nbd: Merge nbd_export_new() and nbd_export_create()

There is no real reason any more why nbd_export_new() and
nbd_export_create() should be separate functions. The latter only
performs a few checks before it calls the former.

What makes the current state stand out is that it's the only function in
BlockExportDriver that is not a static function inside nbd/server.c, but
a small wrapper in blockdev-nbd.c that then calls back into nbd/server.c
for the real functionality.

Move all the checks to nbd/server.c and make the resulting function
static to improve readability.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200924152717.287415-27-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/include/block/nbd.h b/include/block/nbd.h
index 5270b7e..3dd9a04 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -330,12 +330,6 @@
 typedef struct NBDExport NBDExport;
 typedef struct NBDClient NBDClient;
 
-int nbd_export_create(BlockExport *exp, BlockExportOptions *exp_args,
-                      Error **errp);
-int nbd_export_new(BlockExport *blk_exp,
-                   const char *name, const char *desc,
-                   const char *bitmap, bool readonly, bool shared,
-                   Error **errp);
 void nbd_export_set_on_eject_blk(BlockExport *exp, BlockBackend *blk);
 
 AioContext *nbd_export_aio_context(NBDExport *exp);
@@ -349,6 +343,7 @@
 void nbd_client_put(NBDClient *client);
 
 void nbd_server_is_qemu_nbd(bool value);
+bool nbd_server_is_running(void);
 void nbd_server_start(SocketAddress *addr, const char *tls_creds,
                       const char *tls_authz, uint32_t max_connections,
                       Error **errp);