vhdx: DIV_ROUND_UP() in vhdx_calc_bat_entries()

We have DIV_ROUND_UP(), so we can use it to produce more easily readable
code. It may be slower than the bit shifting currently performed
(because it actually performs a division), but since
vhdx_calc_bat_entries() is never used in a hot path, this is completely
fine.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 1450451066-13335-2-git-send-email-mreitz@redhat.com
Signed-off-by: Jeff Cody <jcody@redhat.com>

diff --git a/block/vhdx.c b/block/vhdx.c
index 72042e9..1e7e03e 100644 (file)
--- a/block/vhdx.c
+++ b/block/vhdx.c
@@ -857,14 +857,8 @@ static void vhdx_calc_bat_entries(BDRVVHDXState *s)
 {
     uint32_t data_blocks_cnt, bitmap_blocks_cnt;
 
-    data_blocks_cnt = s->virtual_disk_size >> s->block_size_bits;
-    if (s->virtual_disk_size - (data_blocks_cnt << s->block_size_bits)) {
-        data_blocks_cnt++;
-    }
-    bitmap_blocks_cnt = data_blocks_cnt >> s->chunk_ratio_bits;
-    if (data_blocks_cnt - (bitmap_blocks_cnt << s->chunk_ratio_bits)) {
-        bitmap_blocks_cnt++;
-    }
+    data_blocks_cnt = DIV_ROUND_UP(s->virtual_disk_size, s->block_size);
+    bitmap_blocks_cnt = DIV_ROUND_UP(data_blocks_cnt, s->chunk_ratio);
 
     if (s->parent_entries) {
         s->bat_entries = bitmap_blocks_cnt * (s->chunk_ratio + 1);