rculfhash: check for callers from RCU read-side C.S.

This is an error.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/src/common/hashtable/rculfhash.c b/src/common/hashtable/rculfhash.c
index 06fec785e8ba0e23eee72907e8fb7cce1d2473a1..b430a3dec76e681ebf561f33bb9fcc767c713037 100644 (file)
--- a/src/common/hashtable/rculfhash.c
+++ b/src/common/hashtable/rculfhash.c
@@ -1733,10 +1733,25 @@ int cds_lfht_delete_bucket(struct cds_lfht *ht)
 int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr)
 {
        int ret;
+#ifdef rcu_read_ongoing_mb
+       int was_online;
+#endif
 
        /* Wait for in-flight resize operations to complete */
        _CMM_STORE_SHARED(ht->in_progress_destroy, 1);
        cmm_smp_mb();   /* Store destroy before load resize */
+#ifdef rcu_read_ongoing_mb
+       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;
+       }
+#endif
        while (uatomic_read(&ht->in_progress_resize))
                poll(NULL, 0, 100);     /* wait for 100ms */
        ret = cds_lfht_delete_bucket(ht);
@@ -1746,6 +1761,9 @@ int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr)
        if (attr)
                *attr = ht->resize_attr;
        poison_free(ht);
+#ifdef rcu_read_ongoing_mb
+end:
+#endif
        return ret;
 }
 
@@ -1874,13 +1892,34 @@ void resize_target_update_count(struct cds_lfht *ht,
 
 void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size)
 {
+#ifdef rcu_read_ongoing_mb
+       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;
+       }
+#endif
        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();
+#ifdef rcu_read_ongoing_mb
+end:
+       if (was_online)
+               ht->flavor->thread_online();
+#endif
 }
 
 static