tracing: Separate out initializing top level dir from instances

The top level trace array is treated a little different than the
instances, as it has to deal with more of the general tracing.
The tr->dir is the tracing directory, which is an immutable
dentry, where as the tr->dir of instances are the dentry that
was created, and can be destroyed later. These should have different
functions accessing them.

As only tracing_init_dentry() deals with the top level array, fold
the code for it into that function, and remove the trace_init_dentry_tr()
that was also used by the instances to get their directory dentry.

Add a tracing_get_dentry() to just get the tracing dir entry for
instances as well as the top level array.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 30 insertions, 21 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 2668a0d742ee..5afce60e1b68 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5815,28 +5815,11 @@ static __init int register_snapshot_cmd(void)
 static inline __init int register_snapshot_cmd(void) { return 0; }
 #endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
 
-static struct dentry *tracing_init_dentry_tr(struct trace_array *tr)
+static struct dentry *tracing_get_dentry(struct trace_array *tr)
 {
-        if (tr->dir)
-                return tr->dir;
-
-        if (!debugfs_initialized())
-                return ERR_PTR(-ENODEV);
-
-        if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
-                tr->dir = debugfs_create_dir("tracing", NULL);
-
-        if (!tr->dir)
-                pr_warn_once("Could not create debugfs directory 'tracing'\n");
-
         return tr->dir;
 }
 
-struct dentry *tracing_init_dentry(void)
-{
-        return tracing_init_dentry_tr(&global_trace);
-}
-
 static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
 {
         struct dentry *d_tracer;
@@ -5844,7 +5827,7 @@ static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
         if (tr->percpu_dir)
                 return tr->percpu_dir;
 
-        d_tracer = tracing_init_dentry_tr(tr);
+        d_tracer = tracing_get_dentry(tr);
         if (IS_ERR(d_tracer))
                 return NULL;
 
@@ -6047,7 +6030,7 @@ static struct dentry *trace_options_init_dentry(struct trace_array *tr)
         if (tr->options)
                 return tr->options;
 
-        d_tracer = tracing_init_dentry_tr(tr);
+        d_tracer = tracing_get_dentry(tr);
         if (IS_ERR(d_tracer))
                 return NULL;
 
@@ -6532,6 +6515,33 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer)
 
 }
 
+/**
+ * tracing_init_dentry - initialize top level trace array
+ *
+ * This is called when creating files or directories in the tracing
+ * directory. It is called via fs_initcall() by any of the boot up code
+ * and expects to return the dentry of the top level tracing directory.
+ */
+struct dentry *tracing_init_dentry(void)
+{
+        struct trace_array *tr = &global_trace;
+
+        if (tr->dir)
+                return tr->dir;
+
+        if (WARN_ON(!debugfs_initialized()))
+                return ERR_PTR(-ENODEV);
+
+        tr->dir = debugfs_create_dir("tracing", NULL);
+
+        if (!tr->dir) {
+                pr_warn_once("Could not create debugfs directory 'tracing'\n");
+                return ERR_PTR(-ENOMEM);
+        }
+
+        return tr->dir;
+}
+
 static __init int tracer_init_debugfs(void)
 {
         struct dentry *d_tracer;
@@ -6772,7 +6782,6 @@ __init static int tracer_alloc_buffers(void)
         int ring_buf_size;
         int ret = -ENOMEM;
 
-
         if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
                 goto out;