1 files changed, 70 insertions, 64 deletions

diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index b33c3861fbbb..d45448947094 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -159,7 +159,7 @@ static void *trigger_start(struct seq_file *m, loff_t *pos)
 
 	/* ->stop() is called even if ->start() fails */
 	mutex_lock(&event_mutex);
-	event_file = event_file_data(m->private);
+	event_file = event_file_file(m->private);
 	if (unlikely(!event_file))
 		return ERR_PTR(-ENODEV);
 
@@ -211,12 +211,10 @@ static int event_trigger_regex_open(struct inode *inode, struct file *file)
 	if (ret)
 		return ret;
 
-	mutex_lock(&event_mutex);
+	guard(mutex)(&event_mutex);
 
-	if (unlikely(!event_file_data(file))) {
-		mutex_unlock(&event_mutex);
+	if (unlikely(!event_file_file(file)))
 		return -ENODEV;
-	}
 
 	if ((file->f_mode & FMODE_WRITE) &&
 	    (file->f_flags & O_TRUNC)) {
@@ -239,8 +237,6 @@ static int event_trigger_regex_open(struct inode *inode, struct file *file)
 		}
 	}
 
-	mutex_unlock(&event_mutex);
-
 	return ret;
 }
 
@@ -248,7 +244,6 @@ int trigger_process_regex(struct trace_event_file *file, char *buff)
 {
 	char *command, *next;
 	struct event_command *p;
-	int ret = -EINVAL;
 
 	next = buff = skip_spaces(buff);
 	command = strsep(&next, ": \t");
@@ -259,17 +254,14 @@ int trigger_process_regex(struct trace_event_file *file, char *buff)
 	}
 	command = (command[0] != '!') ? command : command + 1;
 
-	mutex_lock(&trigger_cmd_mutex);
+	guard(mutex)(&trigger_cmd_mutex);
+
 	list_for_each_entry(p, &trigger_commands, list) {
-		if (strcmp(p->name, command) == 0) {
-			ret = p->parse(p, file, buff, command, next);
-			goto out_unlock;
-		}
+		if (strcmp(p->name, command) == 0)
+			return p->parse(p, file, buff, command, next);
 	}
- out_unlock:
-	mutex_unlock(&trigger_cmd_mutex);
 
-	return ret;
+	return -EINVAL;
 }
 
 static ssize_t event_trigger_regex_write(struct file *file,
@@ -278,7 +270,7 @@ static ssize_t event_trigger_regex_write(struct file *file,
 {
 	struct trace_event_file *event_file;
 	ssize_t ret;
-	char *buf;
+	char *buf __free(kfree) = NULL;
 
 	if (!cnt)
 		return 0;
@@ -292,24 +284,18 @@ static ssize_t event_trigger_regex_write(struct file *file,
 
 	strim(buf);
 
-	mutex_lock(&event_mutex);
-	event_file = event_file_data(file);
-	if (unlikely(!event_file)) {
-		mutex_unlock(&event_mutex);
-		kfree(buf);
+	guard(mutex)(&event_mutex);
+
+	event_file = event_file_file(file);
+	if (unlikely(!event_file))
 		return -ENODEV;
-	}
-	ret = trigger_process_regex(event_file, buf);
-	mutex_unlock(&event_mutex);
 
-	kfree(buf);
+	ret = trigger_process_regex(event_file, buf);
 	if (ret < 0)
-		goto out;
+		return ret;
 
 	*ppos += cnt;
-	ret = cnt;
- out:
-	return ret;
+	return cnt;
 }
 
 static int event_trigger_regex_release(struct inode *inode, struct file *file)
@@ -359,20 +345,16 @@ const struct file_operations event_trigger_fops = {
 __init int register_event_command(struct event_command *cmd)
 {
 	struct event_command *p;
-	int ret = 0;
 
-	mutex_lock(&trigger_cmd_mutex);
+	guard(mutex)(&trigger_cmd_mutex);
+
 	list_for_each_entry(p, &trigger_commands, list) {
-		if (strcmp(cmd->name, p->name) == 0) {
-			ret = -EBUSY;
-			goto out_unlock;
-		}
+		if (strcmp(cmd->name, p->name) == 0)
+			return -EBUSY;
 	}
 	list_add(&cmd->list, &trigger_commands);
- out_unlock:
-	mutex_unlock(&trigger_cmd_mutex);
 
-	return ret;
+	return 0;
 }
 
 /*
@@ -382,20 +364,17 @@ __init int register_event_command(struct event_command *cmd)
 __init int unregister_event_command(struct event_command *cmd)
 {
 	struct event_command *p, *n;
-	int ret = -ENODEV;
 
-	mutex_lock(&trigger_cmd_mutex);
+	guard(mutex)(&trigger_cmd_mutex);
+
 	list_for_each_entry_safe(p, n, &trigger_commands, list) {
 		if (strcmp(cmd->name, p->name) == 0) {
-			ret = 0;
 			list_del_init(&p->list);
-			goto out_unlock;
+			return 0;
 		}
 	}
- out_unlock:
-	mutex_unlock(&trigger_cmd_mutex);
 
-	return ret;
+	return -ENODEV;
 }
 
 /**
@@ -597,20 +576,12 @@ out:
 	return ret;
 }
 
-/**
- * unregister_trigger - Generic event_command @unreg implementation
- * @glob: The raw string used to register the trigger
- * @test: Trigger-specific data used to find the trigger to remove
- * @file: The trace_event_file associated with the event
- *
- * Common implementation for event trigger unregistration.
- *
- * Usually used directly as the @unreg method in event command
- * implementations.
+/*
+ * True if the trigger was found and unregistered, else false.
  */
-static void unregister_trigger(char *glob,
-			       struct event_trigger_data *test,
-			       struct trace_event_file *file)
+static bool try_unregister_trigger(char *glob,
+				   struct event_trigger_data *test,
+				   struct trace_event_file *file)
 {
 	struct event_trigger_data *data = NULL, *iter;
 
@@ -626,8 +597,32 @@ static void unregister_trigger(char *glob,
 		}
 	}
 
-	if (data && data->ops->free)
-		data->ops->free(data);
+	if (data) {
+		if (data->ops->free)
+			data->ops->free(data);
+
+		return true;
+	}
+
+	return false;
+}
+
+/**
+ * unregister_trigger - Generic event_command @unreg implementation
+ * @glob: The raw string used to register the trigger
+ * @test: Trigger-specific data used to find the trigger to remove
+ * @file: The trace_event_file associated with the event
+ *
+ * Common implementation for event trigger unregistration.
+ *
+ * Usually used directly as the @unreg method in event command
+ * implementations.
+ */
+static void unregister_trigger(char *glob,
+			       struct event_trigger_data *test,
+			       struct trace_event_file *file)
+{
+	try_unregister_trigger(glob, test, file);
 }
 
 /*
@@ -1470,12 +1465,23 @@ register_snapshot_trigger(char *glob,
 			  struct event_trigger_data *data,
 			  struct trace_event_file *file)
 {
-	int ret = tracing_alloc_snapshot_instance(file->tr);
+	int ret = tracing_arm_snapshot(file->tr);
 
 	if (ret < 0)
 		return ret;
 
-	return register_trigger(glob, data, file);
+	ret = register_trigger(glob, data, file);
+	if (ret < 0)
+		tracing_disarm_snapshot(file->tr);
+	return ret;
+}
+
+static void unregister_snapshot_trigger(char *glob,
+					struct event_trigger_data *data,
+					struct trace_event_file *file)
+{
+	if (try_unregister_trigger(glob, data, file))
+		tracing_disarm_snapshot(file->tr);
 }
 
 static int
@@ -1510,7 +1516,7 @@ static struct event_command trigger_snapshot_cmd = {
 	.trigger_type		= ETT_SNAPSHOT,
 	.parse			= event_trigger_parse,
 	.reg			= register_snapshot_trigger,
-	.unreg			= unregister_trigger,
+	.unreg			= unregister_snapshot_trigger,
 	.get_trigger_ops	= snapshot_get_trigger_ops,
 	.set_filter		= set_trigger_filter,
 };