From 93df28be2d4f620caf18109222d046355ac56327 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Marek=20Marczykowski-G=C3=B3recki?=
 <marmarek@invisiblethingslab.com>
Date: Mon, 13 May 2019 10:12:00 +0200
Subject: [PATCH] bitmap: fix bitmap_fill with zero-sized bitmap
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When bitmap_fill(..., 0) is called, do not try to write anything. Before
this patch, it tried to write almost LONG_MAX, surely overwriting
something.

Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
---
 xen/include/xen/bitmap.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/xen/include/xen/bitmap.h b/xen/include/xen/bitmap.h
index fe3c720e82..0430c1ce2a 100644
--- a/xen/include/xen/bitmap.h
+++ b/xen/include/xen/bitmap.h
@@ -126,6 +126,8 @@ static inline void bitmap_fill(unsigned long *dst, int nbits)
 	size_t nlongs = BITS_TO_LONGS(nbits);
 
 	switch (nlongs) {
+	case 0:
+		break;
 	default:
 		memset(dst, -1, (nlongs - 1) * sizeof(unsigned long));
 		/* fall through */
-- 
2.30.2