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[Qemu-block] [PATCH v2 03/17] block: Fix harmless off-by-one in bdrv_ali
From: |
Eric Blake |
Subject: |
[Qemu-block] [PATCH v2 03/17] block: Fix harmless off-by-one in bdrv_aligned_preadv() |
Date: |
Tue, 14 Jun 2016 15:30:25 -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>
Reviewed-by: Kevin Wolf <address@hidden>
---
v2: no change, add R-b
---
block/io.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block/io.c b/block/io.c
index 9191772..383154f 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1024,7 +1024,7 @@ 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;
--
2.5.5
- [Qemu-block] [PATCH v2 02/17] block: Document supported flags during bdrv_aligned_preadv(), (continued)
- [Qemu-block] [PATCH v2 02/17] block: Document supported flags during bdrv_aligned_preadv(), Eric Blake, 2016/06/14
- [Qemu-block] [PATCH v2 01/17] block: Tighter assertions on bdrv_aligned_pwritev(), Eric Blake, 2016/06/14
- [Qemu-block] [PATCH v2 04/17] nbd: Allow larger requests, Eric Blake, 2016/06/14
- [Qemu-block] [PATCH v2 03/17] block: Fix harmless off-by-one in bdrv_aligned_preadv(),
Eric Blake <=
- [Qemu-block] [PATCH v2 05/17] nbd: Advertise realistic limits to block layer, Eric Blake, 2016/06/14
- [Qemu-block] [PATCH v2 11/17] raw-win32: Set request_alignment during .bdrv_refresh_limits(), Eric Blake, 2016/06/14
- [Qemu-block] [PATCH v2 12/17] block: Set request_alignment during .bdrv_refresh_limits(), Eric Blake, 2016/06/14