From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Tue, 24 May 2011 15:37:06 +0000 (-0400)
Subject: Handle refcount of modules having dynamically alloc event description
X-Git-Tag: v2.0-pre1~97
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=dc7f600a24e263bba4a69d7c94ab9c0bda9bca02;p=lttng-modules.git

Handle refcount of modules having dynamically alloc event description

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/ltt-events.h b/ltt-events.h
index 6cc37531..9baf660d 100644
--- a/ltt-events.h
+++ b/ltt-events.h
@@ -139,6 +139,7 @@ struct lttng_event_desc {
 	const struct lttng_event_ctx *ctx;	/* context */
 	const struct lttng_event_field *fields;	/* event payload */
 	unsigned int nr_fields;
+	struct module *owner;
 };
 
 struct lttng_probe_desc {
diff --git a/ltt-probes.c b/ltt-probes.c
index ad7f7c2b..0efc23c5 100644
--- a/ltt-probes.c
+++ b/ltt-probes.c
@@ -30,11 +30,6 @@ const struct lttng_event_desc *find_event(const char *name)
 	return NULL;
 }
 
-/*
- * TODO: registration of probe descriptions in dynamically allocated memory (not
- * directly in a module memory) will require some care for refcounting: it's
- * currently done by just refcounting the module in event_get/put.
- */
 int ltt_probe_register(struct lttng_probe_desc *desc)
 {
 	int ret = 0;
@@ -76,7 +71,7 @@ const struct lttng_event_desc *ltt_event_get(const char *name)
 	mutex_unlock(&probe_mutex);
 	if (!event)
 		return NULL;
-	ret = try_module_get(__module_text_address((unsigned long) event));
+	ret = try_module_get(event->owner);
 	WARN_ON_ONCE(!ret);
 	return event;
 }
@@ -84,6 +79,6 @@ EXPORT_SYMBOL_GPL(ltt_event_get);
 
 void ltt_event_put(const struct lttng_event_desc *event)
 {
-	module_put(__module_text_address((unsigned long) event));
+	module_put(event->owner);
 }
 EXPORT_SYMBOL_GPL(ltt_event_put);
diff --git a/probes/lttng-events.h b/probes/lttng-events.h
index 9aaf1573..beedb22b 100644
--- a/probes/lttng-events.h
+++ b/probes/lttng-events.h
@@ -195,6 +195,7 @@ static void __event_probe__##_name(void *__data, _proto);
 			.name = #_name,					       \
 			.probe_callback = (void *) &__event_probe__##_template,\
 			.nr_fields = ARRAY_SIZE(__event_fields___##_template), \
+			.owner = THIS_MODULE,				       \
 		},
 
 #define TP_ID1(_token, _system)	_token##_system
diff --git a/probes/lttng-ftrace.c b/probes/lttng-ftrace.c
index 5b4cf2e7..c866876e 100644
--- a/probes/lttng-ftrace.c
+++ b/probes/lttng-ftrace.c
@@ -92,6 +92,7 @@ int lttng_create_ftrace_event(const char *name, struct ltt_event *event)
 	fields[1].type.u.basic.integer.base = 16;
 	fields[1].type.u.basic.integer.encoding = lttng_encode_none;
 
+	desc->owner = THIS_MODULE;
 	event->desc = desc;
 
 	return 0;
diff --git a/probes/lttng-kprobes.c b/probes/lttng-kprobes.c
index 65c1d3ba..650144cb 100644
--- a/probes/lttng-kprobes.c
+++ b/probes/lttng-kprobes.c
@@ -71,6 +71,7 @@ int lttng_create_kprobe_event(const char *name, struct ltt_event *event)
 	field->type.u.basic.integer.reverse_byte_order = 0;
 	field->type.u.basic.integer.base = 16;
 	field->type.u.basic.integer.encoding = lttng_encode_none;
+	desc->owner = THIS_MODULE;
 	event->desc = desc;
 
 	return 0;