doc/examples: lfstack

[urcu.git] / rculfhash.c

diff --git a/rculfhash.c b/rculfhash.c
index 7050d5c47b224c9d91b21610478a3a903aa74789..423609d6c188dd79f6392763ad7b8082f2180def 100644 (file)
--- a/rculfhash.c
+++ b/rculfhash.c
@@ -129,7 +129,7 @@
  *  - cds_lfht_first followed iteration with cds_lfht_next (and/or
  *    cds_lfht_next_duplicate, although less common).
  *
- * We define "write" operations as any of cds_lfht_add,
+ * We define "write" operations as any of cds_lfht_add, cds_lfht_replace,
  * cds_lfht_add_unique (success), cds_lfht_add_replace, cds_lfht_del.
  *
  * When cds_lfht_add_unique succeeds (returns the node passed as
@@ -281,7 +281,7 @@
  * Split-counters lazily update the global counter each 1024
  * addition/removal. It automatically keeps track of resize required.
  * We use the bucket length as indicator for need to expand for small
- * tables and machines lacking per-cpu data suppport.
+ * tables and machines lacking per-cpu data support.
  */
 #define COUNT_COMMIT_ORDER             10
 #define DEFAULT_SPLIT_COUNT_MASK       0xFUL
@@ -833,13 +833,16 @@ void _cds_lfht_gc_bucket(struct cds_lfht_node *bucket, struct cds_lfht_node *nod
 
        assert(!is_bucket(bucket));
        assert(!is_removed(bucket));
+       assert(!is_removal_owner(bucket));
        assert(!is_bucket(node));
        assert(!is_removed(node));
+       assert(!is_removal_owner(node));
        for (;;) {
                iter_prev = bucket;
                /* We can always skip the bucket node initially */
                iter = rcu_dereference(iter_prev->next);
                assert(!is_removed(iter));
+               assert(!is_removal_owner(iter));
                assert(iter_prev->reverse_hash <= node->reverse_hash);
                /*
                 * We should never be called with bucket (start of chain)
@@ -860,6 +863,7 @@ void _cds_lfht_gc_bucket(struct cds_lfht_node *bucket, struct cds_lfht_node *nod
                        iter = next;
                }
                assert(!is_removed(iter));
+               assert(!is_removal_owner(iter));
                if (is_bucket(iter))
                        new_next = flag_bucket(clear_flag(next));
                else
@@ -880,8 +884,10 @@ int _cds_lfht_replace(struct cds_lfht *ht, unsigned long size,
                return -ENOENT;
 
        assert(!is_removed(old_node));
+       assert(!is_removal_owner(old_node));
        assert(!is_bucket(old_node));
        assert(!is_removed(new_node));
+       assert(!is_removal_owner(new_node));
        assert(!is_bucket(new_node));
        assert(new_node != old_node);
        for (;;) {
@@ -956,6 +962,7 @@ void _cds_lfht_add(struct cds_lfht *ht,
 
        assert(!is_bucket(node));
        assert(!is_removed(node));
+       assert(!is_removal_owner(node));
        bucket = lookup_bucket(ht, size, hash);
        for (;;) {
                uint32_t chain_len = 0;
@@ -1016,7 +1023,9 @@ void _cds_lfht_add(struct cds_lfht *ht,
        insert:
                assert(node != clear_flag(iter));
                assert(!is_removed(iter_prev));
+               assert(!is_removal_owner(iter_prev));
                assert(!is_removed(iter));
+               assert(!is_removal_owner(iter));
                assert(iter_prev != node);
                if (!bucket_flag)
                        node->next = clear_flag(iter);
@@ -1036,6 +1045,7 @@ void _cds_lfht_add(struct cds_lfht *ht,
 
        gc_node:
                assert(!is_removed(iter));
+               assert(!is_removal_owner(iter));
                if (is_bucket(iter))
                        new_next = flag_bucket(clear_flag(next));
                else
@@ -1700,6 +1710,7 @@ int cds_lfht_delete_bucket(struct cds_lfht *ht)
                if (!is_bucket(node))
                        return -EPERM;
                assert(!is_removed(node));
+               assert(!is_removal_owner(node));
        } while (!is_end(node));
        /*
         * size accessed without rcu_dereference because hash table is
@@ -1726,15 +1737,25 @@ int cds_lfht_delete_bucket(struct cds_lfht *ht)
  */
 int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr)
 {
-       int ret;
+       int ret, was_online;
 
        /* Wait for in-flight resize operations to complete */
        _CMM_STORE_SHARED(ht->in_progress_destroy, 1);
        cmm_smp_mb();   /* Store destroy before load resize */
-       ht->flavor->thread_offline();
+       was_online = ht->flavor->read_ongoing();
+       if (was_online)
+               ht->flavor->thread_offline();
+       /* Calling with RCU read-side held is an error. */
+       if (ht->flavor->read_ongoing()) {
+               ret = -EINVAL;
+               if (was_online)
+                       ht->flavor->thread_online();
+               goto end;
+       }
        while (uatomic_read(&ht->in_progress_resize))
                poll(NULL, 0, 100);     /* wait for 100ms */
-       ht->flavor->thread_online();
+       if (was_online)
+               ht->flavor->thread_online();
        ret = cds_lfht_delete_bucket(ht);
        if (ret)
                return ret;
@@ -1742,6 +1763,7 @@ int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr)
        if (attr)
                *attr = ht->resize_attr;
        poison_free(ht);
+end:
        return ret;
 }
 
@@ -1870,13 +1892,30 @@ void resize_target_update_count(struct cds_lfht *ht,
 
 void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size)
 {
+       int was_online;
+
+       was_online = ht->flavor->read_ongoing();
+       if (was_online)
+               ht->flavor->thread_offline();
+       /* Calling with RCU read-side held is an error. */
+       if (ht->flavor->read_ongoing()) {
+               static int print_once;
+
+               if (!CMM_LOAD_SHARED(print_once))
+                       fprintf(stderr, "[error] rculfhash: cds_lfht_resize "
+                               "called with RCU read-side lock held.\n");
+               CMM_STORE_SHARED(print_once, 1);
+               assert(0);
+               goto end;
+       }
        resize_target_update_count(ht, new_size);
        CMM_STORE_SHARED(ht->resize_initiated, 1);
-       ht->flavor->thread_offline();
        pthread_mutex_lock(&ht->resize_mutex);
        _do_cds_lfht_resize(ht);
        pthread_mutex_unlock(&ht->resize_mutex);
-       ht->flavor->thread_online();
+end:
+       if (was_online)
+               ht->flavor->thread_online();
 }
 
 static