diff --git a/src/rlc.h b/src/rlc.h
index 135060e..109c5b3 100644
--- a/src/rlc.h
+++ b/src/rlc.h
@@ -177,8 +177,6 @@
 };
 
 struct gprs_rlc_data {
-	uint8_t *prepare(size_t block_data_length);
-
 	/* block data including LI headers */
 	uint8_t block[RLC_MAX_LEN];
 	/* block data len including LI headers*/
@@ -211,6 +209,8 @@
 	union split_block_status spb_status;
 };
 
+uint8_t *prepare(struct gprs_rlc_data *rlc, size_t block_data_length);
+
 void gprs_rlc_data_info_init_dl(struct gprs_rlc_data_info *rlc,
 	GprsCodingScheme cs, bool with_padding, const unsigned int spb);
 void gprs_rlc_data_info_init_ul(struct gprs_rlc_data_info *rlc,