[PATCH v4 18/58] dyndbg: change __dynamic_func_call_cls* macros into expressions

[Louis Chauvet]

Le 03/08/2025 à 05:57, Jim Cromie a écrit :
> The Xe driver's XE_IOCTL_DBG macro calls drm_dbg() from inside an if
> (expression).  This breaks when CONFIG_DRM_USE_DYNAMIC_DEBUG=y because
> the invoked macro has a do-while-0 wrapper, and is not an expression.
> 
>     if (cond && (drm_dbg("expr-form"),1)) {
>        ... do some more stuff
>     }
> 
> Fix for this usage by changing __dynamic_func_call_cls{,_no_desc}
> macros into expressions, by replacing the do-while-0s with a ({ })
> wrapper.  In the common usage, the trailing ';' converts the
> expression into a statement.
> 
>     drm_dbg("statement form");
> 
> Signed-off-by: Jim Cromie <jim.cromie at gmail.com>

Reviewed-by: Louis Chauvet <louis.chauvet at bootlin.com>

> ---
> ---
>   include/linux/dynamic_debug.h | 8 ++++----
>   1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
> index 769f02456c8e0..1785ef5b93b15 100644
> --- a/include/linux/dynamic_debug.h
> +++ b/include/linux/dynamic_debug.h
> @@ -217,20 +217,20 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
>    * (|_cls):	adds in _DPRINT_CLASS_DFLT as needed
>    * (|_no_desc):	former gets callsite descriptor as 1st arg (for prdbgs)
>    */
> -#define __dynamic_func_call_cls(id, cls, fmt, func, ...) do {	\
> +#define __dynamic_func_call_cls(id, cls, fmt, func, ...) ({	\
>   	DEFINE_DYNAMIC_DEBUG_METADATA_CLS(id, cls, fmt);	\
>   	if (DYNAMIC_DEBUG_BRANCH(id))				\
>   		func(&id, ##__VA_ARGS__);			\
> -} while (0)
> +})
>   #define __dynamic_func_call(id, fmt, func, ...)				\
>   	__dynamic_func_call_cls(id, _DPRINTK_CLASS_DFLT, fmt,		\
>   				func, ##__VA_ARGS__)
>   
> -#define __dynamic_func_call_cls_no_desc(id, cls, fmt, func, ...) do {	\
> +#define __dynamic_func_call_cls_no_desc(id, cls, fmt, func, ...) ({	\
>   	DEFINE_DYNAMIC_DEBUG_METADATA_CLS(id, cls, fmt);		\
>   	if (DYNAMIC_DEBUG_BRANCH(id))					\
>   		func(__VA_ARGS__);					\
> -} while (0)
> +})
>   #define __dynamic_func_call_no_desc(id, fmt, func, ...)			\
>   	__dynamic_func_call_cls_no_desc(id, _DPRINTK_CLASS_DFLT,	\
>   					fmt, func, ##__VA_ARGS__)

-- 
Louis Chauvet, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com