Backport of container_of macro

This nifty little macro is used a lot in 2.5 but does not exist in 2.4 yet. Here is a patch to include it.

Hanna

kernel.h | 11 +++++++++++

1 files changed, 11 insertions(+)

diff -Nru linux-2.4.20-rc1/include/linux/kernel.h linux-container_of/include/linux/kernel.h
@@ -174,6 +174,17 @@

extern void __out_of_line_bug(int line) ATTRIB_NORET; #define out_of_line_bug() __out_of_line_bug(__LINE__)

+/*
+ * container_of - cast a member of a structure out to the containing structure
+ *

+ * @ptr:        the pointer to the member.
+ * @type:       the type of the container struct this is embedded in.
+ * @member:     the name of the member within the struct.

+ */
+#define container_of(ptr, type, member) ({ \
+ const typeof( ((type *)0)->member ) *__mptr = (ptr); \
+ (type *)( (char *)__mptr - offsetof(type,member) );})
+
#endif /* __KERNEL__ */

#define SI_LOAD_SHIFT 16