[PATCH net-next v1 1/2] ipv6: make IPV6_FREEBIND setsockopt lockless

[Xuanqiang Luo <xuanqiang.luo@linux.dev>]

From: Xuanqiang Luo <luoxuanqiang@kylinos.cn>

IPV6_FREEBIND still takes the socket lock despite using
inet_assign_bit() to update the flag shared with IP_FREEBIND.
IPv6 TCP and UDP sockets can already update this flag without the
lock through SOL_IP/IP_FREEBIND.

Move IPV6_FREEBIND to the lockless setsockopt path.

Signed-off-by: Xuanqiang Luo <luoxuanqiang@kylinos.cn>
---
 net/ipv6/ipv6_sockglue.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index 1f68fb64a43ef..4124084c3cd79 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -398,6 +398,12 @@ int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
 
 	/* Handle options that can be set without locking the socket. */
 	switch (optname) {
+	case IPV6_FREEBIND:
+		if (optlen < sizeof(int))
+			return -EINVAL;
+		/* Shared with IP_FREEBIND. */
+		inet_assign_bit(FREEBIND, sk, valbool);
+		return 0;
 	case IPV6_UNICAST_HOPS:
 		if (optlen < sizeof(int))
 			return -EINVAL;
@@ -679,14 +685,6 @@ int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
 		retv = 0;
 		break;
 
-	case IPV6_FREEBIND:
-		if (optlen < sizeof(int))
-			goto e_inval;
-		/* we also don't have a separate freebind bit for IPV6 */
-		inet_assign_bit(FREEBIND, sk, valbool);
-		retv = 0;
-		break;
-
 	case IPV6_RECVORIGDSTADDR:
 		if (optlen < sizeof(int))
 			goto e_inval;
-- 
2.43.0