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Commit 69365d1a authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman
Browse files

Revert "tracing: Have trace_event_file have ref counters" 



This reverts commit 961c4511 which is
commit bb32500fb9b78215e4ef6ee8b4345c5f5d7eafb4 upstream.

It breaks the Android ABI and can be brought back later in an abi-safe
way if it is needed.

Bug: 161946584
Change-Id: Id5da117def3da9c182501e30ee84bea05da7e492
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@google.com>
parent 288ce216

include/linux/trace_events.h

+0 −4
Original line number Diff line number Diff line
@@ -341,7 +341,6 @@ enum { 
	EVENT_FILE_FL_TRIGGER_COND_BIT,

	EVENT_FILE_FL_PID_FILTER_BIT,

	EVENT_FILE_FL_WAS_ENABLED_BIT,

	EVENT_FILE_FL_FREED_BIT,

};



/*
@@ -358,7 +357,6 @@ enum { 
 *  TRIGGER_COND  - When set, one or more triggers has an associated filter

 *  PID_FILTER    - When set, the event is filtered based on pid

 *  WAS_ENABLED   - Set when enabled to know to clear trace on module removal

 *  FREED         - File descriptor is freed, all fields should be considered invalid

 */

enum {

	EVENT_FILE_FL_ENABLED		= (1 << EVENT_FILE_FL_ENABLED_BIT),
@@ -372,7 +370,6 @@ enum { 
	EVENT_FILE_FL_TRIGGER_COND	= (1 << EVENT_FILE_FL_TRIGGER_COND_BIT),

	EVENT_FILE_FL_PID_FILTER	= (1 << EVENT_FILE_FL_PID_FILTER_BIT),

	EVENT_FILE_FL_WAS_ENABLED	= (1 << EVENT_FILE_FL_WAS_ENABLED_BIT),

	EVENT_FILE_FL_FREED		= (1 << EVENT_FILE_FL_FREED_BIT),

};



struct trace_event_file {
@@ -401,7 +398,6 @@ struct trace_event_file { 
	 * caching and such. Which is mostly OK ;-)

	 */

	unsigned long		flags;

	atomic_t		ref;	/* ref count for opened files */

	atomic_t		sm_ref;	/* soft-mode reference counter */

	atomic_t		tm_ref;	/* trigger-mode reference counter */

};

kernel/trace/trace.c

+0 −15
Original line number Diff line number Diff line
@@ -4257,20 +4257,6 @@ int tracing_open_file_tr(struct inode *inode, struct file *filp) 
	if (ret)

		return ret;



	mutex_lock(&event_mutex);



	/* Fail if the file is marked for removal */

	if (file->flags & EVENT_FILE_FL_FREED) {

		trace_array_put(file->tr);

		ret = -ENODEV;

	} else {

		event_file_get(file);

	}



	mutex_unlock(&event_mutex);

	if (ret)

		return ret;



	filp->private_data = inode->i_private;



	return 0;
@@ -4281,7 +4267,6 @@ int tracing_release_file_tr(struct inode *inode, struct file *filp) 
	struct trace_event_file *file = inode->i_private;



	trace_array_put(file->tr);

	event_file_put(file);



	return 0;

}

kernel/trace/trace.h

+0 −3
Original line number Diff line number Diff line
@@ -1696,9 +1696,6 @@ extern int register_event_command(struct event_command *cmd); 
extern int unregister_event_command(struct event_command *cmd);

extern int register_trigger_hist_enable_disable_cmds(void);



extern void event_file_get(struct trace_event_file *file);

extern void event_file_put(struct trace_event_file *file);



/**

 * struct event_trigger_ops - callbacks for trace event triggers

 *

kernel/trace/trace_events.c

+13 −26
Original line number Diff line number Diff line
@@ -698,33 +698,21 @@ static void remove_subsystem(struct trace_subsystem_dir *dir) 
	}

}



void event_file_get(struct trace_event_file *file)

{

	atomic_inc(&file->ref);

}



void event_file_put(struct trace_event_file *file)

{

	if (WARN_ON_ONCE(!atomic_read(&file->ref))) {

		if (file->flags & EVENT_FILE_FL_FREED)

			kmem_cache_free(file_cachep, file);

		return;

	}



	if (atomic_dec_and_test(&file->ref)) {

		/* Count should only go to zero when it is freed */

		if (WARN_ON_ONCE(!(file->flags & EVENT_FILE_FL_FREED)))

			return;

		kmem_cache_free(file_cachep, file);

	}

}



static void remove_event_file_dir(struct trace_event_file *file)

{

	struct dentry *dir = file->dir;

	struct dentry *child;



	if (dir) {

		spin_lock(&dir->d_lock);	/* probably unneeded */

		list_for_each_entry(child, &dir->d_subdirs, d_child) {

			if (d_really_is_positive(child))	/* probably unneeded */

				d_inode(child)->i_private = NULL;

		}

		spin_unlock(&dir->d_lock);



	if (dir)

		tracefs_remove_recursive(dir);

	}



	list_del(&file->list);

	remove_subsystem(file->system);
@@ -1045,7 +1033,7 @@ event_enable_read(struct file *filp, char __user *ubuf, size_t cnt, 
		flags = file->flags;

	mutex_unlock(&event_mutex);



	if (!file || flags & EVENT_FILE_FL_FREED)

	if (!file)

		return -ENODEV;



	if (flags & EVENT_FILE_FL_ENABLED &&
@@ -1083,7 +1071,7 @@ event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt, 
		ret = -ENODEV;

		mutex_lock(&event_mutex);

		file = event_file_data(filp);

		if (likely(file && !(file->flags & EVENT_FILE_FL_FREED)))

		if (likely(file))

			ret = ftrace_event_enable_disable(file, val);

		mutex_unlock(&event_mutex);

		break;
@@ -1352,7 +1340,7 @@ event_filter_read(struct file *filp, char __user *ubuf, size_t cnt, 


	mutex_lock(&event_mutex);

	file = event_file_data(filp);

	if (file && !(file->flags & EVENT_FILE_FL_FREED))

	if (file)

		print_event_filter(file, s);

	mutex_unlock(&event_mutex);
@@ -2276,7 +2264,6 @@ trace_create_new_event(struct trace_event_call *call, 
	atomic_set(&file->tm_ref, 0);

	INIT_LIST_HEAD(&file->triggers);

	list_add(&file->list, &tr->events);

	event_file_get(file);



	return file;

}

kernel/trace/trace_events_filter.c

+0 −3
Original line number Diff line number Diff line
@@ -1800,9 +1800,6 @@ int apply_event_filter(struct trace_event_file *file, char *filter_string) 
	struct event_filter *filter = NULL;

	int err;



	if (file->flags & EVENT_FILE_FL_FREED)

		return -ENODEV;



	if (!strcmp(strstrip(filter_string), "0")) {

		filter_disable(file);

		filter = event_filter(file);