arp: switch to dev_getbyhwaddr() in arp_req_set_public()

[ Upstream commit 4eae0ee ]

The arp_req_set_public() function is called with the rtnl lock held,
which provides enough synchronization protection. This makes the RCU
variant of dev_getbyhwaddr() unnecessary. Switch to using the simpler
dev_getbyhwaddr() function since we already have the required rtnl
locking.

This change helps maintain consistency in the networking code by using
the appropriate helper function for the existing locking context.
Since we're not holding the RCU read lock in arp_req_set_public()
existing code could trigger false positive locking warnings.

Fixes: 941666c ("net: RCU conversion of dev_getbyhwaddr() and arp_ioctl()")
Suggested-by: Kuniyuki Iwashima <[email protected]>
Reviewed-by: Kuniyuki Iwashima <[email protected]>
Signed-off-by: Breno Leitao <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
(cherry picked from commit c4a0f115326583dfccb99e45a3cb1bc8ef1bedd4)
Signed-off-by: Jack Vogel <[email protected]>

Author: leitao

net/ipv4/arp.c

@@ -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;