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Re: [Qemu-stable] [PATCH] bitmap: Update count after a merge
From: |
Vladimir Sementsov-Ogievskiy |
Subject: |
Re: [Qemu-stable] [PATCH] bitmap: Update count after a merge |
Date: |
Thu, 27 Sep 2018 11:07:09 +0300 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 |
27.09.2018 06:11, Eric Blake wrote:
We need an accurate count of the number of bits set in a bitmap
after a merge. In particular, since the merge operation short-circuits
a merge from an empty source, if you have bitmaps A, B, and C where
B started empty, then merge C into B, and B into A, an inaccurate
count meant that A did not get the contents of C.
Fixes: be58721db
CC: address@hidden
Signed-off-by: Eric Blake <address@hidden>
Reviewed-by: Vladimir Sementsov-Ogievskiy <address@hidden>
---
Probably worth some testsuite coverage, but for a late-night one-liner,
this is as much as I can do today.
util/hbitmap.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/util/hbitmap.c b/util/hbitmap.c
index bcd304041aa..52e12da4b48 100644
--- a/util/hbitmap.c
+++ b/util/hbitmap.c
@@ -753,3 +753,4 @@ bool hbitmap_merge(HBitmap *a, const HBitmap *b)
a->levels[i][j] |= b->levels[i][j];
}
}
+ a->count = hb_count_between(a, 0, a->size - 1);
return true;
}
--
Best regards,
Vladimir