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-rw-r--r--kernel/trace/trace_stat.c191
1 files changed, 81 insertions, 110 deletions
diff --git a/kernel/trace/trace_stat.c b/kernel/trace/trace_stat.c
index 1515f9e7adfc..cb29282b9485 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;
+}