[Qemu-devel] [PATCH v10 05/13] hbitmap: Add hbitmap_copy

[John Snow <jsnow@redhat.com>]

From: Fam Zheng <famz@redhat.com>

This makes a deep copy of an HBitmap.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
---
 include/qemu/hbitmap.h |  8 ++++++++
 util/hbitmap.c         | 20 ++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/include/qemu/hbitmap.h b/include/qemu/hbitmap.h
index 550d7ce..b645cfc 100644
--- a/include/qemu/hbitmap.h
+++ b/include/qemu/hbitmap.h
@@ -65,6 +65,14 @@ struct HBitmapIter {
 HBitmap *hbitmap_alloc(uint64_t size, int granularity);
 
 /**
+ * hbitmap_copy:
+ * @bitmap: The original bitmap to copy.
+ *
+ * Copy a HBitmap.
+ */
+HBitmap *hbitmap_copy(const HBitmap *bitmap);
+
+/**
  * hbitmap_empty:
  * @hb: HBitmap to operate on.
  *
diff --git a/util/hbitmap.c b/util/hbitmap.c
index ab13971..033ad58 100644
--- a/util/hbitmap.c
+++ b/util/hbitmap.c
@@ -90,6 +90,10 @@ struct HBitmap {
      * bitmap will still allocate HBITMAP_LEVELS arrays.
      */
     unsigned long *levels[HBITMAP_LEVELS];
+
+    /* NB: If additional objects that require a deep copy are added to
+     * this structure, the hbitmap_copy function should be updated accordingly.
+     */
 };
 
 /* Advance hbi to the next nonzero word and return it.  hbi->pos
@@ -395,3 +399,19 @@ HBitmap *hbitmap_alloc(uint64_t size, int granularity)
     hb->levels[0][0] |= 1UL << (BITS_PER_LONG - 1);
     return hb;
 }
+
+HBitmap *hbitmap_copy(const HBitmap *bitmap)
+{
+    int i;
+    uint64_t size;
+    HBitmap *hb = g_memdup(bitmap, sizeof(HBitmap));
+
+    size = bitmap->size;
+    for (i = HBITMAP_LEVELS - 1; i >= 0; i--) {
+        size = MAX((size + BITS_PER_LONG - 1) >> BITS_PER_LEVEL, 1);
+        hb->levels[i] = g_memdup(bitmap->levels[i],
+                                 size * sizeof(unsigned long));
+    }
+
+    return hb;
+}
-- 
1.9.3