tracing: make tracing_init_dentry() returns an integer instead of a d_entry pointer

Current tracing_init_dentry() return a d_entry pointer, while is not
necessary. This function returns NULL on success or error on failure,
which means there is no valid d_entry pointer return.

Let's return 0 on success and negative value for error.

Link: https://lkml.kernel.org/r/20200712011036.70948-5-richard.weiyang@linux.alibaba.com
Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 2a7c263..29a9034 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -8971,21 +8971,21 @@ static struct vfsmount *trace_automount(struct dentry *mntpt, void *ingore)
  * 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)
+int tracing_init_dentry(void)
 {
        struct trace_array *tr = &global_trace;
 
        if (security_locked_down(LOCKDOWN_TRACEFS)) {
                pr_warn("Tracing disabled due to lockdown\n");
-               return ERR_PTR(-EPERM);
+               return -EPERM;
        }
 
        /* The top level trace array uses  NULL as parent */
        if (tr->dir)
-               return NULL;
+               return 0;
 
        if (WARN_ON(!tracefs_initialized()))
-               return ERR_PTR(-ENODEV);
+               return -ENODEV;
 
        /*
         * As there may still be users that expect the tracing
@@ -8996,7 +8996,7 @@ struct dentry *tracing_init_dentry(void)
        tr->dir = debugfs_create_automount("tracing", NULL,
                                           trace_automount, NULL);
 
-       return NULL;
+       return 0;
 }
 
 extern struct trace_eval_map *__start_ftrace_eval_maps[];
@@ -9083,48 +9083,48 @@ static struct notifier_block trace_module_nb = {
 
 static __init int tracer_init_tracefs(void)
 {
-       struct dentry *d_tracer;
+       int ret;
 
        trace_access_lock_init();
 
-       d_tracer = tracing_init_dentry();
-       if (IS_ERR(d_tracer))
+       ret = tracing_init_dentry();
+       if (ret)
                return 0;
 
        event_trace_init();
 
-       init_tracer_tracefs(&global_trace, d_tracer);
-       ftrace_init_tracefs_toplevel(&global_trace, d_tracer);
+       init_tracer_tracefs(&global_trace, NULL);
+       ftrace_init_tracefs_toplevel(&global_trace, NULL);
 
-       trace_create_file("tracing_thresh", 0644, d_tracer,
+       trace_create_file("tracing_thresh", 0644, NULL,
                        &global_trace, &tracing_thresh_fops);
 
-       trace_create_file("README", 0444, d_tracer,
+       trace_create_file("README", 0444, NULL,
                        NULL, &tracing_readme_fops);
 
-       trace_create_file("saved_cmdlines", 0444, d_tracer,
+       trace_create_file("saved_cmdlines", 0444, NULL,
                        NULL, &tracing_saved_cmdlines_fops);
 
-       trace_create_file("saved_cmdlines_size", 0644, d_tracer,
+       trace_create_file("saved_cmdlines_size", 0644, NULL,
                          NULL, &tracing_saved_cmdlines_size_fops);
 
-       trace_create_file("saved_tgids", 0444, d_tracer,
+       trace_create_file("saved_tgids", 0444, NULL,
                        NULL, &tracing_saved_tgids_fops);
 
        trace_eval_init();
 
-       trace_create_eval_file(d_tracer);
+       trace_create_eval_file(NULL);
 
 #ifdef CONFIG_MODULES
        register_module_notifier(&trace_module_nb);
 #endif
 
 #ifdef CONFIG_DYNAMIC_FTRACE
-       trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
+       trace_create_file("dyn_ftrace_total_info", 0444, NULL,
                        NULL, &tracing_dyn_info_fops);
 #endif
 
-       create_trace_instances(d_tracer);
+       create_trace_instances(NULL);
 
        update_tracer_options(&global_trace);
 

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 610d213..0d3a405 100644 (file)
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -737,7 +737,7 @@ struct dentry *trace_create_file(const char *name,
                                 void *data,
                                 const struct file_operations *fops);
 
-struct dentry *tracing_init_dentry(void);
+int tracing_init_dentry(void);
 
 struct ring_buffer_event;
 

diff --git a/kernel/trace/trace_dynevent.c b/kernel/trace/trace_dynevent.c
index 9f2e852..9442a9b 100644 (file)
--- a/kernel/trace/trace_dynevent.c
+++ b/kernel/trace/trace_dynevent.c
@@ -206,14 +206,14 @@ static const struct file_operations dynamic_events_ops = {
 /* Make a tracefs interface for controlling dynamic events */
 static __init int init_dynamic_event(void)
 {
-       struct dentry *d_tracer;
        struct dentry *entry;
+       int ret;
 
-       d_tracer = tracing_init_dentry();
-       if (IS_ERR(d_tracer))
+       ret = tracing_init_dentry();
+       if (ret)
                return 0;
 
-       entry = tracefs_create_file("dynamic_events", 0644, d_tracer,
+       entry = tracefs_create_file("dynamic_events", 0644, NULL,
                                    NULL, &dynamic_events_ops);
 
        /* Event list interface */

diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
index c6cca0d..f86a2aa 100644 (file)
--- a/kernel/trace/trace_events_synth.c
+++ b/kernel/trace/trace_events_synth.c
@@ -1757,7 +1757,6 @@ static const struct file_operations synth_events_fops = {
 static __init int trace_events_synth_init(void)
 {
        struct dentry *entry = NULL;
-       struct dentry *d_tracer;
        int err = 0;
 
        err = dyn_event_register(&synth_event_ops);
@@ -1766,13 +1765,11 @@ static __init int trace_events_synth_init(void)
                return err;
        }
 
-       d_tracer = tracing_init_dentry();
-       if (IS_ERR(d_tracer)) {
-               err = PTR_ERR(d_tracer);
+       err = tracing_init_dentry();
+       if (err)
                goto err;
-       }
 
-       entry = tracefs_create_file("synthetic_events", 0644, d_tracer,
+       entry = tracefs_create_file("synthetic_events", 0644, NULL,
                                    NULL, &synth_events_fops);
        if (!entry) {
                err = -ENODEV;

diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 4a9c49c..60d6627 100644 (file)
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -1336,13 +1336,13 @@ static const struct file_operations graph_depth_fops = {
 
 static __init int init_graph_tracefs(void)
 {
-       struct dentry *d_tracer;
+       int ret;
 
-       d_tracer = tracing_init_dentry();
-       if (IS_ERR(d_tracer))
+       ret = tracing_init_dentry();
+       if (ret)
                return 0;
 
-       trace_create_file("max_graph_depth", 0644, d_tracer,
+       trace_create_file("max_graph_depth", 0644, NULL,
                          NULL, &graph_depth_fops);
 
        return 0;

diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c
index 17873e5..c9ad5c6 100644 (file)
--- a/kernel/trace/trace_hwlat.c
+++ b/kernel/trace/trace_hwlat.c
@@ -538,14 +538,14 @@ static const struct file_operations window_fops = {
  */
 static int init_tracefs(void)
 {
-       struct dentry *d_tracer;
+       int ret;
        struct dentry *top_dir;
 
-       d_tracer = tracing_init_dentry();
-       if (IS_ERR(d_tracer))
+       ret = tracing_init_dentry();
+       if (ret)
                return -ENOMEM;
 
-       top_dir = tracefs_create_dir("hwlat_detector", d_tracer);
+       top_dir = tracefs_create_dir("hwlat_detector", NULL);
        if (!top_dir)
                return -ENOMEM;
 

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index aefb606..feca9b1 100644 (file)
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1901,14 +1901,14 @@ subsys_initcall(init_kprobe_trace_early);
 /* Make a tracefs interface for controlling probe points */
 static __init int init_kprobe_trace(void)
 {
-       struct dentry *d_tracer;
+       int ret;
        struct dentry *entry;
 
-       d_tracer = tracing_init_dentry();
-       if (IS_ERR(d_tracer))
+       ret = tracing_init_dentry();
+       if (ret)
                return 0;
 
-       entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
+       entry = tracefs_create_file("kprobe_events", 0644, NULL,
                                    NULL, &kprobe_events_ops);
 
        /* Event list interface */
@@ -1916,7 +1916,7 @@ static __init int init_kprobe_trace(void)
                pr_warn("Could not create tracefs 'kprobe_events' entry\n");
 
        /* Profile interface */
-       entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
+       entry = tracefs_create_file("kprobe_profile", 0444, NULL,
                                    NULL, &kprobe_profile_ops);
 
        if (!entry)

diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c
index d4e31e9..71b2e0f 100644 (file)
--- a/kernel/trace/trace_printk.c
+++ b/kernel/trace/trace_printk.c
@@ -367,13 +367,13 @@ static const struct file_operations ftrace_formats_fops = {
 
 static __init int init_trace_printk_function_export(void)
 {
-       struct dentry *d_tracer;
+       int ret;
 
-       d_tracer = tracing_init_dentry();
-       if (IS_ERR(d_tracer))
+       ret = tracing_init_dentry();
+       if (ret)
                return 0;
 
-       trace_create_file("printk_formats", 0444, d_tracer,
+       trace_create_file("printk_formats", 0444, NULL,
                                    NULL, &ftrace_formats_fops);
 
        return 0;

diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index 98bba47..c408423 100644 (file)
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -554,20 +554,20 @@ __setup("stacktrace", enable_stacktrace);
 
 static __init int stack_trace_init(void)
 {
-       struct dentry *d_tracer;
+       int ret;
 
-       d_tracer = tracing_init_dentry();
-       if (IS_ERR(d_tracer))
+       ret = tracing_init_dentry();
+       if (ret)
                return 0;
 
-       trace_create_file("stack_max_size", 0644, d_tracer,
+       trace_create_file("stack_max_size", 0644, NULL,
                        &stack_trace_max_size, &stack_max_size_fops);
 
-       trace_create_file("stack_trace", 0444, d_tracer,
+       trace_create_file("stack_trace", 0444, NULL,
                        NULL, &stack_trace_fops);
 
 #ifdef CONFIG_DYNAMIC_FTRACE
-       trace_create_file("stack_trace_filter", 0644, d_tracer,
+       trace_create_file("stack_trace_filter", 0644, NULL,
                          &trace_ops, &stack_trace_filter_fops);
 #endif
 

diff --git a/kernel/trace/trace_stat.c b/kernel/trace/trace_stat.c
index d1fa197..8d141c3 100644 (file)
--- a/kernel/trace/trace_stat.c
+++ b/kernel/trace/trace_stat.c
@@ -276,13 +276,13 @@ static const struct file_operations tracing_stat_fops = {
 
 static int tracing_stat_init(void)
 {
-       struct dentry *d_tracing;
+       int ret;
 
-       d_tracing = tracing_init_dentry();
-       if (IS_ERR(d_tracing))
+       ret = tracing_init_dentry();
+       if (ret)
                return -ENODEV;
 
-       stat_dir = tracefs_create_dir("trace_stat", d_tracing);
+       stat_dir = tracefs_create_dir("trace_stat", NULL);
        if (!stat_dir) {
                pr_warn("Could not create tracefs 'trace_stat' entry\n");
                return -ENOMEM;

diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index f4286c9..56729c6 100644 (file)
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -1625,21 +1625,20 @@ void destroy_local_trace_uprobe(struct trace_event_call *event_call)
 /* Make a trace interface for controling probe points */
 static __init int init_uprobe_trace(void)
 {
-       struct dentry *d_tracer;
        int ret;
 
        ret = dyn_event_register(&trace_uprobe_ops);
        if (ret)
                return ret;
 
-       d_tracer = tracing_init_dentry();
-       if (IS_ERR(d_tracer))
+       ret = tracing_init_dentry();
+       if (ret)
                return 0;
 
-       trace_create_file("uprobe_events", 0644, d_tracer,
+       trace_create_file("uprobe_events", 0644, NULL,
                                    NULL, &uprobe_events_ops);
        /* Profile interface */
-       trace_create_file("uprobe_profile", 0444, d_tracer,
+       trace_create_file("uprobe_profile", 0444, NULL,
                                    NULL, &uprobe_profile_ops);
        return 0;
 }