test-qht: perform lookups under rcu_read_lock

qht_lookup is meant to be called from an RCU read-critical
section. Make sure we're in such a section in test-qht
when performing lookups, despite the fact that no races
in qht can be triggered by test-qht since it is single-threaded.

Note that rcu_register_thread is already called by the
rcu_after_fork hook, and therefore duplicating it here would
be a bug.

Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <1475706880-10667-4-git-send-email-cota@braap.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/tests/test-qht.c b/tests/test-qht.c
index 46a64b6..9b7423a 100644
--- a/tests/test-qht.c
+++ b/tests/test-qht.c
@@ -6,6 +6,7 @@
  */
 #include "qemu/osdep.h"
 #include "qemu/qht.h"
+#include "qemu/rcu.h"
 
 #define N 5000
 
@@ -51,6 +52,7 @@ static void check(int a, int b, bool expected)
     struct qht_stats stats;
     int i;
 
+    rcu_read_lock();
     for (i = a; i < b; i++) {
         void *p;
         uint32_t hash;
@@ -61,6 +63,8 @@ static void check(int a, int b, bool expected)
         p = qht_lookup(&ht, is_equal, &val, hash);
         g_assert_true(!!p == expected);
     }
+    rcu_read_unlock();
+
     qht_statistics_init(&ht, &stats);
     if (stats.used_head_buckets) {
         g_assert_cmpfloat(qdist_avg(&stats.chain), >=, 1.0);