2 files changed, 22 insertions, 19 deletions

diff --git a/util/aio-wait.c b/util/aio-wait.c
index bdb3d3af22..98c5accd29 100644
--- a/util/aio-wait.c
+++ b/util/aio-wait.c
@@ -35,7 +35,21 @@ static void dummy_bh_cb(void *opaque)
 
 void aio_wait_kick(void)
 {
-    /* The barrier (or an atomic op) is in the caller.  */
+    /*
+     * Paired with smp_mb in AIO_WAIT_WHILE. Here we have:
+     * write(condition);
+     * aio_wait_kick() {
+     *      smp_mb();
+     *      read(num_waiters);
+     * }
+     *
+     * And in AIO_WAIT_WHILE:
+     * write(num_waiters);
+     * smp_mb();
+     * read(condition);
+     */
+    smp_mb();
+
     if (qatomic_read(&global_aio_wait.num_waiters)) {
         aio_bh_schedule_oneshot(qemu_get_aio_context(), dummy_bh_cb, NULL);
     }
diff --git a/util/hbitmap.c b/util/hbitmap.c
index ea989e1f0e..297db35fb1 100644
--- a/util/hbitmap.c
+++ b/util/hbitmap.c
@@ -873,11 +873,6 @@ void hbitmap_truncate(HBitmap *hb, uint64_t size)
     }
 }
 
-bool hbitmap_can_merge(const HBitmap *a, const HBitmap *b)
-{
-    return (a->orig_size == b->orig_size);
-}
-
 /**
  * hbitmap_sparse_merge: performs dst = dst | src
  * works with differing granularities.
@@ -901,28 +896,24 @@ static void hbitmap_sparse_merge(HBitmap *dst, const HBitmap *src)
  * Given HBitmaps A and B, let R := A (BITOR) B.
  * Bitmaps A and B will not be modified,
  *     except when bitmap R is an alias of A or B.
- *
- * @return true if the merge was successful,
- *         false if it was not attempted.
+ * Bitmaps must have same size.
  */
-bool hbitmap_merge(const HBitmap *a, const HBitmap *b, HBitmap *result)
+void hbitmap_merge(const HBitmap *a, const HBitmap *b, HBitmap *result)
 {
     int i;
     uint64_t j;
 
-    if (!hbitmap_can_merge(a, b) || !hbitmap_can_merge(a, result)) {
-        return false;
-    }
-    assert(hbitmap_can_merge(b, result));
+    assert(a->orig_size == result->orig_size);
+    assert(b->orig_size == result->orig_size);
 
     if ((!hbitmap_count(a) && result == b) ||
         (!hbitmap_count(b) && result == a)) {
-        return true;
+        return;
     }
 
     if (!hbitmap_count(a) && !hbitmap_count(b)) {
         hbitmap_reset_all(result);
-        return true;
+        return;
     }
 
     if (a->granularity != b->granularity) {
@@ -935,7 +926,7 @@ bool hbitmap_merge(const HBitmap *a, const HBitmap *b, HBitmap *result)
         if (b != result) {
             hbitmap_sparse_merge(result, b);
         }
-        return true;
+        return;
     }
 
     /* This merge is O(size), as BITS_PER_LONG and HBITMAP_LEVELS are constant.
@@ -951,8 +942,6 @@ bool hbitmap_merge(const HBitmap *a, const HBitmap *b, HBitmap *result)
 
     /* Recompute the dirty count */
     result->count = hb_count_between(result, 0, result->size - 1);
-
-    return true;
 }
 
 char *hbitmap_sha256(const HBitmap *bitmap, Error **errp)