tracing: Use IS_ERR() check for return value of tracing_init_dentry()

tracing_init_dentry() will soon return NULL as a valid pointer for the
top level tracing directroy. NULL can not be used as an error value.
Instead, switch to ERR_PTR() and check the return status with
IS_ERR().
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

kernel/trace/ftrace.c

@@ -5419,7 +5419,7 @@ static __init int ftrace_init_debugfs(void)
 	struct dentry *d_tracer;
 
 	d_tracer = tracing_init_dentry();
-	if (!d_tracer)
+	if (IS_ERR(d_tracer))
 		return 0;
 
 	ftrace_init_dyn_debugfs(d_tracer);

kernel/trace/trace.c

@@ -5820,7 +5820,7 @@ struct dentry *tracing_init_dentry_tr(struct trace_array *tr)
 		return tr->dir;
 
 	if (!debugfs_initialized())
-		return NULL;
+		return ERR_PTR(-ENODEV);
 
 	if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
 		tr->dir = debugfs_create_dir("tracing", NULL);
@@ -5844,7 +5844,7 @@ static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
 		return tr->percpu_dir;
 
 	d_tracer = tracing_init_dentry_tr(tr);
-	if (!d_tracer)
+	if (IS_ERR(d_tracer))
 		return NULL;
 
 	tr->percpu_dir = debugfs_create_dir("per_cpu", d_tracer);
@@ -6047,7 +6047,7 @@ static struct dentry *trace_options_init_dentry(struct trace_array *tr)
 		return tr->options;
 
 	d_tracer = tracing_init_dentry_tr(tr);
-	if (!d_tracer)
+	if (IS_ERR(d_tracer))
 		return NULL;
 
 	tr->options = debugfs_create_dir("options", d_tracer);
@@ -6538,7 +6538,7 @@ static __init int tracer_init_debugfs(void)
 	trace_access_lock_init();
 
 	d_tracer = tracing_init_dentry();
-	if (!d_tracer)
+	if (IS_ERR(d_tracer))
 		return 0;
 
 	init_tracer_debugfs(&global_trace, d_tracer);

kernel/trace/trace_events.c

@@ -2490,7 +2490,7 @@ static __init int event_trace_init(void)
 		return -ENODEV;
 
 	d_tracer = tracing_init_dentry();
-	if (!d_tracer)
+	if (IS_ERR(d_tracer))
 		return 0;
 
 	entry = debugfs_create_file("available_events", 0444, d_tracer,

kernel/trace/trace_functions_graph.c

@@ -1437,7 +1437,7 @@ static __init int init_graph_debugfs(void)
 	struct dentry *d_tracer;
 
 	d_tracer = tracing_init_dentry();
-	if (!d_tracer)
+	if (IS_ERR(d_tracer))
 		return 0;
 
 	trace_create_file("max_graph_depth", 0644, d_tracer,

kernel/trace/trace_kprobe.c

@@ -1320,7 +1320,7 @@ static __init int init_kprobe_trace(void)
 		return -EINVAL;
 
 	d_tracer = tracing_init_dentry();
-	if (!d_tracer)
+	if (IS_ERR(d_tracer))
 		return 0;
 
 	entry = debugfs_create_file("kprobe_events", 0644, d_tracer,

kernel/trace/trace_printk.c

@@ -347,7 +347,7 @@ static __init int init_trace_printk_function_export(void)
 	struct dentry *d_tracer;
 
 	d_tracer = tracing_init_dentry();
-	if (!d_tracer)
+	if (IS_ERR(d_tracer))
 		return 0;
 
 	trace_create_file("printk_formats", 0444, d_tracer,

kernel/trace/trace_stack.c

@@ -460,7 +460,7 @@ static __init int stack_trace_init(void)
 	struct dentry *d_tracer;
 
 	d_tracer = tracing_init_dentry();
-	if (!d_tracer)
+	if (IS_ERR(d_tracer))
 		return 0;
 
 	trace_create_file("stack_max_size", 0644, d_tracer,

kernel/trace/trace_stat.c

@@ -276,7 +276,7 @@ static int tracing_stat_init(void)
 	struct dentry *d_tracing;
 
 	d_tracing = tracing_init_dentry();
-	if (!d_tracing)
+	if (IS_ERR(d_tracing))
 		return 0;
 
 	stat_dir = debugfs_create_dir("trace_stat", d_tracing);

kernel/trace/trace_uprobe.c

@@ -1321,7 +1321,7 @@ static __init int init_uprobe_trace(void)
 	struct dentry *d_tracer;
 
 	d_tracer = tracing_init_dentry();
-	if (!d_tracer)
+	if (IS_ERR(d_tracer))
 		return 0;
 
 	trace_create_file("uprobe_events", 0644, d_tracer,