[PATCH v3 1/2] dynamic debug: split enable and printk flags

From: Vincent Whitchurch
Date: Tue Aug 25 2020 - 11:33:55 EST


We're going to add support to allow dynamic debug locations to print to
a trace event, and that will make _DPRINTK_FLAGS_PRINT a bit ambiguous.
Will it mean printk(), or printing to the trace event, or any of the
two?

To make it clearer, split _DPRINTK_FLAGS_PRINT into two:

(1) _DPRINTK_FLAGS_PRINTK for turning on the printk() and
(2) _DPRINTK_FLAGS_ENABLE when checking if the dynamic debug location
is enabled.

_DPRINTK_FLAGS_ENABLE is currently just an alias of
_DPRINTK_FLAGS_PRINTK but will later also include a new flag for
enabling printing to the trace event.

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@xxxxxxxx>
---
include/linux/dynamic_debug.h | 9 +++++----
lib/dynamic_debug.c | 8 ++++----
2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index aa9ff9e1c0b3..738421898aac 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -27,13 +27,14 @@ struct _ddebug {
* writes commands to <debugfs>/dynamic_debug/control
*/
#define _DPRINTK_FLAGS_NONE 0
-#define _DPRINTK_FLAGS_PRINT (1<<0) /* printk() a message using the format */
+#define _DPRINTK_FLAGS_PRINTK (1<<0) /* printk() a message using the format */
#define _DPRINTK_FLAGS_INCL_MODNAME (1<<1)
#define _DPRINTK_FLAGS_INCL_FUNCNAME (1<<2)
#define _DPRINTK_FLAGS_INCL_LINENO (1<<3)
#define _DPRINTK_FLAGS_INCL_TID (1<<4)
+#define _DPRINTK_FLAGS_ENABLE _DPRINTK_FLAGS_PRINTK
#if defined DEBUG
-#define _DPRINTK_FLAGS_DEFAULT _DPRINTK_FLAGS_PRINT
+#define _DPRINTK_FLAGS_DEFAULT _DPRINTK_FLAGS_PRINTK
#else
#define _DPRINTK_FLAGS_DEFAULT 0
#endif
@@ -111,10 +112,10 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,

#ifdef DEBUG
#define DYNAMIC_DEBUG_BRANCH(descriptor) \
- likely(descriptor.flags & _DPRINTK_FLAGS_PRINT)
+ likely(descriptor.flags & _DPRINTK_FLAGS_ENABLE)
#else
#define DYNAMIC_DEBUG_BRANCH(descriptor) \
- unlikely(descriptor.flags & _DPRINTK_FLAGS_PRINT)
+ unlikely(descriptor.flags & _DPRINTK_FLAGS_ENABLE)
#endif

#endif
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 1d012e597cc3..88af85cb5222 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -84,7 +84,7 @@ static inline const char *trim_prefix(const char *path)
}

static struct { unsigned flag:8; char opt_char; } opt_array[] = {
- { _DPRINTK_FLAGS_PRINT, 'p' },
+ { _DPRINTK_FLAGS_PRINTK, 'p' },
{ _DPRINTK_FLAGS_INCL_MODNAME, 'm' },
{ _DPRINTK_FLAGS_INCL_FUNCNAME, 'f' },
{ _DPRINTK_FLAGS_INCL_LINENO, 'l' },
@@ -206,10 +206,10 @@ static int ddebug_change(const struct ddebug_query *query,
if (newflags == dp->flags)
continue;
#ifdef CONFIG_JUMP_LABEL
- if (dp->flags & _DPRINTK_FLAGS_PRINT) {
- if (!(modifiers->flags & _DPRINTK_FLAGS_PRINT))
+ if (dp->flags & _DPRINTK_FLAGS_ENABLE) {
+ if (!(modifiers->flags & _DPRINTK_FLAGS_ENABLE))
static_branch_disable(&dp->key.dd_key_true);
- } else if (modifiers->flags & _DPRINTK_FLAGS_PRINT)
+ } else if (modifiers->flags & _DPRINTK_FLAGS_ENABLE)
static_branch_enable(&dp->key.dd_key_true);
#endif
dp->flags = newflags;
--
2.28.0