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[Qemu-devel] [PATCH v3 15/15] qcow2: small optimization


From: Frediano Ziglio
Subject: [Qemu-devel] [PATCH v3 15/15] qcow2: small optimization
Date: Tue, 23 Aug 2011 15:21:22 +0200

Signed-off-by: Frediano Ziglio <address@hidden>
---
 block/qcow2-refcount.c |   11 +++++------
 1 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index 0f9a64a..243c24b 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -681,14 +681,13 @@ void qcow2_create_refcount_update(QCowCreateState *s, 
int64_t offset,
     int64_t size)
 {
     int refcount;
-    int64_t start, last, cluster_offset;
+    int64_t start, last, cluster;
     uint16_t *p;
 
-    start = offset & ~(s->cluster_size - 1);
-    last = (offset + size - 1)  & ~(s->cluster_size - 1);
-    for(cluster_offset = start; cluster_offset <= last;
-        cluster_offset += s->cluster_size) {
-        p = &s->refcount_block[cluster_offset >> s->cluster_bits];
+    start = offset >> s->cluster_bits;
+    last = (offset + size - 1)  >> s->cluster_bits;
+    for(cluster = start; cluster <= last; ++cluster) {
+        p = &s->refcount_block[cluster];
         refcount = be16_to_cpu(*p);
         refcount++;
         *p = cpu_to_be16(refcount);
-- 
1.7.1




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