[PATCH v2] batman-adv: tracing: Use the new __vstring() helper

From: "Steven Rostedt (Google)" <rostedt@goodmis.org>

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: Marek Lindner <redacted>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Simon Wunderlich <sw@simonwunderlich.de>
Cc: Antonio Quartulli <redacted>
Cc: Sven Eckelmann <sven@narfation.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: b.a.t.m.a.n@lists.open-mesh.org
Cc: netdev@vger.kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
Changes since v1:  https://lkml.kernel.org/r/20220705224751.080390002@goodmis.org

 - Removed no longer used BATADV_MAX_MSG_LEN

 net/batman-adv/trace.h | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/net/batman-adv/trace.h b/net/batman-adv/trace.h
index d673ebdd0426..31c8f922651d 100644
--- a/net/batman-adv/trace.h
+++ b/net/batman-adv/trace.h

@@ -28,8 +28,6 @@
 
 #endif /* CONFIG_BATMAN_ADV_TRACING */
 
-#define BATADV_MAX_MSG_LEN	256
-
 TRACE_EVENT(batadv_dbg,
 
 	    TP_PROTO(struct batadv_priv *bat_priv,

@@ -40,16 +38,13 @@ TRACE_EVENT(batadv_dbg,
 	    TP_STRUCT__entry(
 		    __string(device, bat_priv->soft_iface->name)
 		    __string(driver, KBUILD_MODNAME)
-		    __dynamic_array(char, msg, BATADV_MAX_MSG_LEN)
+		    __vstring(msg, vaf->fmt, vaf->va)
 	    ),
 
 	    TP_fast_assign(
 		    __assign_str(device, bat_priv->soft_iface->name);
 		    __assign_str(driver, KBUILD_MODNAME);
-		    WARN_ON_ONCE(vsnprintf(__get_dynamic_array(msg),
-					   BATADV_MAX_MSG_LEN,
-					   vaf->fmt,
-					   *vaf->va) >= BATADV_MAX_MSG_LEN);
+		    __assign_vstr(msg, vaf->fmt, vaf->va);
 	    ),
 
 	    TP_printk(

-- 
2.35.1