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From: Tom Zanussi <zanussi@kernel.org>
To: rostedt@goodmis.org
Cc: artem.bityutskiy@linux.intel.com, mhiramat@kernel.org,
	linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org
Subject: [PATCH v4 01/12] tracing: Add trace_array_find/_get() to find instance trace arrays
Date: Wed, 29 Jan 2020 12:59:21 -0600	[thread overview]
Message-ID: <cb68528c975eba95bee4561ac67dd1499423b2e5.1580323897.git.zanussi@kernel.org> (raw)
In-Reply-To: <cover.1580323897.git.zanussi@kernel.org>
In-Reply-To: <cover.1580323897.git.zanussi@kernel.org>

Add a new trace_array_find() function that can be used to find a trace
array given the instance name, and replace existing code that does the
same thing with it.  Also add trace_array_find_get() which does the
same but returns the trace array after upping its refcount.

Also make both available for use outside of trace.c.

Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 kernel/trace/trace.c | 43 +++++++++++++++++++++++++++++++++----------
 kernel/trace/trace.h |  2 ++
 2 files changed, 35 insertions(+), 10 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 6a28b1b9bf42..6e415057d373 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -8501,6 +8501,34 @@ static void update_tracer_options(struct trace_array *tr)
 	mutex_unlock(&trace_types_lock);
 }
 
+/* Must have trace_types_lock held */
+struct trace_array *trace_array_find(const char *instance)
+{
+	struct trace_array *tr, *found = NULL;
+
+	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
+		if (tr->name && strcmp(tr->name, instance) == 0) {
+			found = tr;
+			break;
+		}
+	}
+
+	return found;
+}
+
+struct trace_array *trace_array_find_get(const char *instance)
+{
+	struct trace_array *tr;
+
+	mutex_lock(&trace_types_lock);
+	tr = trace_array_find(instance);
+	if (tr)
+		tr->ref++;
+	mutex_unlock(&trace_types_lock);
+
+	return tr;
+}
+
 static struct trace_array *trace_array_create(const char *name)
 {
 	struct trace_array *tr;
@@ -8577,10 +8605,8 @@ static int instance_mkdir(const char *name)
 	mutex_lock(&trace_types_lock);
 
 	ret = -EEXIST;
-	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
-		if (tr->name && strcmp(tr->name, name) == 0)
-			goto out_unlock;
-	}
+	if (trace_array_find(name))
+		goto out_unlock;
 
 	tr = trace_array_create(name);
 
@@ -8708,12 +8734,9 @@ static int instance_rmdir(const char *name)
 	mutex_lock(&trace_types_lock);
 
 	ret = -ENODEV;
-	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
-		if (tr->name && strcmp(tr->name, name) == 0) {
-			ret = __remove_instance(tr);
-			break;
-		}
-	}
+	tr = trace_array_find(name);
+	if (tr)
+		ret = __remove_instance(tr);
 
 	mutex_unlock(&trace_types_lock);
 	mutex_unlock(&event_mutex);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 6bb64d89c321..0db5341c113d 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -358,6 +358,8 @@ extern struct mutex trace_types_lock;
 
 extern int trace_array_get(struct trace_array *tr);
 extern int tracing_check_open_get_tr(struct trace_array *tr);
+extern struct trace_array *trace_array_find(const char *instance);
+extern struct trace_array *trace_array_find_get(const char *instance);
 
 extern int tracing_set_time_stamp_abs(struct trace_array *tr, bool abs);
 extern int tracing_set_clock(struct trace_array *tr, const char *clockstr);
-- 
2.14.1


  reply	other threads:[~2020-01-29 19:01 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-29 18:59 [PATCH v4 00/12] tracing: Add support for in-kernel dynamic event API Tom Zanussi
2020-01-29 18:59 ` Tom Zanussi [this message]
2020-01-29 21:14   ` [PATCH v4 01/12] tracing: Add trace_array_find/_get() to find instance trace arrays Steven Rostedt
2020-01-29 18:59 ` [PATCH v4 02/12] tracing: Add trace_get/put_event_file() Tom Zanussi
2020-01-29 18:59 ` [PATCH v4 03/12] tracing: Add synth_event_delete() Tom Zanussi
2020-01-29 18:59 ` [PATCH v4 04/12] tracing: Add dynamic event command creation interface Tom Zanussi
2020-01-30  2:40   ` Masami Hiramatsu
2020-01-30  2:58     ` Steven Rostedt
2020-01-29 18:59 ` [PATCH v4 05/12] tracing: Add synthetic event command generation functions Tom Zanussi
2020-01-29 18:59 ` [PATCH v4 06/12] tracing: Change trace_boot to use synth_event interface Tom Zanussi
2020-01-31 17:49   ` Tom Zanussi
2020-01-31 17:55     ` Steven Rostedt
2020-01-31 18:00       ` Steven Rostedt
2020-01-31 18:01         ` Tom Zanussi
2020-01-29 18:59 ` [PATCH v4 07/12] tracing: Add synth_event_trace() and related functions Tom Zanussi
2020-01-29 21:09   ` Steven Rostedt
2020-01-29 22:58     ` Tom Zanussi
2020-01-30  3:01       ` Steven Rostedt
2020-01-29 18:59 ` [PATCH v4 08/12] tracing: Add synth event generation test module Tom Zanussi
2020-01-29 18:59 ` [PATCH v4 09/12] tracing: Add kprobe event command generation functions Tom Zanussi
2020-01-29 18:59 ` [PATCH v4 10/12] tracing: Change trace_boot to use kprobe_event interface Tom Zanussi
2020-01-29 18:59 ` [PATCH v4 11/12] tracing: Add kprobe event command generation test module Tom Zanussi
2020-01-29 18:59 ` [PATCH v4 12/12] tracing: Documentation for in-kernel synthetic event API Tom Zanussi

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