nbd: make refcount interface public

After the next patch, the close callback will have to release its
reference.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

nbd.c

@@ -647,12 +647,12 @@ static ssize_t nbd_send_reply(int csock, struct nbd_reply *reply)
 
 #define MAX_NBD_REQUESTS 16
 
-static void nbd_client_get(NBDClient *client)
+void nbd_client_get(NBDClient *client)
 {
     client->refcount++;
 }
 
-static void nbd_client_put(NBDClient *client)
+void nbd_client_put(NBDClient *client)
 {
     if (--client->refcount == 0) {
         g_free(client);

nbd.h

@@ -81,7 +81,10 @@ typedef struct NBDClient NBDClient;
 NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset,
                           off_t size, uint32_t nbdflags);
 void nbd_export_close(NBDExport *exp);
+
 NBDClient *nbd_client_new(NBDExport *exp, int csock,
                           void (*close)(NBDClient *));
+void nbd_client_get(NBDClient *client);
+void nbd_client_put(NBDClient *client);
 
 #endif