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[v4,qemu,4/6] bitmap: Add a new bitmap_move function

Message ID 1484124524-481-5-git-send-email-liang.z.li@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Liang Li Jan. 11, 2017, 8:48 a.m. UTC 
Sometimes, it is need to move a portion of bitmap to another place
in a large bitmap, if overlap happens, the bitmap_copy can't not
work correctly, we need a new function to do this work.

Signed-off-by: Liang Li <liang.z.li@intel.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
 include/qemu/bitmap.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)
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Patch

diff --git a/include/qemu/bitmap.h b/include/qemu/bitmap.h
index 63ea2d0..775d05e 100644
--- a/include/qemu/bitmap.h
+++ b/include/qemu/bitmap.h
@@ -37,6 +37,7 @@ 
  * bitmap_set(dst, pos, nbits)			Set specified bit area
  * bitmap_set_atomic(dst, pos, nbits)   Set specified bit area with atomic ops
  * bitmap_clear(dst, pos, nbits)		Clear specified bit area
+ * bitmap_move(dst, src, nbits)                 Move *src to *dst
  * bitmap_test_and_clear_atomic(dst, pos, nbits)    Test and clear area
  * bitmap_find_next_zero_area(buf, len, pos, n, mask)	Find bit free area
  */
@@ -129,6 +130,18 @@  static inline void bitmap_copy(unsigned long *dst, const unsigned long *src,
     }
 }
 
+static inline void bitmap_move(unsigned long *dst, const unsigned long *src,
+                               long nbits)
+{
+    if (small_nbits(nbits)) {
+        unsigned long tmp = *src;
+        *dst = tmp;
+    } else {
+        long len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
+        memmove(dst, src, len);
+    }
+}
+
 static inline int bitmap_and(unsigned long *dst, const unsigned long *src1,
                              const unsigned long *src2, long nbits)
 {