5 files changed, 172 insertions, 180 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 0418fc338b5..40217fb499e 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2353,7 +2353,6 @@ static int tracing_set_tracer(char *buf)
 		if (ret)
 			goto out;
 	}
-	init_tracer_stat(t);
 
 	trace_branch_enable(tr);
  out:
@@ -3218,7 +3217,6 @@ __init static int tracer_alloc_buffers(void)
 #else
 	current_trace = &nop_trace;
 #endif
-	init_tracer_stat(current_trace);
 	/* All seems OK, enable tracing */
 	tracing_disabled = 0;
 
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index b3f9ad1b4d8..79c872100dd 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -334,24 +334,6 @@ struct tracer_flags {
 /* Makes more easy to define a tracer opt */
 #define TRACER_OPT(s, b)	.name = #s, .bit = b
 
-/*
- * If you want to provide a stat file (one-shot statistics), fill
- * an iterator with stat_start/stat_next and a stat_show callbacks.
- * The others callbacks are optional.
- */
-struct tracer_stat {
-	/* The name of your stat file */
-	const char		*name;
-	/* Iteration over statistic entries */
-	void			*(*stat_start)(void);
-	void			*(*stat_next)(void *prev, int idx);
-	/* Compare two entries for sorting (optional) for stats */
-	int			(*stat_cmp)(void *p1, void *p2);
-	/* Print a stat entry */
-	int			(*stat_show)(struct seq_file *s, void *p);
-	/* Print the headers of your stat entries */
-	int			(*stat_headers)(struct seq_file *s);
-};
 
 /*
  * A specific tracer, represented by methods that operate on a trace array:
@@ -466,8 +448,6 @@ void tracing_start_sched_switch_record(void);
 int register_tracer(struct tracer *type);
 void unregister_tracer(struct tracer *type);
 
-void init_tracer_stat(struct tracer *trace);
-
 extern unsigned long nsecs_to_usecs(unsigned long nsecs);
 
 extern unsigned long tracing_max_latency;
diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
index da5cf3e5581..ca017e0a9a2 100644
--- a/kernel/trace/trace_branch.c
+++ b/kernel/trace/trace_branch.c
@@ -16,12 +16,12 @@
 #include <asm/local.h>
 
 #include "trace.h"
+#include "trace_stat.h"
 #include "trace_output.h"
 
-static struct tracer branch_trace;
-
 #ifdef CONFIG_BRANCH_TRACER
 
+static struct tracer branch_trace;
 static int branch_tracing_enabled __read_mostly;
 static DEFINE_MUTEX(branch_tracing_mutex);
 
@@ -191,6 +191,30 @@ static struct trace_event trace_branch_event = {
 	.binary		= trace_nop_print,
 };
 
+static struct tracer branch_trace __read_mostly =
+{
+	.name		= "branch",
+	.init		= branch_trace_init,
+	.reset		= branch_trace_reset,
+#ifdef CONFIG_FTRACE_SELFTEST
+	.selftest	= trace_selftest_startup_branch,
+#endif /* CONFIG_FTRACE_SELFTEST */
+};
+
+__init static int init_branch_tracer(void)
+{
+	int ret;
+
+	ret = register_ftrace_event(&trace_branch_event);
+	if (!ret) {
+		printk(KERN_WARNING "Warning: could not register "
+				    "branch events\n");
+		return 1;
+	}
+	return register_tracer(&branch_trace);
+}
+device_initcall(init_branch_tracer);
+
 #else
 static inline
 void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect)
@@ -305,6 +329,29 @@ static int annotated_branch_stat_cmp(void *p1, void *p2)
 		return 0;
 }
 
+static struct tracer_stat annotated_branch_stats = {
+	.name = "branch_annotated",
+	.stat_start = annotated_branch_stat_start,
+	.stat_next = annotated_branch_stat_next,
+	.stat_cmp = annotated_branch_stat_cmp,
+	.stat_headers = annotated_branch_stat_headers,
+	.stat_show = branch_stat_show
+};
+
+__init static int init_annotated_branch_stats(void)
+{
+	int ret;
+
+	ret = register_stat_tracer(&annotated_branch_stats);
+	if (!ret) {
+		printk(KERN_WARNING "Warning: could not register "
+				    "annotated branches stats\n");
+		return 1;
+	}
+	return 0;
+}
+fs_initcall(init_annotated_branch_stats);
+
 #ifdef CONFIG_PROFILE_ALL_BRANCHES
 
 extern unsigned long __start_branch_profile[];
@@ -339,60 +386,25 @@ all_branch_stat_next(void *v, int idx)
 	return p;
 }
 
-static struct tracer_stat branch_stats[] = {
-	{.name = "annotated",
-	.stat_start = annotated_branch_stat_start,
-	.stat_next = annotated_branch_stat_next,
-	.stat_cmp = annotated_branch_stat_cmp,
-	.stat_headers = annotated_branch_stat_headers,
-	.stat_show = branch_stat_show},
-
-	{.name = "all",
+static struct tracer_stat all_branch_stats = {
+	.name = "branch_all",
 	.stat_start = all_branch_stat_start,
 	.stat_next = all_branch_stat_next,
 	.stat_headers = all_branch_stat_headers,
-	.stat_show = branch_stat_show},
-
-	{ }
-};
-#else
-static struct tracer_stat branch_stats[] = {
-	{.name = "annotated",
-	.stat_start = annotated_branch_stat_start,
-	.stat_next = annotated_branch_stat_next,
-	.stat_cmp = annotated_branch_stat_cmp,
-	.stat_headers = annotated_branch_stat_headers,
-	.stat_show = branch_stat_show},
-
-	{ }
+	.stat_show = branch_stat_show
 };
-#endif /* CONFIG_PROFILE_ALL_BRANCHES */
 
-
-static struct tracer branch_trace __read_mostly =
+__init static int all_annotated_branch_stats(void)
 {
-	.name		= "branch",
-#ifdef CONFIG_BRANCH_TRACER
-	.init		= branch_trace_init,
-	.reset		= branch_trace_reset,
-#ifdef CONFIG_FTRACE_SELFTEST
-	.selftest	= trace_selftest_startup_branch,
-#endif /* CONFIG_FTRACE_SELFTEST */
-#endif
-	.stats		= branch_stats
-};
-
-__init static int init_branch_trace(void)
-{
-#ifdef CONFIG_BRANCH_TRACER
 	int ret;
-	ret = register_ftrace_event(&trace_branch_event);
+
+	ret = register_stat_tracer(&all_branch_stats);
 	if (!ret) {
-		printk(KERN_WARNING "Warning: could not register branch events\n");
+		printk(KERN_WARNING "Warning: could not register "
+				    "all branches stats\n");
 		return 1;
 	}
-#endif
-
-	return register_tracer(&branch_trace);
+	return 0;
 }
-device_initcall(init_branch_trace);
+fs_initcall(all_annotated_branch_stats);
+#endif /* CONFIG_PROFILE_ALL_BRANCHES */
diff --git a/kernel/trace/trace_stat.c b/kernel/trace/trace_stat.c
index 1515f9e7adf..cb29282b948 100644
--- a/kernel/trace/trace_stat.c
+++ b/kernel/trace/trace_stat.c
@@ -10,28 +10,32 @@
 
 
 #include <linux/list.h>
-#include <linux/seq_file.h>
 #include <linux/debugfs.h>
+#include "trace_stat.h"
 #include "trace.h"
 
 
 /* List of stat entries from a tracer */
 struct trace_stat_list {
-	struct list_head list;
-	void *stat;
+	struct list_head 	list;
+	void 			*stat;
 };
 
 /* A stat session is the stats output in one file */
 struct tracer_stat_session {
-	struct tracer_stat *ts;
-	struct list_head stat_list;
-	struct mutex stat_mutex;
+	struct list_head	session_list;
+	struct tracer_stat 	*ts;
+	struct list_head 	stat_list;
+	struct mutex 		stat_mutex;
+	struct dentry		*file;
 };
 
 /* All of the sessions currently in use. Each stat file embeed one session */
-static struct tracer_stat_session **all_stat_sessions;
-static int nb_sessions;
-static struct dentry *stat_dir, **stat_files;
+static LIST_HEAD(all_stat_sessions);
+static DEFINE_MUTEX(all_stat_sessions_mutex);
+
+/* The root directory for all stat files */
+static struct dentry *stat_dir;
 
 
 static void reset_stat_session(struct tracer_stat_session *session)
@@ -44,66 +48,77 @@ static void reset_stat_session(struct tracer_stat_session *session)
 	INIT_LIST_HEAD(&session->stat_list);
 }
 
-/* Called when a tracer is initialized */
-static int init_all_sessions(int nb, struct tracer_stat *ts)
+static void destroy_session(struct tracer_stat_session *session)
 {
-	int i, j;
-	struct tracer_stat_session *session;
+	debugfs_remove(session->file);
+	reset_stat_session(session);
+	mutex_destroy(&session->stat_mutex);
+	kfree(session);
+}
 
-	nb_sessions = 0;
 
-	if (all_stat_sessions) {
-		for (i = 0; i < nb_sessions; i++) {
-			session = all_stat_sessions[i];
-			reset_stat_session(session);
-			mutex_destroy(&session->stat_mutex);
-			kfree(session);
-		}
-	}
-	all_stat_sessions = kmalloc(sizeof(struct tracer_stat_session *) * nb,
-				    GFP_KERNEL);
-	if (!all_stat_sessions)
-		return -ENOMEM;
+static int init_stat_file(struct tracer_stat_session *session);
 
-	for (i = 0; i < nb; i++) {
-		session = kmalloc(sizeof(struct tracer_stat_session) * nb,
-				  GFP_KERNEL);
-		if (!session)
-			goto free_sessions;
+int register_stat_tracer(struct tracer_stat *trace)
+{
+	struct tracer_stat_session *session, *node, *tmp;
+	int ret;
+
+	if (!trace)
+		return -EINVAL;
+
+	if (!trace->stat_start || !trace->stat_next || !trace->stat_show)
+		return -EINVAL;
 
-		INIT_LIST_HEAD(&session->stat_list);
-		mutex_init(&session->stat_mutex);
-		session->ts = &ts[i];
-		all_stat_sessions[i] = session;
+	/* Already registered? */
+	mutex_lock(&all_stat_sessions_mutex);
+	list_for_each_entry_safe(node, tmp, &all_stat_sessions, session_list) {
+		if (node->ts == trace)
+			return -EINVAL;
 	}
-	nb_sessions = nb;
-	return 0;
+	mutex_unlock(&all_stat_sessions_mutex);
+
+	/* Init the session */
+	session = kmalloc(sizeof(struct tracer_stat_session), GFP_KERNEL);
+	if (!session)
+		return -ENOMEM;
 
-free_sessions:
+	session->ts = trace;
+	INIT_LIST_HEAD(&session->session_list);
+	INIT_LIST_HEAD(&session->stat_list);
+	mutex_init(&session->stat_mutex);
+	session->file = NULL;
 
-	for (j = 0; j < i; j++)
-		kfree(all_stat_sessions[i]);
+	ret = init_stat_file(session);
+	if (ret) {
+		destroy_session(session);
+		return ret;
+	}
 
-	kfree(all_stat_sessions);
-	all_stat_sessions = NULL;
+	/* Register */
+	mutex_lock(&all_stat_sessions_mutex);
+	list_add_tail(&session->session_list, &all_stat_sessions);
+	mutex_unlock(&all_stat_sessions_mutex);
 
-	return -ENOMEM;
+	return 0;
 }
 
-static int basic_tracer_stat_checks(struct tracer_stat *ts)
+void unregister_stat_tracer(struct tracer_stat *trace)
 {
-	int i;
+	struct tracer_stat_session *node, *tmp;
 
-	if (!ts)
-		return 0;
-
-	for (i = 0; ts[i].name; i++) {
-		if (!ts[i].stat_start || !ts[i].stat_next || !ts[i].stat_show)
-			return -EBUSY;
+	mutex_lock(&all_stat_sessions_mutex);
+	list_for_each_entry_safe(node, tmp, &all_stat_sessions, session_list) {
+		if (node->ts == trace) {
+			list_del(&node->session_list);
+			destroy_session(node);
+			break;
+		}
 	}
-	return i;
+	mutex_unlock(&all_stat_sessions_mutex);
 }
 
+
 /*
  * For tracers that don't provide a stat_cmp callback.
  * This one will force an immediate insertion on tail of
@@ -280,63 +295,7 @@ static const struct file_operations tracing_stat_fops = {
 	.release	= tracing_stat_release
 };
 
-
-static void destroy_trace_stat_files(void)
-{
-	int i;
-
-	if (stat_files) {
-		for (i = 0; i < nb_sessions; i++)
-			debugfs_remove(stat_files[i]);
-		kfree(stat_files);
-		stat_files = NULL;
-	}
-}
-
-static void init_trace_stat_files(void)
-{
-	int i;
-
-	if (!stat_dir || !nb_sessions)
-		return;
-
-	stat_files = kmalloc(sizeof(struct dentry *) * nb_sessions, GFP_KERNEL);
-
-	if (!stat_files) {
-		pr_warning("trace stat: not enough memory\n");
-		return;
-	}
-
-	for (i = 0; i < nb_sessions; i++) {
-		struct tracer_stat_session *session = all_stat_sessions[i];
-		stat_files[i] = debugfs_create_file(session->ts->name, 0644,
-						stat_dir,
-						session, &tracing_stat_fops);
-		if (!stat_files[i])
-			pr_warning("cannot create %s entry\n",
-				   session->ts->name);
-	}
-}
-
-void init_tracer_stat(struct tracer *trace)
-{
-	int nb = basic_tracer_stat_checks(trace->stats);
-
-	destroy_trace_stat_files();
-
-	if (nb < 0) {
-		pr_warning("stat tracing: missing stat callback on %s\n",
-			   trace->name);
-		return;
-	}
-	if (!nb)
-		return;
-
-	init_all_sessions(nb, trace->stats);
-	init_trace_stat_files();
-}
-
-static int __init tracing_stat_init(void)
+static int tracing_stat_init(void)
 {
 	struct dentry *d_tracing;
 
@@ -348,4 +307,16 @@ static int __init tracing_stat_init(void)
 			   "'trace_stat' entry\n");
 	return 0;
 }
-fs_initcall(tracing_stat_init);
+
+static int init_stat_file(struct tracer_stat_session *session)
+{
+	if (!stat_dir && tracing_stat_init())
+		return -ENODEV;
+
+	session->file = debugfs_create_file(session->ts->name, 0644,
+					    stat_dir,
+					    session, &tracing_stat_fops);
+	if (!session->file)
+		return -ENOMEM;
+	return 0;
+}
diff --git a/kernel/trace/trace_stat.h b/kernel/trace/trace_stat.h
new file mode 100644
index 00000000000..202274cf7f3
--- /dev/null
+++ b/kernel/trace/trace_stat.h
@@ -0,0 +1,31 @@
+#ifndef __TRACE_STAT_H
+#define __TRACE_STAT_H
+
+#include <linux/seq_file.h>
+
+/*
+ * If you want to provide a stat file (one-shot statistics), fill
+ * an iterator with stat_start/stat_next and a stat_show callbacks.
+ * The others callbacks are optional.
+ */
+struct tracer_stat {
+	/* The name of your stat file */
+	const char		*name;
+	/* Iteration over statistic entries */
+	void			*(*stat_start)(void);
+	void			*(*stat_next)(void *prev, int idx);
+	/* Compare two entries for stats sorting */
+	int			(*stat_cmp)(void *p1, void *p2);
+	/* Print a stat entry */
+	int			(*stat_show)(struct seq_file *s, void *p);
+	/* Print the headers of your stat entries */
+	int			(*stat_headers)(struct seq_file *s);
+};
+
+/*
+ * Destroy or create a stat file
+ */
+extern int register_stat_tracer(struct tracer_stat *trace);
+extern void unregister_stat_tracer(struct tracer_stat *trace);
+
+#endif /* __TRACE_STAT_H */