diff --git a/crypto/bio/bss_acpt.c b/crypto/bio/bss_acpt.c
index e49c7ce5ea0135b8222d8f129a9ead9a28951476..e426ecd7fd7efd628e01415661677c22a56d7a47 100644
--- a/crypto/bio/bss_acpt.c
+++ b/crypto/bio/bss_acpt.c
@@ -61,11 +61,11 @@ static const BIO_METHOD methods_acceptp = {
     bread_conv,
     acpt_read,
     acpt_puts,
-    NULL,                       /* connect_gets, */
+    NULL,                       /* connect_gets,         */
     acpt_ctrl,
     acpt_new,
     acpt_free,
-    NULL,
+    NULL,                       /* connect_callback_ctrl */
 };
 
 const BIO_METHOD *BIO_s_accept(void)
diff --git a/crypto/bio/bss_conn.c b/crypto/bio/bss_conn.c
index 78e42d0525a2556cfce7433d4e2e5f4e546917cb..5c461ae751990c029657aa9950c7175df7f7a0d4 100644
--- a/crypto/bio/bss_conn.c
+++ b/crypto/bio/bss_conn.c
@@ -65,7 +65,7 @@ static const BIO_METHOD methods_connectp = {
     bread_conv,
     conn_read,
     conn_puts,
-    NULL,                       /* connect_gets, */
+    NULL,                       /* conn_gets, */
     conn_ctrl,
     conn_new,
     conn_free,
diff --git a/crypto/bio/bss_dgram.c b/crypto/bio/bss_dgram.c
index aad8c8511d9ee5d2f25d0081573737b733f84c48..90fe3c8efd2319b5f2ee79127275a0713fb25fe6 100644
--- a/crypto/bio/bss_dgram.c
+++ b/crypto/bio/bss_dgram.c
@@ -73,11 +73,11 @@ static const BIO_METHOD methods_dgramp = {
     bread_conv,
     dgram_read,
     dgram_puts,
-    NULL,                       /* dgram_gets, */
+    NULL,                       /* dgram_gets,         */
     dgram_ctrl,
     dgram_new,
     dgram_free,
-    NULL,
+    NULL,                       /* dgram_callback_ctrl */
 };
 
 # ifndef OPENSSL_NO_SCTP
@@ -91,11 +91,11 @@ static const BIO_METHOD methods_dgramp_sctp = {
     bread_conv,
     dgram_sctp_read,
     dgram_sctp_puts,
-    NULL,                       /* dgram_gets, */
+    NULL,                       /* dgram_gets,         */
     dgram_sctp_ctrl,
     dgram_sctp_new,
     dgram_sctp_free,
-    NULL,
+    NULL,                       /* dgram_callback_ctrl */
 };
 # endif
 
diff --git a/crypto/bio/bss_fd.c b/crypto/bio/bss_fd.c
index 269a08baa942faa847cf66608aa0df01ff9d4360..5bc539c90b961fb89cd7084f4ba9b3fe1e761c04 100644
--- a/crypto/bio/bss_fd.c
+++ b/crypto/bio/bss_fd.c
@@ -71,7 +71,7 @@ static const BIO_METHOD methods_fdp = {
     fd_ctrl,
     fd_new,
     fd_free,
-    NULL,
+    NULL,                       /* fd_callback_ctrl */
 };
 
 const BIO_METHOD *BIO_s_fd(void)
diff --git a/crypto/bio/bss_file.c b/crypto/bio/bss_file.c
index 25d7cc0f6b290d73ee4477a61dc06b6f08dc658e..8de2391267afe8d9d2b33edb03b0750ee12c1d46 100644
--- a/crypto/bio/bss_file.c
+++ b/crypto/bio/bss_file.c
@@ -56,7 +56,7 @@ static const BIO_METHOD methods_filep = {
     file_ctrl,
     file_new,
     file_free,
-    NULL,
+    NULL,                      /* file_callback_ctrl */
 };
 
 BIO *BIO_new_file(const char *filename, const char *mode)
@@ -408,7 +408,7 @@ static const BIO_METHOD methods_filep = {
     file_ctrl,
     file_new,
     file_free,
-    NULL,
+    NULL,                      /* file_callback_ctrl */
 };
 
 const BIO_METHOD *BIO_s_file(void)
diff --git a/crypto/bio/bss_log.c b/crypto/bio/bss_log.c
index 040fbcd2bbdada77992c5ec86ff46dc99acc3542..c26b10eeaec487f562b472b89af8186e437339b7 100644
--- a/crypto/bio/bss_log.c
+++ b/crypto/bio/bss_log.c
@@ -90,14 +90,14 @@ static const BIO_METHOD methods_slg = {
     /* TODO: Convert to new style write function */
     bwrite_conv,
     slg_write,
-    NULL,
-    NULL,
+    NULL,                      /* slg_write_old,    */
+    NULL,                      /* slg_read,         */
     slg_puts,
     NULL,
     slg_ctrl,
     slg_new,
     slg_free,
-    NULL,
+    NULL,                      /* slg_callback_ctrl */
 };
 
 const BIO_METHOD *BIO_s_log(void)
diff --git a/crypto/bio/bss_mem.c b/crypto/bio/bss_mem.c
index a50d416f2ddca5739cac4a648a78c3b60bbfd88f..7678a1df58c5273abb0f8c5aada95ca2090aea08 100644
--- a/crypto/bio/bss_mem.c
+++ b/crypto/bio/bss_mem.c
@@ -37,7 +37,7 @@ static const BIO_METHOD mem_method = {
     mem_ctrl,
     mem_new,
     mem_free,
-    NULL,
+    NULL,                      /* mem_callback_ctrl */
 };
 
 static const BIO_METHOD secmem_method = {
@@ -54,7 +54,7 @@ static const BIO_METHOD secmem_method = {
     mem_ctrl,
     secmem_new,
     mem_free,
-    NULL,
+    NULL,                      /* mem_callback_ctrl */
 };
 
 /* BIO memory stores buffer and read pointer  */
diff --git a/crypto/bio/bss_null.c b/crypto/bio/bss_null.c
index 13982c085189489c153eb074c0b6301ffaf137a7..df3a9214f940257f6d4b1f512639837dd5afa402 100644
--- a/crypto/bio/bss_null.c
+++ b/crypto/bio/bss_null.c
@@ -33,7 +33,7 @@ static const BIO_METHOD null_method = {
     null_ctrl,
     null_new,
     null_free,
-    NULL,
+    NULL,                     /* null_callback_ctrl */
 };
 
 const BIO_METHOD *BIO_s_null(void)
diff --git a/crypto/bio/bss_sock.c b/crypto/bio/bss_sock.c
index 09f127b92dfeae2cf10659be554fb44204cb2444..ad38453201f17114645ebda814c593ce43f40d2a 100644
--- a/crypto/bio/bss_sock.c
+++ b/crypto/bio/bss_sock.c
@@ -44,11 +44,11 @@ static const BIO_METHOD methods_sockp = {
     bread_conv,
     sock_read,
     sock_puts,
-    NULL,                       /* sock_gets, */
+    NULL,                       /* sock_gets,         */
     sock_ctrl,
     sock_new,
     sock_free,
-    NULL,
+    NULL,                       /* sock_callback_ctrl */
 };
 
 const BIO_METHOD *BIO_s_socket(void)
diff --git a/crypto/comp/c_zlib.c b/crypto/comp/c_zlib.c
index 5d82e15979bdd8fa6348287a612b44b8b8b3555e..d688deee5f23fbb3fea610d8c8788d3a715713f4 100644
--- a/crypto/comp/c_zlib.c
+++ b/crypto/comp/c_zlib.c
@@ -302,8 +302,8 @@ static const BIO_METHOD bio_meth_zlib = {
     /* TODO: Convert to new style read function */
     bread_conv,
     bio_zlib_read,
-    NULL,
-    NULL,
+    NULL,                      /* bio_zlib_puts, */
+    NULL,                      /* bio_zlib_gets, */
     bio_zlib_ctrl,
     bio_zlib_new,
     bio_zlib_free,
diff --git a/ssl/bio_ssl.c b/ssl/bio_ssl.c
index ccc0c769c5e0993b852a6f503e55a1d91b7121e7..d1876d8b8c1f4a37586641625e99b791adedd17a 100644
--- a/ssl/bio_ssl.c
+++ b/ssl/bio_ssl.c
@@ -37,11 +37,11 @@ static const BIO_METHOD methods_sslp = {
     BIO_TYPE_SSL,
     "ssl",
     ssl_write,
-    NULL,
+    NULL,                       /* ssl_write_old, */
     ssl_read,
-    NULL,
+    NULL,                       /* ssl_read_old,  */
     ssl_puts,
-    NULL,                       /* ssl_gets, */
+    NULL,                       /* ssl_gets,      */
     ssl_ctrl,
     ssl_new,
     ssl_free,