NFS: Start PF_INET6 callback listener only if IPv6 support is available

Apparently a lot of people need to disable IPv6 completely on their
distributor-built systems, which have CONFIG_IPV6_MODULE enabled at
build time.

They do this by blacklisting the ipv6.ko module.  This causes the
creation of the NFSv4 callback service listener to fail if
CONFIG_IPV6_MODULE is set, but the module cannot be loaded.

Now that the kernel's PF_INET6 RPC listeners are completely separate
from PF_INET listeners, we can always start PF_INET.  Then the NFS
client can try to start a PF_INET6 listener, but it isn't required
to be available.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 8 insertions, 2 deletions

diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 2022fe47966f..0298e909559f 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -62,8 +62,14 @@ static LIST_HEAD(nfs4_clientid_list);
 
 static int nfs4_init_client(struct nfs_client *clp, struct rpc_cred *cred)
 {
-	int status = nfs4_proc_setclientid(clp, NFS4_CALLBACK,
-			nfs_callback_tcpport, cred);
+	unsigned short port;
+	int status;
+
+	port = nfs_callback_tcpport;
+	if (clp->cl_addr.ss_family == AF_INET6)
+		port = nfs_callback_tcpport6;
+
+	status = nfs4_proc_setclientid(clp, NFS4_CALLBACK, port, cred);
 	if (status == 0)
 		status = nfs4_proc_setclientid_confirm(clp, cred);
 	if (status == 0)