[PATCH v2] USB: mtu3: tracing: Use the new __vstring() helper

[Steven Rostedt]

From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx>

Instead of open coding a __dynamic_array() with a fixed length (which
defeats the purpose of the dynamic array in the first place). Use the new
__vstring() helper that will use a va_list and only write enough of the
string into the ring buffer that is needed.

Cc: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: linux-usb@xxxxxxxxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-mediatek@xxxxxxxxxxxxxxxxxxx
Acked-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
Changes since v1: https://lkml.kernel.org/r/20220705224750.354926535@xxxxxxxxxxx

 - Removed MTU3_MSG_MAX define. (Chunfeng Yun)

 drivers/usb/mtu3/mtu3_trace.h | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/mtu3/mtu3_trace.h b/drivers/usb/mtu3/mtu3_trace.h
index 1b897636daf2..a98fa012b729 100644
--- a/drivers/usb/mtu3/mtu3_trace.h
+++ b/drivers/usb/mtu3/mtu3_trace.h
@@ -18,18 +18,16 @@
 
 #include "mtu3.h"
 
-#define MTU3_MSG_MAX	256
-
 TRACE_EVENT(mtu3_log,
 	TP_PROTO(struct device *dev, struct va_format *vaf),
 	TP_ARGS(dev, vaf),
 	TP_STRUCT__entry(
 		__string(name, dev_name(dev))
-		__dynamic_array(char, msg, MTU3_MSG_MAX)
+		__vstring(msg, vaf->fmt, vaf->va)
 	),
 	TP_fast_assign(
 		__assign_str(name, dev_name(dev));
-		vsnprintf(__get_str(msg), MTU3_MSG_MAX, vaf->fmt, *vaf->va);
+		__assign_vstr(msg, vaf->fmt, vaf->va);
 	),
 	TP_printk("%s: %s", __get_str(name), __get_str(msg))
 );
-- 
2.35.1