From: Jan Blunck <jblu...@infradead.org>
This macro is based on Jan Viktorin's original patch but also checks the
type of the passed pointer against the type of the member.
Signed-off-by: Jan Viktorin <vikto...@rehivetech.com>
[shreyansh.j...@nxp.com: Fix checkpatch error]
Signed-off-by: Shreyansh Jain <shreyansh.j...@nxp.com>
[jblu...@infradead.org: add type checking and __extension__]
Signed-off-by: Jan Blunck <jblu...@infradead.org>
--
v2:
- fix checkpatch error
---
lib/librte_eal/common/include/rte_common.h | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/lib/librte_eal/common/include/rte_common.h
b/lib/librte_eal/common/include/rte_common.h
index db5ac91..3eb8d11 100644
--- a/lib/librte_eal/common/include/rte_common.h
+++ b/lib/librte_eal/common/include/rte_common.h
@@ -331,6 +331,27 @@ rte_bsf32(uint32_t v)
#define offsetof(TYPE, MEMBER) __builtin_offsetof (TYPE, MEMBER)
#endif
+/**
+ * Return pointer to the wrapping struct instance.
+ *
+ * Example:
+ *
+ * struct wrapper {
+ * ...
+ * struct child c;
+ * ...
+ * };
+ *
+ * struct child *x = obtain(...);
+ * struct wrapper *w = container_of(x, struct wrapper, c);
+ */
+#ifndef container_of
+#define container_of(ptr, type, member) (__extension__ ({
\
+ typeof(((type *)0)->member) * _ptr = (ptr); \
+ (type *)(((char *)_ptr) - offsetof(type, member));\
+ }))
+#endif
+
#define _RTE_STR(x) #x
/** Take a macro value and get a string version of it */
#define RTE_STR(x) _RTE_STR(x)
--
2.7.4
