[batman-adv] master: batman-adv: tracing: Use the new __vstring() helper (fce06f6d) - commits - lists.open-mesh.org

17 Aug 2022

Repository : ssh://git@diktynna/batman-adv
On branch  : master
...

commit fce06f6da01b39e16391de141466fb7e0a35c02e
Author: Steven Rostedt (Google) rostedt@goodmis.org
Date:   Sun Jul 31 15:03:31 2022 -0400
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
    [sven@narfation.org: add compat code]
    Signed-off-by: Sven Eckelmann sven@narfation.org
...

fce06f6da01b39e16391de141466fb7e0a35c02e
 compat-include/linux/tracepoint.h | 24 ++++++++++++++++++++++++
 net/batman-adv/trace.h            |  9 ++-------
 2 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/compat-include/linux/tracepoint.h b/compat-include/linux/tracepoint.h
new file mode 100644
index 00000000..4a79f51a
--- /dev/null
+++ b/compat-include/linux/tracepoint.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) B.A.T.M.A.N. contributors:
+ *
+ * Marek Lindner, Simon Wunderlich
+ *
+ * This file contains macros for maintaining compatibility with older versions
+ * of the Linux kernel.
+ */
+
+#ifndef _NET_BATMAN_ADV_COMPAT_LINUX_TRACEPOINT_H_
+#define _NET_BATMAN_ADV_COMPAT_LINUX_TRACEPOINT_H_
+
+#include <linux/version.h>
+#include_next <linux/tracepoint.h>
+
+#if LINUX_VERSION_IS_LESS(6, 0, 0)
+
+#define __vstring(item, fmt, ap) __dynamic_array(char, item, 256)
+#define __assign_vstr(dst, fmt, va) \
+	WARN_ON_ONCE(vsnprintf(__get_dynamic_array(dst), 256, fmt, *va) >= 256)
+
+#endif /* LINUX_VERSION_IS_LESS(6, 0, 0) */
+
+#endif	/* _NET_BATMAN_ADV_COMPAT_LINUX_TRACEPOINT_H_ */
diff --git a/net/batman-adv/trace.h b/net/batman-adv/trace.h
index d673ebdd..31c8f922 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(

    