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From: Masami Hiramatsu <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
	Tom Zanussi <tom.zanussi@linux.intel.com>,
	Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Subject: [PATCH v2 03/12] tracing: Simplify creation and deletion of synthetic event
Date: Mon,  5 Nov 2018 18:01:12 +0900
Message-ID: <154140847194.17322.17960275728005067803.stgit@devbox> (raw)
In-Reply-To: <154140838606.17322.15294184388075458777.stgit@devbox>

Simplify creation and deletion code of synthetic event.

Since the event_mutex and synth_event_mutex ordering issue
is gone, we can skip existing event check when adding or
deleting event, and some redundant code in error path.

This changes release_all_synth_events() to abort the process
when it hits any error and returns the error code. It succeeds
only if it has no error.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 kernel/trace/trace_events_hist.c |   53 +++++++++++++-------------------------
 1 file changed, 18 insertions(+), 35 deletions(-)

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 1670c65389fe..0feb7f460123 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -1008,18 +1008,6 @@ struct hist_var_data {
 	struct hist_trigger_data *hist_data;
 };
 
-static void add_or_delete_synth_event(struct synth_event *event, int delete)
-{
-	if (delete)
-		free_synth_event(event);
-	else {
-		if (!find_synth_event(event->name))
-			list_add(&event->list, &synth_event_list);
-		else
-			free_synth_event(event);
-	}
-}
-
 static int create_synth_event(int argc, char **argv)
 {
 	struct synth_field *field, *fields[SYNTH_FIELDS_MAX];
@@ -1052,15 +1040,16 @@ static int create_synth_event(int argc, char **argv)
 	if (event) {
 		if (delete_event) {
 			if (event->ref) {
-				event = NULL;
 				ret = -EBUSY;
 				goto out;
 			}
-			list_del(&event->list);
-			goto out;
-		}
-		event = NULL;
-		ret = -EEXIST;
+			ret = unregister_synth_event(event);
+			if (!ret) {
+				list_del(&event->list);
+				free_synth_event(event);
+			}
+		} else
+			ret = -EEXIST;
 		goto out;
 	} else if (delete_event) {
 		ret = -ENOENT;
@@ -1100,29 +1089,21 @@ static int create_synth_event(int argc, char **argv)
 		event = NULL;
 		goto err;
 	}
+	ret = register_synth_event(event);
+	if (!ret)
+		list_add(&event->list, &synth_event_list);
+	else
+		free_synth_event(event);
  out:
-	if (event) {
-		if (delete_event) {
-			ret = unregister_synth_event(event);
-			add_or_delete_synth_event(event, !ret);
-		} else {
-			ret = register_synth_event(event);
-			add_or_delete_synth_event(event, ret);
-		}
-	}
 	mutex_unlock(&synth_event_mutex);
 	mutex_unlock(&event_mutex);
 
 	return ret;
  err:
-	mutex_unlock(&synth_event_mutex);
-	mutex_unlock(&event_mutex);
-
 	for (i = 0; i < n_fields; i++)
 		free_synth_field(fields[i]);
-	free_synth_event(event);
 
-	return ret;
+	goto out;
 }
 
 static int release_all_synth_events(void)
@@ -1141,10 +1122,12 @@ static int release_all_synth_events(void)
 	}
 
 	list_for_each_entry_safe(event, e, &synth_event_list, list) {
-		list_del(&event->list);
-
 		ret = unregister_synth_event(event);
-		add_or_delete_synth_event(event, !ret);
+		if (!ret) {
+			list_del(&event->list);
+			free_synth_event(event);
+		} else
+			break;
 	}
 	mutex_unlock(&synth_event_mutex);
 	mutex_unlock(&event_mutex);


  parent reply index

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-05  8:59 [PATCH v2 00/12] tracing: Unifying dynamic event interface Masami Hiramatsu
2018-11-05  9:00 ` [PATCH v2 01/12] tracing/uprobes: Add busy check when cleanup all uprobes Masami Hiramatsu
2018-12-04 17:43   ` Steven Rostedt
2018-12-07  2:19     ` Masami Hiramatsu
2018-11-05  9:00 ` [PATCH v2 02/12] tracing: Lock event_mutex before synth_event_mutex Masami Hiramatsu
2018-11-05  9:01 ` Masami Hiramatsu [this message]
2018-11-05  9:01 ` [PATCH v2 04/12] tracing: Integrate similar probe argument parsers Masami Hiramatsu
2018-11-05  9:02 ` [PATCH v2 05/12] tracing: Add unified dynamic event framework Masami Hiramatsu
2018-11-05  9:02 ` [PATCH v2 06/12] tracing/kprobes: Use dyn_event framework for kprobe events Masami Hiramatsu
2018-11-05  9:03 ` [PATCH v2 07/12] tracing/uprobes: Use dyn_event framework for uprobe events Masami Hiramatsu
2018-11-05  9:03 ` [PATCH v2 08/12] tracing: Use dyn_event framework for synthetic events Masami Hiramatsu
2018-11-05  9:04 ` [PATCH v2 09/12] tracing: Remove unneeded synth_event_mutex Masami Hiramatsu
2018-11-05  9:04 ` [PATCH v2 10/12] tracing: Remove orphaned trace_add/remove_event_call functions Masami Hiramatsu
2018-12-04 18:51   ` Steven Rostedt
2018-12-07  2:22     ` Masami Hiramatsu
2018-11-05  9:04 ` [PATCH v2 11/12] tracing: Add generic event-name based remove event method Masami Hiramatsu
2018-11-05  9:05 ` [PATCH v2 12/12] selftests/ftrace: Add testcases for dynamic event Masami Hiramatsu
2018-11-28  7:31 ` [PATCH v2 00/12] tracing: Unifying dynamic event interface Masami Hiramatsu
2018-11-28 23:42   ` Tom Zanussi
2018-11-29  3:46     ` Steven Rostedt
2018-11-29  5:20     ` Masami Hiramatsu
2018-11-29 15:08       ` Tom Zanussi

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