Move to kernel style SPDX license identifiers

[lttng-ust.git] / liblttng-ust / tracepoint.c

diff --git a/liblttng-ust/tracepoint.c b/liblttng-ust/tracepoint.c
index b109fe30152b2968f7aba03736bab0cae53dbd89..f65097f6aaa92cc640eab93751847d32abf9556d 100644 (file)
--- a/liblttng-ust/tracepoint.c
+++ b/liblttng-ust/tracepoint.c
@@ -1,21 +1,9 @@
 /*
+ * SPDX-License-Identifier: LGPL-2.1-only
+ *
  * Copyright (C) 2008-2011 Mathieu Desnoyers
  * Copyright (C) 2009 Pierre-Marc Fournier
  *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation;
- * version 2.1 of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
- *
  * Ported to userspace by Pierre-Marc Fournier.
  */
 
@@ -26,7 +14,7 @@
 #include <stdio.h>
 
 #include <urcu/arch.h>
-#include <urcu/urcu-bp.h>
+#include <lttng/urcu/urcu-ust.h>
 #include <urcu/hlist.h>
 #include <urcu/uatomic.h>
 #include <urcu/compiler.h>
@@ -60,15 +48,6 @@ static int initialized;
  */
 static int tracepoint_destructors_state = 1;
 
-/*
- * Expose the now deprecated symbol __tracepoints__disable_destructors for
- * backward compatibility of applications built against old versions of
- * lttng-ust. We need to keep __tracepoints__disable_destructors up to date
- * within the new destructor disabling API because old applications read this
- * symbol directly.
- */
-int __tracepoints__disable_destructors __attribute__((weak));
-
 static void (*new_tracepoint_cb)(struct lttng_ust_tracepoint *);
 
 /*
@@ -166,7 +145,7 @@ static void release_probes(void *old)
        if (old) {
                struct tp_probes *tp_probes = caa_container_of(old,
                        struct tp_probes, probes[0]);
-               urcu_bp_synchronize_rcu();
+               lttng_ust_synchronize_trace();
                free(tp_probes);
        }
 }
@@ -386,7 +365,7 @@ static void set_tracepoint(struct tracepoint_entry **entry,
         * include/linux/tracepoints.h. A matching cmm_smp_read_barrier_depends()
         * is used.
         */
-       rcu_assign_pointer(elem->probes, (*entry)->probes);
+       lttng_ust_rcu_assign_pointer(elem->probes, (*entry)->probes);
        CMM_STORE_SHARED(elem->state, active);
 }
 
@@ -399,7 +378,7 @@ static void set_tracepoint(struct tracepoint_entry **entry,
 static void disable_tracepoint(struct lttng_ust_tracepoint *elem)
 {
        CMM_STORE_SHARED(elem->state, 0);
-       rcu_assign_pointer(elem->probes, NULL);
+       lttng_ust_rcu_assign_pointer(elem->probes, NULL);
 }
 
 /*
@@ -750,7 +729,7 @@ void __tracepoint_probe_prune_release_queue(void)
        release_queue_need_update = 0;
 
        /* Wait for grace period between all sync_callsites and free. */
-       urcu_bp_synchronize_rcu();
+       lttng_ust_synchronize_trace();
 
        cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) {
                cds_list_del(&pos->u.list);
@@ -841,7 +820,7 @@ void tracepoint_probe_update_all(void)
 
        tracepoint_update_probes();
        /* Wait for grace period between update_probes and free. */
-       urcu_bp_synchronize_rcu();
+       lttng_ust_synchronize_trace();
        cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) {
                cds_list_del(&pos->u.list);
                free(pos);
@@ -868,8 +847,20 @@ static void new_tracepoints(struct lttng_ust_tracepoint * const *start,
        }
 }
 
+/*
+ * tracepoint_{un,}register_lib is meant to be looked up by instrumented
+ * applications through dlsym(). If found, those can register their
+ * tracepoints, else those tracepoints will not be available for
+ * tracing. The number at the end of those symbols acts as a major
+ * version for tracepoints.
+ *
+ * Older instrumented applications should still work with newer
+ * liblttng-ust, but it is fine that instrumented applications compiled
+ * against recent liblttng-ust headers require a recent liblttng-ust
+ * runtime for those tracepoints to be taken into account.
+ */
 int tracepoint_register_lib(struct lttng_ust_tracepoint * const *tracepoints_start,
-                           int tracepoints_count)
+                            int tracepoints_count)
 {
        struct tracepoint_lib *pl, *iter;
 
@@ -981,23 +972,23 @@ void exit_tracepoint(void)
 /*
  * Create the wrapper symbols.
  */
-#undef tp_rcu_read_lock_bp
-#undef tp_rcu_read_unlock_bp
-#undef tp_rcu_dereference_bp
+#undef tp_rcu_read_lock
+#undef tp_rcu_read_unlock
+#undef tp_rcu_dereference
 
-void tp_rcu_read_lock_bp(void)
+void tp_rcu_read_lock(void)
 {
-       urcu_bp_read_lock();
+       lttng_ust_urcu_read_lock();
 }
 
-void tp_rcu_read_unlock_bp(void)
+void tp_rcu_read_unlock(void)
 {
-       urcu_bp_read_unlock();
+       lttng_ust_urcu_read_unlock();
 }
 
-void *tp_rcu_dereference_sym_bp(void *p)
+void *tp_rcu_dereference_sym(void *p)
 {
-       return urcu_bp_dereference(p);
+       return lttng_ust_rcu_dereference(p);
 }
 
 /*
@@ -1024,3 +1015,8 @@ int tp_get_destructors_state(void)
 {
        return uatomic_read(&tracepoint_destructors_state);
 }
+
+void lttng_ust_synchronize_trace(void)
+{
+       lttng_ust_urcu_synchronize_rcu();
+}