[RFC PATCH 17/17] CODING_STYLE: Add a section on header guards naming conventions

[Alessandro Zucchelli <alessandro.zucchelli@xxxxxxxxxxx>]

This section explains which format should be followed by header
inclusion guards via a drop-down list of rules.

No functional change.

Signed-off-by: Alessandro Zucchelli <alessandro.zucchelli@xxxxxxxxxxx>
---
 CODING_STYLE | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/CODING_STYLE b/CODING_STYLE
index 7f6e9ad065..87836c97d4 100644
--- a/CODING_STYLE
+++ b/CODING_STYLE
@@ -167,3 +167,22 @@ the end of files.  It should be:
  * indent-tabs-mode: nil
  * End:
  */
+
+Header inclusion guards
+-----------------------
+
+Unless differently specified all header files should have proper inclusion
+guards in order to avoid being included multiple times.
+The following naming conventions have been devised:
+- private headers -> <dir>_<filename>_H
+- asm-generic headers -> ASM_GENERIC_<filename>_H
+    - #ifndef ASM_GENERIC_X86_PERCPU_H
+      #define ASM_GENERIC_X86_PERCPU_H
+      //...
+      #endif /* ASM_GENERIC_X86_PERCPU_H */
+- arch/<architecture>/include/asm/<subdir>/<filename>.h -> 
ASM_<architecture>_<subdir>_<filename>_H
+    - #ifndef ASM_X86_DOMAIN_H
+      #define ASM_X86_DOMAIN_H
+      //...
+      #endif /* ASM_X86_DOMAIN_H */
+
-- 
2.34.1