[PATCH v2 net-next 0/5] net: switchdev: Tracepoints

[PATCH v2 net-next 0/5] net: switchdev: Tracepoints

[Tobias Waldekranz]

This series starts off (1-2/5) by creating stringifiers for common
switchdev objects. This will primarily be used by the tracepoints for
decoding switchdev notifications, but drivers could also make use of
them to provide richer debug/error messages.

Then follows two refactoring commits (3-4/5), with no (intended)
functional changes:

- 3/5: Wrap all replay callbacks in br_switchdev.c in a switchdev
       function to make it easy to trace all of these.

- 4/5: Instead of using a different format for deferred items, reuse
       the existing notification structures when enqueuing. This lets
       us share a bit more code, and it unifies the data presented by
       the tracepoints.

Finally, add the tracepoints.

v1 -> v2:

- Fixup kernel-doc comment for switchdev_call_replay

I know that there are still some warnings issued by checkpatch, but
I'm not sure how to work around them, given the nature of the mapper
macros. Please advise.

Tobias Waldekranz (5):
  net: switchdev: Wrap enums in mapper macros
  net: switchdev: Add helpers to display switchdev objects as strings
  net: switchdev: Relay all replay messages through a central function
  net: switchdev: Prepare deferred notifications before enqueuing them
  net: switchdev: Add tracepoints

 include/net/switchdev.h          | 130 ++++++++----
 include/trace/events/switchdev.h |  89 ++++++++
 net/bridge/br_switchdev.c        |  10 +-
 net/switchdev/Makefile           |   2 +-
 net/switchdev/switchdev-str.c    | 278 +++++++++++++++++++++++++
 net/switchdev/switchdev.c        | 346 +++++++++++++++++--------------
 6 files changed, 650 insertions(+), 205 deletions(-)
 create mode 100644 include/trace/events/switchdev.h
 create mode 100644 net/switchdev/switchdev-str.c

-- 
2.34.1

[PATCH v2 net-next 1/5] net: switchdev: Wrap enums in mapper macros

[Tobias Waldekranz]

In order to avoid having to maintain separate mappings from enum
values to strings, wrap enumerators in mapper macros, so that
enum-to-string tables can be generated.

This will make it easier to create helpers that convert switchdev
objects to strings.

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
---
 include/net/switchdev.h | 113 ++++++++++++++++++++++++----------------
 1 file changed, 68 insertions(+), 45 deletions(-)

diff --git a/include/net/switchdev.h b/include/net/switchdev.h
index a43062d4c734..76eabf95c647 100644
--- a/include/net/switchdev.h
+++ b/include/net/switchdev.h
@@ -16,21 +16,28 @@
 #define SWITCHDEV_F_SKIP_EOPNOTSUPP	BIT(1)
 #define SWITCHDEV_F_DEFER		BIT(2)
 
+#define SWITCHDEV_ATTR_ID_MAPPER(_fn)	\
+	_fn(UNDEFINED),			\
+	_fn(PORT_STP_STATE),		\
+	_fn(PORT_MST_STATE),		\
+	_fn(PORT_BRIDGE_FLAGS),		\
+	_fn(PORT_PRE_BRIDGE_FLAGS),	\
+	_fn(PORT_MROUTER),		\
+	_fn(BRIDGE_AGEING_TIME),	\
+	_fn(BRIDGE_VLAN_FILTERING),	\
+	_fn(BRIDGE_VLAN_PROTOCOL),	\
+	_fn(BRIDGE_MC_DISABLED),	\
+	_fn(BRIDGE_MROUTER),		\
+	_fn(BRIDGE_MST),		\
+	_fn(MRP_PORT_ROLE),		\
+	_fn(VLAN_MSTI),			\
+	/*  */
+
+#define SWITCHDEV_ATTR_ID_ENUMERATOR(_id) \
+	SWITCHDEV_ATTR_ID_ ## _id
+
 enum switchdev_attr_id {
-	SWITCHDEV_ATTR_ID_UNDEFINED,
-	SWITCHDEV_ATTR_ID_PORT_STP_STATE,
-	SWITCHDEV_ATTR_ID_PORT_MST_STATE,
-	SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS,
-	SWITCHDEV_ATTR_ID_PORT_PRE_BRIDGE_FLAGS,
-	SWITCHDEV_ATTR_ID_PORT_MROUTER,
-	SWITCHDEV_ATTR_ID_BRIDGE_AGEING_TIME,
-	SWITCHDEV_ATTR_ID_BRIDGE_VLAN_FILTERING,
-	SWITCHDEV_ATTR_ID_BRIDGE_VLAN_PROTOCOL,
-	SWITCHDEV_ATTR_ID_BRIDGE_MC_DISABLED,
-	SWITCHDEV_ATTR_ID_BRIDGE_MROUTER,
-	SWITCHDEV_ATTR_ID_BRIDGE_MST,
-	SWITCHDEV_ATTR_ID_MRP_PORT_ROLE,
-	SWITCHDEV_ATTR_ID_VLAN_MSTI,
+	SWITCHDEV_ATTR_ID_MAPPER(SWITCHDEV_ATTR_ID_ENUMERATOR)
 };
 
 struct switchdev_mst_state {
@@ -69,18 +76,25 @@ struct switchdev_attr {
 	} u;
 };
 
+#define SWITCHDEV_OBJ_ID_MAPPER(_fn)	\
+	_fn(UNDEFINED),			\
+	_fn(PORT_VLAN),			\
+	_fn(PORT_MDB),			\
+	_fn(HOST_MDB),			\
+	_fn(MRP),			\
+	_fn(RING_TEST_MRP),		\
+	_fn(RING_ROLE_MRP),		\
+	_fn(RING_STATE_MRP),		\
+	_fn(IN_TEST_MRP),		\
+	_fn(IN_ROLE_MRP),		\
+	_fn(IN_STATE_MRP),		\
+	/*  */
+
+#define SWITCHDEV_OBJ_ID_ENUMERATOR(_id) \
+	SWITCHDEV_OBJ_ID_ ## _id
+
 enum switchdev_obj_id {
-	SWITCHDEV_OBJ_ID_UNDEFINED,
-	SWITCHDEV_OBJ_ID_PORT_VLAN,
-	SWITCHDEV_OBJ_ID_PORT_MDB,
-	SWITCHDEV_OBJ_ID_HOST_MDB,
-	SWITCHDEV_OBJ_ID_MRP,
-	SWITCHDEV_OBJ_ID_RING_TEST_MRP,
-	SWITCHDEV_OBJ_ID_RING_ROLE_MRP,
-	SWITCHDEV_OBJ_ID_RING_STATE_MRP,
-	SWITCHDEV_OBJ_ID_IN_TEST_MRP,
-	SWITCHDEV_OBJ_ID_IN_ROLE_MRP,
-	SWITCHDEV_OBJ_ID_IN_STATE_MRP,
+	SWITCHDEV_OBJ_ID_MAPPER(SWITCHDEV_OBJ_ID_ENUMERATOR)
 };
 
 struct switchdev_obj {
@@ -209,27 +223,36 @@ struct switchdev_brport {
 	bool tx_fwd_offload;
 };
 
+#define SWITCHDEV_TYPE_MAPPER(_fn)	\
+	_fn(UNKNOWN),			\
+					\
+	_fn(FDB_ADD_TO_BRIDGE),		\
+	_fn(FDB_DEL_TO_BRIDGE),		\
+	_fn(FDB_ADD_TO_DEVICE),		\
+	_fn(FDB_DEL_TO_DEVICE),		\
+	_fn(FDB_OFFLOADED),		\
+	_fn(FDB_FLUSH_TO_BRIDGE),	\
+					\
+	_fn(PORT_OBJ_ADD),		\
+	_fn(PORT_OBJ_DEL),		\
+	_fn(PORT_ATTR_SET),		\
+					\
+	_fn(VXLAN_FDB_ADD_TO_BRIDGE),	\
+	_fn(VXLAN_FDB_DEL_TO_BRIDGE),	\
+	_fn(VXLAN_FDB_ADD_TO_DEVICE),	\
+	_fn(VXLAN_FDB_DEL_TO_DEVICE),	\
+	_fn(VXLAN_FDB_OFFLOADED),	\
+					\
+	_fn(BRPORT_OFFLOADED),		\
+	_fn(BRPORT_UNOFFLOADED),	\
+	_fn(BRPORT_REPLAY),		\
+	/*  */
+
+#define SWITCHDEV_TYPE_ENUMERATOR(_id) \
+	SWITCHDEV_ ## _id
+
 enum switchdev_notifier_type {
-	SWITCHDEV_FDB_ADD_TO_BRIDGE = 1,
-	SWITCHDEV_FDB_DEL_TO_BRIDGE,
-	SWITCHDEV_FDB_ADD_TO_DEVICE,
-	SWITCHDEV_FDB_DEL_TO_DEVICE,
-	SWITCHDEV_FDB_OFFLOADED,
-	SWITCHDEV_FDB_FLUSH_TO_BRIDGE,
-
-	SWITCHDEV_PORT_OBJ_ADD, /* Blocking. */
-	SWITCHDEV_PORT_OBJ_DEL, /* Blocking. */
-	SWITCHDEV_PORT_ATTR_SET, /* May be blocking . */
-
-	SWITCHDEV_VXLAN_FDB_ADD_TO_BRIDGE,
-	SWITCHDEV_VXLAN_FDB_DEL_TO_BRIDGE,
-	SWITCHDEV_VXLAN_FDB_ADD_TO_DEVICE,
-	SWITCHDEV_VXLAN_FDB_DEL_TO_DEVICE,
-	SWITCHDEV_VXLAN_FDB_OFFLOADED,
-
-	SWITCHDEV_BRPORT_OFFLOADED,
-	SWITCHDEV_BRPORT_UNOFFLOADED,
-	SWITCHDEV_BRPORT_REPLAY,
+	SWITCHDEV_TYPE_MAPPER(SWITCHDEV_TYPE_ENUMERATOR)
 };
 
 struct switchdev_notifier_info {
-- 
2.34.1

[PATCH v2 net-next 2/5] net: switchdev: Add helpers to display switchdev objects as strings

[Tobias Waldekranz]

Useful both in error messages and in tracepoints.

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
---
 include/net/switchdev.h       |  14 ++
 net/switchdev/Makefile        |   2 +-
 net/switchdev/switchdev-str.c | 278 ++++++++++++++++++++++++++++++++++
 3 files changed, 293 insertions(+), 1 deletion(-)
 create mode 100644 net/switchdev/switchdev-str.c

diff --git a/include/net/switchdev.h b/include/net/switchdev.h
index 76eabf95c647..250053748c08 100644
--- a/include/net/switchdev.h
+++ b/include/net/switchdev.h
@@ -391,6 +391,20 @@ int switchdev_handle_port_attr_set(struct net_device *dev,
 			int (*set_cb)(struct net_device *dev, const void *ctx,
 				      const struct switchdev_attr *attr,
 				      struct netlink_ext_ack *extack));
+
+/* switchdev-str.c */
+ssize_t switchdev_attr_str(const struct switchdev_attr *attr,
+			   char *buf, size_t len);
+ssize_t switchdev_obj_str(const struct switchdev_obj *obj,
+			  char *buf, size_t len);
+ssize_t switchdev_fdb_info_str(enum switchdev_notifier_type nt,
+			       const struct switchdev_notifier_fdb_info *fdbi,
+			       char *buf, size_t len);
+ssize_t switchdev_brport_str(const struct switchdev_brport *brport,
+			     char *buf, size_t len);
+ssize_t switchdev_notifier_str(enum switchdev_notifier_type nt,
+			       const struct switchdev_notifier_info *info,
+			       char *buf, size_t len);
 #else
 
 static inline int
diff --git a/net/switchdev/Makefile b/net/switchdev/Makefile
index c5561d7f3a7c..a40e4421087b 100644
--- a/net/switchdev/Makefile
+++ b/net/switchdev/Makefile
@@ -3,4 +3,4 @@
 # Makefile for the Switch device API
 #
 
-obj-y += switchdev.o
+obj-y += switchdev.o switchdev-str.o
diff --git a/net/switchdev/switchdev-str.c b/net/switchdev/switchdev-str.c
new file mode 100644
index 000000000000..a1fa7315cc28
--- /dev/null
+++ b/net/switchdev/switchdev-str.c
@@ -0,0 +1,278 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/if_bridge.h>
+#include <net/switchdev.h>
+
+static ssize_t switchdev_str_write_id(char *buf, size_t len, unsigned long id,
+				      const char *const *names, size_t n_names)
+{
+	if (id < n_names && names[id])
+		return snprintf(buf, len, "%s", names[id]);
+
+	return snprintf(buf, len, "UNKNOWN<%lu>", id);
+}
+
+ssize_t switchdev_attr_str(const struct switchdev_attr *attr,
+			   char *buf, size_t len)
+{
+#define _ATTR_ID_STRINGER(_id) [SWITCHDEV_ATTR_ID_ ## _id] = #_id
+	static const char *const attr_id_strs[] = {
+		SWITCHDEV_ATTR_ID_MAPPER(_ATTR_ID_STRINGER)
+	};
+#undef _ATTR_ID_STRINGER
+
+	static const char *const stp_state_strs[] = {
+		[BR_STATE_DISABLED] = "disabled",
+		[BR_STATE_LISTENING] = "listening",
+		[BR_STATE_LEARNING] = "learning",
+		[BR_STATE_FORWARDING] = "forwarding",
+		[BR_STATE_BLOCKING] = "blocking",
+	};
+
+	char *cur = buf;
+	ssize_t n;
+
+	n = switchdev_str_write_id(cur, len, attr->id, attr_id_strs,
+				   ARRAY_SIZE(attr_id_strs));
+	if (n < 0)
+		return n;
+
+	cur += n;
+	len -= n;
+
+	n = snprintf(cur, len, "(flags %#x orig %s) ", attr->flags,
+		     attr->orig_dev ? netdev_name(attr->orig_dev) : "(null)");
+	if (n < 0)
+		return n;
+
+	cur += n;
+	len -= n;
+
+	switch (attr->id) {
+	case SWITCHDEV_ATTR_ID_PORT_STP_STATE:
+		n = switchdev_str_write_id(cur, len, attr->u.stp_state,
+					   stp_state_strs, ARRAY_SIZE(stp_state_strs));
+		break;
+	case SWITCHDEV_ATTR_ID_PORT_MST_STATE:
+		n = snprintf(cur, len, "msti %u", attr->u.mst_state.msti);
+		if (n < 0)
+			return n;
+
+		cur += n;
+		len -= n;
+
+		n = switchdev_str_write_id(cur, len, attr->u.mst_state.state,
+					   stp_state_strs, ARRAY_SIZE(stp_state_strs));
+		break;
+	case SWITCHDEV_ATTR_ID_PORT_PRE_BRIDGE_FLAGS:
+	case SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS:
+		n = snprintf(cur, len, "val %#lx mask %#lx",
+			     attr->u.brport_flags.val,
+			     attr->u.brport_flags.mask);
+		break;
+	case SWITCHDEV_ATTR_ID_PORT_MROUTER:
+	case SWITCHDEV_ATTR_ID_BRIDGE_MROUTER:
+		n = snprintf(cur, len, "%s",
+			     attr->u.mrouter ? "enabled" : "disabled");
+		break;
+	case SWITCHDEV_ATTR_ID_BRIDGE_AGEING_TIME:
+		n = snprintf(cur, len, "%ums",
+			     jiffies_to_msecs(clock_t_to_jiffies(attr->u.ageing_time)));
+		break;
+	case SWITCHDEV_ATTR_ID_BRIDGE_VLAN_FILTERING:
+		n = snprintf(cur, len, "%s",
+			     attr->u.vlan_filtering ? "enabled" : "disabled");
+		break;
+	case SWITCHDEV_ATTR_ID_BRIDGE_VLAN_PROTOCOL:
+		n = snprintf(cur, len, "%#x", attr->u.vlan_protocol);
+		break;
+	case SWITCHDEV_ATTR_ID_BRIDGE_MC_DISABLED:
+		n = snprintf(cur, len, "%s",
+			     attr->u.mc_disabled ? "active" : "inactive");
+		break;
+	case SWITCHDEV_ATTR_ID_BRIDGE_MST:
+		n = snprintf(cur, len, "%s",
+			     attr->u.mst ? "enabled" : "disabled");
+		break;
+	case SWITCHDEV_ATTR_ID_VLAN_MSTI:
+		n = snprintf(cur, len, "vid %u msti %u",
+			     attr->u.vlan_msti.vid, attr->u.vlan_msti.msti);
+		break;
+	default:
+		/* Trim trailing space */
+		return --cur - buf;
+	}
+
+	if (n < 0)
+		return n;
+
+	cur += n;
+	return cur - buf;
+}
+EXPORT_SYMBOL_GPL(switchdev_attr_str);
+
+ssize_t switchdev_obj_str(const struct switchdev_obj *obj,
+			  char *buf, size_t len)
+{
+#define _OBJ_ID_STRINGER(_id) [SWITCHDEV_OBJ_ID_ ## _id] = #_id
+	static const char *const obj_id_strs[] = {
+		SWITCHDEV_OBJ_ID_MAPPER(_OBJ_ID_STRINGER)
+	};
+#undef _OBJ_ID_STRINGER
+
+	const struct switchdev_obj_port_vlan *vlan;
+	const struct switchdev_obj_port_mdb *mdb;
+	char *cur = buf;
+	ssize_t n;
+
+	n = switchdev_str_write_id(cur, len, obj->id, obj_id_strs,
+				   ARRAY_SIZE(obj_id_strs));
+	if (n < 0)
+		return n;
+
+	cur += n;
+	len -= n;
+
+	n = snprintf(cur, len, "(flags %#x orig %s) ", obj->flags,
+		     obj->orig_dev ? netdev_name(obj->orig_dev) : "(null)");
+	if (n < 0)
+		return n;
+
+	cur += n;
+	len -= n;
+
+	switch (obj->id) {
+	case SWITCHDEV_OBJ_ID_PORT_VLAN:
+		vlan = SWITCHDEV_OBJ_PORT_VLAN(obj);
+		n = snprintf(cur, len, "vid %u flags %#x%s", vlan->vid,
+			     vlan->flags, vlan->changed ? "(changed)" : "");
+		break;
+	case SWITCHDEV_OBJ_ID_PORT_MDB:
+	case SWITCHDEV_OBJ_ID_HOST_MDB:
+		mdb = SWITCHDEV_OBJ_PORT_MDB(obj);
+		n = snprintf(cur, len, "vid %u addr %pM", mdb->vid, mdb->addr);
+		break;
+	default:
+		/* Trim trailing space */
+		return --cur - buf;
+	}
+
+	if (n < 0)
+		return n;
+
+	cur += n;
+	return cur - buf;
+}
+EXPORT_SYMBOL_GPL(switchdev_obj_str);
+
+ssize_t switchdev_fdb_info_str(enum switchdev_notifier_type nt,
+			       const struct switchdev_notifier_fdb_info *fdbi,
+			       char *buf, size_t len)
+{
+	switch (nt) {
+	case SWITCHDEV_FDB_FLUSH_TO_BRIDGE:
+		return snprintf(buf, len, "vid %u", fdbi->vid);
+	case SWITCHDEV_FDB_ADD_TO_BRIDGE:
+	case SWITCHDEV_FDB_DEL_TO_BRIDGE:
+	case SWITCHDEV_FDB_ADD_TO_DEVICE:
+	case SWITCHDEV_FDB_DEL_TO_DEVICE:
+	case SWITCHDEV_FDB_OFFLOADED:
+	case SWITCHDEV_VXLAN_FDB_ADD_TO_BRIDGE:
+	case SWITCHDEV_VXLAN_FDB_DEL_TO_BRIDGE:
+	case SWITCHDEV_VXLAN_FDB_ADD_TO_DEVICE:
+	case SWITCHDEV_VXLAN_FDB_DEL_TO_DEVICE:
+	case SWITCHDEV_VXLAN_FDB_OFFLOADED:
+		return snprintf(buf, len, "vid %u addr %pM%s%s%s%s",
+				fdbi->vid, fdbi->addr,
+				fdbi->added_by_user ? " added_by_user" : "",
+				fdbi->is_local ? " is_local" : "",
+				fdbi->locked ? " locked" : "",
+				fdbi->offloaded ? " offloaded" : "");
+	default:
+		break;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(switchdev_fdb_info_str);
+
+ssize_t switchdev_brport_str(const struct switchdev_brport *brport,
+			     char *buf, size_t len)
+{
+	return snprintf(buf, len, "dev %s%s",
+			brport->dev ? netdev_name(brport->dev) : "(null)",
+			brport->tx_fwd_offload ? " tx_fwd_offload" : "");
+}
+EXPORT_SYMBOL_GPL(switchdev_brport_str);
+
+ssize_t switchdev_notifier_str(enum switchdev_notifier_type nt,
+			       const struct switchdev_notifier_info *info,
+			       char *buf, size_t len)
+{
+#define _TYPE_STRINGER(_id) [SWITCHDEV_ ## _id] = #_id
+	static const char *const type_strs[] = {
+		SWITCHDEV_TYPE_MAPPER(_TYPE_STRINGER)
+	};
+#undef _TYPE_STRINGER
+
+	const struct switchdev_notifier_port_attr_info *attri;
+	const struct switchdev_notifier_brport_info *brporti;
+	const struct switchdev_notifier_port_obj_info *obji;
+	const struct switchdev_notifier_fdb_info *fdbi;
+	char *cur = buf;
+	ssize_t n;
+
+	n = switchdev_str_write_id(cur, len, nt, type_strs,
+				   ARRAY_SIZE(type_strs));
+	if (n < 0)
+		return n;
+
+	cur += n;
+	len -= n;
+
+	if (len > 0) {
+		*cur++ = ' ';
+		len--;
+	}
+
+	switch (nt) {
+	case SWITCHDEV_FDB_FLUSH_TO_BRIDGE:
+	case SWITCHDEV_FDB_ADD_TO_BRIDGE:
+	case SWITCHDEV_FDB_DEL_TO_BRIDGE:
+	case SWITCHDEV_FDB_ADD_TO_DEVICE:
+	case SWITCHDEV_FDB_DEL_TO_DEVICE:
+	case SWITCHDEV_FDB_OFFLOADED:
+	case SWITCHDEV_VXLAN_FDB_ADD_TO_BRIDGE:
+	case SWITCHDEV_VXLAN_FDB_DEL_TO_BRIDGE:
+	case SWITCHDEV_VXLAN_FDB_ADD_TO_DEVICE:
+	case SWITCHDEV_VXLAN_FDB_DEL_TO_DEVICE:
+	case SWITCHDEV_VXLAN_FDB_OFFLOADED:
+		fdbi = container_of(info, typeof(*fdbi), info);
+		n = switchdev_fdb_info_str(nt, fdbi, cur, len);
+		break;
+	case SWITCHDEV_PORT_OBJ_ADD:
+	case SWITCHDEV_PORT_OBJ_DEL:
+		obji = container_of(info, typeof(*obji), info);
+		n = switchdev_obj_str(obji->obj, cur, len);
+		break;
+	case SWITCHDEV_PORT_ATTR_SET:
+		attri = container_of(info, typeof(*attri), info);
+		n = switchdev_attr_str(attri->attr, cur, len);
+		break;
+	case SWITCHDEV_BRPORT_OFFLOADED:
+	case SWITCHDEV_BRPORT_UNOFFLOADED:
+	case SWITCHDEV_BRPORT_REPLAY:
+		brporti = container_of(info, typeof(*brporti), info);
+		n = switchdev_brport_str(&brporti->brport, cur, len);
+		break;
+	default:
+		/* Trim trailing space */
+		return --cur - buf;
+	}
+
+	if (n < 0)
+		return n;
+
+	cur += n;
+	return cur - buf;
+}
+EXPORT_SYMBOL_GPL(switchdev_notifier_str);
-- 
2.34.1

Re: [PATCH v2 net-next 2/5] net: switchdev: Add helpers to display switchdev objects as strings

[Jakub Kicinski]

On Tue, 30 Jan 2024 21:19:34 +0100 Tobias Waldekranz wrote:
> Useful both in error messages and in tracepoints.

Are you printing things together into one big string?
Seems like leaving a lot of features on the table.
trace point events can be filtered, not to mention attaching
to them with bpftrace. 
There's also a built-in way to show traces how to convert numerical ids
to strings for the basic output - __print_symbolic().
None of that can help here?

Re: [PATCH v2 net-next 2/5] net: switchdev: Add helpers to display switchdev objects as strings

[Tobias Waldekranz]

On tor, feb 01, 2024 at 20:49, Jakub Kicinski <kuba@kernel.org> wrote:
> On Tue, 30 Jan 2024 21:19:34 +0100 Tobias Waldekranz wrote:
>> Useful both in error messages and in tracepoints.
>
> Are you printing things together into one big string?
> Seems like leaving a lot of features on the table.
> trace point events can be filtered, not to mention attaching
> to them with bpftrace. 

My thinking was that __entry->msg was mostly for use by the tracepoint's
printf, and that if you are using some dynamic tracer, __entry->info
points to the verbatim notification which you can use to apply arbitrary
filtering.

> There's also a built-in way to show traces how to convert numerical ids
> to strings for the basic output - __print_symbolic().
> None of that can help here?

Originally, I did use it to display the `val` argument to the
tracepoint, but the problem with that macro is that it wants the mapping
table as an inline list of tuples, and the list must _not_ include a
trailing comma. This means that SWITCHDEV_TYPE_MAPPER can't use the
trailing-comment-after-the-last-item trick, which introduced an
asymmetry with the other mappers that I did not like.

At first, I thought about adding some variant of __print_symbolic that
would take a pointer to an existing table instead. Then I realized that
I would still need some separate stringer helper to put together the
rest of the printed message from the TLV-ish layout of
switchdev_notifier_info.

At that point, it seems more reasonable to just collect all logic of
turning switchdev related structs into strings in one place - with the
added benefit that drivers could use them to log richer error messages.

Re: [PATCH v2 net-next 2/5] net: switchdev: Add helpers to display switchdev objects as strings

[Jakub Kicinski]

On Fri, 02 Feb 2024 08:48:39 +0100 Tobias Waldekranz wrote:
> > Are you printing things together into one big string?
> > Seems like leaving a lot of features on the table.
> > trace point events can be filtered, not to mention attaching
> > to them with bpftrace.   
> 
> My thinking was that __entry->msg was mostly for use by the tracepoint's
> printf, and that if you are using some dynamic tracer, __entry->info
> points to the verbatim notification which you can use to apply arbitrary
> filtering.

Ah, I see. That works.

[PATCH v2 net-next 3/5] net: switchdev: Relay all replay messages through a central function

[Tobias Waldekranz]

This will make it easier to add a tracepoint for all replay messages
later on.

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
---
 include/net/switchdev.h   |  3 +++
 net/bridge/br_switchdev.c | 10 +++++-----
 net/switchdev/switchdev.c | 17 +++++++++++++++++
 3 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/include/net/switchdev.h b/include/net/switchdev.h
index 250053748c08..974cd8467131 100644
--- a/include/net/switchdev.h
+++ b/include/net/switchdev.h
@@ -337,6 +337,9 @@ int switchdev_port_obj_add(struct net_device *dev,
 int switchdev_port_obj_del(struct net_device *dev,
 			   const struct switchdev_obj *obj);
 
+int switchdev_call_replay(struct notifier_block *nb, unsigned long type,
+			  struct switchdev_notifier_info *info);
+
 int register_switchdev_notifier(struct notifier_block *nb);
 int unregister_switchdev_notifier(struct notifier_block *nb);
 int call_switchdev_notifiers(unsigned long val, struct net_device *dev,
diff --git a/net/bridge/br_switchdev.c b/net/bridge/br_switchdev.c
index ee84e783e1df..b9e69b522544 100644
--- a/net/bridge/br_switchdev.c
+++ b/net/bridge/br_switchdev.c
@@ -306,7 +306,7 @@ br_switchdev_fdb_replay_one(struct net_bridge *br, struct notifier_block *nb,
 
 	br_switchdev_fdb_populate(br, &item, fdb, ctx);
 
-	err = nb->notifier_call(nb, action, &item);
+	err = switchdev_call_replay(nb, action, &item.info);
 	return notifier_to_errno(err);
 }
 
@@ -376,8 +376,8 @@ static int br_switchdev_vlan_attr_replay(struct net_device *br_dev,
 			attr.u.vlan_msti.vid = v->vid;
 			attr.u.vlan_msti.msti = v->msti;
 
-			err = nb->notifier_call(nb, SWITCHDEV_PORT_ATTR_SET,
-						&attr_info);
+			err = switchdev_call_replay(nb, SWITCHDEV_PORT_ATTR_SET,
+						    &attr_info.info);
 			err = notifier_to_errno(err);
 			if (err)
 				return err;
@@ -404,7 +404,7 @@ br_switchdev_vlan_replay_one(struct notifier_block *nb,
 	};
 	int err;
 
-	err = nb->notifier_call(nb, action, &obj_info);
+	err = switchdev_call_replay(nb, action, &obj_info.info);
 	return notifier_to_errno(err);
 }
 
@@ -590,7 +590,7 @@ br_switchdev_mdb_replay_one(struct notifier_block *nb, struct net_device *dev,
 	};
 	int err;
 
-	err = nb->notifier_call(nb, action, &obj_info);
+	err = switchdev_call_replay(nb, action, &obj_info.info);
 	return notifier_to_errno(err);
 }
 
diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c
index 5b045284849e..e50863a03095 100644
--- a/net/switchdev/switchdev.c
+++ b/net/switchdev/switchdev.c
@@ -307,6 +307,23 @@ int switchdev_port_obj_del(struct net_device *dev,
 }
 EXPORT_SYMBOL_GPL(switchdev_port_obj_del);
 
+/**
+ *	switchdev_call_replay - Replay switchdev message to driver
+ *	@nb: notifier block to send the message to
+ *	@type: value passed unmodified to notifier function
+ *	@info: notifier information data
+ *
+ *	Typically issued by the bridge, as a response to a replay
+ *	request initiated by a port that is either attaching to, or
+ *	detaching from, that bridge.
+ */
+int switchdev_call_replay(struct notifier_block *nb, unsigned long type,
+			  struct switchdev_notifier_info *info)
+{
+	return nb->notifier_call(nb, type, info);
+}
+EXPORT_SYMBOL_GPL(switchdev_call_replay);
+
 static ATOMIC_NOTIFIER_HEAD(switchdev_notif_chain);
 static BLOCKING_NOTIFIER_HEAD(switchdev_blocking_notif_chain);
 
-- 
2.34.1

[PATCH v2 net-next 4/5] net: switchdev: Prepare deferred notifications before enqueuing them

[Tobias Waldekranz]

Instead of having a separate format for storing the canned objects and
attributes going to the deferred queue, store it using the
notification structures that will be needed once the item is dequeued
and sent to the driver.

This will be useful when we add switchdev tracepoints, as we can
uniformly trace deferred and immediate calls.

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
---
 net/switchdev/switchdev.c | 307 +++++++++++++++++++-------------------
 1 file changed, 156 insertions(+), 151 deletions(-)

diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c
index e50863a03095..309e6d68b179 100644
--- a/net/switchdev/switchdev.c
+++ b/net/switchdev/switchdev.c
@@ -22,17 +22,103 @@
 static LIST_HEAD(deferred);
 static DEFINE_SPINLOCK(deferred_lock);
 
-typedef void switchdev_deferred_func_t(struct net_device *dev,
-				       const void *data);
-
 struct switchdev_deferred_item {
 	struct list_head list;
-	struct net_device *dev;
+
+	enum switchdev_notifier_type nt;
+	union {
+		/* Guaranteed to be first in all subtypes */
+		struct switchdev_notifier_info info;
+
+		struct {
+			struct switchdev_notifier_port_attr_info info;
+			struct switchdev_attr attr;
+		} attr;
+
+		struct {
+			struct switchdev_notifier_port_obj_info info;
+			union {
+				struct switchdev_obj_port_vlan vlan;
+				struct switchdev_obj_port_mdb mdb;
+			};
+		} obj;
+	};
 	netdevice_tracker dev_tracker;
-	switchdev_deferred_func_t *func;
-	unsigned long data[];
 };
 
+static int switchdev_port_notify(struct net_device *dev,
+				 enum switchdev_notifier_type nt,
+				 struct switchdev_notifier_info *info,
+				 struct netlink_ext_ack *extack)
+{
+	const struct switchdev_notifier_port_attr_info *attri;
+	const struct switchdev_notifier_port_obj_info *obji;
+	int err;
+	int rc;
+
+	rc = call_switchdev_blocking_notifiers(nt, dev, info, extack);
+	err = notifier_to_errno(rc);
+
+	switch (nt) {
+	case SWITCHDEV_PORT_ATTR_SET:
+		attri = container_of(info, typeof(*attri), info);
+		if (err) {
+			WARN_ON(!attri->handled);
+			return err;
+		}
+		if (!attri->handled)
+			return -EOPNOTSUPP;
+		break;
+	case SWITCHDEV_PORT_OBJ_ADD:
+	case SWITCHDEV_PORT_OBJ_DEL:
+		obji = container_of(info, typeof(*obji), info);
+		if (err) {
+			WARN_ON(!obji->handled);
+			return err;
+		}
+		if (!obji->handled)
+			return -EOPNOTSUPP;
+		break;
+	default:
+		break;
+	}
+
+	return err;
+}
+
+static void switchdev_deferred_notify(struct switchdev_deferred_item *dfitem)
+{
+	const struct switchdev_attr *attr;
+	const struct switchdev_obj *obj;
+	char info_str[128];
+	int err;
+
+	err = switchdev_port_notify(dfitem->info.dev, dfitem->nt, &dfitem->info, NULL);
+	if (err && err != -EOPNOTSUPP) {
+		switchdev_notifier_str(dfitem->nt, &dfitem->info,
+				       info_str, sizeof(info_str));
+		netdev_err(dfitem->info.dev,
+			   "deferred switchdev call failed (err=%d): %s",
+			   err, info_str);
+	}
+
+	switch (dfitem->nt) {
+	case SWITCHDEV_PORT_ATTR_SET:
+		attr = &dfitem->attr.attr;
+		if (attr->complete)
+			attr->complete(dfitem->info.dev, err, attr->complete_priv);
+		break;
+	case SWITCHDEV_PORT_OBJ_ADD:
+	case SWITCHDEV_PORT_OBJ_DEL:
+		obj = dfitem->obj.info.obj;
+		if (obj->complete)
+			obj->complete(dfitem->info.dev, err, obj->complete_priv);
+		break;
+	default:
+		break;
+	}
+}
+
 static struct switchdev_deferred_item *switchdev_deferred_dequeue(void)
 {
 	struct switchdev_deferred_item *dfitem;
@@ -63,8 +149,8 @@ void switchdev_deferred_process(void)
 	ASSERT_RTNL();
 
 	while ((dfitem = switchdev_deferred_dequeue())) {
-		dfitem->func(dfitem->dev, dfitem->data);
-		netdev_put(dfitem->dev, &dfitem->dev_tracker);
+		switchdev_deferred_notify(dfitem);
+		netdev_put(dfitem->info.dev, &dfitem->dev_tracker);
 		kfree(dfitem);
 	}
 }
@@ -79,19 +165,9 @@ static void switchdev_deferred_process_work(struct work_struct *work)
 
 static DECLARE_WORK(deferred_process_work, switchdev_deferred_process_work);
 
-static int switchdev_deferred_enqueue(struct net_device *dev,
-				      const void *data, size_t data_len,
-				      switchdev_deferred_func_t *func)
+static int switchdev_deferred_enqueue(struct switchdev_deferred_item *dfitem)
 {
-	struct switchdev_deferred_item *dfitem;
-
-	dfitem = kmalloc(struct_size(dfitem, data, data_len), GFP_ATOMIC);
-	if (!dfitem)
-		return -ENOMEM;
-	dfitem->dev = dev;
-	dfitem->func = func;
-	memcpy(dfitem->data, data, data_len);
-	netdev_hold(dev, &dfitem->dev_tracker, GFP_ATOMIC);
+	netdev_hold(dfitem->info.dev, &dfitem->dev_tracker, GFP_ATOMIC);
 	spin_lock_bh(&deferred_lock);
 	list_add_tail(&dfitem->list, &deferred);
 	spin_unlock_bh(&deferred_lock);
@@ -99,62 +175,24 @@ static int switchdev_deferred_enqueue(struct net_device *dev,
 	return 0;
 }
 
-static int switchdev_port_attr_notify(enum switchdev_notifier_type nt,
-				      struct net_device *dev,
-				      const struct switchdev_attr *attr,
-				      struct netlink_ext_ack *extack)
+static int switchdev_port_attr_defer(struct net_device *dev,
+				     const struct switchdev_attr *attr)
 {
-	int err;
-	int rc;
-
-	struct switchdev_notifier_port_attr_info attr_info = {
-		.attr = attr,
-		.handled = false,
-	};
-
-	rc = call_switchdev_blocking_notifiers(nt, dev,
-					       &attr_info.info, extack);
-	err = notifier_to_errno(rc);
-	if (err) {
-		WARN_ON(!attr_info.handled);
-		return err;
-	}
+	struct switchdev_deferred_item *dfitem;
 
-	if (!attr_info.handled)
-		return -EOPNOTSUPP;
+	dfitem = kzalloc(sizeof(*dfitem), GFP_ATOMIC);
+	if (!dfitem)
+		return -ENOMEM;
 
+	dfitem->nt = SWITCHDEV_PORT_ATTR_SET;
+	dfitem->info.dev = dev;
+	dfitem->attr.attr = *attr;
+	dfitem->attr.info.attr = &dfitem->attr.attr;
+	dfitem->attr.info.handled = false;
+	switchdev_deferred_enqueue(dfitem);
 	return 0;
 }
 
-static int switchdev_port_attr_set_now(struct net_device *dev,
-				       const struct switchdev_attr *attr,
-				       struct netlink_ext_ack *extack)
-{
-	return switchdev_port_attr_notify(SWITCHDEV_PORT_ATTR_SET, dev, attr,
-					  extack);
-}
-
-static void switchdev_port_attr_set_deferred(struct net_device *dev,
-					     const void *data)
-{
-	const struct switchdev_attr *attr = data;
-	int err;
-
-	err = switchdev_port_attr_set_now(dev, attr, NULL);
-	if (err && err != -EOPNOTSUPP)
-		netdev_err(dev, "failed (err=%d) to set attribute (id=%d)\n",
-			   err, attr->id);
-	if (attr->complete)
-		attr->complete(dev, err, attr->complete_priv);
-}
-
-static int switchdev_port_attr_set_defer(struct net_device *dev,
-					 const struct switchdev_attr *attr)
-{
-	return switchdev_deferred_enqueue(dev, attr, sizeof(*attr),
-					  switchdev_port_attr_set_deferred);
-}
-
 /**
  *	switchdev_port_attr_set - Set port attribute
  *
@@ -169,73 +207,75 @@ int switchdev_port_attr_set(struct net_device *dev,
 			    const struct switchdev_attr *attr,
 			    struct netlink_ext_ack *extack)
 {
+	struct switchdev_notifier_port_attr_info attr_info = {
+		.attr = attr,
+		.handled = false,
+	};
+
 	if (attr->flags & SWITCHDEV_F_DEFER)
-		return switchdev_port_attr_set_defer(dev, attr);
+		return switchdev_port_attr_defer(dev, attr);
+
 	ASSERT_RTNL();
-	return switchdev_port_attr_set_now(dev, attr, extack);
+	return switchdev_port_notify(dev, SWITCHDEV_PORT_ATTR_SET,
+				     &attr_info.info, extack);
 }
 EXPORT_SYMBOL_GPL(switchdev_port_attr_set);
 
-static size_t switchdev_obj_size(const struct switchdev_obj *obj)
+static int switchdev_port_obj_defer(struct net_device *dev,
+				    enum switchdev_notifier_type nt,
+				    const struct switchdev_obj *obj)
 {
+	const struct switchdev_obj_port_vlan *vlan;
+	const struct switchdev_obj_port_mdb *mdb;
+	struct switchdev_deferred_item *dfitem;
+
+	dfitem = kzalloc(sizeof(*dfitem), GFP_ATOMIC);
+	if (!dfitem)
+		return -ENOMEM;
+
+	dfitem->nt = nt;
+	dfitem->info.dev = dev;
+	dfitem->obj.info.handled = false;
+
 	switch (obj->id) {
 	case SWITCHDEV_OBJ_ID_PORT_VLAN:
-		return sizeof(struct switchdev_obj_port_vlan);
+		vlan = SWITCHDEV_OBJ_PORT_VLAN(obj);
+		dfitem->obj.vlan = *vlan;
+		dfitem->obj.info.obj = &dfitem->obj.vlan.obj;
+		break;
 	case SWITCHDEV_OBJ_ID_PORT_MDB:
-		return sizeof(struct switchdev_obj_port_mdb);
 	case SWITCHDEV_OBJ_ID_HOST_MDB:
-		return sizeof(struct switchdev_obj_port_mdb);
+		mdb = SWITCHDEV_OBJ_PORT_MDB(obj);
+		dfitem->obj.mdb = *mdb;
+		dfitem->obj.info.obj = &dfitem->obj.mdb.obj;
+		break;
 	default:
-		BUG();
+		goto err_free;
 	}
+
+	switchdev_deferred_enqueue(dfitem);
 	return 0;
+
+err_free:
+	kfree(dfitem);
+	return -EINVAL;
 }
 
-static int switchdev_port_obj_notify(enum switchdev_notifier_type nt,
-				     struct net_device *dev,
-				     const struct switchdev_obj *obj,
-				     struct netlink_ext_ack *extack)
+static int switchdev_port_obj_op(struct net_device *dev,
+				 enum switchdev_notifier_type nt,
+				 const struct switchdev_obj *obj,
+				 struct netlink_ext_ack *extack)
 {
-	int rc;
-	int err;
-
 	struct switchdev_notifier_port_obj_info obj_info = {
 		.obj = obj,
 		.handled = false,
 	};
 
-	rc = call_switchdev_blocking_notifiers(nt, dev, &obj_info.info, extack);
-	err = notifier_to_errno(rc);
-	if (err) {
-		WARN_ON(!obj_info.handled);
-		return err;
-	}
-	if (!obj_info.handled)
-		return -EOPNOTSUPP;
-	return 0;
-}
-
-static void switchdev_port_obj_add_deferred(struct net_device *dev,
-					    const void *data)
-{
-	const struct switchdev_obj *obj = data;
-	int err;
+	if (obj->flags & SWITCHDEV_F_DEFER)
+		return switchdev_port_obj_defer(dev, nt, obj);
 
 	ASSERT_RTNL();
-	err = switchdev_port_obj_notify(SWITCHDEV_PORT_OBJ_ADD,
-					dev, obj, NULL);
-	if (err && err != -EOPNOTSUPP)
-		netdev_err(dev, "failed (err=%d) to add object (id=%d)\n",
-			   err, obj->id);
-	if (obj->complete)
-		obj->complete(dev, err, obj->complete_priv);
-}
-
-static int switchdev_port_obj_add_defer(struct net_device *dev,
-					const struct switchdev_obj *obj)
-{
-	return switchdev_deferred_enqueue(dev, obj, switchdev_obj_size(obj),
-					  switchdev_port_obj_add_deferred);
+	return switchdev_port_notify(dev, nt, &obj_info.info, extack);
 }
 
 /**
@@ -252,42 +292,10 @@ int switchdev_port_obj_add(struct net_device *dev,
 			   const struct switchdev_obj *obj,
 			   struct netlink_ext_ack *extack)
 {
-	if (obj->flags & SWITCHDEV_F_DEFER)
-		return switchdev_port_obj_add_defer(dev, obj);
-	ASSERT_RTNL();
-	return switchdev_port_obj_notify(SWITCHDEV_PORT_OBJ_ADD,
-					 dev, obj, extack);
+	return switchdev_port_obj_op(dev, SWITCHDEV_PORT_OBJ_ADD, obj, extack);
 }
 EXPORT_SYMBOL_GPL(switchdev_port_obj_add);
 
-static int switchdev_port_obj_del_now(struct net_device *dev,
-				      const struct switchdev_obj *obj)
-{
-	return switchdev_port_obj_notify(SWITCHDEV_PORT_OBJ_DEL,
-					 dev, obj, NULL);
-}
-
-static void switchdev_port_obj_del_deferred(struct net_device *dev,
-					    const void *data)
-{
-	const struct switchdev_obj *obj = data;
-	int err;
-
-	err = switchdev_port_obj_del_now(dev, obj);
-	if (err && err != -EOPNOTSUPP)
-		netdev_err(dev, "failed (err=%d) to del object (id=%d)\n",
-			   err, obj->id);
-	if (obj->complete)
-		obj->complete(dev, err, obj->complete_priv);
-}
-
-static int switchdev_port_obj_del_defer(struct net_device *dev,
-					const struct switchdev_obj *obj)
-{
-	return switchdev_deferred_enqueue(dev, obj, switchdev_obj_size(obj),
-					  switchdev_port_obj_del_deferred);
-}
-
 /**
  *	switchdev_port_obj_del - Delete port object
  *
@@ -300,10 +308,7 @@ static int switchdev_port_obj_del_defer(struct net_device *dev,
 int switchdev_port_obj_del(struct net_device *dev,
 			   const struct switchdev_obj *obj)
 {
-	if (obj->flags & SWITCHDEV_F_DEFER)
-		return switchdev_port_obj_del_defer(dev, obj);
-	ASSERT_RTNL();
-	return switchdev_port_obj_del_now(dev, obj);
+	return switchdev_port_obj_op(dev, SWITCHDEV_PORT_OBJ_DEL, obj, NULL);
 }
 EXPORT_SYMBOL_GPL(switchdev_port_obj_del);
 
-- 
2.34.1

[PATCH v2 net-next 5/5] net: switchdev: Add tracepoints

[Tobias Waldekranz]

Add a basic set of tracepoints:

- switchdev_defer: Triggers whenever an operation is enqueued to the
  switchdev workqueue.

- switchdev_call_atomic/switchdev_call_blocking: Triggers whenever a
  notification is sent on the corresponding notifier block.

- switchdev_call_replay: Triggers whenever a notification is sent back
  to a driver's own notifier block, in response to a replay request.

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
---
 include/trace/events/switchdev.h | 89 ++++++++++++++++++++++++++++++++
 net/switchdev/switchdev.c        | 24 +++++++--
 2 files changed, 109 insertions(+), 4 deletions(-)
 create mode 100644 include/trace/events/switchdev.h

diff --git a/include/trace/events/switchdev.h b/include/trace/events/switchdev.h
new file mode 100644
index 000000000000..b587965da2f6
--- /dev/null
+++ b/include/trace/events/switchdev.h
@@ -0,0 +1,89 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM	switchdev
+
+#if !defined(_TRACE_SWITCHDEV_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_SWITCHDEV_H
+
+#include <linux/tracepoint.h>
+#include <net/switchdev.h>
+
+#define SWITCHDEV_TRACE_MSG_MAX 128
+
+TRACE_EVENT(switchdev_defer,
+	TP_PROTO(unsigned long val,
+		 const struct switchdev_notifier_info *info),
+
+	TP_ARGS(val, info),
+
+	TP_STRUCT__entry(
+		__field(unsigned long, val)
+		__string(dev, info->dev ? netdev_name(info->dev) : "(null)")
+		__field(const struct switchdev_notifier_info *, info)
+		__array(char, msg, SWITCHDEV_TRACE_MSG_MAX)
+	),
+
+	TP_fast_assign(
+		__entry->val = val;
+		__assign_str(dev, info->dev ? netdev_name(info->dev) : "(null)");
+		__entry->info = info;
+		switchdev_notifier_str(val, info, __entry->msg, SWITCHDEV_TRACE_MSG_MAX);
+	),
+
+	TP_printk("dev %s %s", __get_str(dev), __entry->msg)
+);
+
+DECLARE_EVENT_CLASS(switchdev_call,
+	TP_PROTO(unsigned long val,
+		 const struct switchdev_notifier_info *info,
+		 int err),
+
+	TP_ARGS(val, info, err),
+
+	TP_STRUCT__entry(
+		__field(unsigned long, val)
+		__string(dev, info->dev ? netdev_name(info->dev) : "(null)")
+		__field(const struct switchdev_notifier_info *, info)
+		__field(int, err)
+		__array(char, msg, SWITCHDEV_TRACE_MSG_MAX)
+	),
+
+	TP_fast_assign(
+		__entry->val = val;
+		__assign_str(dev, info->dev ? netdev_name(info->dev) : "(null)");
+		__entry->info = info;
+		__entry->err = err;
+		switchdev_notifier_str(val, info, __entry->msg, SWITCHDEV_TRACE_MSG_MAX);
+	),
+
+	TP_printk("dev %s %s -> %d", __get_str(dev), __entry->msg, __entry->err)
+);
+
+DEFINE_EVENT(switchdev_call, switchdev_call_atomic,
+	TP_PROTO(unsigned long val,
+		 const struct switchdev_notifier_info *info,
+		 int err),
+
+	TP_ARGS(val, info, err)
+);
+
+DEFINE_EVENT(switchdev_call, switchdev_call_blocking,
+	TP_PROTO(unsigned long val,
+		 const struct switchdev_notifier_info *info,
+		 int err),
+
+	TP_ARGS(val, info, err)
+);
+
+DEFINE_EVENT(switchdev_call, switchdev_call_replay,
+	TP_PROTO(unsigned long val,
+		 const struct switchdev_notifier_info *info,
+		 int err),
+
+	TP_ARGS(val, info, err)
+);
+
+#endif /* _TRACE_SWITCHDEV_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c
index 309e6d68b179..078a8c68e9e8 100644
--- a/net/switchdev/switchdev.c
+++ b/net/switchdev/switchdev.c
@@ -19,6 +19,9 @@
 #include <linux/rtnetlink.h>
 #include <net/switchdev.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/switchdev.h>
+
 static LIST_HEAD(deferred);
 static DEFINE_SPINLOCK(deferred_lock);
 
@@ -171,6 +174,7 @@ static int switchdev_deferred_enqueue(struct switchdev_deferred_item *dfitem)
 	spin_lock_bh(&deferred_lock);
 	list_add_tail(&dfitem->list, &deferred);
 	spin_unlock_bh(&deferred_lock);
+	trace_switchdev_defer(dfitem->nt, &dfitem->info);
 	schedule_work(&deferred_process_work);
 	return 0;
 }
@@ -325,7 +329,11 @@ EXPORT_SYMBOL_GPL(switchdev_port_obj_del);
 int switchdev_call_replay(struct notifier_block *nb, unsigned long type,
 			  struct switchdev_notifier_info *info)
 {
-	return nb->notifier_call(nb, type, info);
+	int ret;
+
+	ret = nb->notifier_call(nb, type, info);
+	trace_switchdev_call_replay(type, info, notifier_to_errno(ret));
+	return ret;
 }
 EXPORT_SYMBOL_GPL(switchdev_call_replay);
 
@@ -368,9 +376,13 @@ int call_switchdev_notifiers(unsigned long val, struct net_device *dev,
 			     struct switchdev_notifier_info *info,
 			     struct netlink_ext_ack *extack)
 {
+	int ret;
+
 	info->dev = dev;
 	info->extack = extack;
-	return atomic_notifier_call_chain(&switchdev_notif_chain, val, info);
+	ret = atomic_notifier_call_chain(&switchdev_notif_chain, val, info);
+	trace_switchdev_call_atomic(val, info, notifier_to_errno(ret));
+	return ret;
 }
 EXPORT_SYMBOL_GPL(call_switchdev_notifiers);
 
@@ -394,10 +406,14 @@ int call_switchdev_blocking_notifiers(unsigned long val, struct net_device *dev,
 				      struct switchdev_notifier_info *info,
 				      struct netlink_ext_ack *extack)
 {
+	int ret;
+
 	info->dev = dev;
 	info->extack = extack;
-	return blocking_notifier_call_chain(&switchdev_blocking_notif_chain,
-					    val, info);
+	ret = blocking_notifier_call_chain(&switchdev_blocking_notif_chain,
+					   val, info);
+	trace_switchdev_call_blocking(val, info, notifier_to_errno(ret));
+	return ret;
 }
 EXPORT_SYMBOL_GPL(call_switchdev_blocking_notifiers);
 
-- 
2.34.1

Re: [PATCH v2 net-next 0/5] net: switchdev: Tracepoints

[Jakub Kicinski]

On Tue, 30 Jan 2024 21:19:32 +0100 Tobias Waldekranz wrote:
> This series starts off (1-2/5) by creating stringifiers for common
> switchdev objects. This will primarily be used by the tracepoints for
> decoding switchdev notifications, but drivers could also make use of
> them to provide richer debug/error messages.
> 
> Then follows two refactoring commits (3-4/5), with no (intended)
> functional changes:
> 
> - 3/5: Wrap all replay callbacks in br_switchdev.c in a switchdev
>        function to make it easy to trace all of these.
> 
> - 4/5: Instead of using a different format for deferred items, reuse
>        the existing notification structures when enqueuing. This lets
>        us share a bit more code, and it unifies the data presented by
>        the tracepoints.
> 
> Finally, add the tracepoints.

Is there any risk with conflicting with the fixes which are getting
worked on in parallel? Sorry for not investigating myself, ENOTIME.

> v1 -> v2:
> 
> - Fixup kernel-doc comment for switchdev_call_replay
> 
> I know that there are still some warnings issued by checkpatch, but
> I'm not sure how to work around them, given the nature of the mapper
> macros. Please advise.

It's a known problem, don't worry about those.

Re: [PATCH v2 net-next 0/5] net: switchdev: Tracepoints

[Tobias Waldekranz]

On tor, feb 01, 2024 at 20:44, Jakub Kicinski <kuba@kernel.org> wrote:
> On Tue, 30 Jan 2024 21:19:32 +0100 Tobias Waldekranz wrote:
>> This series starts off (1-2/5) by creating stringifiers for common
>> switchdev objects. This will primarily be used by the tracepoints for
>> decoding switchdev notifications, but drivers could also make use of
>> them to provide richer debug/error messages.
>> 
>> Then follows two refactoring commits (3-4/5), with no (intended)
>> functional changes:
>> 
>> - 3/5: Wrap all replay callbacks in br_switchdev.c in a switchdev
>>        function to make it easy to trace all of these.
>> 
>> - 4/5: Instead of using a different format for deferred items, reuse
>>        the existing notification structures when enqueuing. This lets
>>        us share a bit more code, and it unifies the data presented by
>>        the tracepoints.
>> 
>> Finally, add the tracepoints.
>
> Is there any risk with conflicting with the fixes which are getting
> worked on in parallel? Sorry for not investigating myself, ENOTIME.

They will unfortunately conflict with this series, yes. My journey was:

1. There's a problem with the MDB
2. I need tracepoints to figure this out
3. Having a light down here is pretty nice, I should upstream this
4. Find/understand/fix (1)
5. (4) probably should go into net

In hindsight, I should probably have anticipated this situation and done
away with (5) before proceeding with (3).

My idea now is to get the fix accepted, wait for the next merge of net
back to net-next, then fixup this series so that it does not reintroduce
the MDB sync issue. I already have a version of the fix that applies on
top of this series, so I'll just work it in to the switchdev refactor
steps in the next version.

Is there a better way to go about this?

>> v1 -> v2:
>> 
>> - Fixup kernel-doc comment for switchdev_call_replay
>> 
>> I know that there are still some warnings issued by checkpatch, but
>> I'm not sure how to work around them, given the nature of the mapper
>> macros. Please advise.
>
> It's a known problem, don't worry about those.

Re: [PATCH v2 net-next 0/5] net: switchdev: Tracepoints

[Jakub Kicinski]

On Fri, 02 Feb 2024 08:21:01 +0100 Tobias Waldekranz wrote:
> My idea now is to get the fix accepted, wait for the next merge of net
> back to net-next, then fixup this series so that it does not reintroduce
> the MDB sync issue. I already have a version of the fix that applies on
> top of this series, so I'll just work it in to the switchdev refactor
> steps in the next version.
> 
> Is there a better way to go about this?

No no, that's perfect! This set was still active in patchwork
yesterday, tho, so we could have applied it by mistake..
If you realize there's a conflict it's worth sending a comment 
to the already-posted net-next series notifying maintainers of
the situation.