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From d133282ff639fd022fe64172f89b203cf8669114 Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Fri, 7 Feb 2014 16:00:09 +0100
Subject: [PATCH 37/37] block: Don't call ROUND_UP with negative values

Message-id: <1392117622-28812-37-git-send-email-kwolf@redhat.com>
Patchwork-id: 57201
O-Subject: [RHEL-7.0 qemu-kvm PATCH v2 37/37] block: Don't call ROUND_UP with negative values
Bugzilla: 748906
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Max Reitz <mreitz@redhat.com>

The behaviour of the ROUND_UP macro with negative numbers isn't obvious.
It happens to do the right thing in this please, but better avoid it.

Suggested-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
 block.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/block.c b/block.c
index b878c8b..1b57236 100644
--- a/block.c
+++ b/block.c
@@ -2760,8 +2760,8 @@ static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs,
         }
 
         total_sectors = DIV_ROUND_UP(len, BDRV_SECTOR_SIZE);
-        max_nb_sectors = MAX(0, ROUND_UP(total_sectors - sector_num,
-                                         align >> BDRV_SECTOR_BITS));
+        max_nb_sectors = ROUND_UP(MAX(0, total_sectors - sector_num),
+                                  align >> BDRV_SECTOR_BITS);
         if (max_nb_sectors > 0) {
             ret = drv->bdrv_co_readv(bs, sector_num,
                                      MIN(nb_sectors, max_nb_sectors), qiov);
-- 
1.7.1