diff options
Diffstat (limited to 'util/rcu.c')
| -rw-r--r-- | util/rcu.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/util/rcu.c b/util/rcu.c index f4d09c8304..5676c22bd1 100644 --- a/util/rcu.c +++ b/util/rcu.c @@ -92,10 +92,11 @@ static void wait_for_readers(void) atomic_set(&index->waiting, true); } - /* Here, order the stores to index->waiting before the - * loads of index->ctr. + /* Here, order the stores to index->waiting before the loads of + * index->ctr. Pairs with smp_mb_placeholder() in rcu_read_unlock(), + * ensuring that the loads of index->ctr are sequentially consistent. */ - smp_mb(); + smp_mb_global(); QLIST_FOREACH_SAFE(index, ®istry, node, tmp) { if (!rcu_gp_ongoing(&index->ctr)) { @@ -142,8 +143,13 @@ static void wait_for_readers(void) void synchronize_rcu(void) { qemu_mutex_lock(&rcu_sync_lock); - qemu_mutex_lock(&rcu_registry_lock); + /* Write RCU-protected pointers before reading p_rcu_reader->ctr. + * Pairs with smp_mb_placeholder() in rcu_read_lock(). + */ + smp_mb_global(); + + qemu_mutex_lock(&rcu_registry_lock); if (!QLIST_EMPTY(®istry)) { /* In either case, the atomic_mb_set below blocks stores that free * old RCU-protected pointers. @@ -370,6 +376,7 @@ static void rcu_init_child(void) static void __attribute__((__constructor__)) rcu_init(void) { + smp_mb_global_init(); #ifdef CONFIG_POSIX pthread_atfork(rcu_init_lock, rcu_init_unlock, rcu_init_child); #endif |