Tracepoints and markers: cleanup init, add missing mutex lock/unlock

[ust.git] / libust / marker.c

diff --git a/libust/marker.c b/libust/marker.c
index 3c3a5b7e4eb20d6c653f49a075f8a85c9f0a929e..f9acab6af41ba8a2565a6a9466450eb09160c354 100644 (file)
--- a/libust/marker.c
+++ b/libust/marker.c
@@ -19,6 +19,7 @@
 #define _LGPL_SOURCE
 #include <stdlib.h>
 #include <errno.h>
+#include <pthread.h>
 #include <urcu-bp.h>
 #include <urcu/rculist.h>
 #include <urcu/hlist.h>
@@ -39,6 +40,8 @@ extern struct ust_marker * const __stop___ust_marker_ptrs[] __attribute__((visib
 
 /* Set to 1 to enable ust_marker debug output */
 static const int ust_marker_debug;
+static int initialized;
+static void (*new_ust_marker_cb)(struct ust_marker *);
 
 /*
  * ust_marker mutex protects the builtin and module ust_marker and the
@@ -47,14 +50,21 @@ static const int ust_marker_debug;
 static DEFINE_MUTEX(ust_marker_mutex);
 static CDS_LIST_HEAD(ust_marker_libs);
 
+/*
+ * Allow nested mutex for mutex listing and nested enable.
+ */
+static __thread int nested_mutex;
+
 void lock_ust_marker(void)
 {
-       pthread_mutex_lock(&ust_marker_mutex);
+       if (!(nested_mutex++))
+               pthread_mutex_lock(&ust_marker_mutex);
 }
 
 void unlock_ust_marker(void)
 {
-       pthread_mutex_unlock(&ust_marker_mutex);
+       if (!(--nested_mutex))
+               pthread_mutex_unlock(&ust_marker_mutex);
 }
 
 /*
@@ -638,9 +648,9 @@ int is_ust_marker_enabled(const char *channel, const char *name)
 {
        struct ust_marker_entry *entry;
 
-       pthread_mutex_lock(&ust_marker_mutex);
+       lock_ust_marker();
        entry = get_ust_marker(channel, name);
-       pthread_mutex_unlock(&ust_marker_mutex);
+       unlock_ust_marker();
 
        return entry && !!entry->refcount;
 }
@@ -678,11 +688,11 @@ static void lib_update_ust_marker(void)
 {
        struct ust_marker_lib *lib;
 
-       pthread_mutex_lock(&ust_marker_mutex);
+       lock_ust_marker();
        cds_list_for_each_entry(lib, &ust_marker_libs, list)
                ust_marker_update_probe_range(lib->ust_marker_start,
                                lib->ust_marker_start + lib->ust_marker_count);
-       pthread_mutex_unlock(&ust_marker_mutex);
+       unlock_ust_marker();
 }
 
 /*
@@ -729,7 +739,7 @@ int ust_marker_probe_register(const char *channel, const char *name,
        struct ust_marker_probe_array *old;
        int first_probe = 0;
 
-       pthread_mutex_lock(&ust_marker_mutex);
+       lock_ust_marker();
        entry = get_ust_marker(channel, name);
        if (!entry) {
                first_probe = 1;
@@ -774,7 +784,7 @@ int ust_marker_probe_register(const char *channel, const char *name,
                else
                        goto end;
        }
-       pthread_mutex_unlock(&ust_marker_mutex);
+       unlock_ust_marker();
 
        /* Activate ust_marker if necessary */
        ust_marker_update_probes();
@@ -792,7 +802,7 @@ error_remove_ust_marker:
        ret_err = remove_ust_marker(channel, name);
        WARN_ON(ret_err);
 end:
-       pthread_mutex_unlock(&ust_marker_mutex);
+       unlock_ust_marker();
        return ret;
 }
 
@@ -816,14 +826,14 @@ int ust_marker_probe_unregister(const char *channel, const char *name,
        struct ust_marker_probe_array *old;
        int ret = 0;
 
-       pthread_mutex_lock(&ust_marker_mutex);
+       lock_ust_marker();
        entry = get_ust_marker(channel, name);
        if (!entry) {
                ret = -ENOENT;
                goto end;
        }
        old = ust_marker_entry_remove_probe(entry, probe, probe_private);
-       pthread_mutex_unlock(&ust_marker_mutex);
+       unlock_ust_marker();
 
        ust_marker_update_probes();
 
@@ -834,7 +844,7 @@ int ust_marker_probe_unregister(const char *channel, const char *name,
        return ret;
 
 end:
-       pthread_mutex_unlock(&ust_marker_mutex);
+       unlock_ust_marker();
        return ret;
 }
 
@@ -891,7 +901,7 @@ int ust_marker_probe_unregister_private_data(ust_marker_probe_func *probe,
        struct ust_marker_probe_array *old;
        char *channel = NULL, *name = NULL;
 
-       pthread_mutex_lock(&ust_marker_mutex);
+       lock_ust_marker();
        entry = get_ust_marker_from_private_data(probe, probe_private);
        if (!entry) {
                ret = -ENOENT;
@@ -902,7 +912,7 @@ int ust_marker_probe_unregister_private_data(ust_marker_probe_func *probe,
        name = strdup(entry->name);
        /* Ignore busy error message */
        remove_ust_marker(channel, name);
-       pthread_mutex_unlock(&ust_marker_mutex);
+       unlock_ust_marker();
 
        ust_marker_update_probes();
 
@@ -913,7 +923,7 @@ int ust_marker_probe_unregister_private_data(ust_marker_probe_func *probe,
        goto end;
 
 unlock:
-       pthread_mutex_unlock(&ust_marker_mutex);
+       unlock_ust_marker();
 end:
        free(channel);
        free(name);
@@ -1032,9 +1042,9 @@ static void ust_marker_get_iter(struct ust_marker_iter *iter)
                ust_marker_iter_reset(iter);
 }
 
-/* Called with markers mutex held. */
 void ust_marker_iter_start(struct ust_marker_iter *iter)
 {
+       lock_ust_marker();
        ust_marker_get_iter(iter);
 }
 
@@ -1050,12 +1060,11 @@ void ust_marker_iter_next(struct ust_marker_iter *iter)
        ust_marker_get_iter(iter);
 }
 
-/* Called with markers mutex held. */
 void ust_marker_iter_stop(struct ust_marker_iter *iter)
 {
+       unlock_ust_marker();
 }
 
-/* Called with markers mutex held. */
 void ust_marker_iter_reset(struct ust_marker_iter *iter)
 {
        iter->lib = NULL;
@@ -1070,7 +1079,7 @@ void ltt_dump_ust_marker_state(struct ust_trace *trace)
        struct cds_hlist_node *node;
        unsigned int i;
 
-       pthread_mutex_lock(&ust_marker_mutex);
+       lock_ust_marker();
        call_data.trace = trace;
        call_data.serializer = NULL;
 
@@ -1098,11 +1107,9 @@ void ltt_dump_ust_marker_state(struct ust_trace *trace)
                                        entry->format);
                }
        }
-       pthread_mutex_unlock(&ust_marker_mutex);
+       unlock_ust_marker();
 }
 
-static void (*new_ust_marker_cb)(struct ust_marker *) = NULL;
-
 void ust_marker_set_new_ust_marker_cb(void (*cb)(struct ust_marker *))
 {
        new_ust_marker_cb = cb;
@@ -1114,7 +1121,7 @@ static void new_ust_marker(struct ust_marker * const *start,
        if (new_ust_marker_cb) {
                struct ust_marker * const *m;
 
-               for(m = start; m < end; m++) {
+               for (m = start; m < end; m++) {
                        if (*m)
                                new_ust_marker_cb(*m);
                }
@@ -1177,11 +1184,10 @@ int ust_marker_unregister_lib(struct ust_marker * const *ust_marker_start)
        return 0;
 }
 
-static int initialized = 0;
-
 void __attribute__((constructor)) init_ust_marker(void)
 {
        if (!initialized) {
+               init_tracepoint();
                ust_marker_register_lib(__start___ust_marker_ptrs,
                        __stop___ust_marker_ptrs
                        - __start___ust_marker_ptrs);