[PATCH] mctp: accept MSG_CMSG_COMPAT in recvmsg

[Davidlohr Bueso]

32-bit userspace running on a 64-bit kernel is unable to receive MCTP
messages on an AF_MCTP socket, even though sending succeeds. There is
nothing for MCTP to do with it beyond not rejecting it, as af_packet,
af_key and can/isotp already do, for example.

Fixes: 833ef3b91de6 ("mctp: Populate socket implementation")
Signed-off-by: Davidlohr Bueso <dave@xxxxxxxxxxxx>
---
 net/mctp/af_mctp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/mctp/af_mctp.c b/net/mctp/af_mctp.c
index 8af5e2b3c8d1..aa22c0860712 100644
--- a/net/mctp/af_mctp.c
+++ b/net/mctp/af_mctp.c
@@ -292,8 +292,7 @@ static int mctp_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 	u8 type;
 	int rc;
 
-	if (flags & ~(MSG_DONTWAIT | MSG_TRUNC | MSG_PEEK))
+	if (flags & ~(MSG_DONTWAIT | MSG_TRUNC | MSG_PEEK | MSG_CMSG_COMPAT))
 		return -EOPNOTSUPP;
 
 	skb = skb_recv_datagram(sk, flags, &rc);
--
2.39.5