diff --git a/block.c b/block.c
index dd40b56..916f08e 100644
--- a/block.c
+++ b/block.c
@@ -55,6 +55,12 @@
     int ret;
 } BlockDriverAIOCBSync;
 
+static BlockDriverAIOCB *bdrv_aio_read(BlockDriverState *bs,
+        int64_t sector_num, uint8_t *buf, int nb_sectors,
+        BlockDriverCompletionFunc *cb, void *opaque);
+static BlockDriverAIOCB *bdrv_aio_write(BlockDriverState *bs,
+        int64_t sector_num, const uint8_t *buf, int nb_sectors,
+        BlockDriverCompletionFunc *cb, void *opaque);
 static BlockDriverAIOCB *bdrv_aio_read_em(BlockDriverState *bs,
         int64_t sector_num, uint8_t *buf, int nb_sectors,
         BlockDriverCompletionFunc *cb, void *opaque);
@@ -1370,7 +1376,7 @@
                               cb, opaque, 1);
 }
 
-BlockDriverAIOCB *bdrv_aio_read(BlockDriverState *bs, int64_t sector_num,
+static BlockDriverAIOCB *bdrv_aio_read(BlockDriverState *bs, int64_t sector_num,
                                 uint8_t *buf, int nb_sectors,
                                 BlockDriverCompletionFunc *cb, void *opaque)
 {
@@ -1393,7 +1399,7 @@
     return ret;
 }
 
-BlockDriverAIOCB *bdrv_aio_write(BlockDriverState *bs, int64_t sector_num,
+static BlockDriverAIOCB *bdrv_aio_write(BlockDriverState *bs, int64_t sector_num,
                                  const uint8_t *buf, int nb_sectors,
                                  BlockDriverCompletionFunc *cb, void *opaque)
 {