Commit 89c95fce authored by Tom Zanussi's avatar Tom Zanussi Committed by Steven Rostedt (VMware)
Browse files

tracing: Add trace_array_find/_get() to find instance trace arrays 

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.

Link: http://lkml.kernel.org/r/cb68528c975eba95bee4561ac67dd1499423b2e5.1580323897.git.zanussi@kernel.org



Acked-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarTom Zanussi <zanussi@kernel.org>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 6722b23e

kernel/trace/trace.c

+33 −10
Original line number Diff line number Diff line
@@ -8499,6 +8499,34 @@ 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;
@@ -8575,10 +8603,8 @@ 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)

	if (trace_array_find(name))

		goto out_unlock;

	}



	tr = trace_array_create(name);
@@ -8706,12 +8732,9 @@ 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) {

	tr = trace_array_find(name);

	if (tr)

		ret = __remove_instance(tr);

			break;

		}

	}



	mutex_unlock(&trace_types_lock);

	mutex_unlock(&event_mutex);

kernel/trace/trace.h

+2 −0
Original line number Diff line number Diff line
@@ -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);

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