diff --git a/dlls/ntdll/cdrom.c b/dlls/ntdll/cdrom.c
index f288bfe4df8..e245aadcc8a 100644
--- a/dlls/ntdll/cdrom.c
+++ b/dlls/ntdll/cdrom.c
@@ -1738,7 +1738,7 @@ static NTSTATUS CDROM_GetAddress(int fd, SCSI_ADDRESS* address)
  *
  *
  */
-static NTSTATUS DVD_StartSession(int fd, PDVD_SESSION_ID sid_in, PDVD_SESSION_ID sid_out)
+static NTSTATUS DVD_StartSession(int fd, const DVD_SESSION_ID *sid_in, PDVD_SESSION_ID sid_out)
 {
 #if defined(linux)
     NTSTATUS ret = STATUS_NOT_SUPPORTED;
@@ -1746,7 +1746,7 @@ static NTSTATUS DVD_StartSession(int fd, PDVD_SESSION_ID sid_in, PDVD_SESSION_ID
 
     memset( &auth_info, 0, sizeof( auth_info ) );
     auth_info.type = DVD_LU_SEND_AGID;
-    if (sid_in) auth_info.lsa.agid = *(int*)sid_in; /* ?*/
+    if (sid_in) auth_info.lsa.agid = *(const int*)sid_in; /* ?*/
 
     TRACE("fd 0x%08x\n",fd);
     ret =CDROM_GetStatusCode(ioctl(fd, DVD_AUTH, &auth_info));
@@ -1764,14 +1764,14 @@ static NTSTATUS DVD_StartSession(int fd, PDVD_SESSION_ID sid_in, PDVD_SESSION_ID
  *
  *
  */
-static NTSTATUS DVD_EndSession(int fd, PDVD_SESSION_ID sid)
+static NTSTATUS DVD_EndSession(int fd, const DVD_SESSION_ID *sid)
 {
 #if defined(linux)
     dvd_authinfo auth_info;
 
     memset( &auth_info, 0, sizeof( auth_info ) );
     auth_info.type = DVD_INVALIDATE_AGID;
-    auth_info.lsa.agid = *(int*)sid;
+    auth_info.lsa.agid = *(const int*)sid;
 
     TRACE("\n");
     return CDROM_GetStatusCode(ioctl(fd, DVD_AUTH, &auth_info));
@@ -1787,7 +1787,7 @@ static NTSTATUS DVD_EndSession(int fd, PDVD_SESSION_ID sid)
  *
  *
  */
-static NTSTATUS DVD_SendKey(int fd, PDVD_COPY_PROTECT_KEY key)
+static NTSTATUS DVD_SendKey(int fd, const DVD_COPY_PROTECT_KEY *key)
 {
 #if defined(linux)
     NTSTATUS ret = STATUS_NOT_SUPPORTED;
@@ -1931,7 +1931,7 @@ static NTSTATUS DVD_GetRegion(int dev, PDVD_REGION region)
  *
  *
  */
-static NTSTATUS DVD_ReadStructure(int dev, PDVD_READ_STRUCTURE structure, PDVD_LAYER_DESCRIPTOR layer)
+static NTSTATUS DVD_ReadStructure(int dev, const DVD_READ_STRUCTURE *structure, PDVD_LAYER_DESCRIPTOR layer)
 {
 #ifdef DVD_READ_STRUCT
     dvd_struct s;
diff --git a/dlls/ntdll/debugbuffer.c b/dlls/ntdll/debugbuffer.c
index e9625974975..be1ddffc1da 100644
--- a/dlls/ntdll/debugbuffer.c
+++ b/dlls/ntdll/debugbuffer.c
@@ -35,7 +35,7 @@
 
 WINE_DEFAULT_DEBUG_CHANNEL(debug_buffer);
 
-static void dump_DEBUG_MODULE_INFORMATION(PDEBUG_MODULE_INFORMATION iBuf)
+static void dump_DEBUG_MODULE_INFORMATION(const DEBUG_MODULE_INFORMATION *iBuf)
 {
   TRACE( "MODULE_INFORMATION:%p\n", iBuf );
   if (NULL == iBuf) return ;
@@ -44,7 +44,7 @@ static void dump_DEBUG_MODULE_INFORMATION(PDEBUG_MODULE_INFORMATION iBuf)
   TRACE( "Flags:%d\n", iBuf->Flags );
 }
 
-static void dump_DEBUG_HEAP_INFORMATION(PDEBUG_HEAP_INFORMATION iBuf)
+static void dump_DEBUG_HEAP_INFORMATION(const DEBUG_HEAP_INFORMATION *iBuf)
 {
   TRACE( "HEAP_INFORMATION:%p\n", iBuf );
   if (NULL == iBuf) return ;
@@ -52,7 +52,7 @@ static void dump_DEBUG_HEAP_INFORMATION(PDEBUG_HEAP_INFORMATION iBuf)
   TRACE( "Flags:%d\n", iBuf->Flags );
 }
 
-static void dump_DEBUG_LOCK_INFORMATION(PDEBUG_LOCK_INFORMATION iBuf)
+static void dump_DEBUG_LOCK_INFORMATION(const DEBUG_LOCK_INFORMATION *iBuf)
 {
   TRACE( "LOCK_INFORMATION:%p\n", iBuf );
 
@@ -70,7 +70,7 @@ static void dump_DEBUG_LOCK_INFORMATION(PDEBUG_LOCK_INFORMATION iBuf)
   TRACE( "NumberOfExclusiveWaiters:%d\n", iBuf->NumberOfExclusiveWaiters );
 }
 
-static void dump_DEBUG_BUFFER(PDEBUG_BUFFER iBuf)
+static void dump_DEBUG_BUFFER(const DEBUG_BUFFER *iBuf)
 {
   if (NULL == iBuf) return ;
   TRACE( "SectionHandle:%p\n", iBuf->SectionHandle);
diff --git a/dlls/ntdll/directory.c b/dlls/ntdll/directory.c
index 5eac7f383f1..99754556118 100644
--- a/dlls/ntdll/directory.c
+++ b/dlls/ntdll/directory.c
@@ -161,7 +161,7 @@ static inline BOOL is_invalid_dos_char( WCHAR ch )
 }
 
 /* check if the device can be a mounted volume */
-static inline int is_valid_mounted_device( struct stat *st )
+static inline int is_valid_mounted_device( const struct stat *st )
 {
 #if defined(linux) || defined(__sun__)
     return S_ISBLK( st->st_mode );