diff mbox

[v9,04/10] hbitmap: Add hbitmap_copy

Message ID 1417465816-19345-5-git-send-email-jsnow@redhat.com
State New
Headers show

Commit Message

John Snow Dec. 1, 2014, 8:30 p.m. UTC 
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>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 include/qemu/hbitmap.h |  8 ++++++++
 util/hbitmap.c         | 16 ++++++++++++++++
 2 files changed, 24 insertions(+)

Comments

Stefan Hajnoczi Dec. 9, 2014, 5:19 p.m. UTC | #1 
On Mon, Dec 01, 2014 at 03:30:10PM -0500, John Snow wrote:
> +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;
> +}

It would be handy to put a comment in struct HBitmap warning people that
hbitmap_copy() must be kept in sync when new pointer fields are added.
diff mbox

Patch

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 b3060e6..8aa7406 100644
--- a/util/hbitmap.c
+++ b/util/hbitmap.c
@@ -395,3 +395,19 @@  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;
+}