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authorTom Zanussi <zanussi@kernel.org>2020-01-29 12:59:21 -0600
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2020-01-30 09:46:27 -0500
commit89c95fcef1942415e0f20d8c82e6e36ff8eeca9c (patch)
tree5c7ff66ce0f2250652c7cbcea3e5e46128c92a4e /kernel/trace
parent6722b23e7a2ace078344064a9735fb73e554e9ef (diff)
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: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Tom Zanussi <zanussi@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/trace.c43
-rw-r--r--kernel/trace/trace.h2
2 files changed, 35 insertions, 10 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 8d144fd94aa8..183b031a3828 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -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)
- goto out_unlock;
- }
+ 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) {
- 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 b3075b637d14..f5480a2aa334 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);