URCU : use pthread_equal()
[urcu.git] / urcu.c
diff --git a/urcu.c b/urcu.c
index c55a5a2be9395ad691876e8e1b58d787729207d4..e401d8dc75d34bf04d2e62da56df3cc08f0d470d 100644 (file)
--- a/urcu.c
+++ b/urcu.c
@@ -1,3 +1,13 @@
+/*
+ * urcu.c
+ *
+ * Userspace RCU library
+ *
+ * Copyright February 2009 - Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
+ *
+ * Distributed under GPLv2
+ */
+
 #include <stdio.h>
 #include <pthread.h>
 #include <signal.h>
@@ -26,6 +36,27 @@ static struct reader_data *reader_data;
 static int num_readers, alloc_readers;
 static int sig_done;
 
+void rcu_write_lock(void)
+{
+       int ret;
+       ret = pthread_mutex_lock(&urcu_mutex);
+       if (ret) {
+               perror("Error in pthread mutex lock");
+               exit(-1);
+       }
+}
+
+void rcu_write_unlock(void)
+{
+       int ret;
+
+       ret = pthread_mutex_unlock(&urcu_mutex);
+       if (ret) {
+               perror("Error in pthread mutex unlock");
+               exit(-1);
+       }
+}
+
 /*
  * called with urcu_mutex held.
  */
@@ -70,7 +101,7 @@ void wait_for_quiescent_state(int parity)
                /*
                 * BUSY-LOOP.
                 */
-               while (*index->urcu_active_readers != 0)
+               while (index->urcu_active_readers[parity] != 0)
                        barrier();
        }
        /*
@@ -84,18 +115,13 @@ void wait_for_quiescent_state(int parity)
 
 /*
  * Return old pointer, OK to free, no more reference exist.
+ * Called under rcu_write_lock.
  */
 void *urcu_publish_content(void **ptr, void *new)
 {
-       int ret, prev_parity;
+       int prev_parity;
        void *oldptr;
 
-       ret = pthread_mutex_lock(&urcu_mutex);
-       if (ret) {
-               perror("Error in pthread mutex lock");
-               exit(-1);
-       }
-
        /*
         * We can publish the new pointer before we change the current qparity.
         * Readers seeing the new pointer while being in the previous qparity
@@ -108,8 +134,8 @@ void *urcu_publish_content(void **ptr, void *new)
         */
        oldptr = *ptr;
        *ptr = new;
-       wmb();          /* Write ptr before changing the qparity */
        /* All threads should read qparity before ptr */
+       /* Write ptr before changing the qparity */
        force_mb_all_threads();
        prev_parity = switch_next_urcu_qparity();
 
@@ -121,11 +147,6 @@ void *urcu_publish_content(void **ptr, void *new)
         * Deleting old data is ok !
         */
        
-       ret = pthread_mutex_unlock(&urcu_mutex);
-       if (ret) {
-               perror("Error in pthread mutex lock");
-               exit(-1);
-       }
        return oldptr;
 }
 
@@ -164,7 +185,7 @@ void urcu_remove_reader(pthread_t id)
 
        assert(reader_data != NULL);
        for (index = reader_data; index < reader_data + num_readers; index++) {
-               if (index->tid == id) {
+               if (pthread_equal(index->tid, id)) {
                        memcpy(index, &reader_data[num_readers - 1],
                                sizeof(struct reader_data));
                        reader_data[num_readers - 1].tid = 0;
@@ -179,44 +200,16 @@ void urcu_remove_reader(pthread_t id)
 
 void urcu_register_thread(void)
 {
-       pthread_t self = pthread_self();
-       int ret;
-
-       ret = pthread_mutex_lock(&urcu_mutex);
-       if (ret) {
-               perror("Error in pthread mutex lock");
-               exit(-1);
-       }
-
-       urcu_add_reader(self);
-
-
-       ret = pthread_mutex_unlock(&urcu_mutex);
-       if (ret) {
-               perror("Error in pthread mutex unlock");
-               exit(-1);
-       }
+       rcu_write_lock();
+       urcu_add_reader(pthread_self());
+       rcu_write_unlock();
 }
 
 void urcu_unregister_thread(void)
 {
-       pthread_t self = pthread_self();
-       int ret;
-
-       ret = pthread_mutex_lock(&urcu_mutex);
-       if (ret) {
-               perror("Error in pthread mutex lock");
-               exit(-1);
-       }
-
-       urcu_remove_reader(self);
-
-       ret = pthread_mutex_unlock(&urcu_mutex);
-       if (ret) {
-               perror("Error in pthread mutex unlock");
-               exit(-1);
-       }
-
+       rcu_write_lock();
+       urcu_remove_reader(pthread_self());
+       rcu_write_unlock();
 }
 
 void sigurcu_handler(int signo, siginfo_t *siginfo, void *context)
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