[Qemu-devel] [PATCH 1/5] block/vpc: optimize vpc_co_get_block_status

[Peter Lieven <pl@kamp.de>]

*pnum can't be greater than s->block_size / BDRV_SECTOR_SIZE for allocated
sectors since there is always a bitmap in between.

Signed-off-by: Peter Lieven <pl@kamp.de>
---
 block/vpc.c |   15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/block/vpc.c b/block/vpc.c
index 1533b6a..326c2bb 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -602,7 +602,7 @@ static int64_t coroutine_fn vpc_co_get_block_status(BlockDriverState *bs,
 {
     BDRVVPCState *s = bs->opaque;
     VHDFooter *footer = (VHDFooter*) s->footer_buf;
-    int64_t start, offset, next;
+    int64_t start, offset;
     bool allocated;
     int n;
 
@@ -626,20 +626,17 @@ static int64_t coroutine_fn vpc_co_get_block_status(BlockDriverState *bs,
         *pnum += n;
         sector_num += n;
         nb_sectors -= n;
-        next = start + (*pnum * BDRV_SECTOR_SIZE);
 
+        if (allocated) {
+            return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | start;
+        }
         if (nb_sectors == 0) {
             break;
         }
-
         offset = get_sector_offset(bs, sector_num, 0);
-    } while ((allocated && offset == next) || (!allocated && offset == -1));
+    } while (offset == -1);
 
-    if (allocated) {
-        return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | start;
-    } else {
-        return 0;
-    }
+    return 0;
 }
 
 /*
-- 
1.7.9.5