2021-09-04 08:00:44

by Utkarsh Verma

Subject: [PATCH] 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 <[email protected]>
Signed-off-by: Utkarsh Verma <[email protected]>
---
Documentation/dev-tools/checkpatch.rst | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)

diff --git a/Documentation/dev-tools/checkpatch.rst b/Documentation/dev-tools/checkpatch.rst
index f0956e9ea2d8..30eda8f4a8bd 100644
--- a/Documentation/dev-tools/checkpatch.rst
+++ b/Documentation/dev-tools/checkpatch.rst
@@ -845,6 +845,27 @@ Macros, Attributes and Symbols
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.
--
2.25.1

2021-09-14 21:09:10

by Jonathan Corbet

Subject: Re: [PATCH] Documentation: checkpatch: Add TRAILING_SEMICOLON message

Utkarsh Verma <[email protected]> writes:

> Add a new message type TRAILING_SEMICOLON for the macro definitions
> that conclude with a semicolon.
>
> Suggested-by: Lukas Bulwahn <[email protected]>
> Signed-off-by: Utkarsh Verma <[email protected]>
> ---
> Documentation/dev-tools/checkpatch.rst | 21 +++++++++++++++++++++
> 1 file changed, 21 insertions(+)

Applied, thanks.

jon