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From: Paolo Bonzini <pbonzini@redhat.com>
To: qemu-devel@nongnu.org
Cc: famz@redhat.com, stefanha@redhat.com
Subject: [Qemu-devel] [PATCH] block: get_block_status: use "else" when testing the opposite condition
Date: Thu, 14 May 2015 12:35:02 +0200	[thread overview]
Message-ID: <1431599702-10431-1-git-send-email-pbonzini@redhat.com> (raw)

A bit of Boolean algebra (and common sense) tells us that the
second "if" here is looking for blocks that are not allocated.
This is the opposite of the "if" that sets BDRV_BLOCK_ALLOCATED,
and thus it can use an "else".

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 block/io.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/block/io.c b/block/io.c
index 1ce62c4..494e3b3 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1456,9 +1456,7 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,
 
     if (ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ZERO)) {
         ret |= BDRV_BLOCK_ALLOCATED;
-    }
-
-    if (!(ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO)) {
+    } else {
         if (bdrv_unallocated_blocks_are_zero(bs)) {
             ret |= BDRV_BLOCK_ZERO;
         } else if (bs->backing_hd) {
-- 
2.4.0

             reply	other threads:[~2015-05-14 10:35 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-14 10:35 Paolo Bonzini [this message]
2015-05-14 14:07 ` [Qemu-devel] [PATCH] block: get_block_status: use "else" when testing the opposite condition Eric Blake
2015-05-14 14:09 ` Fam Zheng
2015-05-19 10:49 ` Stefan Hajnoczi

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