diff --git a/src/openvpn/buffer.c b/src/openvpn/buffer.c
index 75110ed..07e3985 100644
--- a/src/openvpn/buffer.c
+++ b/src/openvpn/buffer.c
@@ -43,7 +43,7 @@
     unsigned long long res =
         (unsigned long long)m1 * (unsigned long long)m2 + (unsigned long long)extra;
     if (unlikely(m1 > limit) || unlikely(m2 > limit) || unlikely(extra > limit)
-        || unlikely(res > (unsigned long long)limit))
+        || unlikely(res > limit))
     {
         msg(M_FATAL, "attempted allocation of excessively large array");
     }
@@ -53,7 +53,7 @@
 void
 buf_size_error(const size_t size)
 {
-    msg(M_FATAL, "fatal buffer size error, size=%lu", (unsigned long)size);
+    msg(M_FATAL, "fatal buffer size error, size=%zu", size);
 }
 
 struct buffer
diff --git a/src/openvpn/mbuf.c b/src/openvpn/mbuf.c
index 5e1b585..7b790ed 100644
--- a/src/openvpn/mbuf.c
+++ b/src/openvpn/mbuf.c
@@ -34,11 +34,6 @@
 
 #include "memdbg.h"
 
-#if defined(__GNUC__) || defined(__clang__)
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wconversion"
-#endif
-
 struct mbuf_set *
 mbuf_init(unsigned int size)
 {
@@ -46,22 +41,17 @@
 
     struct mbuf_set *ret;
     ALLOC_OBJ_CLEAR(ret, struct mbuf_set);
-    ret->capacity = adjust_power_of_2(size);
+    ret->capacity = (unsigned int)adjust_power_of_2(size);
     ALLOC_ARRAY(ret->array, struct mbuf_item, ret->capacity);
     return ret;
 }
 
-#if defined(__GNUC__) || defined(__clang__)
-#pragma GCC diagnostic pop
-#endif
-
 void
 mbuf_free(struct mbuf_set *ms)
 {
     if (ms)
     {
-        int i;
-        for (i = 0; i < (int)ms->len; ++i)
+        for (unsigned int i = 0; i < ms->len; ++i)
         {
             struct mbuf_item *item = &ms->array[MBUF_INDEX(ms->head, i, ms->capacity)];
             mbuf_free_buf(item->buffer);
@@ -145,8 +135,7 @@
     struct multi_instance *ret = NULL;
     if (ms)
     {
-        int i;
-        for (i = 0; i < (int)ms->len; ++i)
+        for (unsigned int i = 0; i < ms->len; ++i)
         {
             struct mbuf_item *item = &ms->array[MBUF_INDEX(ms->head, i, ms->capacity)];
             if (item->instance)
@@ -164,8 +153,7 @@
 {
     if (ms)
     {
-        int i;
-        for (i = 0; i < (int)ms->len; ++i)
+        for (unsigned int i = 0; i < ms->len; ++i)
         {
             struct mbuf_item *item = &ms->array[MBUF_INDEX(ms->head, i, ms->capacity)];
             if (item->instance == mi)