[B.A.T.M.A.N.] [PATCH 0/2] batman-adv: Continue with deprecation of debugfs

[B.A.T.M.A.N.] [PATCH 0/2] batman-adv: Continue with deprecation of debugfs

[Sven Eckelmann]

Hi,

these two changes should help batman-adv during the ongoing process of
replacing the debugfs code. We already have:

* replaced most debugfs "tables" with netlink dumpit commands
* replaced the socket file code in batctl with direct captures/injects for
  traceroute/ping
* made the debugfs code optional

These first two things were required to get it working in network namespaces.
The last point allows in theory to disable the debugfs code but distributions
will still continue to build the debugfs support for a while. The first patch
in this series will therefore log access requests to this deprecated
functionality in the kernel message buffer. This will hopefully cause more
developers to switch their tools to netlink in the near future:

    $ cat /sys/kernel/debug/batman_adv/bat0/neighbors > /dev/null 
    batman_adv: [Deprecated]: cat (pid 12053) Use of debugfs file "neighbors".
    Use genl command BATADV_CMD_GET_NEIGHBORS instead

But we also have some other functionality in batman-adv's debugfs which could
be integrated better in the rest of the kernel infrastructure: the logging.
The log ringbuffer from batman-adv is completely isolated from the rest of
the kernel even when the kernel itself already provides its own tracing
infrastructure. The tooling for the kernel infrastructure is also a lot
better and should replace the batman_adv/*/log file in batman-adv/batctl
completely - but let us postpone the removal for now.

Some examples for the usage of batadv_dbg via tracepoints can be found in the
commit message of this change. A lot more complex things are possible with
TRACE_EVENT and co but let us start now with the conversion of the already
existing messages. There is also a good introduction on LWN [1,2,3]

Kind regards,
	Sven

[1] https://lwn.net/Articles/379903/
[2] https://lwn.net/Articles/381064/
[3] https://lwn.net/Articles/383362/

Sven Eckelmann (2):
  batman-adv: Mark debugfs functionality as deprecated
  batman-adv: Provide debug messages as trace events

 Makefile                     |  3 ++
 README.external.rst          |  1 +
 compat-include/linux/fs.h    | 37 +++++++++++++++++
 gen-compat-autoconf.sh       |  1 +
 net/batman-adv/Kconfig       | 11 +++++
 net/batman-adv/Makefile      |  3 ++
 net/batman-adv/debugfs.c     | 37 +++++++++++++++++
 net/batman-adv/debugfs.h     |  6 +++
 net/batman-adv/icmp_socket.c |  3 ++
 net/batman-adv/log.c         | 19 +++++++--
 net/batman-adv/trace.c       | 22 ++++++++++
 net/batman-adv/trace.h       | 78 ++++++++++++++++++++++++++++++++++++
 12 files changed, 217 insertions(+), 4 deletions(-)
 create mode 100644 compat-include/linux/fs.h
 create mode 100644 net/batman-adv/trace.c
 create mode 100644 net/batman-adv/trace.h

-- 
2.18.0

[B.A.T.M.A.N.] [PATCH 1/2] batman-adv: Mark debugfs functionality as deprecated

[Sven Eckelmann]

CONFIG_BATMAN_ADV_DEBUGFS is disabled by default because debugfs is not
supported for batman-adv interfaces in any non-default netns. Any remaining
users of this interface should still be informed about the deprecation and
the generic netlink alternative.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
 compat-include/linux/fs.h    | 37 ++++++++++++++++++++++++++++++++++++
 net/batman-adv/debugfs.c     | 37 ++++++++++++++++++++++++++++++++++++
 net/batman-adv/debugfs.h     |  6 ++++++
 net/batman-adv/icmp_socket.c |  3 +++
 net/batman-adv/log.c         |  4 ++++
 5 files changed, 87 insertions(+)
 create mode 100644 compat-include/linux/fs.h

diff --git a/compat-include/linux/fs.h b/compat-include/linux/fs.h
new file mode 100644
index 00000000..4d6bb1d7
--- /dev/null
+++ b/compat-include/linux/fs.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2007-2018  B.A.T.M.A.N. contributors:
+ *
+ * Marek Lindner, Simon Wunderlich
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * This file contains macros for maintaining compatibility with older versions
+ * of the Linux kernel.
+ */
+
+#ifndef _NET_BATMAN_ADV_COMPAT_LINUX_FS_H_
+#define _NET_BATMAN_ADV_COMPAT_LINUX_FS_H_
+
+#include <linux/version.h>
+#include_next <linux/fs.h>
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 6, 0)
+
+static inline struct dentry *file_dentry(const struct file *file)
+{
+	return file->f_path.dentry;
+}
+
+#endif /* < KERNEL_VERSION(4, 6, 0) */
+
+#endif	/* _NET_BATMAN_ADV_COMPAT_LINUX_FS_H_ */
diff --git a/net/batman-adv/debugfs.c b/net/batman-adv/debugfs.c
index 3cb82378..8b608a2e 100644
--- a/net/batman-adv/debugfs.c
+++ b/net/batman-adv/debugfs.c
@@ -47,8 +47,24 @@
 
 static struct dentry *batadv_debugfs;
 
+/**
+ * batadv_debugfs_deprecated() - Log use of deprecated batadv debugfs access
+ * @file: file which was accessed
+ * @alt: explanation what can be used as alternative
+ */
+void batadv_debugfs_deprecated(struct file *file, const char *alt)
+{
+	struct dentry *dentry = file_dentry(file);
+	const char *name = dentry->d_name.name;
+
+	pr_warn_ratelimited(DEPRECATED "%s (pid %d) Use of debugfs file \"%s\".\n%s",
+			    current->comm, task_pid_nr(current), name, alt);
+}
+
 static int batadv_algorithms_open(struct inode *inode, struct file *file)
 {
+	batadv_debugfs_deprecated(file,
+				  "Use genl command BATADV_CMD_GET_ROUTING_ALGOS instead\n");
 	return single_open(file, batadv_algo_seq_print_text, NULL);
 }
 
@@ -56,6 +72,8 @@ static int neighbors_open(struct inode *inode, struct file *file)
 {
 	struct net_device *net_dev = (struct net_device *)inode->i_private;
 
+	batadv_debugfs_deprecated(file,
+				  "Use genl command BATADV_CMD_GET_NEIGHBORS instead\n");
 	return single_open(file, batadv_hardif_neigh_seq_print_text, net_dev);
 }
 
@@ -63,6 +81,8 @@ static int batadv_originators_open(struct inode *inode, struct file *file)
 {
 	struct net_device *net_dev = (struct net_device *)inode->i_private;
 
+	batadv_debugfs_deprecated(file,
+				  "Use genl command BATADV_CMD_GET_ORIGINATORS instead\n");
 	return single_open(file, batadv_orig_seq_print_text, net_dev);
 }
 
@@ -79,6 +99,8 @@ static int batadv_originators_hardif_open(struct inode *inode,
 {
 	struct net_device *net_dev = (struct net_device *)inode->i_private;
 
+	batadv_debugfs_deprecated(file,
+				  "Use genl command BATADV_CMD_GET_HARDIFS instead\n");
 	return single_open(file, batadv_orig_hardif_seq_print_text, net_dev);
 }
 
@@ -86,6 +108,8 @@ static int batadv_gateways_open(struct inode *inode, struct file *file)
 {
 	struct net_device *net_dev = (struct net_device *)inode->i_private;
 
+	batadv_debugfs_deprecated(file,
+				  "Use genl command BATADV_CMD_GET_GATEWAYS instead\n");
 	return single_open(file, batadv_gw_client_seq_print_text, net_dev);
 }
 
@@ -93,6 +117,8 @@ static int batadv_transtable_global_open(struct inode *inode, struct file *file)
 {
 	struct net_device *net_dev = (struct net_device *)inode->i_private;
 
+	batadv_debugfs_deprecated(file,
+				  "Use genl command BATADV_CMD_GET_TRANSTABLE_GLOBAL instead\n");
 	return single_open(file, batadv_tt_global_seq_print_text, net_dev);
 }
 
@@ -101,6 +127,8 @@ static int batadv_bla_claim_table_open(struct inode *inode, struct file *file)
 {
 	struct net_device *net_dev = (struct net_device *)inode->i_private;
 
+	batadv_debugfs_deprecated(file,
+				  "Use genl command BATADV_CMD_GET_BLA_CLAIM instead\n");
 	return single_open(file, batadv_bla_claim_table_seq_print_text,
 			   net_dev);
 }
@@ -110,6 +138,8 @@ static int batadv_bla_backbone_table_open(struct inode *inode,
 {
 	struct net_device *net_dev = (struct net_device *)inode->i_private;
 
+	batadv_debugfs_deprecated(file,
+				  "Use genl command BATADV_CMD_GET_BLA_BACKBONE instead\n");
 	return single_open(file, batadv_bla_backbone_table_seq_print_text,
 			   net_dev);
 }
@@ -128,6 +158,8 @@ static int batadv_dat_cache_open(struct inode *inode, struct file *file)
 {
 	struct net_device *net_dev = (struct net_device *)inode->i_private;
 
+	batadv_debugfs_deprecated(file,
+				  "Use genl command BATADV_CMD_GET_DAT_CACHE instead\n");
 	return single_open(file, batadv_dat_cache_seq_print_text, net_dev);
 }
 #endif
@@ -136,6 +168,8 @@ static int batadv_transtable_local_open(struct inode *inode, struct file *file)
 {
 	struct net_device *net_dev = (struct net_device *)inode->i_private;
 
+	batadv_debugfs_deprecated(file,
+				  "Use genl command BATADV_CMD_GET_TRANSTABLE_LOCAL instead\n");
 	return single_open(file, batadv_tt_local_seq_print_text, net_dev);
 }
 
@@ -149,6 +183,7 @@ static int batadv_nc_nodes_open(struct inode *inode, struct file *file)
 {
 	struct net_device *net_dev = (struct net_device *)inode->i_private;
 
+	batadv_debugfs_deprecated(file, "");
 	return single_open(file, batadv_nc_nodes_seq_print_text, net_dev);
 }
 #endif
@@ -165,6 +200,8 @@ static int batadv_mcast_flags_open(struct inode *inode, struct file *file)
 {
 	struct net_device *net_dev = (struct net_device *)inode->i_private;
 
+	batadv_debugfs_deprecated(file,
+				  "Use genl command BATADV_CMD_GET_MCAST_FLAGS instead\n");
 	return single_open(file, batadv_mcast_flags_seq_print_text, net_dev);
 }
 #endif
diff --git a/net/batman-adv/debugfs.h b/net/batman-adv/debugfs.h
index 08a592ff..8de018e5 100644
--- a/net/batman-adv/debugfs.h
+++ b/net/batman-adv/debugfs.h
@@ -21,12 +21,14 @@
 
 #include "main.h"
 
+struct file;
 struct net_device;
 
 #define BATADV_DEBUGFS_SUBDIR "batman_adv"
 
 #if IS_ENABLED(CONFIG_BATMAN_ADV_DEBUGFS)
 
+void batadv_debugfs_deprecated(struct file *file, const char *alt);
 void batadv_debugfs_init(void);
 void batadv_debugfs_destroy(void);
 int batadv_debugfs_add_meshif(struct net_device *dev);
@@ -38,6 +40,10 @@ void batadv_debugfs_del_hardif(struct batadv_hard_iface *hard_iface);
 
 #else
 
+static inline void batadv_debugfs_deprecated(struct file *file, const char *alt)
+{
+}
+
 static inline void batadv_debugfs_init(void)
 {
 }
diff --git a/net/batman-adv/icmp_socket.c b/net/batman-adv/icmp_socket.c
index 55c358ad..d70f363c 100644
--- a/net/batman-adv/icmp_socket.c
+++ b/net/batman-adv/icmp_socket.c
@@ -47,6 +47,7 @@
 #include <linux/wait.h>
 #include <uapi/linux/batadv_packet.h>
 
+#include "debugfs.h"
 #include "hard-interface.h"
 #include "log.h"
 #include "originator.h"
@@ -74,6 +75,8 @@ static int batadv_socket_open(struct inode *inode, struct file *file)
 	if (!try_module_get(THIS_MODULE))
 		return -EBUSY;
 
+	batadv_debugfs_deprecated(file, "");
+
 	nonseekable_open(inode, file);
 
 	socket_client = kmalloc(sizeof(*socket_client), GFP_KERNEL);
diff --git a/net/batman-adv/log.c b/net/batman-adv/log.c
index 853773e4..1032d84e 100644
--- a/net/batman-adv/log.c
+++ b/net/batman-adv/log.c
@@ -40,6 +40,8 @@
 #include <linux/wait.h>
 #include <stdarg.h>
 
+#include "debugfs.h"
+
 #define BATADV_LOG_BUFF_MASK (batadv_log_buff_len - 1)
 
 static const int batadv_log_buff_len = BATADV_LOG_BUF_LEN;
@@ -115,6 +117,8 @@ static int batadv_log_open(struct inode *inode, struct file *file)
 	if (!try_module_get(THIS_MODULE))
 		return -EBUSY;
 
+	batadv_debugfs_deprecated(file, "");
+
 	nonseekable_open(inode, file);
 	file->private_data = inode->i_private;
 	return 0;
-- 
2.18.0

[B.A.T.M.A.N.] [PATCH 2/2] batman-adv: Provide debug messages as trace events

[Sven Eckelmann]

A private debug logging infrastructure is currently provided via
$debug_fs/batman_adv/*/log when CONFIG_BATMAN_ADV_DEBUG is enabled. This is
not well integrated in the rest of the tracing infrastructure of the
kernel.

Other components (like mac80211 or ath10k) allow to gather the debug
messages using generic trace events which are better integrated. This makes
it possible to interact with them using the existing userspace tools.

The tracepoint batadv:batadv_dbg will now be available when
CONFIG_BATMAN_ADV_DEBUG and CONFIG_BATMAN_ADV_TRACING is activated. The log
level mask is still used for filtering as usual.

A full system trace for offline parsing can be created (and read) using:

  $ batctl ll all
  $ trace-cmd record -e batadv:batadv_dbg
  $ trace-cmd report

The same can also be done without recording to a file

  $ batctl ll all
  $ trace-cmd stream -e batadv:batadv_dbg

The trace infrastructure is especially helpful when tracing processes:

  $ batctl ll all
  $ ./tools/perf/perf trace --event "batadv:*" batctl p 10.204.32.1
     0.000 batadv:batadv_dbg:batman_adv bat0 Parsing outgoing ARP REQUEST
     0.045 batadv:batadv_dbg:batman_adv bat0 ARP MSG = [src: a2:64:14:53:f8:22-10.204.32.185 dst: 00:00:00:00:00:00-10.204.32.1]
     0.067 batadv:batadv_dbg:batman_adv bat0 Entry updated: 10.204.32.185 a2:64:14:53:f8:22 (vid: -1)
     0.099 batadv:batadv_dbg:batman_adv bat0 batadv_dat_select_candidates(): IP=10.204.32.1 hash(IP)=48902
     0.757 batadv:batadv_dbg:batman_adv bat0 dat_select_candidates() 0: selected fe:2c:91:68:29:2b addr=48977 dist=65460
     1.178 batadv:batadv_dbg:batman_adv bat0 dat_select_candidates() 1: selected fe:81:ab:c5:e3:03 addr=49181 dist=65256
     1.809 batadv:batadv_dbg:batman_adv bat0 dat_select_candidates() 2: selected 66:25:a7:48:37:fb addr=49328 dist=65109
     1.828 batadv:batadv_dbg:batman_adv bat0 DHT_SEND for 10.204.32.1

Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
 Makefile                |  3 ++
 README.external.rst     |  1 +
 gen-compat-autoconf.sh  |  1 +
 net/batman-adv/Kconfig  | 11 ++++++
 net/batman-adv/Makefile |  3 ++
 net/batman-adv/log.c    | 17 ++++++---
 net/batman-adv/trace.c  | 22 ++++++++++++
 net/batman-adv/trace.h  | 78 +++++++++++++++++++++++++++++++++++++++++
 8 files changed, 131 insertions(+), 5 deletions(-)
 create mode 100644 net/batman-adv/trace.c
 create mode 100644 net/batman-adv/trace.h

diff --git a/Makefile b/Makefile
index 7c6fa1e4..d665c0ba 100644
--- a/Makefile
+++ b/Makefile
@@ -29,6 +29,8 @@ export CONFIG_BATMAN_ADV_DAT=y
 export CONFIG_BATMAN_ADV_NC=n
 # B.A.T.M.A.N. multicast optimizations:
 export CONFIG_BATMAN_ADV_MCAST=y
+# B.A.T.M.A.N. tracing support:
+export CONFIG_BATMAN_ADV_TRACING=n
 # B.A.T.M.A.N. V routing algorithm (experimental):
 export CONFIG_BATMAN_ADV_BATMAN_V=y
 
@@ -75,6 +77,7 @@ BUILD_FLAGS := \
 	CONFIG_BATMAN_ADV_DAT=$(CONFIG_BATMAN_ADV_DAT) \
 	CONFIG_BATMAN_ADV_NC=$(CONFIG_BATMAN_ADV_NC) \
 	CONFIG_BATMAN_ADV_MCAST=$(CONFIG_BATMAN_ADV_MCAST) \
+	CONFIG_BATMAN_ADV_TRACING=$(CONFIG_BATMAN_ADV_TRACING) \
 	CONFIG_BATMAN_ADV_BATMAN_V=$(CONFIG_BATMAN_ADV_BATMAN_V) \
 	INSTALL_MOD_DIR=updates/
 
diff --git a/README.external.rst b/README.external.rst
index 2faec155..3f6539ed 100644
--- a/README.external.rst
+++ b/README.external.rst
@@ -49,6 +49,7 @@ module).  Available  options  and  their    possible   values are
  * ``CONFIG_BATMAN_ADV_DAT=[y*|n]`` (B.A.T.M.A.N. Distributed ARP Table)
  * ``CONFIG_BATMAN_ADV_MCAST=[y*|n]`` (B.A.T.M.A.N. multicast optimizations)
  * ``CONFIG_BATMAN_ADV_NC=[y|n*]`` (B.A.T.M.A.N. Network Coding)
+ * ``CONFIG_BATMAN_ADV_TRACING=[y|n*]`` (B.A.T.M.A.N. tracing support)
  * ``CONFIG_BATMAN_ADV_BATMAN_V=[y*|n]`` (B.A.T.M.A.N. V routing algorithm)
 
 e.g., debugging can be enabled by::
diff --git a/gen-compat-autoconf.sh b/gen-compat-autoconf.sh
index 5dcd875d..a4eb1136 100755
--- a/gen-compat-autoconf.sh
+++ b/gen-compat-autoconf.sh
@@ -58,6 +58,7 @@ gen_config 'CONFIG_BATMAN_ADV_BLA' ${CONFIG_BATMAN_ADV_BLA:="y"} >> "${TMP}"
 gen_config 'CONFIG_BATMAN_ADV_DAT' ${CONFIG_BATMAN_ADV_DAT:="y"} >> "${TMP}"
 gen_config 'CONFIG_BATMAN_ADV_MCAST' ${CONFIG_BATMAN_ADV_MCAST:="y"} >> "${TMP}"
 gen_config 'CONFIG_BATMAN_ADV_NC' ${CONFIG_BATMAN_ADV_NC:="n"} >> "${TMP}"
+gen_config 'CONFIG_BATMAN_ADV_TRACING' ${CONFIG_BATMAN_ADV_TRACING:="n"} >> "${TMP}"
 gen_config 'CONFIG_BATMAN_ADV_BATMAN_V' ${CONFIG_BATMAN_ADV_BATMAN_V:="y"} >> "${TMP}"
 
 # only regenerate compat-autoconf.h when config was changed
diff --git a/net/batman-adv/Kconfig b/net/batman-adv/Kconfig
index 361116f7..f75816f5 100644
--- a/net/batman-adv/Kconfig
+++ b/net/batman-adv/Kconfig
@@ -106,3 +106,14 @@ config BATMAN_ADV_DEBUG
 	  say N here. This enables compilation of support for
 	  outputting debugging information to the kernel log. The
 	  output is controlled via the module parameter debug.
+
+config BATMAN_ADV_TRACING
+	bool "B.A.T.M.A.N. tracing support"
+	depends on BATMAN_ADV
+	depends on EVENT_TRACING
+	help
+	  This is an option for use by developers; most people should
+	  say N here. Select this option to gather traces like the debug
+	  messages using the generic tracing infrastructure of the kernel.
+	  BATMAN_ADV_DEBUG must also be selected to get trace events for
+	  batadv_dbg.
diff --git a/net/batman-adv/Makefile b/net/batman-adv/Makefile
index b97ba6fb..9b58160f 100644
--- a/net/batman-adv/Makefile
+++ b/net/batman-adv/Makefile
@@ -42,6 +42,9 @@ batman-adv-y += routing.o
 batman-adv-y += send.o
 batman-adv-y += soft-interface.o
 batman-adv-y += sysfs.o
+batman-adv-$(CONFIG_BATMAN_ADV_TRACING) += trace.o
 batman-adv-y += tp_meter.o
 batman-adv-y += translation-table.o
 batman-adv-y += tvlv.o
+
+CFLAGS_trace.o := -I$(src)
diff --git a/net/batman-adv/log.c b/net/batman-adv/log.c
index 1032d84e..8a3d6910 100644
--- a/net/batman-adv/log.c
+++ b/net/batman-adv/log.c
@@ -41,6 +41,7 @@
 #include <stdarg.h>
 
 #include "debugfs.h"
+#include "trace.h"
 
 #define BATADV_LOG_BUFF_MASK (batadv_log_buff_len - 1)
 
@@ -100,13 +101,19 @@ static int batadv_fdebug_log(struct batadv_priv_debug_log *debug_log,
  */
 int batadv_debug_log(struct batadv_priv *bat_priv, const char *fmt, ...)
 {
+	struct va_format vaf;
 	va_list args;
-	char tmp_log_buf[256];
 
 	va_start(args, fmt);
-	vscnprintf(tmp_log_buf, sizeof(tmp_log_buf), fmt, args);
-	batadv_fdebug_log(bat_priv->debug_log, "[%10u] %s",
-			  jiffies_to_msecs(jiffies), tmp_log_buf);
+
+	vaf.fmt = fmt;
+	vaf.va = &args;
+
+	batadv_fdebug_log(bat_priv->debug_log, "[%10u] %pV",
+			  jiffies_to_msecs(jiffies), &vaf);
+
+	trace_batadv_dbg(bat_priv, &vaf);
+
 	va_end(args);
 
 	return 0;
@@ -117,7 +124,7 @@ static int batadv_log_open(struct inode *inode, struct file *file)
 	if (!try_module_get(THIS_MODULE))
 		return -EBUSY;
 
-	batadv_debugfs_deprecated(file, "");
+	batadv_debugfs_deprecated(file, "Use tracepoint batadv:batadv_dbg instead\n");
 
 	nonseekable_open(inode, file);
 	file->private_data = inode->i_private;
diff --git a/net/batman-adv/trace.c b/net/batman-adv/trace.c
new file mode 100644
index 00000000..3d57f998
--- /dev/null
+++ b/net/batman-adv/trace.c
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2010-2018  B.A.T.M.A.N. contributors:
+ *
+ * Sven Eckelmann
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/module.h>
+
+#define CREATE_TRACE_POINTS
+#include "trace.h"
diff --git a/net/batman-adv/trace.h b/net/batman-adv/trace.h
new file mode 100644
index 00000000..3acda26a
--- /dev/null
+++ b/net/batman-adv/trace.h
@@ -0,0 +1,78 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2010-2018  B.A.T.M.A.N. contributors:
+ *
+ * Sven Eckelmann
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#if !defined(_NET_BATMAN_ADV_TRACE_H_) || defined(TRACE_HEADER_MULTI_READ)
+#define _NET_BATMAN_ADV_TRACE_H_
+
+#include "main.h"
+
+#include <linux/tracepoint.h>
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM batadv
+
+/* provide dummy function when tracing is disabled */
+#if !defined(CONFIG_BATMAN_ADV_TRACING)
+
+#undef TRACE_EVENT
+#define TRACE_EVENT(name, proto, ...) \
+	static inline void trace_ ## name(proto) {}
+
+#endif /* CONFIG_BATMAN_ADV_TRACING */
+
+#define BATADV_MAX_MSG_LEN	256
+
+TRACE_EVENT(batadv_dbg,
+
+	    TP_PROTO(struct batadv_priv *bat_priv,
+		     struct va_format *vaf),
+
+	    TP_ARGS(bat_priv, vaf),
+
+	    TP_STRUCT__entry(
+		    __string(device, bat_priv->soft_iface->name)
+		    __string(driver, KBUILD_MODNAME)
+		    __dynamic_array(char, msg, BATADV_MAX_MSG_LEN)
+	    ),
+
+	    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);
+	    ),
+
+	    TP_printk(
+		    "%s %s %s",
+		    __get_str(driver),
+		    __get_str(device),
+		    __get_str(msg)
+	    )
+);
+
+#endif /* _NET_BATMAN_ADV_TRACE_H_ || TRACE_HEADER_MULTI_READ */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE trace
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
-- 
2.18.0

Re: [B.A.T.M.A.N.] [PATCH 0/2] batman-adv: Continue with deprecation of debugfs

[Sven Eckelmann]

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On Freitag, 10. August 2018 23:36:14 CEST Sven Eckelmann wrote:
[...]
> Sven Eckelmann (2):
>   batman-adv: Mark debugfs functionality as deprecated
>   batman-adv: Provide debug messages as trace events
[...]

Applied as fee04b6f72cf [1] and a0e9c94f2903 [2]

Kind regards,
	Sven

[1] https://git.open-mesh.org/batman-adv.git/commit/fee04b6f72cf92f6a3173ef55e3e32dd98ce7242
[2] https://git.open-mesh.org/batman-adv.git/commit/a0e9c94f2903de053455f884cb0095a7a23ae084

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