[PATCH 1/5] linux/kernel.h: Add sizeof_member macro

[Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com>]

At present we have 3 different macros to calculate the size of a
member of a struct:
  - SIZEOF_FIELD
  - FIELD_SIZEOF
  - sizeof_field

To bring uniformity in entire kernel source tree let's add
sizeof_member macro.

Replace all occurrences of above 3 macro's with sizeof_member in
future patches.

Signed-off-by: Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com>
---
 include/linux/kernel.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 4fa360a13c1e..0b80d8bb3978 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -79,6 +79,15 @@
  */
 #define round_down(x, y) ((x) & ~__round_mask(x, y))
 
+/**
+ * sizeof_member - get the size of a struct's member
+ * @T: the target struct
+ * @m: the target struct's member
+ * Return: the size of @m in the struct definition without having a
+ * declared instance of @T.
+ */
+#define sizeof_member(T, m) (sizeof(((T *)0)->m))
+
 /**
  * FIELD_SIZEOF - get the size of a struct's field
  * @t: the target struct
-- 
2.17.1