drm_print: add struct _ddebug desc to drm_*dbg

A recent commit adding trace-events to drm noted:

   trace_*() additions are strictly redundant with printks to syslog,
   not properly placed to reduce overall work.

That was because it didn't have the struct _ddebug *descriptor, whose
.flags specify TRACE and PRINTK actions on a controlled callsite.  So
it could only duplicate the stream (from the enabled callsites).

To issue TRACE, PRINTK selectively:

- add struct _ddebug * param to prototypes and functions:
  ___drm_dbg(), __drm_dev_dbg()
  add "struct _ddebug;" to name the ptr-type, to silence warning.

- adjust the forwarding macros: drm_dbg, drm_dev_dbg
  to provide a descriptor, or NULL.
  basically this is dropping the _no_desc_,
  ie using _dynamic_func_call_cls(), since the callee can now accept it.

- add if (desc->flags ...) TRACE / PRINTK actions.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>

drivers/gpu/drm/drm_print.c

@@ -274,33 +274,40 @@ void drm_dev_printk(const struct device *dev, const char *level,
 }
 EXPORT_SYMBOL(drm_dev_printk);
 
-void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
-		   const char *format, ...)
+void __drm_dev_dbg(struct _ddebug *desc, const struct device *dev,
+		   enum drm_debug_category category, const char *format, ...)
 {
 	struct va_format vaf;
 	va_list args;
 
 	if (!__drm_debug_enabled(category))
 		return;
 
+	/* we know we are printing for either syslog, tracefs, or both */
 	va_start(args, format);
 	vaf.fmt = format;
 	vaf.va = &args;
 
 	if (dev) {
-		dev_printk(KERN_DEBUG, dev, "[" DRM_NAME ":%ps] %pV",
-			   __builtin_return_address(0), &vaf);
-		trace_drm_devdbg(dev, category, &vaf);
+		if (desc->flags & _DPRINTK_FLAGS_PRINTK)
+			dev_printk(KERN_DEBUG, dev, "[" DRM_NAME ":%ps] %pV",
+				   __builtin_return_address(0), &vaf);
+
+		if (desc->flags & _DPRINTK_FLAGS_TRACE)
+			trace_drm_devdbg(dev, category, &vaf);
 	} else {
-		printk(KERN_DEBUG "[" DRM_NAME ":%ps] %pV",
-		       __builtin_return_address(0), &vaf);
-		trace_drm_debug(category, &vaf);
+		if (desc->flags & _DPRINTK_FLAGS_PRINTK)
+			printk(KERN_DEBUG "[" DRM_NAME ":%ps] %pV",
+			       __builtin_return_address(0), &vaf);
+
+		if (desc->flags & _DPRINTK_FLAGS_TRACE)
+			trace_drm_debug(category, &vaf);
 	}
 	va_end(args);
 }
 EXPORT_SYMBOL(__drm_dev_dbg);
 
-void ___drm_dbg(enum drm_debug_category category, const char *format, ...)
+void ___drm_dbg(struct _ddebug *desc, enum drm_debug_category category, const char *format, ...)
 {
 	struct va_format vaf;
 	va_list args;

include/drm/drm_print.h

@@ -362,9 +362,9 @@ static inline bool drm_debug_enabled(enum drm_debug_category category)
 __printf(3, 4)
 void drm_dev_printk(const struct device *dev, const char *level,
 		    const char *format, ...);
-__printf(3, 4)
-void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
-		 const char *format, ...);
+__printf(4, 5)
+void __drm_dev_dbg(struct _ddebug *desc, const struct device *dev,
+		   enum drm_debug_category category, const char *format, ...);
 
 /**
  * DRM_DEV_ERROR() - Error output.
@@ -414,11 +414,11 @@ void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
 
 #if !defined(CONFIG_DRM_USE_DYNAMIC_DEBUG)
 #define drm_dev_dbg(dev, cat, fmt, ...)				\
-	__drm_dev_dbg(dev, cat, fmt, ##__VA_ARGS__)
+	__drm_dev_dbg(NULL, dev, cat, fmt, ##__VA_ARGS__)
 #else
 #define drm_dev_dbg(dev, cat, fmt, ...)				\
-	_dynamic_func_call_no_desc_cls(fmt, cat, __drm_dev_dbg,	\
-				       dev, cat, fmt, ##__VA_ARGS__)
+	_dynamic_func_call_cls(cat, fmt, __drm_dev_dbg,		\
+			       dev, cat, fmt, ##__VA_ARGS__)
 #endif
 
 /**
@@ -521,17 +521,17 @@ void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
  * Prefer drm_device based logging over device or prink based logging.
  */
 
-__printf(2, 3)
-void ___drm_dbg(enum drm_debug_category category, const char *format, ...);
+__printf(3, 4)
+void ___drm_dbg(struct _ddebug *desc, enum drm_debug_category category, const char *format, ...);
 __printf(1, 2)
 void __drm_err(const char *format, ...);
 
 #if !defined(CONFIG_DRM_USE_DYNAMIC_DEBUG)
 #define __drm_dbg(cat, fmt, ...)	___drm_dbg(cat, fmt, ##__VA_ARGS__)
 #else
 #define __drm_dbg(cat, fmt, ...)					\
-	_dynamic_func_call_no_desc_cls(fmt, cat, ___drm_dbg,		\
-				       cat, fmt, ##__VA_ARGS__)
+	_dynamic_func_call_cls(cat, fmt, ___drm_dbg,			\
+			       cat, fmt, ##__VA_ARGS__)
 #endif
 
 /* Macros to make printk easier */