ -1141,14 +1147,39 @@ 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;

2
net/ipv4/arp.c
View File

@ -1077,7 +1077,7 @@ static int arp_req_set_public(struct net *net, struct arpreq *r,
__be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
if (!dev && (r->arp_flags & ATF_COM)) {
dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family,
dev = dev_getbyhwaddr(net, r->arp_ha.sa_family,
r->arp_ha.sa_data);
if (!dev)
return -ENODEV;