LAN9118 improvements

[qemu.git] / osdep.h

diff --git a/osdep.h b/osdep.h
index 32ee94b5ad48892eced2158f4c5b3d3ff5d53cb7..75b581630f2a26e7c374884f7b8b700232d5eca3 100644 (file)
--- a/osdep.h
+++ b/osdep.h
@@ -2,6 +2,7 @@
 #define QEMU_OSDEP_H
 
 #include <stdarg.h>
+#include <stddef.h>
 #ifdef __OpenBSD__
 #include <sys/types.h>
 #include <sys/signal.h>
@@ -27,7 +28,7 @@
 #define unlikely(x)   __builtin_expect(!!(x), 0)
 #endif
 
-#ifndef offsetof
+#ifdef CONFIG_NEED_OFFSETOF
 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *) 0)->MEMBER)
 #endif
 #ifndef container_of
@@ -36,6 +37,16 @@
         (type *) ((char *) __mptr - offsetof(type, member));})
 #endif
 
+/* Convert from a base type to a parent type, with compile time checking.  */
+#ifdef __GNUC__
+#define DO_UPCAST(type, field, dev) ( __extension__ ( { \
+    char __attribute__((unused)) offset_must_be_zero[ \
+        -offsetof(type, field)]; \
+    container_of(dev, type, field);}))
+#else
+#define DO_UPCAST(type, field, dev) container_of(dev, type, field)
+#endif
+
 #define typeof_field(type, field) typeof(((type *)0)->field)
 #define type_check(t1,t2) ((t1*)0 - (t2*)0)