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

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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>
This commit is contained in:
Tom Zanussi
2020-01-29 12:59:21 -06:00
committed by Steven Rostedt (VMware)
parent 6722b23e7a
commit 89c95fcef1
2 changed files with 35 additions and 10 deletions
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43
kernel/trace/trace.c
View File

@@ -8499,6 +8499,34 @@ static void update_tracer_options(struct trace_array *tr)
mutex_unlock(&trace_types_lock); 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) static struct trace_array *trace_array_create(const char *name)
{ {
struct trace_array *tr; struct trace_array *tr;
@@ -8575,10 +8603,8 @@ static int instance_mkdir(const char *name)
mutex_lock(&trace_types_lock); mutex_lock(&trace_types_lock);
ret = -EEXIST; ret = -EEXIST;
list_for_each_entry(tr, &ftrace_trace_arrays, list) { if (trace_array_find(name))
if (tr->name && strcmp(tr->name, name) == 0) goto out_unlock;
goto out_unlock;
}
tr = trace_array_create(name); tr = trace_array_create(name);
@@ -8706,12 +8732,9 @@ static int instance_rmdir(const char *name)
mutex_lock(&trace_types_lock); mutex_lock(&trace_types_lock);
ret = -ENODEV; ret = -ENODEV;
list_for_each_entry(tr, &ftrace_trace_arrays, list) { tr = trace_array_find(name);
if (tr->name && strcmp(tr->name, name) == 0) { if (tr)
ret = __remove_instance(tr); ret = __remove_instance(tr);
break;
}
}
mutex_unlock(&trace_types_lock); mutex_unlock(&trace_types_lock);
mutex_unlock(&event_mutex); mutex_unlock(&event_mutex);

2
kernel/trace/trace.h
View File

@@ -358,6 +358,8 @@ extern struct mutex trace_types_lock;
extern int trace_array_get(struct trace_array *tr); extern int trace_array_get(struct trace_array *tr);
extern int tracing_check_open_get_tr(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_time_stamp_abs(struct trace_array *tr, bool abs);
extern int tracing_set_clock(struct trace_array *tr, const char *clockstr); extern int tracing_set_clock(struct trace_array *tr, const char *clockstr);