[RFC PATCH v3 09/18] dyndbg: optimize ddebug_emit_prefix

[Jim Cromie]

Add early return if no callsite info is specified in site-flags.
This avoids fetching site info that isn't going to be printed.

Signed-off-by: Jim Cromie <jim.cromie@xxxxxxxxx>
---
 include/linux/dynamic_debug.h | 9 +++++++++
 lib/dynamic_debug.c           | 3 +++
 2 files changed, 12 insertions(+)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index bc8027292c02..aa4a3f5d8d35 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -40,6 +40,15 @@ struct _ddebug {
 #define _DPRINTK_FLAGS_INCL_FUNCNAME	(1<<2)
 #define _DPRINTK_FLAGS_INCL_LINENO	(1<<3)
 #define _DPRINTK_FLAGS_INCL_TID		(1<<4)
+
+#define _DPRINTK_FLAGS_INCL_ANYSITE		\
+	(_DPRINTK_FLAGS_INCL_MODNAME		\
+	 | _DPRINTK_FLAGS_INCL_FUNCNAME		\
+	 | _DPRINTK_FLAGS_INCL_LINENO)
+#define _DPRINTK_FLAGS_INCL_ANY			\
+	(_DPRINTK_FLAGS_INCL_ANYSITE		\
+	 | _DPRINTK_FLAGS_INCL_TID)
+
 #if defined DEBUG
 #define _DPRINTK_FLAGS_DEFAULT _DPRINTK_FLAGS_PRINT
 #else
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 1f0cac4a66af..af9cf97f869b 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -632,6 +632,9 @@ static char *dynamic_emit_prefix(const struct _ddebug *dp, char *buf)
 	}
 	pos_after_tid = pos;
 
+	if (!(dp->flags & _DPRINTK_FLAGS_INCL_ANYSITE))
+		return buf;
+
 	if (desc) {
 		if (dp->flags & _DPRINTK_FLAGS_INCL_MODNAME)
 			pos += snprintf(buf + pos, remaining(pos), "%s:",
-- 
2.29.2