diff --git a/block/copy-on-read.c b/block/copy-on-read.c
index 64dcc424b5..d670fec42b 100644
--- a/block/copy-on-read.c
+++ b/block/copy-on-read.c
@@ -134,7 +134,7 @@ static bool cor_recurse_is_first_non_filter(BlockDriverState *bs,
 }
 
 
-BlockDriver bdrv_copy_on_read = {
+static BlockDriver bdrv_copy_on_read = {
     .format_name                        = "copy-on-read",
 
     .bdrv_open                          = cor_open,
diff --git a/block/crypto.c b/block/crypto.c
index fd8c7cfac6..3af46b805f 100644
--- a/block/crypto.c
+++ b/block/crypto.c
@@ -625,7 +625,7 @@ static const char *const block_crypto_strong_runtime_opts[] = {
     NULL
 };
 
-BlockDriver bdrv_crypto_luks = {
+static BlockDriver bdrv_crypto_luks = {
     .format_name        = "luks",
     .instance_size      = sizeof(BlockCrypto),
     .bdrv_probe         = block_crypto_probe_luks,
diff --git a/block/replication.c b/block/replication.c
index b95bd28802..3d4dedddfc 100644
--- a/block/replication.c
+++ b/block/replication.c
@@ -682,7 +682,7 @@ static const char *const replication_strong_runtime_opts[] = {
     NULL
 };
 
-BlockDriver bdrv_replication = {
+static BlockDriver bdrv_replication = {
     .format_name                = "replication",
     .instance_size              = sizeof(BDRVReplicationState),