batman-adv: tracing: Use the new __vstring() helper

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.

Link: https://lkml.kernel.org/r/20220724191650.236b1355@rorschach.local.home
Cc: Marek Lindner <mareklindner@neomailbox.ch>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Simon Wunderlich <sw@simonwunderlich.de>
Cc: Antonio Quartulli <a@unstable.cc>
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
Acked-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

diff --git a/net/batman-adv/trace.h b/net/batman-adv/trace.h
index d673ebdd042673b86b2d497926a1cbabe769cf7f..31c8f922651d587538508375fa413c9e6b416e56 100644 (file)
--- 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(