Create default call rcu data upon per-cpu call-rcu teardown

[urcu.git] / urcu-call-rcu-impl.h

diff --git a/urcu-call-rcu-impl.h b/urcu-call-rcu-impl.h
index 700d1289192a31a5f2693cf79e4efd99be993220..3e947af2fd84bfd6c6843788d9f31a5ff720b876 100644 (file)
--- a/urcu-call-rcu-impl.h
+++ b/urcu-call-rcu-impl.h
@@ -386,6 +386,7 @@ int set_cpu_call_rcu_data(int cpu, struct call_rcu_data *crdp)
        static int warned = 0;
 
        call_rcu_lock(&call_rcu_mutex);
+       alloc_cpu_call_rcu_data();
        if (cpu < 0 || maxcpus <= cpu) {
                if (!warned) {
                        fprintf(stderr, "[error] liburcu: set CPU # out of range\n");
@@ -395,13 +396,21 @@ int set_cpu_call_rcu_data(int cpu, struct call_rcu_data *crdp)
                errno = EINVAL;
                return -EINVAL;
        }
-       alloc_cpu_call_rcu_data();
-       call_rcu_unlock(&call_rcu_mutex);
+
        if (per_cpu_call_rcu_data == NULL) {
+               call_rcu_unlock(&call_rcu_mutex);
                errno = ENOMEM;
                return -ENOMEM;
        }
+
+       if (per_cpu_call_rcu_data[cpu] != NULL && crdp != NULL) {
+               call_rcu_unlock(&call_rcu_mutex);
+               errno = EEXIST;
+               return -EEXIST;
+       }
+
        per_cpu_call_rcu_data[cpu] = crdp;
+       call_rcu_unlock(&call_rcu_mutex);
        return 0;
 }
 
@@ -435,22 +444,17 @@ struct call_rcu_data *get_default_call_rcu_data(void)
  */
 struct call_rcu_data *get_call_rcu_data(void)
 {
-       int curcpu;
-       static int warned = 0;
+       struct call_rcu_data *crd;
 
        if (thread_call_rcu_data != NULL)
                return thread_call_rcu_data;
-       if (maxcpus <= 0)
-               return get_default_call_rcu_data();
-       curcpu = sched_getcpu();
-       if (!warned && (curcpu < 0 || maxcpus <= curcpu)) {
-               fprintf(stderr, "[error] liburcu: gcrd CPU # out of range\n");
-               warned = 1;
+
+       if (maxcpus > 0) {
+               crd = get_cpu_call_rcu_data(sched_getcpu());
+               if (crd)
+                       return crd;
        }
-       if (curcpu >= 0 && maxcpus > curcpu &&
-           per_cpu_call_rcu_data != NULL &&
-           per_cpu_call_rcu_data[curcpu] != NULL)
-               return per_cpu_call_rcu_data[curcpu];
+
        return get_default_call_rcu_data();
 }
 
@@ -518,8 +522,13 @@ int create_all_cpu_call_rcu_data(unsigned long flags)
                }
                call_rcu_unlock(&call_rcu_mutex);
                if ((ret = set_cpu_call_rcu_data(i, crdp)) != 0) {
-                       /* FIXME: Leaks crdp for now. */
-                       return ret; /* Can happen on race. */
+                       call_rcu_data_free(crdp);
+
+                       /* it has been created by other thread */
+                       if (ret == -EEXIST)
+                               continue;
+
+                       return ret;
                }
        }
        return 0;
@@ -600,14 +609,18 @@ void call_rcu_data_free(struct call_rcu_data *crdp)
                _CMM_STORE_SHARED(crdp->cbs.head, NULL);
                cbs_tail = (struct cds_wfq_node **)
                        uatomic_xchg(&crdp->cbs.tail, &crdp->cbs.head);
+               /* Create default call rcu data if need be */
+               (void) get_default_call_rcu_data();
                cbs_endprev = (struct cds_wfq_node **)
                        uatomic_xchg(&default_call_rcu_data, cbs_tail);
                *cbs_endprev = cbs;
                uatomic_add(&default_call_rcu_data->qlen,
                            uatomic_read(&crdp->qlen));
-               cds_list_del(&crdp->list);
-               free(crdp);
+               wake_call_rcu_thread(default_call_rcu_data);
        }
+
+       cds_list_del(&crdp->list);
+       free(crdp);
 }
 
 /*
@@ -656,7 +669,7 @@ void call_rcu_after_fork_parent(void)
  */
 void call_rcu_after_fork_child(void)
 {
-       struct call_rcu_data *crdp;
+       struct call_rcu_data *crdp, *next;
 
        /* Release the mutex. */
        call_rcu_unlock(&call_rcu_mutex);
@@ -669,12 +682,9 @@ void call_rcu_after_fork_child(void)
        (void)get_default_call_rcu_data();
 
        /* Dispose of all of the rest of the call_rcu_data structures. */
-       while (call_rcu_data_list.next != call_rcu_data_list.prev) {
-               crdp = cds_list_entry(call_rcu_data_list.prev,
-                                     struct call_rcu_data, list);
+       cds_list_for_each_entry_safe(crdp, next, &call_rcu_data_list, list) {
                if (crdp == default_call_rcu_data)
-                       crdp = cds_list_entry(crdp->list.prev,
-                                             struct call_rcu_data, list);
+                       continue;
                uatomic_set(&crdp->flags, URCU_CALL_RCU_STOPPED);
                call_rcu_data_free(crdp);
        }