[PATCH v7 2/5] migration: use bitmap_mutex in migration_bitmap_clear_dirty

The bitmap mutex is used to synchronize threads to update the dirty
bitmap and the migration_dirty_pages counter. This patch makes
migration_bitmap_clear_dirty update the bitmap and counter under the
mutex.

Signed-off-by: Wei Wang <>
CC: Dr. David Alan Gilbert <>
CC: Juan Quintela <>
CC: Michael S. Tsirkin <>
---
 migration/ram.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/migration/ram.c b/migration/ram.c
index 0e90efa..9a72b1a 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -795,11 +795,14 @@ static inline bool migration_bitmap_clear_dirty(RAMState *rs,
 {
     bool ret;
 
+    qemu_mutex_lock(&rs->bitmap_mutex);
     ret = test_and_clear_bit(page, rb->bmap);
 
     if (ret) {
         rs->migration_dirty_pages--;
     }
+    qemu_mutex_unlock(&rs->bitmap_mutex);
+
     return ret;
 }
 
-- 
1.8.3.1