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[Qemu-block] [PULL 04/43] block: Fix harmless off-by-one in bdrv_aligned
From: |
Kevin Wolf |
Subject: |
[Qemu-block] [PULL 04/43] block: Fix harmless off-by-one in bdrv_aligned_preadv() |
Date: |
Tue, 5 Jul 2016 17:50:13 +0200 |
From: Eric Blake <address@hidden>
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>
Reviewed-by: Kevin Wolf <address@hidden>
Reviewed-by: Fam Zheng <address@hidden>
Reviewed-by: Stefan Hajnoczi <address@hidden>
Signed-off-by: Kevin Wolf <address@hidden>
---
block/io.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block/io.c b/block/io.c
index 994d3fa..82c9ff0 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1036,7 +1036,7 @@ static int coroutine_fn
bdrv_aligned_preadv(BlockDriverState *bs,
}
max_bytes = ROUND_UP(MAX(0, total_bytes - offset), align);
- if (bytes < max_bytes) {
+ if (bytes <= max_bytes) {
ret = bdrv_driver_preadv(bs, offset, bytes, qiov, 0);
} else if (max_bytes > 0) {
QEMUIOVector local_qiov;
--
1.8.3.1
- [Qemu-block] [PULL 00/43] Block layer patches, Kevin Wolf, 2016/07/05
- [Qemu-block] [PULL 01/43] qemu-img: fix failed autotests, Kevin Wolf, 2016/07/05
- [Qemu-block] [PULL 03/43] block: Document supported flags during bdrv_aligned_preadv(), Kevin Wolf, 2016/07/05
- [Qemu-block] [PULL 04/43] block: Fix harmless off-by-one in bdrv_aligned_preadv(),
Kevin Wolf <=
- [Qemu-block] [PULL 05/43] nbd: Allow larger requests, Kevin Wolf, 2016/07/05
- [Qemu-block] [PULL 07/43] iscsi: Advertise realistic limits to block layer, Kevin Wolf, 2016/07/05
- [Qemu-block] [PULL 02/43] block: Tighter assertions on bdrv_aligned_pwritev(), Kevin Wolf, 2016/07/05
- [Qemu-block] [PULL 08/43] scsi: Advertise limits by blocksize, not 512, Kevin Wolf, 2016/07/05
- [Qemu-block] [PULL 06/43] nbd: Advertise realistic limits to block layer, Kevin Wolf, 2016/07/05
- [Qemu-block] [PULL 09/43] block: Give nonzero result to blk_get_max_transfer_length(), Kevin Wolf, 2016/07/05
- [Qemu-block] [PULL 11/43] iscsi: Set request_alignment during .bdrv_refresh_limits(), Kevin Wolf, 2016/07/05
- [Qemu-block] [PULL 10/43] blkdebug: Set request_alignment during .bdrv_refresh_limits(), Kevin Wolf, 2016/07/05
- [Qemu-block] [PULL 12/43] qcow2: Set request_alignment during .bdrv_refresh_limits(), Kevin Wolf, 2016/07/05
- [Qemu-block] [PULL 13/43] raw-win32: Set request_alignment during .bdrv_refresh_limits(), Kevin Wolf, 2016/07/05