[merged mm-nonmm-stable] notifiers-add-tracepoints-to-the-notifiers-infrastructure.patch removed from -mm tree

[merged mm-nonmm-stable] notifiers-add-tracepoints-to-the-notifiers-infrastructure.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: notifiers: add tracepoints to the notifiers infrastructure
has been removed from the -mm tree.  Its filename was
     notifiers-add-tracepoints-to-the-notifiers-infrastructure.patch

This patch was dropped because it was merged into the mm-nonmm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Subject: notifiers: add tracepoints to the notifiers infrastructure
Date: Tue, 14 Mar 2023 17:00:58 -0300

Currently there is no way to show the callback names for registered,
unregistered or executed notifiers. This is very useful for debug
purposes, hence add this functionality here in the form of notifiers'
tracepoints, one per operation.

[akpm@linux-foundation.org: coding-style cleanups]
Link: https://lkml.kernel.org/r/20230314200058.1326909-1-gpiccoli@igalia.com
Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Michael Kelley <mikelley@microsoft.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Xiaoming Ni <nixiaoming@huawei.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Cc: Guilherme G. Piccoli <gpiccoli@igalia.com>
Cc: Guilherme G. Piccoli <kernel@gpiccoli.net>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/trace/events/notifier.h |   69 ++++++++++++++++++++++++++++++
 kernel/notifier.c               |    6 ++
 2 files changed, 75 insertions(+)

--- /dev/null
+++ a/include/trace/events/notifier.h
@@ -0,0 +1,69 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM notifier
+
+#if !defined(_TRACE_NOTIFIERS_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_NOTIFIERS_H
+
+#include <linux/tracepoint.h>
+
+DECLARE_EVENT_CLASS(notifier_info,
+
+	TP_PROTO(void *cb),
+
+	TP_ARGS(cb),
+
+	TP_STRUCT__entry(
+		__field(void *, cb)
+	),
+
+	TP_fast_assign(
+		__entry->cb = cb;
+	),
+
+	TP_printk("%ps", __entry->cb)
+);
+
+/*
+ * notifier_register - called upon notifier callback registration
+ *
+ * @cb:		callback pointer
+ *
+ */
+DEFINE_EVENT(notifier_info, notifier_register,
+
+	TP_PROTO(void *cb),
+
+	TP_ARGS(cb)
+);
+
+/*
+ * notifier_unregister - called upon notifier callback unregistration
+ *
+ * @cb:		callback pointer
+ *
+ */
+DEFINE_EVENT(notifier_info, notifier_unregister,
+
+	TP_PROTO(void *cb),
+
+	TP_ARGS(cb)
+);
+
+/*
+ * notifier_run - called upon notifier callback execution
+ *
+ * @cb:		callback pointer
+ *
+ */
+DEFINE_EVENT(notifier_info, notifier_run,
+
+	TP_PROTO(void *cb),
+
+	TP_ARGS(cb)
+);
+
+#endif /* _TRACE_NOTIFIERS_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
--- a/kernel/notifier.c~notifiers-add-tracepoints-to-the-notifiers-infrastructure
+++ a/kernel/notifier.c
@@ -7,6 +7,9 @@
 #include <linux/vmalloc.h>
 #include <linux/reboot.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/notifier.h>
+
 /*
  *	Notifier list for kernel code which wants to be called
  *	at shutdown. This is used to stop any idling DMA operations
@@ -37,6 +40,7 @@ static int notifier_chain_register(struc
 	}
 	n->next = *nl;
 	rcu_assign_pointer(*nl, n);
+	trace_notifier_register((void *)n->notifier_call);
 	return 0;
 }
 
@@ -46,6 +50,7 @@ static int notifier_chain_unregister(str
 	while ((*nl) != NULL) {
 		if ((*nl) == n) {
 			rcu_assign_pointer(*nl, n->next);
+			trace_notifier_unregister((void *)n->notifier_call);
 			return 0;
 		}
 		nl = &((*nl)->next);
@@ -84,6 +89,7 @@ static int notifier_call_chain(struct no
 			continue;
 		}
 #endif
+		trace_notifier_run((void *)nb->notifier_call);
 		ret = nb->notifier_call(nb, val, v);
 
 		if (nr_calls)
_

Patches currently in -mm which might be from gpiccoli@igalia.com are