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[Qemu-devel] [PATCH 6/5] block: Fix harmless off-by-one in bdrv_aligned_
From: |
Eric Blake |
Subject: |
[Qemu-devel] [PATCH 6/5] block: Fix harmless off-by-one in bdrv_aligned_preadv() |
Date: |
Fri, 3 Jun 2016 17:06:53 -0600 |
If the amount of data to read ends exactly on the total size
of the bs, then we were wasting time creating a local qiov
to read the data in preparation for what would normally be
appending zeroes beyond the end, even though this corner case
has nothing further to do.
Signed-off-by: Eric Blake <address@hidden>
---
block/io.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block/io.c b/block/io.c
index aaeedaa..c8b323e 100644
--- a/block/io.c
+++ b/block/io.c
@@ -996,7 +996,7 @@ static int coroutine_fn
bdrv_aligned_preadv(BlockDriverState *bs,
max_nb_sectors = ROUND_UP(MAX(0, total_sectors - sector_num),
align >> BDRV_SECTOR_BITS);
- if (nb_sectors < max_nb_sectors) {
+ if (nb_sectors <= max_nb_sectors) {
ret = bdrv_driver_preadv(bs, offset, bytes, qiov, flags);
} else if (max_nb_sectors > 0) {
QEMUIOVector local_qiov;
--
2.5.5