Documentation: checkpatch: Add TRAILING_SEMICOLON message
Add a new message type TRAILING_SEMICOLON for the macro definitions
that conclude with a semicolon.
Suggested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Utkarsh Verma <utkarshverma294@gmail.com>
Link: https://lore.kernel.org/r/20210904074201.13532-1-utkarshverma294@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/Documentation/dev-tools/checkpatch.rst b/Documentation/dev-tools/checkpatch.rst
index b7a1288..891779c 100644
--- a/Documentation/dev-tools/checkpatch.rst
+++ b/Documentation/dev-tools/checkpatch.rst
@@ -851,6 +851,27 @@
Use the `fallthrough;` pseudo keyword instead of
`/* fallthrough */` like comments.
+ **TRAILING_SEMICOLON**
+ Macro definition should not end with a semicolon. The macro
+ invocation style should be consistent with function calls.
+ This can prevent any unexpected code paths::
+
+ #define MAC do_something;
+
+ If this macro is used within a if else statement, like::
+
+ if (some_condition)
+ MAC;
+
+ else
+ do_something;
+
+ Then there would be a compilation error, because when the macro is
+ expanded there are two trailing semicolons, so the else branch gets
+ orphaned.
+
+ See: https://lore.kernel.org/lkml/1399671106.2912.21.camel@joe-AO725/
+
**WEAK_DECLARATION**
Using weak declarations like __attribute__((weak)) or __weak
can have unintended link defects. Avoid using them.