NFS: make nfs_callback_tcpport per network context

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/netns.h b/fs/nfs/netns.h
index 0539de1..1538d3a 100644
--- a/fs/nfs/netns.h
+++ b/fs/nfs/netns.h
@@ -22,6 +22,7 @@
 	struct list_head nfs_volume_list;
 #if IS_ENABLED(CONFIG_NFS_V4)
 	struct idr cb_ident_idr; /* Protected by nfs_client_lock */
+	unsigned short nfs_callback_tcpport;
 #endif
 	spinlock_t nfs_client_lock;
 	struct timespec boot_time;