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authorMark McLoughlin <markmc@redhat.com>2009-11-25 18:49:03 +0000
committerAnthony Liguori <aliguori@us.ibm.com>2009-12-03 09:41:29 -0600
commit5096fae3fdabc889545ecae508e3dbd0579fcbc9 (patch)
treece109252b3dfda5add1b80e8ea6bc5f3aec7d57d /osdep.h
parent45460d1a53d202550945e2b144af8ebb1d62bed0 (diff)
qdev: move DO_UPCAST() into osdep.h
Nothing qdev specific about this, make it available throughtout. Signed-off-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Diffstat (limited to 'osdep.h')
-rw-r--r--osdep.h10
1 files changed, 10 insertions, 0 deletions
diff --git a/osdep.h b/osdep.h
index 4b4aad4d49..75b581630f 100644
--- a/osdep.h
+++ b/osdep.h
@@ -37,6 +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)