LGPLv2.1 relicensing

[urcu.git] / urcu.c

diff --git a/urcu.c b/urcu.c
index 38abf7d6a92e045bb2aabbc306a4b7006ed108f8..7ab87c4e4f00fb61ef3a8931494754d7bfcf0188 100644 (file)
--- a/urcu.c
+++ b/urcu.c
@@ -5,7 +5,9 @@
  *
  * Copyright February 2009 - Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
  *
- * Distributed under GPLv2
+ * Distributed under LGPLv2.1
+ *
+ * IBM's contributions to this file may be relicensed under LGPLv2 or later.
  */
 
 #include <stdio.h>
@@ -15,7 +17,10 @@
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
+#include <poll.h>
 
+#include "urcu-static.h"
+/* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */
 #include "urcu.h"
 
 pthread_mutex_t urcu_mutex = PTHREAD_MUTEX_INITIALIZER;
@@ -99,17 +104,19 @@ static void switch_next_urcu_qparity(void)
 }
 
 #ifdef DEBUG_FULL_MB
+#ifdef HAS_INCOHERENT_CACHES
 static void force_mb_single_thread(struct reader_registry *index)
 {
        smp_mb();
 }
+#endif /* #ifdef HAS_INCOHERENT_CACHES */
 
 static void force_mb_all_threads(void)
 {
        smp_mb();
 }
-#else
-
+#else /* #ifdef DEBUG_FULL_MB */
+#ifdef HAS_INCOHERENT_CACHES
 static void force_mb_single_thread(struct reader_registry *index)
 {
        assert(registry);
@@ -132,6 +139,7 @@ static void force_mb_single_thread(struct reader_registry *index)
        }
        smp_mb();       /* read ->need_mb before ending the barrier */
 }
+#endif /* #ifdef HAS_INCOHERENT_CACHES */
 
 static void force_mb_all_threads(void)
 {
@@ -174,7 +182,7 @@ static void force_mb_all_threads(void)
        }
        smp_mb();       /* read ->need_mb before ending the barrier */
 }
-#endif
+#endif /* #else #ifdef DEBUG_FULL_MB */
 
 void wait_for_quiescent_state(void)
 {
@@ -186,6 +194,10 @@ void wait_for_quiescent_state(void)
         * Wait for each thread urcu_active_readers count to become 0.
         */
        for (index = registry; index < registry + num_readers; index++) {
+#ifndef HAS_INCOHERENT_CACHES
+               while (rcu_old_gp_ongoing(index->urcu_active_readers))
+                       cpu_relax();
+#else /* #ifndef HAS_INCOHERENT_CACHES */
                int wait_loops = 0;
                /*
                 * BUSY-LOOP. Force the reader thread to commit its
@@ -199,6 +211,7 @@ void wait_for_quiescent_state(void)
                                cpu_relax();
                        }
                }
+#endif /* #else #ifndef HAS_INCOHERENT_CACHES */
        }
 }
 
@@ -258,7 +271,47 @@ void synchronize_rcu(void)
        internal_urcu_unlock();
 }
 
-void urcu_add_reader(pthread_t id)
+/*
+ * library wrappers to be used by non-LGPL compatible source code.
+ */
+
+void rcu_read_lock(void)
+{
+       _rcu_read_lock();
+}
+
+void rcu_read_unlock(void)
+{
+       _rcu_read_unlock();
+}
+
+void *rcu_dereference(void *p)
+{
+       return _rcu_dereference(p);
+}
+
+void *rcu_assign_pointer_sym(void **p, void *v)
+{
+       wmb();
+       return STORE_SHARED(p, v);
+}
+
+void *rcu_xchg_pointer_sym(void **p, void *v)
+{
+       wmb();
+       return xchg(p, v);
+}
+
+void *rcu_publish_content_sym(void **p, void *v)
+{
+       void *oldptr;
+
+       oldptr = _rcu_xchg_pointer(p, v);
+       synchronize_rcu();
+       return oldptr;
+}
+
+static void rcu_add_reader(pthread_t id)
 {
        struct reader_registry *oldarray;
 
@@ -288,7 +341,7 @@ void urcu_add_reader(pthread_t id)
  * Never shrink (implementation limitation).
  * This is O(nb threads). Eventually use a hash table.
  */
-void urcu_remove_reader(pthread_t id)
+static void rcu_remove_reader(pthread_t id)
 {
        struct reader_registry *index;
 
@@ -307,22 +360,22 @@ void urcu_remove_reader(pthread_t id)
        assert(0);
 }
 
-void urcu_register_thread(void)
+void rcu_register_thread(void)
 {
        internal_urcu_lock();
-       urcu_add_reader(pthread_self());
+       rcu_add_reader(pthread_self());
        internal_urcu_unlock();
 }
 
-void urcu_unregister_thread(void)
+void rcu_unregister_thread(void)
 {
        internal_urcu_lock();
-       urcu_remove_reader(pthread_self());
+       rcu_remove_reader(pthread_self());
        internal_urcu_unlock();
 }
 
 #ifndef DEBUG_FULL_MB
-void sigurcu_handler(int signo, siginfo_t *siginfo, void *context)
+static void sigurcu_handler(int signo, siginfo_t *siginfo, void *context)
 {
        /*
         * Executing this smp_mb() is the only purpose of this signal handler.
@@ -360,4 +413,4 @@ void __attribute__((destructor)) urcu_exit(void)
        assert(act.sa_sigaction == sigurcu_handler);
        free(registry);
 }
-#endif
+#endif /* #ifndef DEBUG_FULL_MB */