Thread (67 messages) 67 messages, 2 authors, 2025-09-08

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

From: Louis Chauvet <louis.chauvet@bootlin.com>
Date: 2025-09-05 21:19:09
Also in: amd-gfx, dri-devel, intel-gfx, linux-arm-msm, lkml


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@gmail.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
quoted hunk ↗ jump to hunk
---
---
  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

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