libxdp: Use 0 as default(or unset) value for fd when creating umem

Signed-off-by: Muyang Tian <[email protected]>

lib/libxdp/xsk.c

@@ -316,7 +316,7 @@ struct xsk_umem *xsk_umem__create_opts(void *umem_area,
 		err = -EINVAL;
 		goto err;
 	}
-	fd = OPTS_GET(opts, fd, -1);
+	fd = OPTS_GET(opts, fd, 0);
 	size = OPTS_GET(opts, size, 0);
 
 	if (!size && !xsk_page_aligned(umem_area)) {
@@ -330,7 +330,7 @@ struct xsk_umem *xsk_umem__create_opts(void *umem_area,
 		goto err;
 	}
 
-	umem->fd = fd < 0 ? socket(AF_XDP, SOCK_RAW, 0) : fd;
+	umem->fd = fd > 0 ? fd : socket(AF_XDP, SOCK_RAW, 0);
 	if (umem->fd < 0) {
 		err = -errno;
 		goto out_umem_alloc;
@@ -412,7 +412,7 @@ int xsk_umem__create(struct xsk_umem **umem_ptr, void *umem_area,
 		     struct xsk_ring_cons *comp,
 		     const struct xsk_umem_config *usr_config)
 {
-	return xsk_umem__create_with_fd(umem_ptr, -1, umem_area, size,
+	return xsk_umem__create_with_fd(umem_ptr, 0, umem_area, size,
 					fill, comp, usr_config);
 }