[PATCH v11 16/19] drm_print: add struct _ddebug desc to drm_*dbg

Jim Cromie
2022-01-07T05:30:37Z

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 | 25 ++++++++++++++++---------
include/drm/drm_print.h | 20 ++++++++++----------
2 files changed, 26 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
index b911f949af5b..8c33302212fc 100644
--- a/drivers/gpu/drm/drm_print.c
+++ b/drivers/gpu/drm/drm_print.c
@@ -258,8 +258,8 @@ 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;
@@ -267,24 +267,31 @@ void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
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;
diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
index 0c704610c770..6d43b81a0ee4 100644
--- a/include/drm/drm_print.h
+++ b/include/drm/drm_print.h
@@ -360,9 +360,9 @@ 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.
@@ -412,11 +412,11 @@ 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, eCat, fmt, ...) \
- __drm_dev_dbg(dev, eCat, fmt, ##__VA_ARGS__)
+ __drm_dev_dbg(NULL, dev, eCat, fmt, ##__VA_ARGS__)
#else
#define drm_dev_dbg(dev, eCat, fmt, ...) \
- _dynamic_func_call_no_desc_cls(fmt, eCat, __drm_dev_dbg, \
- dev, eCat, fmt, ##__VA_ARGS__)
+ _dynamic_func_call_cls(eCat, fmt, __drm_dev_dbg, \
+ dev, eCat, fmt, ##__VA_ARGS__)
#endif

/**
@@ -519,8 +519,8 @@ 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, ...);

@@ -528,8 +528,8 @@ void __drm_err(const char *format, ...);
#define __drm_dbg(fmt, ...) ___drm_dbg(NULL, fmt, ##__VA_ARGS__)
#else
#define __drm_dbg(eCat, fmt, ...) \
- _dynamic_func_call_no_desc_cls(fmt, eCat, ___drm_dbg, \
- eCat, fmt, ##__VA_ARGS__)
+ _dynamic_func_call_cls(eCat, fmt, ___drm_dbg, \
+ eCat, fmt, ##__VA_ARGS__)
#endif

/* Macros to make printk easier */
--
2.33.1